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Background: Nigella sativa L., Anongessius latifolia (Roxb. ex DC.) Wall. ex Euill. and Perr. and shilajit have been used traditionally to treat numerous infectious diseases, including many caused by bacterial pathogens. However, extracts of these traditionally medicines have been poorly studied and are yet to be tested for the ability to inhibit the growth of bacterial triggers of multiple sclerosis and rheumatic fever. Materials and Methods: Antimicrobial activity of selected plant extracts was assessed using disc diffusion and liquid dilution minimum inhibitory concentration (MIC) assays against some bacterial triggers of multiple sclerosis and rheumatic fever. Interactions between the extracts and conventional antibiotics were studied and classified using the sum of the fractional inhibitory concentration (SFIC). The toxicity of the individual samples and the combinations was assessed using the artemia lethality assay (ALA) assay. Results: The methanolic A. latifolia extract displayed notable antibacterial activity against the bacterial triggers of multiple sclerosis (A. baylyi and P. aeruginosa), and rheumatic fever (S. pyogenes). Furthermore, combining the methanolic A. latifolia extract with tetracycline and chloramphenicol resulted in potentiation of the inhibitory activity against P. aeruginosa and S. pyogenes. None of the individual components (nor the combinations) were toxic in the ALA assay. Conclusion: The A. latifolia methanolic displayed clinically relevant antibacterial activity against A. baylyi, P. aeruginosa and S. pyogenes when tested alone. Furthermore, that extract also potentiated the activity of tetracycline and chloramphenicol against some bacteria. The lack of toxicity of the extracts and combinations indicates that these combinations may provide leads in the development of new therapies to prevent and treat the autoimmune diseases multiple sclerosis and rheumatic fever. [ABSTRACT FROM AUTHOR]

Background: Nigella damascena L. (ND) seeds have been incorporated into traditional plant-based medicinal systems for millennia. However, there are conflicting reports on the antibacterial activities of the seed extracts, although phytochemicals known to possess antibacterial activity have been found in the seeds of this species. The toxicities of the extracts have not been studied previously. Aim: This work assesses the ability for aqueous and methanolic ND seed extracts to inhibit the growth of a panel of skin pathogens on agar and in broth, including methicillin-resistant Staphylococcus aureus (MRSA). Qualitative determinations of the phytochemical constituents of the extracts were performed, as well as their toxicity levels. Materials and Methods: Bacterial growth inhibition was evaluated using agar disc diffusion and liquid broth microdilution assays, whilst Artemia nauplii bioassays were used to screen toxicities. Qualitative phytochemical assays were conducted to assess the relative abundance of several important phytochemical compound classes. Results: No inhibition was observed on agar for either the aqueous or methanolic extracts against S. aureus, MRSA, S. epidermidis or S. pyogenes. This was concordant with the liquid microdilution broth assays, with the exception of the methanolic ND extract against S. pyogenes, which produced a minimum inhibitory concentration value of 481 µg/mL. Phenols, saponins, tannins and alkaloid were present in both extract types, while flavonoids could be detected in the methanolic extract only. Both extracts were deemed to be nontoxic in the Artemia nauplii assay. Conclusion: The ND methanolic extract possessed activity against S. pyogenes in liquid broth, but not on agar. The presence of flavonoids in this extract may be responsible for this activity. The extracts were inactive against S. aureus, MRSA and S. epidermidis in agar and broth assays, and were also nontoxic as adjudged by the Artemia nauplii brine shrimp assays. [ABSTRACT FROM AUTHOR]

Background: The increased prevalence of antibiotic-resistant bacterial pathogens has substantially decreased the efficacy of some antibiotics and has rendered others completely ineffective. Widespread bacterial resistance to ß-lactam antibiotics (including resistance to the second-generation drug methicillin) is particularly concerning and new antibiotic therapies are urgently needed. Materials and Methods: The antibacterial activity of commercially sourced water-soluble Eucalyptus major and Melaleuca alternifolia leaf solutions was screened against ß-lactam resistant and sensitive bacterial strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus using disc diffusion assays. The activity was quantified by broth microdilution minimum inhibitory concentration (MIC) assays. Toxicity was evaluated by testing Artemia nauplii mortality assays. Results: Methanolic and aqueous extracts prepared from Eucalyptus major and Melaleuca alternifolia leaves displayed noteworthy growth inhibitory activity against all of the bacteria tested, including against methicillin resistant Staphylococcus aureus MRSA and extended spectrum ß-lactamase (ESBL) strains of E. coli and K. pneumoniae. The methanolic E. major leaf extract had particularly good antibacterial activity (MICs=39-625 µg/mL) against all bacterial strains. Notably, this extract had similar potency against an ESBL strain of E. coli as against the corresponding antibiotic-sensitive strain (MICs=78 µg/mL against each) and was significantly more potent against an ESBL K. pneumoniae strain (MIC=39 µg/mL) than against the corresponding antibiotic sensitive strain (MIC=78 µg/mL). All extracts were non-toxic in the Artemia nauplii lethality assay (ALA), indicating their safety for topical use. Conclusion: The potency of the E. major and M. alternifolia extracts against multi-antibiotic resistant bacteria and their lack of toxicity highlight these species as potential targets for antibiotic drug development. Further phytochemical and mechanistic studies of these species are warranted. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant-based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Materials and Methods: The antibacterial activity of Taraxacum officinale (L.) Weber ex F.H. Wigg. root extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays against some bacterial triggers of autoimmune inflammatory diseases. The extracts were also combined with a range of conventional antibiotics and tested against various bacterial pathogens. The SFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic and ethyl acetate T. officinale root extracts showed good inhibitory activity against several microbial triggers of autoimmune inflammatory diseases, including P. mirabilis, P. vulgaris and A. baylyi. Of further interest, some combinations of the T. officinale root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components alone. Six synergistic and seven additive interactions were noted. Additionally, two antagonistic interactions were evident, indicating that those combinations should be avoided. All extracts were nontoxic in the ALA and HDF assays, verifying their safety for therapeutic usage. Conclusion: Taraxacum officinale root extracts have potential as inhibitors of bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, extract components may also potentiate the activity of three antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several bacteria, including the microbial triggers of rheumatoid arthritis and multiple sclerosis. [ABSTRACT FROM AUTHOR]

Introduction: Nanotechnology is promising for the development of new effective medicines. Silver nanoparticle preparations have been particularly well studied and a range of beneficial effects have been identified. Despite this, the sale of Colloidal silver (CS) preparations for therapeutic purposes has been banned by multiple regulatory authorities (including the FDA and TGA) on the basis of their perceived toxicity. This study evaluates the toxicity of electrolytically produced (CS) preparation, as well as some compounds used to produce CS by chemical synthesis. Materials and Methods: Toxicity of the CS preparation and the chemical toxins were evaluated using the Artemia nauplii toxicity assay. Additionally, the CS was tested for its protective effects against citrate and tannic acid-induced toxicity by screening combinations of CS and the toxins. Results: The CS preparation was nontoxic in the Artemia nauplii bioassay at all concentrations tested and did not induce mortality substantially above the seawater control at all concentrations ≤50 μg/mL. In contrast, citrate and tannic acid were strongly toxic, with LC50 values of 11.6 and 26.8 μg/mL respectively. Interestingly, co-incubation of varying concentrations of the CS preparation with 30 μg/mL of citrate resulted in protection against toxicity, with 50 μg/mL CS inhibiting ~65% of citrate-induced toxicity. In contrast, the CS preparation had no apparent effects on tannic acid-induced toxicity. Conclusion: The CS preparation tested in our study was nontoxic at all concentrations tested. Furthermore, the CS mitigated the toxic effects of citrate, but had no apparent effect on tannic acid-induced toxicity. Further studies are required to verify these findings in other toxicity models and to study the protective molecular mechanisms. [ABSTRACT FROM AUTHOR]

Background: Terminalia ferdinandiana Exell. is an endemic Australian plant with a high anti-oxidant capacity. Liquid solvent extractions of T. ferdinandiana leaves are strong inhibitors of the growth of numerous bacterial pathogens. Despite these promising therapeutic properties, methods for the rapid extraction of large quantities of T. ferdinandiana leaves are lacking. This study aimed to develop a rapid supercritical extraction method to produce extracts which retain therapeutic properties and phytochemistry characteristics. Materials and Methods: Terminalia ferdinandiana leaves were extracted by both solvent maceration extraction and Supercritical fluid extraction (SCE). The extracts were tested for the ability to inhibit bacterial growth using the disc diffusion assay. The antibacterial potency was further quantified using liquid dilution MIC assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay and GC-MS headspace analysis was used to evaluate phytochemical similarity between the extracts. Results: Terminalia ferdinandiana leaf SCE displayed strong bacterial growth inhibitory activity against bacterial triggers of autoimmune inflammatory diseases, with efficacies similar to the smaller laboratory scale methanolic liquid extractions. The growth inhibition of the ethyl acetate and methanolic solvent extracts and the SCE were particularly noteworthy against P. mirabilis (MICs = 128, 227 and 208μg/mL respectively) and A. baylyi (MICs = 452, 780 and 104 μg/mL respectively). GC-MS analysis of the berry SCE revealed similar terpenoid components and similar abundances to those in methanolic solvent leaf extraction. Furthermore, all liquid extracts and the SCE were non-toxic in the Artemia franciscana toxicity assay. Conclusion: The T. ferdinandiana SCE retained the tested therapeutic properties, was non-toxic and had similar phytochemical profiles as the smaller scale liquid solvent extractions. Thus, SCE is a viable method of rapidly extracting large masses of T. ferdinandiana leaves to produce quality extracts that retain therapeutic properties. [ABSTRACT FROM AUTHOR]

Introduction: Podocarpus latifolius (Thunb.) R.Br. ex Mirb. is a large tree that is native to southern Africa. This species has been used extensively for multiple therapeutic purposes across the southern part of the African continent. Despite this, P. latifolius leaf extracts have not been rigorously examined growth inhibitory properties against many bacteria, including the bacterial triggers of autoimmune inflammatory diseases. Materials and Methods: The antimicrobial activity of P. latifolia leaf solvent extractions was investigated by disc diffusion and growth time course assays against some bacterial triggers of rheumatoid arthritis and ankylosing spondylitis. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic and aqueous P. latifolia leaf extracts were good inhibitors of P. mirabilis and K. pneumoniae. The inhibitory activity of both extracts was particularly noteworthy against the bacterial trigger of ankylosing spondylitis (K. pneumonia), with MICs of 343 and 557 µg/mL determined for the methanolic and aqueous extracts respectively. The extracts also displayed noteworthy activity against a bacterial trigger of rheumatoid arthritis (P. mirabilis), with MICs of 580 and 634 µg/mL respectively. The antibacterial activity of the methanolic and aqueous P. latifolia leaf extracts were further investigated by growth time course assays, which showed significant growth inhibition in cultures of P. mirabilis and K. pneumoniae within 1 hr of exposure. The extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for prophylactic use in preventing these autoimmune inflammatory diseases. Conclusion: The lack of toxicity of the P. latifolia leaf extracts and their growth inhibitory bioactivity against the bacterial triggers of rheumatoid arthritis and ankylosing spondylitis indicate their potential in the development of new therapies targeting the onset of these diseases. [ABSTRACT FROM AUTHOR]

Background: Terminalia ferdinandiana Exell. fruit have been used by the First Australians as a nutritious food and as a medicine for thousands of years. The antibacterial properties of T. ferdinandiana fruit extracts are well reported. However, the therapeutic potential of plants growing in different locations and environmental conditions have not previously been compared. Aim: This study compares the antibacterial efficacy of fruit harvested from two distinct locations in Australia and correlates these activities with their physiochemical properties. Materials and Methods: The growth inhibitory activity of the T. ferdinandiana fruit extracts were evaluated using solid phase disc diffusion and liquid microdilution MIC assays. Artemia nauplii bioassays were used to screen and compare the extracts from both locations. Results: The T. ferdinandiana extracts prepared from fruits sourced from the two distinct regions of Australia inhibited the growth of the panel of bacteria screened, including a highly antibiotic MRSA strain. In general, the methanolic extracts were substantially better inhibitors of bacterial growth than the aqueous extracts, and extracts prepared using the Northern Territory (NT)-derived fruit were substantially more potent than the Western Australian (WA) fruit extracts. MICs substantially <1000 μg/mL were noted for the NT methanolic fruit extract against the reference S. aureus and MRSA bacterial strains respectively. The potency of this extract against the MRSA strain indicates that this extract may function via a distinct mechanism compared to the standard antibiotics tested. Interestingly, the greater antibacterial potency of the NT fruit extracts correlated to high ascorbic acid levels, indicating that the antibacterial mechanism may involve modulation of the redox state. All extracts were nontoxic in the Artemia nauplii toxicity assay, indicating their safety for therapeutic usage. Conclusion: The T. ferdinandiana fruit extracts prepared from both NT and WA each had noteworthy antibacterial activity, although greater activity was noted for the NT fruit extracts. This activity correlated with the antioxidant/ascorbic acid content of the extracts. All extracts were also nontoxic in the Artemia nauplii bioassay, although future studies using mammalian cell lines are required to confirm their safety for therapeutic use. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant-based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Materials and Methods: The antibacterial activity of Taraxacum officinale (L.) Weber ex F.H. Wigg root extracts was investigated by disc diffusion assays and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against gastrointestinal disease-causing bacteria. The ΣFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic, aqueous and ethyl acetate T. officinale root extracts showed good inhibitory activity against several gastrointestinal bacterial pathogens. The methanolic were particularly good inhibitors of S. sonneii and S. newport, with MIC values in the range 400-450 μg/mL, whilst the ethyl acetate extract was the most potent inhibitor of S. newport growth (MIC=128 μg/mL). Of further interest, some combinations of the T. officinale root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components. Five synergistic and two additive interactions were noted. Interestingly, only a single antagonistic interaction was evident, indicating that nearly all combinations could be used without decreasing the antibacterial activity of the components. All extracts were nontoxic in the ALA and HDF assays. Conclusion: Taraxacum officinale root extracts have potential as inhibitors of bacterial gastrointestinal pathogens. Furthermore, extract components may also potentiate the activity of some antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several gastrointestinal bacterial pathogens. [ABSTRACT FROM AUTHOR]

The genus Terminalia contains some of the most widely used plants in traditional medicine. Many species possess antifungal, antibacterial, antiviral, antiprotozoal, analgesic, antidiarrheal, antioxidant, antimalarial, anticancer, and anti-inflammatory properties. Some species also have cardiovascular and wound-healing effects. Despite their myriad of traditional uses, relatively few studies have examined the medicinal properties and phytochemistry of most Australian Terminalia spp. The high tannin content of Terminalia spp. has been postulated to be a major contributor to the medicinal properties of this important genus. However, the complexities of tannins are generally believed to make them a poor choice for drug design. Therefore, much of the interest in Terminalia species has been for their nutraceutical and pharmacognostic value, and they remain under-explored in terms of drug discovery. Recent studies have identified many other important phytochemicals within Terminalia species apart from the tannins and have established that these compounds may contribute to their therapeutic bioactivities. Several Australian Terminalia species (particularly Terminalia carpentariae C.T. White, Terminalia catappa L., Terminalia ferdinandiana Exell and Terminalia grandiflora Benth) have received the most attention due to their reported high antioxidant contents. In contrast, other Australian Terminalia spp. have been relatively ignored. This review discusses recent studies into the phytochemistry, medicinal properties and the underlying therapeutic mechanisms of Australian Terminalia species to help direct future areas of research into this important genus. [ABSTRACT FROM AUTHOR]

The escalating global crisis of bacterial resistance to antibiotics poses a threat to public health. Urgent measures are required to identify novel antibacterial treatments. Multidrug-resistant bacterial strains limit the effective therapeutic options available, raising concerns about a post-antibiotic era and a reduced ability to treat infections that were previously not classified as serious. Simultaneously, the threat of emerging infectious diseases, including zoonotic pathogens, underscores the need to develop effective antibiotics against these pathogens. Innovative approaches to antibiotic development, such as novel chemical scaffolds, combination therapies, antimicrobial peptides, and phage therapy, show promise but require the discovery of new antibacterial compounds. Desert and rainforest ecosystems, despite being disparate in climate and biodiversity, offer unique prospects for developing antibacterial compounds. Deserts, which are characterized by extreme aridity and temperature fluctuations, harbor plants and micro-organisms with specialized antibacterial defences honed through evolution. Conversely, rainforests, with their biodiversity and high humidity, are promising for the development of potential antibacterial compounds. To date, much natural product research aimed at discovery of new antibiotic compounds has focussed on rainforest plants due to the biodiversity of these ecosystems, and because plants develop chemical defences against microbes that are prevalent in those environments. In comparison, the search for new antimicrobial compounds from desert plants has been overshadowed, despite some noteworthy antibacterial activities in arid environment plants. This commentary discusses the comparative potential of desert and rainforest ecosystems as reservoirs of novel antibacterial agents and emphasises the importance of screening plants in both environments. [ABSTRACT FROM AUTHOR]

Background: Rubus idaeus L. leaves have been used in traditional healing systems for the treatment of morning sickness, easing labour pains and for preventing miscarriage. Whilst few studies have examined the leaves of this species for therapeutic properties, the fruit have antibacterial activity against multiple bacterial pathogens. This study examines the growth inhibitory effects of R. idaeus leaf extracts, both alone and in combination with conventional antibiotics against bacterial triggers of selected autoimmune inflammatory diseases. Results: Rubus idaeus leaf extracts displayed noteworthy antibacterial activity against several bacterial triggers of autoimmune diseases. The methanolic, aqueous and ethyl acetate extracts were particularly good inhibitors of P. mirabilis, A. baylyi and P. aeruginosa growth, with MIC values as low as 53 µg/mL. Combining the extracts with conventional antibiotics potentiated the inhibitory activity for several combinations containing chloramphenicol or gentamicin against A. baylyi. Interestingly, the other combinations were generally non-interactive and no antagonistic interactions were detected, indicating that all combinations can be used without decreasing the efficacy of the therapy. None of the individual components (or the combinations) were toxic in the ALA assay. Conclusion: Rubus idaeus leaf extracts have potential for the prevention and treatment of rheumatoid arthritis and multiple sclerosis when used alone. Furthermore, some combinations of the extracts and conventional antibiotics had greater potency against the bacterial triggers of multiple sclerosis, indicating they may be beneficial for prophylactic therapy in individuals genetically predisposed to that disease [ABSTRACT FROM AUTHOR]

According to the World Health Organisation (WHO), diarrhoea is the second leading cause of death in children under the age of five. It is a common symptom associated with gastrointestinal bacterial infections. Many antibiotics have lost their efficacy due to the rapid emergence of Antimicrobial Resistant (AMR) bacterial pathogens. Traditional Ayurvedic medicinal plants are likely to play a significant role in the development of new effective and safe therapies in the fight against AMR in gastrointestinal bacteria. Recent research has reported the effectiveness of numerous different Ayurvedic medicines in the treatment of gastrointestinal infections. One example is Triphala, which is a polyherbal formulation consisting of an equal mixture of dried fruit powders from the three Ayurvedic plants Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz. and Emblica officinalis Linn. This review discusses the principles of Ayurveda and summarises the traditional use of Ayurvedic plants in the treatment of diarrhoea, dysentery, and stomach discomfort. [ABSTRACT FROM AUTHOR]

Introduction: The recent development of extensively antibiotic resistant bacteria has necessitated the search for novel anti-bacterial compounds. An examination of aromatic plants and traditional medicines is an attractive option for drug discovery. Phragmites australis (Cav.) Trin. Ex Steud. Reed is native to many regions globally, including Australia. It has yet to be tested for antibacterial activity. Materials and Methods: The ability of P. australis leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: P. australis leaf methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were nontoxic in the Artemia nauplii bioassay following 24 hr exposure. Conclusion: P. australis leaf extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Materials and Methods: The antibacterial activity of Arctium lappa L. root extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The ΣFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic and ethyl acetate A. lappa root extracts showed good inhibitory activity against several gastrointestinal bacterial pathogens. They were particularly good inhibitors of S. sonneii and B. cereus, with MIC values in the range 150-250μg/mL. The aqueous extract was also a noteworthy inhibitor of B. cereus growth. Of further interest, some combinations of the A. lappa root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components. Four synergistic and five additive interactions were noted. Notably, no antagonistic interactions were evident, indicating that all combinations could be used without decreasing the antibacterial activity of the components. All extracts were non-toxic in the ALA and HDF assays. Conclusion: Arctium lappa root extracts have potential as inhibitors of bacterial gastrointestinal pathogens. Furthermore, extract components may also potentiate the activity of some antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several gastrointestinal bacterial pathogens. [ABSTRACT FROM AUTHOR]

Background: Tasmannia lanceolata berries and leaves have high antioxidant capacities and high levels of therapeutic phytochemicals. Despite this, the anticancer activity of T. lanceolata extracts has not been adequately explored. Materials and Methods: This study examined the anti-proliferative of T. lanceolata berry and leaf extracts against a panel of human carcinoma cell lines using MTS assays. The apoptotic activities were examined using cell imaging and caspase-3 activity assays. LC-MS and GC-MS headspace analysis were used to identify noteworthy phytochemical components. Results: The methanolic, aqueous and ethyl acetate extracts inhibited the proliferation of HeLa, Caco-2, Jeg-3, JAR, MC3T3-E1 and MG63 cell lines. The aqueous leaf extract was a particularly potent inhibitor of proliferation against most cell lines (HeLa IC50 = 230µg/mL; Caco-2 IC50 = 150µg/mL; Jeg-3 IC50 = 488µg/mL; JAR IC50 = 450µg/mL; MC3T3 IC50 = 195µg/mL; MG63 IC50 = 315µg/mL). The berry and leaf ethyl acetate extracts were also good inhibitors of proliferation of the same cell lines, albeit with slightly higher IC50 values. Morphological features consistent with apoptosis were evident in Caco-2 cells exposed to the berry and leaf ethyl acetate extracts, and the aqueous leaf extract. Furthermore, exposure of Caco-2 to sub-lethal concentrations of these extracts induced significantly elevated levels of caspase 3, indicating that the extracts induced apoptosis in Caco-2 cells. Conclusion: All T. lanceolata berry and leaf extracts induced apoptosis in a panel of cancer cells and were nontoxic in the ALA toxicity bioassay and in a HDF cell viability assay, supporting their potential as cancer chemotherapies. [ABSTRACT FROM AUTHOR]

Background: Plants of the genus Acaciahave been used by Australian Aborigines to treat a variety of conditions including bacterial pathogens and inflammation. Despite this, many Acacia spp. have not been evaluated for the ability to inhibit the growth of bacterial triggers of autoimmune inflammatory diseases. This study evaluated the effects of Acacia disparrima and Acacia leiocalyx leaf extracts alone and in combination against some bacterial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. Results: Acacia disparrima and Acacia leiocalyx leaf extracts displayed noteworthy antibacterial activity against several bacterial triggers of autoimmune diseases. The methanolic extracts were particularly good inhibitors of P. mirabilis, K. pneumoniae, and A. baylyi with MIC values <1000µg/mL, but were ineffective against P. aeruginosa. Furthermore, combining the extracts with conventional antibiotics resulted in significant potentiation of the inhibitory activity for some combinations. Interestingly, all of the synergistic interactions contained tetracycline as the antibiotic component, whilst all of the antagonistic combinations contained either gentamicin or ciprofloxacin as the antibiotic component. None of the individual components (nor the combinations) were toxic in the ALA assay. Conclusion: The majority of combinational effects were either additive or indifferent, thereby alleviating some concern related to the concurrent use of A. disparrima and A. leiocalyx whilst also taking conventional antibiotics. A few notable combinations were identified, indicating the need for further in vivo testing. [ABSTRACT FROM AUTHOR]

Background: Recent declines in new antibiotic discovery and the increase in antibiotic resistance have resulted in failing against bacterial pathogens. To develop novel antibiotic therapies, medical researchers have begun to focus on traditional therapies. Combinational therapies consisting of medicinal plants and conventional antibiotics may reactivate current drugs that are otherwise ineffective against antibioticresistant bacteria. Terminalia sericea Burch. Ex DC, Terminalia prunioides Laws. and Terminalia gazensis Bak. f. are native South African plants with antimicrobial properties. However, combinations of Terminalia sericea, Terminalia prunioides and Terminalia gazensis with conventional antibiotics are yet to be evaluated for growth inhibitory activity against gastrointestinal pathogens. Methods: Terminalia spp. leaves were extracted with solvents of varying polarity. Antimicrobial screening was performed using disc diffusion and broth microdilution assays. Toxicity was measured using Artemia franciscana nauplii lethality assays. Results: All extracts (except the T. sericea extracts) showed low to moderate inhibitory activity against B. cereus and E. faecalis, A. faecalis, A. hydrophilia, S. sonnei and S. newport in both the disc diffusion and liquid dilution assay. Twenty-three extract/antibiotic combinations produced synergy, 26 were additive, 24 were non-interactive and seven were antagonistic. Most of the antagonist interactions occurred in combinations containing gentamicin. All extracts were either non-toxic or of low toxicity in the Artemia bioassay. Conclusion: Terminalia spp. extracts may mimic the actions of a resistance modifying agents, enhancing the activity of several antibiotics that are relatively ineffective alone. Further studies are required to identify the bioactive and potentiating components and their mechanisms of action. [ABSTRACT FROM AUTHOR]

Introduction: Many high antioxidant fruit extracts can inhibit the growth of multiple bacterial pathogens. They may also inhibit the growth of malodour producing bacteria and thus be useful deodorant components, although this is yet to be tested for many Australian native fruits. Materials and Methods: Methanolic and aqueous K. pomifera and P. elatus fruit extracts were investigated by disc diffusion and liquid dilution MIC assays against the most significant bacterial contributors to axillary and plantar malodour. Toxicity was determined using Artemia franciscana nauplii bioassays and unbiased HPLC-MS QTOF analysis was used to identify interesting consituents of the most active extract. Results: Methanolic and aqueous K. pomifera and P. elatus fruit extracts displayed noteworthy bacterial growth inhibitory activity against all of the malodour forming bacteria tested. The methanolic K. pomifera extract had particularly good antibacterial effects, strongly inhibiting the growth of all bacteria, with MIC values substantially less than 1000 µg/mL. Indeed, liquid dilution (LD) MIC values of 610, 894, 663 and 625 µg/mL were recorded against C. jeikeium, P. acnes, B. linens and S. epidermidis respectively. Similar, albeit slightly higher LD MIC values were noted for the aqueous K. pomifera fruit extract, and for the methanolic and aqueous P. elatus fruit extracts against these bacteria. All K. pomifera and P. elatus fruit extracts were non-toxic in the Artemia fransiscana bioassay. Several interesting phytochemicals, including several tannins, were identified in the methanolic K. pomifera fruit extract. Conclusion: The lack of toxicity of the methanolic and aqueous K. pomifera and P. elatus fruit extracts and their noteworthy growth inhibition of axillary and plantar malodour producing bacteria indicate their potential as deodorant components. Further studies are warranted to isolate and identify the active components and to determine the antibacterial mechanism. [ABSTRACT FROM AUTHOR]

Introduction: Acne vulgaris is a skin conditions that affects most adolescents and may also afflict adults. Medicinal plant extracts may provide leads for the development of new topical and/or oral therapies for acnes vulgaris, yet many traditional medicine plants are yet to be screened for growth inhibitory activity against Cutibacterium acnes (the major bacterial cause of acne). Materials and Methods: Methanolic and aqueous Scaevola spinescens R.Br. leaf extracts were investigated by disc diffusion and liquid dilution MIC assays against Cutibacterium acnes (a significant bacterial cause of acne). Toxicity was determined using Artemia franciscana nauplii bioassays. Results: Methanolic and aqueous S. spinescens leaf extracts displayed noteworthy bacterial growth inhibitory activity against C. acnes growth. The aqueous S. spinescens leaf extract had particularly good antibacterial effects against C. acnes, with an LD MIC value of 344 μg/mL. Similar, albeit slightly higher LD MIC values were noted for the aqueous methanolic S. spinescens leaf extract against C. acnes (LD MIC = 875 μg/mL). The methanolic and aqueous S. spinescens leaf extracts were nontoxic in the Artemia fransiscana bioassay, with LC50 values substantially >1000 μg/mL. Conclusion: The lack of toxicity of the methanolic and aqueous S. spinescens leaf extracts and their noteworthy growth inhibition of C. acnes indicate their potential as treatments to alleviate acne vulgaris. Further studies are warranted to isolate and identify the active components and to determine their antibacterial mechanism. [ABSTRACT FROM AUTHOR]

Introduction: The recent development of extensively antibiotic resistant bacteria has necessitated the search for novel antibacterial therapies. An examination of aromatic plants and traditional medicines is an attractive option for drug discovery. Terminalia sericea Burch. ex DC. is a southern African native species, which has been reported to have antibacterial activity, although the effects of storage on the activity is yet to be determined. Materials and Methods: The ability of T. sericea leaf extracts to inhibit the growth of a panel of bacterial triggers of autoimmune diseases was quantified by disc diffusion and liquid dilution MIC assays. The potency of extracts prepared using fresh and stored leaves was compared. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: The T. sericea leaf methanolic and aqueous extracts displayed noteworthy growth inhibitory activity towards all bacterial pathogens tested. However, a substantial decrease in activity was seen when extracts were prepared using leaves that had been stored for two years, indicating that the leaves become less useful therapeutically over time. All extracts were non-toxic in the Artemia nauplii bioassay following 24hr exposure. Conclusion: The T. sericea leaf extracts had noteworthy antibacterial activity, although the potency decreased substantially following storage of the leaf material. [ABSTRACT FROM AUTHOR]

Background: Antibiotic drugs have been widely applied in the treatment of bacterial infections. However, with the overuse and unreasonable adoption of antibiotics, a variety of bacteria have developed resistance to commonly used antibiotics. Bacterial pathogens with multi-drug resistance mechanisms have made many infectious diseases more difficult to be treat and new therapies are urgently needed. Methods: An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify TCMs used to treat bacterial infections and the individual components of those medicines this information was used to identify gaps in the current research that require further study. Results: Traditional Chinese medicine contain multiple components and function via multiple pathways against multiple targets. Many of these pathways and concepts may be difficult for non-Chinese due to their complexities. However, an evaluation of TCMs for antibacterial activities is an attractive option for antibiotic discovery and development as they generally have low toxicity, low side effects and as combinational therapies, there is no inherent drug resistances in human bacterial pathogens towards these drugs. This study reviews the current status of bacterial resistance, the mechanism of traditional Chinese medicine against bacterial infections, and the adoption progress of Chinese herbal medicines in the treatment of resistant bacterial infections. Conclusion: TCM can inhibit the growth of bacterial pathogens and can participate in mediating the immune function of multiple bodily aspects. Therefore, Chinese herbal medicine may provide new leads to treat drug-resistant bacterial infections. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Methods: The antibacterial activity of Arctium lappa L. root extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The ΣFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic and ethyl acetate A. lappa root extracts showed good inhibitory activity against several microbial triggers of autoimmune inflammatory diseases, including P. mirabilis, P. vulgaris and A. baylyi. The aqueous extract was also a noteworthy inhibitor of A. baylyi growth. Of further interest, some combinations of the A. lappa root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components alone. One synergistic and six additive interactions were noted. Notably, no antagonistic interactions were evident, indicating that all combinations could be used without decreasing the antibacterial activity of the components. All extracts were nontoxic in the ALA and HDF assays. Conclusion: Arctium lappa L. root extracts have potential as inhibitors of bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, extract components may also potentiate the activity of three antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several bacteria, including the microbial triggers of rheumatoid arthritis and multiple sclerosis. [ABSTRACT FROM AUTHOR]

Introduction: Terminalia arjuna (Roxb.) Wight and Arn. is a southern Asian plant commonly used in Ayurveda to treat multiple conditions, including for the treatment of inflammation, and as a general antimicrobial agent. Despite this, few studies have tested this species for the ability to block the growth of bacterial triggers of some autoimmune inflammatory diseases. Furthermore, the ability of T. arjuna to potentiate the activity of conventional antibiotics is yet to be investigated. Materials and Methods: The minimum inhibitory concentration of the extracts and extract-antibiotic combinations was determined by disc diffusion and liquid dilution MIC methods. Fractional inhibitory concentration values were calculated to evaluate the combinational effect of combinations of extracts and conventional antibiotics. When synergistic interactions were detected, isobologram analysis was used to determine the ideal ratios for synergy. Toxicity was evaluated by Artemia nauplii mortality and HDF cell viability assays. Results: Methanolc, aqueous and ethyl acetate T. arjuna extracts were good inhibitors of P. mirabilis and K. pneumoniae growth when tested alone. The methanolic and aqueous extracts also synergised the inhibitory activity of ciprofloxacin against P. mirabilis and K. pneumoniae when used in combination. Additionally, numerous additive combinational effects were noted. T. arjuna chloroform extract was also a moderate inhibitor of a multi-drug resistant P. aeruginosa strain when tested alone, but did not potentiate the activity of any of the conventional antibiotics tested. All extracts and extract-antibiotic combinations were nontoxic in the Artemia nauplii mortality and HDF proliferation assays, indicating their suitability for therapeutic use. Conclusion: T. arjuna extracts have potential as inhibitors of bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, T. arjuna extracts potentiate the activity of ciprofloxacin against P. mirabilis and K. pneumoniae and therefore may be beneficial in drug design against these bacteria. [ABSTRACT FROM AUTHOR]

Introduction: The development of bacterial strains that are resistant to multiple antibiotics has made the discovery of new antibiotics a priority for medical research. Examination of plants for new antimicrobial agents is an attractive prospect and numerous recent studies have screened plants for antibacterial activity. Despite this, Australian native plants have been relatively neglected. Heritiera actinophyllum (F.M.Bailey) Kosterm. is a rainforest tree that is native to eastern coastal regions of Australia. Material from this species has not yet been examined for antibacterial properties against human pathogens. Materials and Methods: The ability of H. actinophyllum leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: H. actinophyllum methanolic and aqueous extracts were ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic or of low toxicity following 24 h exposure. Conclusion: The H. actinophyllum leaf extracts lacked growth inhibitory bioactivity against a panel of pathogenic bacteria and were nontoxic in the Artemia nauplii assay. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, and virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: The development of bacterial strains that are resistant to multiple antibiotics has made the discovery of new antibiotics a priority for medical research. Examination of plants for new antimicrobial agents is an attractive prospect and numerous recent studies have screened plants for antibacterial activity. Despite this, Australian native plants have been relatively neglected. Mirbelia oxylobioides F. Muell. is a native Australian shrub of the family Fabaceae. Very few studies have yet examined species for antibacterial properties against human pathogens. Methods: The ability of M. oxyloboides leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: M. oxyloboides methanolic and aqueous extracts were ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic or of low toxicity following 24 h exposure. Conclusion: The M. oxyloboides leaf extracts lacked growth inhibitory bioactivity against a panel of pathogenic bacteria and were non-toxic in the Artemia nauplii assay. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Kunzea ambigua (Sm.) Druce and Kunzea flavescens C.T. White and W.D. Francis are endemic Australian plants. Decoctions, infusions and essential oils produced from the leaves were used traditionally to treat a variety of bacterial diseases. Despite this, these species have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of K. ambigua and K. flavescens essential oils and a K. ambigua hydrosol was investigated by disc diffusion and liquid dilution MIC assays against a panel of pathogenic bacteria. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: K. ambigua and K. flavescens essential oils displayed noteworthy growth inhibitory activity against A. baylyi, K. pneumonia, P. mirabilis and P. aeruginosa (MIC values substantially <1000μg/mL). Indeed, MIC values as low as 33μg/mL were noted against P. aeruginosa. Noteworthy growth inhibitory activity was also noted for the K. ambigua hydrosol against A. baylyi and P. aeruginosa. All extracts were determined to be non-toxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the Kunzea spp. extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of these species to treat bacterial diseases and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Background: Impairment of the normal progression of the cell cycle affects the growth and development of the daughter cells, which may result in cancer cell proliferation. Herein, we investigate the effect of flavonoid fractions of Hibiscus sabdariffa L. calyx on cell cycle progression in cervical cancer cells. Methods: Flavonoids (bound and free), lipids and aqueous fractions were extracted from a methanolic extract of H. sabdariffa calyx using ethyl acetate, diethyl ether and petroleum ether. Each of these fractions were used to treat HeLa cervical cancer cells and monitored using a flow cytometer. Results: The cells exposed to the extract and its fractions had higher percentages of inactive cells (no cell division) at the quiescent (G0) and gap one phases (G1) of the cell cycle in comparison to control cells. The highest values were obtained from cells treated with the bound and free flavonoid fractions. Conclusion: The results of this study suggest that HeLa cervical cancer cell proliferation is significantly inhibited by H. sabdariffa flavonoid fractions. Daily consumption of beverages consisting of H. sabdariffa may therefore prevent the early stages of cervical cancer and inhibit the progression of the disease once it is established. [ABSTRACT FROM AUTHOR]

Introduction: Eucalyptus baileyana (Bailey's stringy bark) and Eucalyptus major (Queensland grey gum) have been previously used as antimicrobials against a variety of ailments. This study evaluated the effectiveness of E. baileyana and E. major as inhibitory agents against Shewanella putrefaciens, a bacterium widely associated with fish spoilage. Methodology: E. baileyana and E. major extracts were prepared using the leaves of each plant with methanol or water as the extraction solvent. Growth inhibition and minimal inhibitory concentrations were determined against S. putrefaciens through disc diffusion assays. MIC values were subsequently quantified to evaluate the extracts efficacies as antibacterial agents. Finally, the toxicity of each extract was determined using the Artemia franciscana nauplii bioassay. Results: E. baileyana aqueous and methanolic leaf extracts inhibited the growth of S. putrefaciens in the disc diffusion assay, with MIC values of 1411 and 1221 μg/mL respectively. Similarly, E. major leaf extracts also showed growth inhibition of S. putrefaciens, with MIC values of 1686 μg/mL for the aqueous extract, and 1160 μg/mL for the methanolic extract. However, toxicity studies of the extracts revealed that all extracts were toxic and likely unsuitable for human consumption (LC50 values 455-1146 μg/mL) as determined by the Artemia franciscana bioassay. Conclusion: While the E. baileyana and E. major leaf extracts were effective in preventing microbial growth, given their relatively high levels of toxicity, they would not be suitable for use as a preservative in the prevention of fish spoilage. However, the antibacterial capacity of the extracts indicates that the extracts may show promise as a surface disinfectant, and this should be investigated further. [ABSTRACT FROM AUTHOR]

Introduction: The development of antibiotic resistant bacteria has resulted in treatment failure for the current antibiotic regimen against many bacteria. A corresponding decrease in the development of new antibiotic therapies has highlighted the urgent need for the discovery of new antibiotics. An examination of 'superfoods' is an attractive option due to the high antioxidant capacities and beneficial secondary compounds reported in many 'superfoods'. This study was undertaken to test kale and spirulina extracts for the ability to inhibit the growth of a panel of bacterial pathogens of human importance. Methods: Commercially sourced kale and spirulina powders were extracted and tested for antimicrobial activity using modified disc diffusion and liquid dilution MIC methods. Toxicity was evaluated using an Artemia franciscana nauplii bioassay. Results: The methanolic and aqueous extracts of kale and spirulina displayed noteworthy growth inhibitory activity against P. mirabilis. The aqueous spirulina extract was a particularly good inhibitor of P. mirabilis, with MIC values as low as 220µg/mL. In contrast, all extracts were ineffective or of low inhibitory activity against all other bacteria tested. All extracts were non-toxic in the Artemia nauplii bioassay, confirming their suitability as natural antibacterial therapies. Conclusion: These studies indicate that aqueous kale and spirulina extracts are promising inhibitors of P. mirabilis growth and may be useful in the prevention and treatment of rheumatoid arthritis, as well as other diseases caused by that bacterium. [ABSTRACT FROM AUTHOR]

Introduction: The recent development of extensively antibiotic resistant bacteria has necessitated the search for novel antibacterial compounds. An examination of aromatic plants and traditional medicines is an attractive option for drug discovery. Astrotrichia latifolia Benth. is a native Australia shrub that has yet to be tested for antibacterial activity. Methods: The ability of A. latifolia leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: A. latifolia leaf methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic in the Artemia nauplii bioassay following 24 h exposure. Conclusion: A. latifolia leaf extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Trachyspermum ammi leaves and seeds have been used as dietary supplements and to treat multiple pathogenic diseases in several traditional healing systems. Despite this, their therapeutic properties have been poorly studied. Methods: Chloroform, ethyl acetate, hexane, methanol and water extracts of T. ammi were prepared and tested and the activity was compared to that of standard antibiotics for their in vitro antibacterial activity against ten human bacterial pathogens. The antibacterial activity was studied by standard disc diffusion assays and the activity was recorded as zones of inhibition. Results: All T. ammi seed extracts were ineffective at inhibiting the growth of all of the gram-positive and gram-negative bacteria pathogens screened against. Conclusion: Despite their use in traditional healing systems to treat some pathogenic diseases, T. ammi seed extracts were completely ineffective bacterial growth inhibitors. However, these extracts were screened against a limited panel of bacteria and further testing against other pathogens is required. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Methods: The antibacterial activity of Centella asiatica (Gotu Kola) extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The SFIC values obtained from these assays were used to determine the class of combinational effects and isobologram analysis was used to determine the ideal synergistic ratio(s). Toxicity was evaluated by Artemia nauplii mortality assays. Results: The methanolic extracts showed good inhibitory activity against several microbial triggers of autoimmune inflammatory diseases, whilst the chloroform and hexane extracts were also potent inhibitors of K. pneumoniae growth. Combinations of the C. asiatica extracts with conventional antibiotics were often substantially more effective in inhibiting bacterial growth. One synergistic and 10 additive interactions were noted. Notably, the methanolic extract restored significant growth inhibitory activity to chloramphenicol and tetracycline when tested in combination against K. pneumoniae. In contrast, two antagonistic interactions were noted for combinations containing gentamycin (against A. baylyi and S. pyogenes), indicating that those combinations should be avoided when treating infections caused by those bacteria. Conclusion: C. asiatica extracts have potential as inhibitors of bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, extract components may also potentiate the activity of two antibiotics that are relatively ineffective alone. Isolation of these agents may be beneficial in drug design against several bacteria, including the microbial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. [ABSTRACT FROM AUTHOR]

Introduction: High antioxidant levels have been linked with multiple therapeutic properties, including antibacterial activity. Therefore, high antioxidant plant preparations are good targets for antibacterial testing. D. pruriens has high antioxidant capacity although it is yet to be tested for the ability to inhibit the growth of bacterial pathogens. Methods: The ability of D. pruriens fruit and leaf extracts to inhibit the growth of a panel of bacterial and fungal pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: All D. pruriens fruit and leaf extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria, as well as fungi. The extracts were non-toxic in the Artemia bioassay following 24 h exposure. Conclusion: Despite their high antioxidant capacity, D. pruriens fruit and leaf extracts were completely ineffective bacterial and fungal growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Tabebuia impetiginosa (Mart. Ex DC. Mattos) bark has been used to treat inflammation and cancer, as well as a variety of pathogenic diseases, in traditional South American healing systems. As practitioners of complementary medicine frequently use herbal medicines concurrently with conventional antibiotics, the effects of both therapies in combination needs to be evaluated. Methods: The growth inhibitory activity of T. impetiginosa bark extracts was assessed against a panel of gastrointestinal bacterial pathogens by standard disc diffusion and liquid dilution minimum inhibitory concentration (MIC) methods. Combinational effects between the extracts and conventional antimicrobials were classified using the sum of the fractional inhibitory concentration. The toxicity of the individual samples and combinations was evaluated by Artemia lethality and MTS HDF cell viability assays. Results: T. impetiginosa bark extracts strongly inhibited the growth of B. cereus but were ineffective against Escherichia coli, Shigella sonnei, Staphylococcus aureus. The mid polarity ethyl acetate extract was a particularly good inhibitor of B. cereus growth (DD and LD MIC values of 45 and 245 µg/mL respectively). However, the effects of combinations of the extracts and conventional antibiotics was of considerably more interest. Although no synergistic interactions were noted, the potency of some combinations were substantially potentiated compared to activity of the individual components. Additive potentiation was was noted for combinations containing the T. impetiginosa water extract and erythromycin, chloramphenicol or penicillin-G against E. coli and S. aureus. Combinations containing ciprofloxacin also produced additive effects against all of the bacteria tested. Therefore, these combinations have enhanced benefits over either component alone. Of further note, antagonistic interactions were also detected in several combinations containing ciprofloxacin (particularly against S. aureus). These combinations should therefore be avoided against that bacterium. Conclusion: T. impetiginosa bark extracts inhibit the growth of B. cereus when tested alone and potentiated the activity of some conventional antibiotics against a panel of gastrointestinal pathogens when used in combination. Thus, T. impetiginosa bark extracts have potential in the treatment of diarrhoea and other gastrointestinal diseases. [ABSTRACT FROM AUTHOR]

Introduction: Alphitonia excelsa (Fenzl) Benth. is a large tree that is native to the east coast and northern regions of Australia. Decoctions and infusions produced from the leaves were used by the first Australians to treat a variety of bacterial diseases. Despite this, A. excelsa leaf extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of A. excelsa leaf extractions was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Polar to mid-polarity A. excelsa leaf solvent extractions inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gram negative bacteria was inhibited by the A. excelsa leaf extracts to approximately the same extent. The methanolic extracts were the most potent growth inhibitor against all bacteria tested. The methanolic, aqueous and ethyl acetate A. excelsa leaf extracts were particularly potent inhibitors of P. mirabilis growth, with MIC values as low as 118µg/mL for the methanolic extract. A. hydrophilia, E. coli, K. pneumonia, S. marcenscens and B. cereus were also particularly susceptible to the methanolic extract, with MIC values generally substantially <1000 µg/mL. The antibacterial activity of the methanolic A. excelsa leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of P. mirabilis and B. cereus within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the A. excelsa leaf extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of this species to treat bacterial diseases and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: Acronychia acidula F. Muell. (lemon aspen, pigeon berry) has been previously recognized for its antimicrobial properties against a broad panel of pathogenic bacteria. This study assessed the effectiveness of A. acidula as an inhibitory agent against bacteria associated with malodour formation. Methodology: A. acidula fruit extracts were prepared using methanol or water as the extraction solvent. Growth inhibition and minimal inhibitory concentrations were determined against C. jeikeium, P. acnes and B. linens through disc diffusion assays. MIC values were quanti- fied to evaluate their efficacies as antimicrobials. Toxicity of each extract was determined using the Artemia franciscana nauplii bioassay. Results: A. acidula aqueous fruit extracts inhibited the growth of B. linens (MIC = 1258 µg/mL), C. jeikeium (MIC = 1630 µg/mL) and P. acnes (MIC = 1455 µg/mL) in the disc diffusion assay. Similarly, the methanolic fruit extracts inhibited the growth of B. linens (MIC = 2608 µg/mL) and C. jeikeium (MIC = 3044 µg/mL), although no growth inhibition of P. acnes was observed. Both aqueous and methanolic A. acidula extracts were nontoxic towards Artemia nauplii (LC50 values of 1872 µg/mL and 1500 µg/mL). Conclusion: A. acidula fruit extracts were non-toxic and also displayed moderate growth inhibitory bioactivity against B. linens, C. jeikeium and P. acnes, highlighting their potential as additives to deodorants. [ABSTRACT FROM AUTHOR]

Introduction: Closely related plant species often share similar secondary metabolites and bioactivities and are therefore good targets for bioactivity testing when one or more species within a family are known to possess therapeutic properties. The genus Pouteria (family Sapotaceae) has a long history of medicinal usage in many areas of the world. Many species are known to have therapeutic properties, several of which have well established antibacterial bioactivities. Methods: The ability of P. australis leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: P. australis methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were nontoxic to Artemia nauplii following 24 hr exposure. Conclusion: Despite the taxonomic relationship with several bioactive Pouteria spp., P. australis leaf extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: The development of multi-antibiotic resistant strains of bacteria has necessitated the search for new, effective antibacterial therapies. B. collina and B. oblongifolia leaves were used by Australian Aborigines to treat bacterial infections. However, little research has been published on antibacterial activity of these species. Methods: The ability of B. collina and B. oblongifolia leaf extracts to inhibit the growth of gram-negative and gram-positive bacterial species was investigated by disc diffusion and growth time course assays. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The B. collina and B. oblongifolia leaf extracts were good inhibitors of the growth of both gram-positive and gram-negative bacteria. The B. collina and B. oblongifolia leaf extracts were particularly good inhibitors of A. faecalis growth (MICs of 225 and 486µg/mL respectively) and B. cereus growth (MICs of 515 and 875µg/mL respectively). The B. collina extract was also a good inhibitor of B. subtilis growth, whilst the B. oblongifolia extract was a moderate growth inhibitor (MIC values of 923 and 1250µg/mL respectively). A similar, trend was noted for Y. entercolitica growth inhition (MICs of 518 and 1136µg/mL respectively). Whilst MIC values were also determined against other bacterial species, they generally indicated low-moderate activity. The B. collina and B. oblongifolia leaf extracts were further investigated by growth time course assays against A. faecalis and B. cereus. Interestingly, both extracts showed significant growth inhibition within 1h of exposure against both bacterial species. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for the treatment of bacterial infections. Conclusion: The lack of toxicity of the B. collina and B. oblongifolia leaf extracts and their growth inhibitory bioactivity against multiple bacterial species indicate their potential in the development of new antibiotic chemotherapies. [ABSTRACT FROM AUTHOR]

Introduction: Brachychiton acerifolius (A.Cunn. ex G.Don) Macarthur and C. moore is a large tree that is native to subtropical regions of the east of Australia. Decoctions and infusions produced from the leaves of the related species Brachychiton diversifolius were used by the first Australians to treat a variety of bacterial diseases. Despite this, B. acerifolius leaf and flower extracts have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of B. acerifolius leaf and flower extracts was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic B. acerifolius leaf and flower extracts inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gramnegative bacteria was inhibited by the B. acerifolius leaf and flower extracts, although the gram negative bacteria were substantially more susceptible to the extracts than the gram positive bacteria were. The leaf extracts were more potent growth inhibitors than the flower extracts against all bacteria tested. The B. acerifolius leaf extract was a strong inhibitor of A. faecalis, K. pneumonia, P. fluorescens, S. newport, S. sonnei, B. cereus, S. aureus and S. pyogenes growth, with MIC values substantially <1000µg/mL. The antibacterial activity of the methanolic B. acerifolius leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of P. fluorsecens and B. cereus within 1hr of exposure. Both extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the B. acerifolius leaf and flower extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of this species to treat bacterial diseases and indicates their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: Closely related plant species often share similar secondary metabolites and bioactivities and are therefore good targets for bioactivity testing when one or more species within a genus are known to possess therapeutic properties. The genus Ficus has a long history of medicinal usage in many areas of the world. Many species are known to have therapeutic properties, several species of which have well established antibacterial bioactivities. Methods: The ability of F. racemosa leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: F. racemosa methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were nontoxic or of low toxicity following 24 h exposure. Conclusion: Despite the close taxonomic relationship with several bioactive Ficus spp. and its therapeutic uses in traditional medicine, F. racemosa leaf extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Closely related plant species often share similar secondary metabolites and bioactivities and are therefore good targets for bioactivity testing when one or more species within a genus are known to possess therapeutic properties. The genus Eucalyptus has a long history of medicinal usage by the first Australians. Many species are known to have therapeutic properties, several species of which have well established antibacterial bioactivities. Methods: The ability of Eucalyptus grandis leaf and flower extracts to inhibit the growth of a panel of bacterial and fungal pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: E. grandis leaf and flower methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria, as well as fungi. The extracts were nontoxic in the Artemia nauplii bioassay following 24 hr exposure. Conclusion: Despite the taxonomic relationship to several bioactive Eucalyptus spp., E. grandis leaf and flower extracts were completely ineffective bacterial and fungal growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant based medicines. However, synergistic combinations of plant extracts with conventional antibiotics are a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Methods: The antibacterial activity of Rosa canina (Rosehip) extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The ΣFIC values obtained from these assays were used to determine the class of combinational effects and isobologram analysis was used to determine the ideal synergistic ratio(s). Toxicity was evaluated by Artemia nauplii and HDF cell line viability. Results: The methanolic, water and ethyl acetate extracts showed good inhibitory activity against several microbes. However, combinations of the methanolic or aqueous extracts with conventional antibiotics proved significantly more effective in inhibiting the growth of Proteus vulgaris, Klebsiella pneumonia and Acinetobacter baylyi (bacterial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis respectively). In total, 4 synergistic interactions were noted. Notably, the methanolic extract restored significant growth inhibitory activity to chloramphenicol and tetracycline when tested in combination, thereby restoring their activity. Conclusion: Although the mechanisms of synergy are still unclear, studies indicate that compounds within R. canina may mimic the actions of resistance modifying agents, thus potentiating the activity of two antibiotics that are relatively ineffective alone. Isolation of these agents may be beneficial in drug design against several bacteria including the microbial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. [ABSTRACT FROM AUTHOR]

Introduction: Bacillus anthracis is bacterial cause of the highly fatal, zoonotic disease anthrax. Tasmanian pepper (Tasmannia lanceolata) has been previously documented for its antiseptic properties against other pathogenic bacteria. This study sought to investigate the effectiveness of T. lanceolata as an inhibitory agent against B. anthracis. Methods: Tasmannia lanceolata berry and leaf extracts were prepared with either water or methanol as the extraction solvent. Growth inhibition was assessed against B. anthracis strain PMO through disc diffusion as assaying. The relative MIC values of each extract was quantified to evaluate efficacy as a sterilant. The degree of toxicity of each extract was achieved using the widely used Artemia franciscana nauplii bioassay. Results: T. lanceolata leaf extracts inhibited the growth of B. anthracis in the disc diffusion assay, with MIC values of 2333 and 1873 µg/mL respectively. In contrast, the T. lanceolata berry extracts were completely devoid of growth inhibitory activity. All T. lanceolata extracts (both berry and leaf) were non-toxic (LC50 values substantially >1000 µg/mL) as determined via the Artemia franciscana bioassay. Conclusion: T. lanceolata berry and leaf extracts are not only non-toxicity, but also had moderate growth inhibitory bioactivity against B. anthracis, highlighting their potential in the treatment of anthrax. [ABSTRACT FROM AUTHOR]

Introduction: Yersinia enterocolitica is a major source of food poisoning via the consumption of contaminated meat products, causing acute gastroenteric yersiniosis. Tasmannia lanceolata has been widely documented for its antiseptic properties, repressing the growth of an extensive range of bacteria. Despite this, Tasmannia lanceolata has yet to be been tested for its inhibitory capacity against Y. enterocolitica. Methods: T. lanceolata leaf and berry extracts were prepared by maceration and growth inhibitory activity against a clinical strain of Y. enterocolitica was examined by disc diffusion assays. The MIC values of the extracts were determined to quantify and compare their relative efficacies. Toxicity was determined using an Artemia franciscana nauplii bioassay. Results: T. lanceolata leaf and berry extracts displayed potent growth inhibitory activity in the disc diffusion assay against Y. enterocolitica. The ethyl acetate and chloroform leaf extracts (MICs of 30 and 53 µg/mL respectively) and the hexane berry extract (MIC = 34 µg/mL) were particularly potent growth inhibitors. The methanol and water extracts of both the berry and leaf, as well as the leaf ethyl acetate extract, also had strong growth inhibitory activity against Y. enterocolitica, albeit with a higher MIC values (250-300µg/mL). All other extracts had lower efficacy, although their MIC values also indicated good inhibitory activity (with the exception of the chloroform berry extract). When assessed for toxicity, all T. lanceolata extracts were non-toxic (LC50 values >1000 µg/mL) in the Artemia franciscana bioassay. Conclusion: The non-toxicity of the T. lanceolata berry and leaf extracts, combined with the potent inhibitory bioactivity observed against Y. enterocolitica, demonstrates their potential as therapeutic agents in the prevention and treatment of yersiniosis. [ABSTRACT FROM AUTHOR]

Introduction: The development of bacterial strains that are resistant to multiple antibiotics has made the development of new antibiotics a priority for medical research. Traditional plant medicines are important leads for the discovery of new medicines. The family Agavaceae is widely used therapeutically in many areas of the world. Despite this, many members of this family are yet to be examined extensively for therapeutic properties. The species Cordyline rubra Otto and A. Dietr. was screened for antibacterial activity in this study. Methods: The ability of C. rubra leaf and fruit extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: Methanolic C. rubra leaf and fruit extracts were completely ineffective at inhibiting the growth of gram-positive and gramnegative panels of bacteria. The extracts were also non-toxic or of low toxicity following 24 h exposure. Conclusion: C. rubra leaf and fruit extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: The development of multi-antibiotic resistant strains of bacteria has necessitated the search for new effective antibacterial therapies. Several Grevillea spp. were used traditionally to treat pathogenic illness and are rich in phytocompounds with antibacterial activity. Despite this, the antibacterial activity of Australian Grevillea spp. extracts have not been extensively examined. Methods: The ability of G. juncifolia and G. robusta leaf and flower extracts to inhibit the growth of gram-negative and gram-positive bacterial species and some fungi was investigated by disc diffusion assays. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The G. juncifolia and G. robusta extracts were good inhibitors of the growth of both gram-positive and gram-negative bacteria yet were completely ineffective against all fungal species tested. The leaf extracts generally had better antibacterial activity than the flower extracts. The G. juncifolia leaf extract was a particularly good inhibitor of A. faecalis, P. fluorescens, Y. entercolitica and B. subtilis growth, with MIC values of 62, 533, 736 and 682µg/mL respectively. The G. robusta leaf extract was a potent inhibitor of B. cereus and B. subtilis growth (145 and 83µg/mL respectively). That extract was also a good inhibitor of A. faecalis, P. fluorescens, S. salford, S. aureus and S. epidermidis growth, albeit with substantially higher MIC values. In contrast, none of the extracts inhibited fungal growth. All extracts were determined to be non-toxic in the Artemia franciscana nauplii bioassay, indicating their safety for the treatment of bacterial infections. Conclusion: The lack of toxicity of the G. juncifolia and G. robusta extracts and their growth inhibitory bioactivity against grampositive and gram-negative bacteria indicate their potential in the development of new antibiotic chemotherapies. [ABSTRACT FROM AUTHOR]

Introduction: Closely related plant species often share similar secondary metabolites and bioactivities and are therefore good targets for bioactivity testing when one or more species within a family are known to possess therapeutic properties. The family Laminaceae has a long history of medicinal usage globally. Many species are known to have therapeutic properties, several species of which have well established antibacterial bioactivities. Methods: The ability of Westringa fruticosa leaf and flower extracts to inhibit the growth of a panel of bacterial and fungal pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: W. fruticosa leaf methanolic and aqueous extracts were both completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria, as well as fungi. The extracts were non-toxic or of low toxicity in the Artemia bioassay following 24 h exposure. Conclusion: Despite the taxonomic relationship to several bioactive Laminaceae spp., W. fruticosa leaf and flower extracts were completely ineffective bacterial and fungal growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Xanthophyllum fragrans C.T. White is a rainforest tree that is native to north-eastern regions of Australia. X. fragrans leaf extracts were examined for the ability to inhibit the growth of Pseudomonas aeruginosa. Methods: The antimicrobial activity of a methanolic X. fragrans leaf extracts were investigated by disc diffusion and growth time course assays against P. aeruginosa. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The methanolic X. fragrans leaf extract was a potent inhibitor of P. aeruginosa growth (MICs of 430 and 1687µg/mL against the reference and clinical strains respectively). The aqueous X. fragrans leaf extract was also a moderate inhibitor of P. aeruginosa growth (MICs approximately 1000 and 2500µg/mL against the reference and clinical bacterial strains respectively). The antibacterial activities of the methanolic X. fragrans leaf extracts were further investigated using growth time course assays that showed significant growth inhibition in cultures of P. aeruginosa within 1 h of exposure. All extracts were determined to be non-toxic in the Artemia franciscana nauplii bioassay, indicating their safety for use in preventing diseases caused by these pathogens. Conclusion: The lack of toxicity of the X. fragrans leaf extracts and their growth inhibitory bioactivity against P. aeruginosa indicates their potential in the development of new therapies targeting this bacterium. [ABSTRACT FROM AUTHOR]