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Isatis indigotica Fortune is a biennial Chinese woad of the Cruciferae family. It is primarily cultivated in China, where it was a staple in indigo dye manufacture till the end of the 17th century. Today, I. indigotica is used primarily as a therapeutic herb in traditional Chinese medicine (TCM). The medicinal use of the plant is separated into its leaves (Da-Qing-Ye) and roots (Ban-Lan-Gen), whereas its aerial components can be processed into a dried bluish-spruce powder (Qing-Dai), following dehydration for long-term preservation. Over the past several decades, I. indigotica has been generally utilized for its heat-clearing effects and bodily detoxification in TCM, attributed to the presence of several classes of bioactive compounds, including organic acids, alkaloids, terpenoids, and flavonoids, as well as lignans, anthraquinones, glucosides, glucosinolates, sphingolipids, tetrapyrroles, and polysaccharides. This paper aims to delineate I. indigotica from its closely-related species (Isatis tinctoria and Isatis glauca) while highlighting the ethnomedicinal uses of I. indigotica from the perspectives of modern and traditional medicine. A systematic search of PubMed, Embase, PMC, Web of Science, and Google Scholar databases was done for articles on all aspects of the plant, emphasizing those analyzing the bioactivity of constituents of the plant. The various key bioactive compounds of I. indigotica that have been found to exhibit anti-inflammatory, antimicrobial, anticancer, and anti-allergic properties, along with the protective effects against neuronal injury and bone fracture, will be discussed. Collectively, the review hopes to draw attention to the therapeutic potential of I. indigotica not only as a TCM, but also as a potential source of bioactive compounds for disease management and treatment.

The 3D-printed iChip version made from thermoplastics or photopolymers can isolate microbial populations of a peat swamp in situ with a population profile different from that isolated via the standard in vitro Petri dish cultivation method.

In the past decade, researchers have focused on the emergence of drug resistance in fungal pathogens such as Candida albicans, also considered as pathobionts that occur harmlessly in the human body but could potentially be triggered to cause diseases. The increasing rate of antifungal resistance in commensal gut fungi is alarming and should be further investigated. Here, we report seven novel MLST (Multi Locus Sequence Typing) genotypes of multi-drug resistant C. albicans isolates obtained from participants of a community study in Segamat, a district in the state of Johor, Malaysia. A total of eight C. albicans were isolated from four individuals, which were found to express high resistance against fluconazole, itraconazole, voriconazole and 5-fluorocytosine antifungals. MLST was performed to assess the clonal relatedness of these drug resistant isolates among themselves and against other strains isolated from other geographical regions. The novel MLST C. albicans sequence types suggest significant genetic changes compared to previous genotypes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42770-021-00558-4.

In this study, the antibiotic enhancement and quorum sensing (QS) inhibition of allylpyrocatechol (APC) and methyl gallate (MG) isolated from leaves of Piper betle (betel) and leaf shoots of Anacardium occidentale (cashew), respectively, were compared. When applied with streptomycin and tested against Staphylococcus aureus and Pseudomonas aeruginosa, the effect of APC was additive while that of MG was synergistic. In terms of QS inhibition against Chromobacterium violaceum, both compounds were equally effective with violacein inhibition observed at concentrations of 60 μg/mL. We successfully increased the purity of APC in the methanol betel leaf extract from 13.2% to 31.5% w/w through solvent partitioning. This study is the first to document the anti-QS activity of APC, which is comparable to that of MG.

A Gram-negative, filamentous aerobic bacterium designated as strain Mgbs1T was isolated on 12 April 2017 from the subsurface soil and leaf litter substrate at the base of a Koompassia malaccensis tree in a tropical peat swamp forest in the northern regions of the state of Selangor, Malaysia (3° 39′ 04.7′ N 101° 17′ 43.7′′ E). Phylogenetic analyses based on the full 16S rRNA sequence revealed that strain Mgbs1T belongs to the genus Chitinophaga with the greatest sequence similarity to Chitinophaga terrae KP01T (97.65 %), Chitinophaga jiangningensis DSM27406T (97.58 %), and Chitinophaga dinghuensis DHOC24T (97.17 %). The major fatty acids of strain Mgbs1T (>10 %) are iso-C15 : 0, C16 : 1 ω5c and iso-C17 : 0 3-OH while the predominant respiratory quinone is menaquinone-7. Strain Mgbs1T has a complete genome size of 8.03 Mb, with a G+C content of 48.5 mol%. The DNA–DNA hybridization (DDH) score between strain Mgbs1T and C. jiangningensis DSM27406T was 15.9 %, while in silico DDH values of strain Mgbs1T against C. dinghuensis DHOC24T and C. terrae KP01T were 20.0 and 19.10% respectively. Concurrently, Average Nucleotide Identity (ANI) scores between strain Mgbs1T against all three reference strains are 73.2 %. Based on the phenotypic, chemotaxonomic, and phylogenetic consensus, strain Mgbs1T represents a novel species of the genus Chitinophaga , for which the name Chitinophaga extrema sp. nov. is proposed (=DSM 108835T=JCM 33276T).

Biological macromolecules are naturally occurring large cellular components responsible for a wide array of functions necessary for the growth and survival of living organisms. They also possess various bioactivities such as antimicrobial, antioxidant, antitumor, antiviral, antiinflammatory, antiproliferative, and hypoglycemic activities. The growing interest in bioactive macromolecules as potential therapeutical drugs has driven scientists to further study the association between their chemical structures and corresponding functions/activities. This chapter aims to provide a short overview on the structural features influencing the bioactivities of several biological macromolecules, namely l -amino acid oxidases, lysostaphin and metallo-β-lactamase-like lactonase and chitosan. As observed in this chapter, establishing the structure–activity relationship (SAR) can often prove to be challenging for macromolecules given the complexity of the three-dimensional organization level of proteins and the branched chains of the carbohydrates. Nevertheless, certain structural features influencing the bioactivities of macromolecules have been identified and could help to accelerate their development and application in the biomedical field. Indeed, a comprehensive understanding of biomacromolecule SARs remains necessary as information inferred from these studies may be crucial to many aspects of drug discovery and development, whether it is for primary screening or lead optimization, as well as for the designing of synthetic derivatives with improved properties.

The full plethora of environmental bacteria is often poorly represented

The antioxidant and antimicrobial activity of the methanolic extracts of various plant parts of Costus woodsonii were evaluated. The total phenolic content and total flavonoid content in leaves and...

In our previous work, we have demonstrated that at equal volume, green tea extract (GT) exhibited a higher inhibition efficiency (IE) than commercial calcium nitrite corrosion inhibitor, on corrosion of steel reinforcing bar (rebar) embedded in mortar (75–80 vs. 14–24%). GT behaved as a mixed-type corrosion inhibitor which increased rebar polarization resistance (Rp); indicating that it formed a protective layer on rebar surface. In this paper, the formation of a protective layer was confirmed with visual inspection and microscopic examinations. In presence of this layer, rebar corrosion was reduced. This is evidenced by a reduced rebar weight loss and further indicated by a similar chloride permeability between control and GT concrete, and a similar corrosion rate (CR) between control reinforced mortar and reinforced mortar incorporating solely the residual solid of GT. The similarities ruled out the plausible higher IE of GT due to an improved physical barrier of mortar/concrete against corrosion. Analyses with energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), and Fourier-transform infrared spectroscopy (FTIR) suggested that the layer was enriched with calcium, specifically the calcium carbonate polymorphs. Although the formation of protective layer and increase in Rp were influenced by the magnitude of antioxidant activity, in this study GT has shown a better IE than CI. This should encourage more studies on the IE of sustainable ‘green’ corrosion inhibitors in concrete.

In the biomedical field, there is growing interest in using human stem cell-derived neurons as in vitro models for pharmacological and toxicological screening of bioactive compounds extracted from natural products. Lignosus rhinocerus (Tiger Milk Mushroom) is used by indigenous communities in Malaysia as a traditional medicine to treat various diseases. The sclerotium of L. rhinocerus has been reported to have medicinal properties, including various bioactivities such as neuritogenic, anti-inflammatory, and anticancer effects. This study aims to investigate the neuroprotective activities of L. rhinocerus sclerotial extracts. Human embryonic stem cell (hESC)-derived neural lineages exposed to the synthetic glucocorticoid, dexamethasone (DEX), were used as the in vitro models. Excess glucocorticoids have been shown to adversely affect fetal brain development and impair differentiation of neural progenitor cells. Screening of different L. rhinocerus sclerotial extracts and DEX on the hESC-derived neural lineages was conducted using cell viability and neurite outgrowth assays. The neuroprotective effects of L. rhinocerus sclerotial extracts against DEX were further evaluated using apoptosis assays and Western blot analysis. Hot aqueous and methanol extracts of L. rhinocerus sclerotium promoted neurite outgrowth of hESC-derived neural stem cells (NSCs) with negligible cytotoxicity. Treatment with DEX decreased viability of NSCs by inducing apoptosis. Coincubation of L. rhinocerus methanol extract with DEX attenuated the DEX-induced apoptosis and reduction in phospho-Akt (pAkt) level in NSCs. These results suggest the involvement of Akt signaling in the neuroprotection of L. rhinocerus methanol extract against DEX-induced apoptosis in NSCs. Methanol extract of L. rhinocerus sclerotium exhibited potential neuroprotective activities against DEX-induced toxicity in hESC-derived NSCs. This study thus validates the use of human stem cell-derived neural lineages as potential in vitro models for screening of natural products with neuroprotective properties.

Although several studies have already been carried out in investigating the general profile of the gut mycobiome across several countries, there has yet to be an officially established baseline of a healthy human gut mycobiome, to the best of our knowledge. Microbial composition within the gastrointestinal tract differ across individuals worldwide, and most human gut fungi studies concentrate specifically on individuals from developed countries or diseased cohorts. The present study is the first culture-dependent community study assessing the prevalence and diversity of gut fungi among different ethnic groups from South East Asia. Samples were obtained from a multi-ethnic semi-rural community from Segamat in southern Malaysia. Faecal samples were screened for culturable fungi and questionnaire data analysis was performed. Culturable fungi were present in 45% of the participants' stool samples. Ethnicity had an impact on fungal prevalence and density in stool samples. The prevalence of resistance to fluconazole, itraconazole, voriconazole and 5-fluorocytosine, from the Segamat community, were 14%, 14%, 11% and 7% respectively. It was found that Jakun individuals had lower levels of antifungal resistance irrespective of the drug tested, and male participants had more fluconazole resistant yeast in their stool samples. Two novel point mutations were identified in the ERG11 gene from one azole resistant Candida glabrata, suggesting a possible cause of the occurrence of antifungal resistant isolates in the participant's faecal sample.

Although several studies have already been carried out in investigating the general profile of the gut mycobiome across several countries, there has yet to be an officially established baseline of a healthy human gut mycobiome, to the best of our knowledge. Microbial composition within the gastrointestinal tract differ across individuals worldwide, and most human gut fungi studies concentrate specifically on individuals from developed countries or diseased cohorts. The present study is the first culture-dependent community study assessing the prevalence and diversity of gut fungi among different ethnic groups from South East Asia. Samples were obtained from a multi-ethnic semi-rural community from Segamat in southern Malaysia. Faecal samples were screened for culturable fungi and questionnaire data analysis was performed. Culturable fungi were present in 45% of the participants' stool samples. Ethnicity had an impact on fungal prevalence and density in stool samples. The prevalence of resistance to fluconazole, itraconazole, voriconazole and 5-fluorocytosine, from the Segamat community, were 14%, 14%, 11% and 7% respectively. It was found that Jakun individuals had lower levels of antifungal resistance irrespective of the drug tested, and male participants had more fluconazole resistant yeast in their stool samples. Two novel point mutations were identified in the ERG11 gene from one azole resistant Candida glabrata, suggesting a possible cause of the occurrence of antifungal resistant isolates in the participant's faecal sample.

Objectives Metabolic syndrome (MetS), a multiplex risk factor for cardiovascular disease and type 2 diabetes, is increasingly prevalent worldwide. Ellagitannin geraniin, a polyphenol found in the rind of rambutan (Nephelium lappaceum), has demonstrated therapeutic effects against metabolism dysfunction. The aim of this study was to characterize the metabolic effects and possible mechanism of geraniin in rats with MetS induced by a high-fat diet (HFD). Methods MetS was induced in Sprague Dawley rats on an HFD, followed by a daily oral gavage of geraniin (25 mg/kg) for 4 wk. The outcomes of geraniin-treated rats were compared with those of untreated rats on either a control diet or an HFD and with rats with MetS treated with metformin on a daily basis (200 mg/kg). Results The supplementation of geraniin ameliorated multiple metabolic abnormalities caused by HFD, including hypertension, impaired glucose and lipid metabolism, ectopic fat deposition in the visceral fat and liver, and disturbed antioxidant mechanism and inflammatory response. The benefits conferred by geraniin were comparable to metformin. Transcriptomic analysis revealed a profound influence of geraniin on the hepatic expression profiles. The lipid and steroid metabolic processes that were aberrantly activated by HFD were suppressed by geraniin. Based on the differential transcriptomes, geraniin also exerted a significant modulatory effect on the expression of mitochondrial genes, potentially influencing the mitochondrial activity and leading to the observed beneficial effects. Conclusion Geraniin supplementation mitigated metabolic anomalies of MetS in rats, making it an attractive drug candidate for further investigation.

Species of fungi belonging to the order Mucorales can be found everywhere in the environment. Gilbertella persicaria, which belongs to this order, have often been isolated from fruits and in water systems. However, there has been no report of isolation of this fungus from human samples. During a gut mycobiome study, from the Segamat community, Gilbertella persicaria was isolated from a human fecal sample and was characterized through a series of morphological assessment, biochemical tests, and molecular techniques. The isolate produced a white velvety surface that turned grayish after 24 h. Although no biofilm production was observed, the results indicated that the isolate could form calcium oxalate crystals, produced urease, and was resistant to low pH. The isolate was sensitive to amphotericin but resistant to voriconazole and itraconazole. The features of this fungus that could help in its survival in the human gut are also discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s42770-020-00323-z) contains supplementary material, which is available to authorized users.

Cardiovascular disease (CVD) affects millions of people worldwide, thereby warranting more effective therapeutic approaches. Epidemiological studies have highlighted that a lower incidence of CVD rate is associated with long-term consumption of plant-based diets rich in polyphenols. Many polyphenolic compounds have been purported to possess significant protective effects against oxidative stress and inflammation in the vascular system, and may prevent myocardial ischemia through a complex signalling transduction pathway. Taken together, this suggests that cardiovascular health may be associated with long-term intake of dietary polyphenols. This chapter aims to both review the possible mechanism(s) by which polyphenols exert cardiovascular benefits, as well as collate the available evidence from preclinical and clinical trials of polyphenolic supplementation.

Zingiberaceae is a family that consists of many edible ginger plants. Etlingera pubescens (B.L.Burtt & R.M.Sm.) R.M.Sm. was studied for its antioxidant properties. Preliminary screening of the methanol extracts of its leaves, stems, rhizomes showed that the fresh leaves had the highest antioxidant activity, with total phenolic content (TPC), ascorbic acid equivalent antioxidant capacity (AEAC), and oxygen radical absorbance capacity (ORAC) values of 1020 ± 20 mg GAE/100 g, 1130 ± 30 mg AAE/100 g, and 140 ± 30 µmol TE/g, respectively. Subsequently, a diarylheptanoid, etlingerin, was isolated from the leaf methanol extract. When contrasted with curcumin (a well-known diarylheptanoid), etlingerin showed comparable free radical scavenging properties. However, using a cell-based antioxidant assay, etlingerin showed significantly better protective effects (with cellular antioxidant activity values as high as 84 ± 4%) than curcumin at all concentrations tested. In the cytoprotective study, only etlingerin could protect cells that were challenged with hydrogen peroxide. These effects might be explained by etlingerin's high lipophilicity and good free radical scavenging properties. Etlingerin was also found to be significantly less cytotoxic than curcumin (up to 10-fold, as determined using a MTT cell viability assay), thus suggesting its safety. The work showed that etlingerin has better antioxidant properties, hence highlighting its potential as a functional food component that could reduce the risks of oxidative stress-related diseases.

The present study exploits the potential of spent coffee grounds (SCGs) as a supplementary substrate for cultivating Pleurotus species. Increased levels of SCG in mixed substrate resulted in retardation of mycelial growth rate in a concentration-dependent manner. Subsequently, fruitification was inhibited when concentrations of SCG in the mixed substrate exceeded 30% (w/w) due to the relatively high phenolic and caffeine concentrations in SCG. Partial reductions in phenolic content and caffeine have been observed whenever SCG was present in the substrate; trace amounts of caffeine were also detected in fruiting bodies grown on all SCG-containing substrate mixtures. This finding suggests that Pleurotus spp. can reduce the levels of caffeine and phenolic compounds in SCG via bioaccumulation and biodegradation, respectively. Next, the supplementation of up to 20% (w/w) SCG did not significantly affect the proximate compositions, mineral contents, and fatty acid profiles in basidiocarps of both Pleurotus species compared to standard formulations.

Halloysite nanotubes (Hal) with unique nanosized tubular structures are promising nanoclay for potential applications as reinforcement fillers, anticorrosion coatings, as well as drug carriers, and adsorbents. Thus far, previous studies on acid treatment of Hal have focused only on Hal from a single source under various conditions of acid strength, temperature, and treatment duration. This study is the first to characterize and compare the effects of acid treatment on three types of Hal (Dragonite (DG), HalloPure (HP), and Camel Lake (CLA)) originated from different geological deposits, and the results considered in terms of their suitability for various applications. Analyses revealed porous tubular structure with an increased lumen diameter of up to 78% and improved surface area from 54 m2 g−1 to 160 m2 g−1 on acid-treated CLA (acid-CLA). By comparison, lumen diameters were reported to increase by only 46% and 52% for acid-DG and acid-HP, respectively. Despite that, crystallinity of acid-DG showed the most reduction, from 64.5% to 59.4%, with a high recorded surface area of 229 m2 g−1, whereas crystallinity of acid-HP showed the least reduction from 62.5% to 61.1% with a surface area of 121 m2 g−1. Therefore, the obtained results support the hypothesis that various Hal can be affected differently by acid treatment, and not all types of Hal are suitable for acid treatment, especially for those intended for use as reinforcement materials.

Graphical abstract The effective high-calorie diet for metabolic syndrome induction is different between Sprague Dawley rats of different developmental stages. The post-weaning rats on high-fat diet for 8 weeks developed all phenotypes of metabolic syndrome while the adult rats on high-fat-high-sucrose diet merely became obese and hypertensive. The post-weaning rats on high-fat diet is a better and less time-consuming model for metabolic syndrome research., The present study aimed to examine the effects of the types of high-calorie diets (high-fat and high-fat-high-sucrose diets) and two different developmental stages (post-weaning and young adult) on the induction of metabolic syndrome. Male, post-weaning and adult (3- and 8-week old, respectively) Sprague Dawley rats were given control, high-fat (60% kcal), and high-fat-high-sucrose (60% kcal fat + 30% sucrose water) diets for eight weeks (n = 6 to 7 per group). Physical, biochemical, and transcriptional changes as well as liver histology were noted. Post-weaning rats had higher weight gain, abdominal fat mass, fasting glucose, high density lipoprotein cholesterol, faster hypertension onset, but lower circulating advanced glycation end products compared to adult rats. This is accompanied by upregulation of peroxisome proliferator-activated receptor (PPAR) α and γ in the liver and receptor for advanced glycation end products (RAGE) in the visceral adipose tissue. Post-weaning rats on high-fat diet manifested all phenotypes of metabolic syndrome and increased hepatic steatosis, which are linked to increased hepatic and adipocyte PPARγ expression. Adult rats on high-fat-high-sucrose diet merely became obese and hypertensive within the same treatment duration. Thus, it is more effective and less time-consuming to induce metabolic syndrome in male post-weaning rats with high-fat diet compared to young adult rats. As male rats were selectively included into the study, the results may not be generalisable to all post-weaning rats and further investigation on female rats is required.

In the biomedical field, there is growing interest in using human stem cell-derived neurons as in vitro models for pharmacological and toxicological screening of bioactive compounds extracted from natural products. Lignosus rhinocerus (Tiger Milk Mushroom) is used by indigenous communities in Malaysia as a traditional medicine to treat various diseases. The sclerotium of L. rhinocerus has been reported to have medicinal properties, including various bioactivities such as neuritogenic, anti-inflammatory, and anticancer effects. This study aims to investigate the neuroprotective activities of L. rhinocerus sclerotial extracts. Human embryonic stem cell (hESC)-derived neural lineages exposed to the synthetic glucocorticoid, dexamethasone (DEX), were used as the in vitro models. Excess glucocorticoids have been shown to adversely affect fetal brain development and impair differentiation of neural progenitor cells. Screening of different L. rhinocerus sclerotial extracts and DEX on the hESC-derived neural lineages was conducted using cell viability and neurite outgrowth assays. The neuroprotective effects of L. rhinocerus sclerotial extracts against DEX were further evaluated using apoptosis assays and Western blot analysis. Hot aqueous and methanol extracts of L. rhinocerus sclerotium promoted neurite outgrowth of hESC-derived neural stem cells (NSCs) with negligible cytotoxicity. Treatment with DEX decreased viability of NSCs by inducing apoptosis. Coincubation of L. rhinocerus methanol extract with DEX attenuated the DEX-induced apoptosis and reduction in phospho-Akt (pAkt) level in NSCs. These results suggest the involvement of Akt signaling in the neuroprotection of L. rhinocerus methanol extract against DEX-induced apoptosis in NSCs. Methanol extract of L. rhinocerus sclerotium exhibited potential neuroprotective activities against DEX-induced toxicity in hESC-derived NSCs. This study thus validates the use of human stem cell-derived neural lineages as potential in vitro models for screening of natural products with neuroprotective properties.

Aims The aim of this study was to investigate the antimicrobial activities of Etlingera pubescens, and to isolate and identify the antimicrobial compound. Methods and results The crude extracts of E. pubescens were obtained through methanol extraction, and evaluated for antimicrobial activities. From this extract, 1,7-bis(3,4-dihydroxyphenyl)heptan-3-yl acetate (etlingerin) was isolated. When compared to curcumin (a compound with a similar chemical structure), etlingerin showed twofold lower minimum inhibitory concentration values while also being bactericidal. Through time kill assay, etlingerin showed rapid killing effects (as fast as 60 min) against the Gram-positive bacteria (Staphylococcus aureus ATCC 43300 and Bacillus subtilis ATCC 8188). Further assessment revealed that etlingerin caused leakage of intracellular materials, therefore suggesting alteration in membrane permeability as its antimicrobial mechanism. Cytotoxicity study demonstrated that etlingerin exhibited approximately 5- to 12-fold higher IC50 values against several cell lines, as compared to curcumin. Conclusions Etlingerin isolated from E. pubescens showed better antibacterial and cytotoxic activities when compared to curcumin. Etlingerin could be safe for human use, though further cytotoxicity study using animal models is needed. Significance and impact of the study Etlingerin has a potential to be used in treating bacterial infections due to its good antimicrobial activity, while having potentially low cytotoxicity.

The search for new and novel drugs is never-ending. Despite advances in synthetic chemistry, nature nevertheless remains as an important resource for the drug discovery. For decades, a routine screening of ethnopharmacologically important plants, followed by chromatographic isolation has been the basis of bioprospecting. Recent advances in bioinformatics and in silico screening have further improved our rate and likelihood of finding medicinal metabolites. Multiple classes of naturally occurring plant secondary metabolites, such as polyphenols, terpenoids, and alkaloids have been proven to possess significant medicinal potentials including antioxidant, anti-allergic, anti-inflammatory, anticancer, antihypertensive, and antimicrobial activities. The compounds of interest are often used as a basis or inspiration for semisynthetic drugs with improved pharmacokinetic and pharmacodynamic parameters. However, when a new biologically active compound has been identified, further in vivo testing and clinical trials may not reflect results seen in vitro. As with any promising fields, pitfalls and drawbacks are inevitable; these include poor bioavailability and unknown pharmacodynamics/pharmacokinetics. The drug development is further complicated by other challenges, such as processing, formulation, scaling up, and intellectual property protection. This chapter aims to discuss on the prospects of plant metabolites leading to drug discovery, along with the process and outcomes of testing and the potential pitfalls or challenges faced by researchers and the pharmaceutical industry in this endeavour.

Widely used throughout the world as traditional medicine for treating a variety of diseases ranging from cancer to microbial infections, members of the Tradescantia genus show promise as sources of desirable bioactive compounds. The bioactivity of several noteworthy species has been well-documented in scientific literature, but with nearly seventy-five species, there remains much to explore in this genus. This review aims to discuss all the bioactivity-related studies of Tradescantia plants and the compounds discovered, including their anticancer, antimicrobial, antioxidant, and antidiabetic activities. Gaps in knowledge will also be identified for future research opportunities.

Ursolic acid (UA) is a pentacyclic triterpene of the ursane type. As a common chemical constituent among species of the family Lamiaceae, UA possesses a broad spectrum of pharmacological properties. This overview focuses on the anticancer properties of UA against breast cancer (BC) and colorectal cancer (CRC) that are most common among women and men, respectively. In vitro studies have shown that UA inhibited the growth of BC and CRC cell lines through various molecular targets and signaling pathways. There are several in vivo studies on the cytotoxic activity of UA against BC and CRC. UA also inhibits the growth of other types of cancer. Studies on structural modifications of UA have shown that the -OH groups at C3 and at C28 are critical factors influencing the cytotoxic activity of UA and its derivatives. Some needs for future research are suggested. Sources of information were from ScienceDirect, Google Scholar and PubMed.

The present study aimed to outline the physiological and metabolic disparity between chow- and purified ingredient-based high-fat diets and their efficacy in the induction of metabolic syndrome (MetS). Male, 3-week-old Sprague Dawley rats were randomly assigned to chow-based control diet, chow-based high-fat diet, purified control diet, and purified high-fat diet for 12 weeks. Physical and biochemical changes were documented. Chow-based diets, irrespective of the lipid content, resulted in significantly lower weight gain and organ weight compared to purified ingredient-based diets. Circulating insulin, total proteins, albumin, and certain lipid components like the triglycerides, total cholesterol, and high-density lipoprotein-cholesterol were also lower in the chow-based diet groups. Both chow- and purified high-fat diets induced central obesity, hypertension, and hyperglycaemia, but the latter was associated with earlier onset of the metabolic aberrations and additionally, dyslipidaemia. In conclusion, purified high-fat diet is a better diet for MetS induction in rats. PRACTICAL APPLICATIONS: Modeling metabolic syndrome is commonly accomplished with the use of chow- or purified ingredient diets enriched with carbohydrates and/or lipids, but the differences and associated drawbacks are unclear. This study highlights that chow- or modified chow-based diets have a tendency to introduce unwanted metabolic changes which are inconsistent with the progression of metabolic syndrome. Thus, the use of these diets in metabolic disease study should be avoided. On the other hand, purified high-fat diet which can effectively induce the features of metabolic syndrome is highly recommended.

The effects of oven-drying at 50 and 100C, sun-drying and ambient air-drying at 24 ± 1C on the antioxidant properties (AOPs) of mulberry (Morus alba L.) leaves were studied. Except for leaves oven-dried at 50C which showed minimal AOP changes, leaves dried under other conditions resulted in a significant decrease in AOP. Fresh mulberry leaves contained low oxidative enzyme activities (polyphenol oxidase [PPO]: 1.40 ± 0.58 ΔA435/min/g of fresh leaves and peroxidase: 1.59 ± 0.42 ΔA418/min/g of fresh leaves) which were reduced to nonmeasureable or lower values when they were dried at 50, 100C and blanched in boiling water. The major factor causing AOP decrease in thermally treated leaves (oven-drying at 100C and sun-drying) was due to thermal degradation but the decrease in AOP for ambient air-dried leaves was associated with the presence of PPO. Overall, oven-drying at 50C was the most preferred drying method. Practical Applications Mulberry with excellent free radical scavenging, antioxidant, anticancer and anti-hyperglycemic properties has long been used as traditional medicine and health food product. Generally, mulberry leaves are processed and consumed as tea. Drying, which helps preserve the nutrient contents of mulberry leaves, is an important method in mulberry tea processing. In order to exploit mulberry leaves more scientifically and efficiently for commercial purpose, the present study serves as an important work in providing insights into how oxidative enzymes and thermal stability of antioxidants in mulberry leaves affect the antioxidant properties when subjected to different drying conditions. The optimum drying condition found in this study will be beneficial to the tea processing industry.

Natural product research is an active branch of science, driven by the increased value placed on individual health and well-being. Many naturally-occurring phytochemicals in plants, fruits and vegetables have been reported to exhibit antioxidant and antibacterial activity; often touted as being beneficial for human health. In vitro screening is a common practice in many research laboratories as a means of rapidly assessing these properties. However, the methods used by many are not necessarily optimal; a result of poor standardization, redundant assays and/or outdated methodology. This review primarily aims to give a better understanding in the selection of in vitro assays, with emphasis placed on some common assays such as the total phenolic content assay, free radical scavenging activity, disc-diffusion and broth microdilution. This includes a discussion on the reasons for choosing a particular assay, its strengths and weaknesses, ways to improve the accuracy of results and alternative assays.

Aims To investigate the antimicrobial properties of Etlingera coccinea and Etlingera sessilanthera and to isolate and identify the antimicrobial compounds. Methods and results Extracts were obtained via sequential solvent extraction method using hexane, dichloromethane, ethyl acetate, methanol and water. Antimicrobial activity testing was done using broth microdilution assay against 17 strains of bacteria. The leaf hexane extract of E. coccinea and rhizome hexane extract of E. sessilanthera showed best antimicrobial activities, with minimum inhibitory concentration (MIC) values ranging from 0·016 to 1 mg ml-1 against Gram-positive bacteria. From these active extracts, two antimicrobials were isolated and identified as trans-2-dodecenal and 8(17),12-labdadiene-15,16-dial with MIC values ranging from 4 to 8 μg ml-1 against Bacillus cereus, Bacillus subtilis and Staphylococcus aureus. Conclusion Etlingera coccinea and E. sessilanthera demonstrated good antimicrobial activities against clinically relevant bacteria strains. The antimicrobial compounds isolated showed low MIC values, hence suggesting their potential use as antimicrobial agents. Significance and impact of the study This study is the first to identify the potent antimicrobials from these gingers. The antimicrobials isolated could potentially be developed further for use in treatment of bacterial infections. Also, this study warrants further research into other Etlingera species in search for more antimicrobial compounds.

Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC), of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5–10 mg/mL based on the broth microdilution method.

Anthocyanins, a popular choice for natural food colorants, are unstable at low acidity or neutral pH. Thus, anthocyanins that are less affected by pH, such as those with multiple acylated groups, are highly desirable. One such source is from the leaves of Rhoeo spathacea (Swartz) Stearn, an herbal plant traditionally decocted and consumed orally. This study tests the stability of the purple-red colour of R. spathacea extract from pH 1.0 to 11.5 stored under refrigerated and room temperature conditions, in the presence and absence of light over a period of 60 days. The colour stability was also monitored in a solid food model (jelly) and a liquid food model (barley water) for a month. The colour was found to be remarkably stable in acidic pH, and completely stable in the food models. The primary anthocyanin in R. spathacea leaves was isolated and identified by NMR to be rhoeonin.

Natural antioxidants with multiple polar atoms and electron-rich bonds are potential mixed-type corrosion inhibitors and ‘green’ alternatives to commercial inorganic corrosion inhibitors. Green tea is one of the richest sources of natural antioxidants. Therefore, this paper compares the corrosion inhibition efficiency (IE) of green tea extract (GT) against commercial calcium nitrite corrosion inhibitor (CI), on steel reinforcing bars (rebars) embedded in mortar. Rebar corrosion was accelerated with impressed current and cyclic wetting-drying, and corrosion development was measured with linear polarization resistance. Selected CI dosages encompassed four chloride-to-nitrite ratios, and the IE of CI and GT were compared at: 1) similar concentration and 2) equal volume. At similar concentration, CI and GT demonstrated a similar IE (51–70%). However, at equal volume, GT exhibited a higher IE than CI (75–80% vs. 14–24%), due to a significant increase in rebar polarization resistance and reduction in iron oxidation rate (anodic slope). Meanwhile, oxygen reduction rate (cathodic slope) and open circuit potential did not change significantly. The changes in anodic and cathodic slope without a significant open circuit potential change suggested that GT was a mixed-type corrosion inhibitor as hypothesized, which formed a protective layer on rebar surface and increased the polarization resistance of the rebars. Based on liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry analyses, it is hypothesized that (-)-epigallocatechin gallate, (-)-epicatechin gallate, and catechin or (-)-epicatechin are responsible for the anti-corrosion activity of GT as a mixed-type corrosion inhibitor.

Antioxidant properties (AOP) of thirteen tropical and five temperate herbal teas were screened. Comparisons were made with green, oolong and black teas of Camellia sinensis. The AOP studied were total phenolic content, radical-scavenging activity, ferric-reducing power and ferrous ion-chelating (FIC) ability. Tropical herbal teas were more diverse in types and more variable in AOP values than temperate herbal teas. Herbal teas generally had lower antioxidant values than teas of C. sinensis. Exceptions were lemon myrtle, guava and oregano teas with AOP comparable to black teas. FIC ability of mint and peppermint teas was significantly stronger than all C. sinensis teas.

The clinical value of tocotrienols is increasingly appreciated because of the unique therapeutic effects that are not shared by tocopherols. However, their effect on metabolic syndrome is not well-established. This study aimed to investigate the effects of a tocotrienol-rich fraction (TRF) from palm oil in high-fat-diet-treated rats. Male, post-weaning Sprague Dawley rats were provided high-fat (60% kcal) diet for eight weeks followed by a TRF (60 mg/kg) treatment for another four weeks. Physical, metabolic, and histological changes were compared to those on control and high-fat diets respectively. High-fat feeding for eight weeks induced all hallmarks of metabolic syndrome. The TRF reversed systolic and diastolic hypertension, hypercholesterolemia, hepatic steatosis, impaired antioxidant defense, and myeloperoxidase hyperactivity triggered by the high-fat diet. It also conferred an inhibitory effect on protein glycation to reduce glycated hemoglobin A1c and advanced glycation end products (AGE). This was accompanied by the suppression of the receptor for advanced glycation end product (RAGE) expression in the liver. The treatment effects on visceral adiposity, glycemic control, triglyceride level, as well as peroxisome proliferator-activated receptor α and γ expression were negligible. To conclude, treatment with a TRF exhibited protective effects on the cardiovascular and liver health in addition to the amelioration of plasma redox imbalance and AGE-RAGE activation. Further investigation as a therapy for metabolic syndrome is therefore worthwhile.

The decoction and infusion of Rhoeo spathacea (Swartz) Stearn leaves have been recognized as a functional food particularly in South America, but has not yet gained international popularity as a beverage. The primary aim of this study was to establish the viability of R. spathacea aqueous leaf extracts as a beverage, in terms of its antioxidant activity and antibacterial activity. The antioxidant contents of aqueous and methanol leaf extracts were evaluated by the total phenolic content (TPC) and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH radical scavenging activity (FRS), ferric reducing power (FRP) and ferrous ion chelating (FIC) activity. The aqueous leaf extracts in the forms of decoction and infusion, were found to have comparable TPC and antioxidant activity with other herbal teas previously reported by our research group. Both decoction and infusion also exhibited antibacterial activity against six species of Gram positive and four species of Gram negative bacteria, notably methicillin-resistant Staphylococcus aureus and Neisseria gonorrhoeae. A total of four different known phenolic compounds were identified by HPLC and MS, three of which have not been previously reported to be found in this plant. Both the decoction and infusion of the leaves R. spathacea have potential to be popularized into a common beverage.

Background For generations, the rhizomes of Drynaria ferns have been used as traditional medicine in Asia. Despite this, the bioactivities of Drynaria rhizomes and leaves have rarely been studied scientifically. Methods This study evaluates the antioxidant properties of the methanolic extracts of the fertile fronds and rhizomes from three species in this genus: Drynaria quercifolia, Drynaria rigidula and Drynaria sparsisora. The phenolic and flavonoid contents of the samples were respectively quantified with the total phenolic content (TPC) and total flavonoid content (TFC) assays, while the antioxidant activities were determined via measuring the DPPH radical scavenging activity (FRS), ferric reducing power (FRP), ferrous ion chelating (FIC) activity and lipid peroxidation inhibition (LPI). The tyrosinase inhibition activity of all three species was also reported. Results The fertile fronds of D. quercifolia were found to exhibit the highest overall TPC (2939 ± 469 mg GAE/100 g) and antioxidant activity amongst all the samples, and the fertile fronds of D. quercifolia and D. rigidula exhibited superior TPC and FRP compared to their rhizomes, despite only the latter being widely used in traditional medicine. The fronds of D. quercifolia had high tyrosinase inhibition activity (56.6 ± 5.0 %), but most of the Drynaria extracts showed unexpected tyrosinase enhancement instead, particularly for D. sparsisora’s fronds. Conclusion The high bioactivity of the fertile fronds in the fern species indicate that there is value in further research on the fronds of ferns which are commonly used mostly, or only, for their rhizomes.