Search

Limited solubility is the main cause of the low local availability of anti-candidiasis drug, miconazole nitrate (MN). The study's objective was to develop and characterize microemulsion (ME) based temperature-triggered in situ gel of MN for intravaginal administration to enhance local availability and antifungal activity. The solubility of MN was initially studied in different oils, surfactants, and co-surfactants. Then, pseudo-ternary phase diagrams were constructed to select the best ratio of various components. The ME formulations were characterized by thermodynamic study, droplet size, polydispersity index (PDI), viscosity, and in-vitro antifungal mean inhibition zone (MIZ). Selected MEs were incorporated into different in situ gel bases using a combination of two thermosensitive polymers (poloxamer (PLX) 407 and 188), with 0.6% of hydroxypropyl methylcellulose (HPMC K4M) and gellan gum (GG) as mucoadhesive polymer. ME-based gels (MG) were investigated for gelation temperature, gelation time, viscosity, spreadability, mucoadhesive strength, in vitro release profile, and MIZ test. Furthermore, the optimum MG was assessed for in vivo animal irritation test and FESEM investigation. Tea tree oil, lavender oil, tween 80, and propylene glycol (PG) were chosen for ME preparation for the optimal formulation; formulation ME7 and ME10 were chosen. After incorporation of the selected formulation into a mixture of P407 and P188 (18:2% w/w) with 0.6% mucoadhesive polymer, the resultant MG formulation (MG1) revealed optimum gelation temperature (33 ± 0.01℃) and appropriate viscosity with enhanced sustained release (98%) and retention through sheep vaginal mucosa, MG1 exhibited a better MIZ compared to the 2% MN gel formulation and the marketed MN product, and no rabbit vagina irritation. In conclusion, the miconazole nitrate-loaded MG-based formula sustained the duration of action and better antifungal activity than the marketed miconazole nitrate formulation. [ABSTRACT FROM AUTHOR]

Aims To identify efficient, broad-spectrum, and non-toxic preservatives for natural agricultural products, eight essential oils were screened for high inhibitory and antioxidant activities against spoilage microbes. Methods and results The zone of inhibition test and minimum inhibitory concentration (MIC) assay were performed to assess the antimicrobial activity of eight essential oils against Bacillus subtilis, Staphylococcus aureus, Penicillium, Saccharomyces , and Escherichia coli. Among the eight essential oils, garlic and rose essential oils exhibited the best inhibitory effects, their MICs against the spoilage microbes were 40–640 μl/l and 10–320 μl/l, respectively. In addition, the antioxidant activities of eight essential oils were compared using the DPPH and ABTS radical-scavenging assays and the reducing power assay. Eight essential oils had antioxidant capacity, among which rosemary, thyme, rose, and tea tree essential oils performed the best. Moreover, the combination of thyme and rose exerted stronger antioxidant activity. Therefore, the concentrations of rose and garlic, and thyme essential oils were optimized using response surface methodology to obtain the optimal composite ratios, which were 1254 μl/l, 640 μl/l, and 1228 μl/l for rose, garlic, and thyme, respectively. The DPPH free radical-scavenging rate detected using this formulation was 50.2%, basically consistent with the prediction. Zone of inhibition diameters with the compound essential oil, against five spoilage microbes, were all greater than 45 mm. Conclusions The essential oil combination had high antimicrobial, against agricultural product spoilage microbes, and antioxidant activities. [ABSTRACT FROM AUTHOR]

Melanoma, primarily caused by solar ultraviolet (UV) radiation, can be prevented by the use of sunscreens. However, the use of synthetic sunscreens raises environmental concerns. Natural compounds with antioxidant photoprotective properties and cytotoxic effects against cancer cells can be promising for the prevention and treatment of melanoma with less environmental effect. This study focuses on Melaleuca leucadendron essential oil (EO) for photoprotection and antitumor applications. EO was hydrodistilled from M. leucadendron leaves with a 0.59% yield. Gas chromatography–mass spectrometry detected monoterpenes and sesquiterpenes. Nanoemulsions were prepared with (NE-EO) and without EO (NE-B) using the phase inversion method, showing good stability, spherical or oval morphology, and a pseudoplastic profile. Photoprotective activity assessed spectrophotometrically showed that the NE-EO was more effective than NE-B and free EO. Antioxidant activity evaluated by DPPH and ABTS methods indicated that pure and nanoemulsified EO mainly inhibited the ABTS radical, showing IC50 40.72 and 5.30 µg/mL, respectively. Cytotoxicity tests on L-929 mouse fibroblasts, NGM human melanocyte, B16-F10 melanoma, and MeWo human melanoma revealed that EO and NE-EO were more cytotoxic to melanoma cells than to non-tumor cells. The stable NE-EO demonstrates potential for melanoma prevention and treatment. Further research is required to gain a better understanding of these activities. [ABSTRACT FROM AUTHOR]

Melaleuca polandii, commonly known as "Gold-tipped Bottlebrush", is widely grown in Indian gardens and parks as an ornamental plant. In the present study, the chemical composition, antioxidant, antimicrobial and cytotoxic activities of M. polandii leaf essential oil (MPLEO) have been investigated. GC-MS analysis of MPLEO isolated from plants grown along the coastal plains of Eastern India revealed the presence of 50 constituents with α-pinene (46.17%), 3Z-hexenyl acetate (10.10 %), α-terpineol (5.43%), limonene (3.63%) and ρ-cymene (2.44 %) as the major constituents. MPLEO exhibited moderate antioxidant capacity in DPPH, ABTS and Reducing ability assays with IC50 values of 7.94 ± 0.34 μg/mL, 5.71 ± 0.21 μg/mL and EC50 7.09 ± 0.35 μg/mL, respectively. Of the 5 bacterial strains tested, the EO exhibited highest sensitivity against Bacillus subtilis with the ZOI of 12.66 ± 0.57 mm and strong antimicrobial activity against Staphylococcus saprophyticus with MIC value of 6.25 μg/mL. MPLEO exhibited significant cytotoxic effects against Human alveolar lung adenocarcinoma (A549), Human hepato-cellular carcinoma (HepG2), Human cervix adenocarcinoma (HeLa) and normal Human Embryonic Kidney cell (HEK-293) as evaluated through MTT assay with IC50 values of 9.5 ± 0.38 μg/mL, 22.73 ± 0.95 μg/mL, 20.41 ± 0.82 μg/mL and 237.68 ± 9.26 μg/mL, respectively. The findings of the present study demonstrated that MPLEO could be considered as a potential bioresource having applications in pharmaceutical industries as an antibacterial and antiproliferative agent. [ABSTRACT FROM AUTHOR]

This article has systematized the current scientific literature comprising the use of essential oils for acne treatment. The methods for essential oils obtention and their chemical constitution have been presented. The pharmaceutical formulations and advanced technologies used for essential oil topical application have been addressed. The concentration of use, main biological activities and reported adverse effects of essential oils regarding the topical treatment of acne have been presented. The methods for in vitro activity evaluation and the in vivo studies have been discussed. A search in different databases was conducted using the keywords 'essential oil' AND 'acne'. Seventy species of essential oils were identified, demonstrating anti-inflammatory, antibacterial and antioxidant activities. The essential oils of Melaleuca alternifolia Cheel, Cinnamomum zeylanicum Blume, Thymus vulgaris L., Fortunella japonica (Thunb.) Swingle, Copaiba langsdorfii (Desf.) Kuntze and Trachyspermum ammi (L.) Sprague showed the best results. Nonetheless, more in vivo studies should be carried out to confirm efficiency and fully determine adverse reactions and toxicity. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to investigate the synergistic anti-inflammatory effects of combined essential oils from Melaleuca alternifolia and Citrus hystrix peel. Methodology: An emulsion-based gel containing combined essential oils from Melaleuca alternifolia and Citrus hystrix peel was topically applied to the injected area of the carrageenan-induced hind paw edema mouse model. Diclofenac sodium was used as a positive control. The inhibition percentage of protein denaturation in all mice was assessed and calculated based on paw volume (Pv). Results: The highest inhibition percentage, recorded at the third hour in the carrageenan-induced hind paw edema mouse model, was 44.76%, achieved by the mice treated with combined essential oils. This was followed by diclofenac-treated (37.14%), tea tree essential oil-treated (27.62%), and kaffir lime peel essential oil-treated mice (20.10%). A similar trend was observed after 24 hours of treatment, with the anti-inflammatory activity of combined essential oils-treated mice recorded at 46.74%, followed by diclofenac-treated (35.87%), tea tree essential oil-treated (24.97%) and kaffir lime peel essential oil-treated mice (11.97%). Conclusion: These findings confirm the synergistic anti-inflammatory effects of the combined essential oilsincorporated emulsion-based gel on the carrageenan-induced hind paw edema mouse model. [ABSTRACT FROM AUTHOR]

A method was developed for the isolation of geranyl acetate from the crude essential oil (EO) of Melaleuca armillaris (Sol. ex Gaertn.) Sm. leaves, and the purity of the isolated compound was analyzed by GC/MS spectral and NMR analysis and was found to have high purity (98.9%). In addition, the EO isolated presented 0.907 g/cm3, 1.474 and [ α ] D 20 = − 17.6 of density, refraction index and optical rotation, respectively. The chemical composition of the EO obtained for steam distillation from M. armillaris was analyzed by gas chromatographic and spectroscopic techniques (GC/MS and GC/FID). Thirty-eight compounds were identified, representing 99.92% of the total EO analyzed on a DB-5 ms (5% phenylmethylpolysiloxane) capillary column. This analysis showed that the EO consisted mainly of oxygenated monoterpenes (77.01%), followed by monoterpene hydrocarbons (21.31%) and sesquiterpene hydrocarbons (1.31%). Furthermore, the essential oil of M. armillaris was rich in 1,8-cineol (67 ± 2%), followed by limonene (10 ± 1%), α-Terpineol (9 ± 1%) and α-Pinene (5 ± 1%). Finally, the results suggest that the geranyl acetate isolated with high purity from crude essential oil is recommended to be explored as a component in medicinal or industrial use. [ABSTRACT FROM AUTHOR]

Background: Tea tree (Melaleuca alternifolia) oil is an essential oil that is steam distilled from the leaves of the tea tree, native to Australia. The oil has fresh and pleasant odour and some medicinal properties of odour eliminating as well as antibacterial and antiseptic action. Tea tree oil has found increasing use in certain consumer products including cosmetics. Tea tree oil components will vary depending on the growing environment including air and sunlight conditions. Methods: The present study on estimation and seasonal variation on essential oils from different plant parts of tea tree was carried by hydro distillation method. Result: The study reveals that, the needle leaves and flowers have the higher oil content of 2.30% and 2.25% respectively. The effect of months on different plant parts showed that the oil recovery from needle leaves and flowers were higher during the month of July and August. [ABSTRACT FROM AUTHOR]

Surface-active compounds (SACs) of microbial origin are an active group of biomolecules with potential use in the formulation of emulsions. In this sense, the present study aimed to isolate and select yeasts from fruits that could produce SACs for essential oil emulsions. The Candida krusei M4CK was isolated from the Byrsonima crassifolia fruit to make SACs. This emulsification activity (E24) was equal to or greater 50% in all carbon sources, such as olive oil, sunflower oil, kerosene, hexane, and hexadecane. E24 followed exponential growth according to the growth phase. The stability of emulsions was maintained over a wide range of temperatures, pH, and salinity. The OMBE4CK (melaleuca essential oil emulsion) had better and more significant inhibitory potential for biofilm reduction formation. In addition, bioemulsifier BE4CK alone on Escherichia coli and Pseudomonas aeruginosa biofilm showed few effective results, while there was a significant eradication for Staphylococcus aureus biofilms. The biofilms formed by S. aureus were eradicated in all concentrations of OMBE4CK. At the same time, the preformed biofilm by E. coli and P. aeruginosa were removed entirely at concentrations of 25 mg/mL, 12.5 mg/mL, and 6.25 mg/mL. The results show that the bioemulsifier BE4CK may represent a new potential for antibiofilm application. [ABSTRACT FROM AUTHOR]

Essential oil from Melaleuca alternifolia (also known as Tea tree essential oil, TTO) is used as traditional medicine and used as therapeutic in medicine, food and cosmetic sectors. However, this oil is highly unstable, volatile and prone to oxidation which limits its practical use. The objective of this study was synthesis of tea tree oil based O/W (oil/water) nanoemulsions (tea tree essential oil nanoemulsions, TNE) and evaluation of its biological potential. Physiological characterization was carried out using UV, fluorescent, and FT-IR techniques. Various biological activities such as anticancerous, antidiabetic and anti-inflammatory were also estimated. Pharmacokinetics study on TNE was carried out. Encapsulation efficiency of nanoemulsions was found to be 83%. Nanoemulsions were spherical in shape with globule size 308nm, zeta potential -9.42 and polydispersity index was 0.31. Nanoemulsions were stable even after 50days of storage at different temperatures. Anti-oxidant potential of TNE was conducted by various assays and IC50 were: Nitric oxide radical scavenging activity:225.1, DPPH radical scavenging activity:30.66, Iron chelating assay:38.73, and Iron reducing assay:39.36. Notable anticancer activity was observed with the percent cell viability of HeLa cells after treatment with 1, 2 and 5µl of TNE was 82%, 41% and 24%, respectively. Antidiabetic study revealed that TNE inhibited -amylase in a dose-dependent manner, with 88% inhibition at its higher volume of 250µl. Drug kinetic study revealed that nanoemulsions exhibited first-order model. Based on this, the possible role of M. alternifolia oil-based nanoemulsions in cosmetic, food, and pharma sectors has been discussed. [ABSTRACT FROM AUTHOR]

In the context of addressing antimicrobial drug resistance in periocular infections, Tea Tree Oil (TTO) has emerged as a promising therapeutic option. This study aimed to assess the efficacy of TTO against bacterial strains isolated from ocular infections, with a particular focus on its ability to inhibit biofilm formation. Additionally, we designed and analyzed microcapsules containing TTO to overcome certain unfavorable physicochemical properties and enhance its inherent biological attributes. The quality of TTO was confirmed through rigorous analysis using GC-MS and UV-Vis techniques. Our agar diffusion assay demonstrated the effectiveness of Tea Tree Oil (TTO) against ocular bacterial strains, including Corynebacterium spp., coagulase-negative Staphylococcus spp., and Staphylococcus aureus, as well as a reference strain of Staphylococcus aureus (ATCC 25923). Notably, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for all tested microorganisms were found to be 0.2% and 0.4%, respectively, with the exception of Corynebacterium spp., which exhibited resistance to TTO. Furthermore, TTO exhibited a substantial reduction in biofilm biomass, ranging from 30% to 70%, as determined by the MTT method. Through the spray-drying technique, we successfully prepared two TTO-containing formulations with high encapsulation yields (80–85%), microencapsulation efficiency (90–95%), and embedding rates (approximately 40%). These formulations yielded microcapsules with diameters of 6–12 μm, as determined by laser scattering particle size distribution analysis, and exhibited regular, spherical morphologies under scanning electron microscopy. Importantly, UV-Vis analysis post-encapsulation confirmed the presence of TTO within the capsules, with preserved antioxidant and antimicrobial activities. In summary, our findings underscore the substantial therapeutic potential of TTO and its microcapsules for treating ocular infections. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the efficacy of Corymbia citriodora, Melaleuca alternifolia (Myrtaceae), Mentha × piperita (Lamiaceae), and Schinus terebinthifolius (Anacardiaceae) essential oils as an alternative to manage Sitophilus zeamais (Coleoptera: Curculionidae) adults. Methods: Acute contact toxicity, acute toxicity on treated maize grain, fumigation toxicity, repellency bioassays, and GC-MS analysis of the essential oils were carried out. Results: Corymbia citriodora, M. alternifolia, M. × piperita, and S. terebinthifolius oils were toxic at different levels to S. zeamais through residual contact, ingestion and via fumigation, and were also repellent to adults of this pest. Melaleuca alternifolia oil was the most active in contact (LC50 = 18.98 μL.mL−1), ingestion (LC50 = 1.03 μL.g−1), and fumigant (LC50 = 20.05 μL.L−1 air) bioassays. Citronelal (53.6% in C. citriodora), terpinen-4-ol (46.9% in M. alternifolia), menthol (44.8% in M. × piperita), and β -caryophyllene (16.2% in S terebinthifolius) are the major constituents of these oils. Conclusions: Melaleuca alternifolia and M. × piperita essential oils can be used by residual contact, while those of C. citriodora, M. alternifolia, and M. × piperita by mixing with maize grains. Melaleuca alternifolia essential oil can be used as a fumigant, while those of C. citriodora and S. terebinthifolius as repellents for S. zeamais adults. [ABSTRACT FROM AUTHOR]

Objective: To analyse the clinical characteristics and sensitivity of an essential oil patch test series (EOS) in patients sensitized to their own essential oils (EOs). Method: We analysed the clinical data and patch test results obtained with the European baseline series (BSE) and an EOS, as well as the mode of use of EOs, through a questionnaire included in the patient file. Results: The study included 42 patients (79% women, average age 50 years) with allergic contact dermatitis (ACD), 8 patients required hospitalization. All patients were sensitized to the EO they used, primarily lavender (Lavandula augustifolia, 8000‐28‐0), tea tree (Melaleuca alternifolia leaf oil, 68647‐73‐4), ravintsara (Cinnamomum camphora oil, 92201‐50‐8), and 2 cases were attributed to helichrysum (helichrysum italicum flower absolute, 90045‐56‐0). 71% had positive patch tests to fragrance mix I or II, 9 only to the EOS and 4 only with their personal EO. Interestingly, 40% of patients did not spontaneously mention the use of EOs, and only 33% received advice on their use at the time of purchase. Conclusion: Patch tests with the BSE, limonene and linalool HP, and oxidized tea tree oil is sufficient to detect most EO‐sensitized patients. The most important is to test the patient's own used EOs. [ABSTRACT FROM AUTHOR]

Adulteration of tea tree (Melaleuca alternifolia) oil with cheaper essential oils—such as eucalyptus oil—is a major threat to the Australian tea tree oil industry. Near-infrared spectroscopy may offer a rapid, cheap and non-destructive method of assessing adulteration levels in tea tree oil. In this study, near-infrared (NIR) spectra were collected through PCR tubes containing tea tree oil samples with varying concentrations of eucalyptus oil adulterant. Partial least squares regression was able to predict the level of adulteration in the tea tree oil samples with moderate accuracy (R2pred of 0.97 and RMSEP of 5.9% v/v). Furthermore, PLS-DA could discriminate between tea tree oil samples with a high level of adulteration (> 10% eucalyptus oil) and low or no adulteration (0–5% eucalyptus oil) with 93% accuracy for cross-validation and 100% accuracy in the dependent test set. This supports the use of through-container NIRS as a potential quality control method for detecting adulteration of pure tea tree oil samples. [ABSTRACT FROM AUTHOR]

Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompatibility and osteo-inductive behaviour. The generation of mesoporous bioactive glass (nano) particles adds a high surface area for the dissolution and release of bioactive ions, and the possibility to load them with different drugs for antibacterial purposes. Essential oils (EO) are an interesting resource for alternative medical therapy, providing antimicrobial compounds that come from organic/natural resources like aromatic plants. Also, a biological polymer, such as chitosan, could be used to control the release of active agents from mesoporous bioactive glass (MBG) loaded particles. This work presents MBG particles with nominal composition (in mol) 60% SiO2, 30% CaO and 10% P2O5, loaded with essential oil of Melaleuca armillaris, which contains 1,8-cineol as the main active component, with an inhibitory in vitro activity against several bacterial species. Also, co-loading with a broad-spectrum antibiotic, namely gentamicin, was investigated. The MBG particles were found to be of around 300nm in diameter and to exhibit highly porous open structure. The release of EO from the particles reached 72% of the initial content after the first 24 h, and 80% at 48 h of immersion in phosphate buffered solution. Also, the MBG particles with EO and EO-gentamicin loading presented in vitro apatite formation after 7 days of immersion in simulated body fluid. The antibacterial tests indicated that the main effect, after 24 h of contact with the bacteria, was reached either for the MBG EO or MBG EO-gentamicin particles against E. coli, while the effect against S. aureus was less marked. The results indicate that MBG particles are highly bioactive with the tested composition and loaded with EO of Melaleuca armillaris. The EO, also combined with gentamicin, acts as an antibacterial agent but with different efficacy depending on the bacteria type. [ABSTRACT FROM AUTHOR]

The genus Melaleuca (Myrtaceae) is a valuable plant resource for research and applications in medicine, pharmacy, the pharmaceutical industry and folklore medicine. The present study aimed to investigate the chemical components and biological properties of the essential oils (EOs) of three Melaleuca species. Gas chromatography-mass spectrometry analyses revealed that the EOs extracted from the leaves of M. cajuputi, M. quinquenervia and M. leucadendra contained 19-21 compounds with high amounts of oxygenated monoterpenes and sesquiterpenes. Subsequent bioassays demonstrated that the EOs of M. cajuputi, M. quinquenervia and M. leucadendra exhibited antimicrobial activity against all tested microorganisms, including Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aegurinosa and Candida albicans, with minimum inhibitory concentrations in the range 640-2,560 µg/ml. The same EOs exerted inhibitory effects against α-amylase, α-glucosidase, acetylcholinesterase and xanthine oxidase with IC50 values ranging from 331.9±20.64 to 1,453±93.79 µg/ml. The findings obtained in the present study provide additional insight into the enzyme inhibitory properties of the leaf EOs from Melaleuca species that have not been reported in previous research, at least to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Tick infestation is a serious problem in many countries since it has an impact on the health of animals used for food production and pets, and frequently affects humans. Therefore, the present study aimed to investigate the acaricidal effects of nanoemulsions of essential oils of Melaleuca alternifolia (tea tree, TT) and Citrus limon (lemon oil, CL) against the different stages (adult, eggs, and larvae) of deltamethrin-resistant Rhipicephalus annulatus ticks. Three forms of these oils were tested: pure oils, nanoemulsions, and a binary combination. Tea tree and lemon oil nanoemulsions were prepared, and their properties were assessed using a zeta droplet size measurement and a UV-Vis spectrophotometer. The results showed that TT and CL exhibited higher adulticidal effects in their pure forms than in their nanoemulsion forms, as demonstrated by the lower concentrations required to achieve LC50 (2.05 and 1.26%, vs. 12.8 and 11.4%, respectively) and LC90 (4.01% and 2.62%, vs. 20.8 and 19.9%, respectively). Significant larvicidal activity was induced by the TTCL combination, and LC50 was reached at a lower concentration (0.79%) than that required for the pure and nanoemulsion forms. The use of pure CL oil was found to have the most effective ovicidal effects. In conclusion, pure TT and CL have potent acaricidal effects against phenotypically resistant R. annulatus isolates. It is interesting that the activity levels of TT and CL EOs' binary and nanoemulsion forms were lower than those of their individual pure forms. [ABSTRACT FROM AUTHOR]

The GC-MS analysis of tea tree oil (TTO) revealed 38 volatile components with sesquiterpene hydrocarbons (43.56%) and alcohols (41.03%) as major detected classes. TTO efficacy is masked by its hydrophobicity; nanoencapsulation can address this drawback. The results showed that TTO-loaded solid lipid nanoparticles (SLN1), composed of glyceryl monostearate (2% w/w) and Poloxamer188 (5% w/w), was spherical in shape with a core-shell microstructure. TTO-SLN1 showed a high entrapment efficiency (96.26 ± 2.3%), small particle size (235.0 ± 20.4 nm), low polydispersity index (0.31 ± 0.01), and high negative Zeta potential (−32 mV). Moreover, it exhibited a faster active agent release (almost complete within 4 h) compared to other formulated TTO-SLNs as well as the plain oil. TTO-SLN1 was then incorporated into cellulose nanofibers gel, isolated from sugarcane bagasse, to form the 'TTO-loaded nanolipogel' which had a shear-thinning behavior. Second-degree thermal injuries were induced in Wistar rats, then the burned skin areas were treated daily for 7 days with the TTO-loaded nanolipogel compared to the unmedicated nanolipogel, the TTO-loaded conventional gel, and the normal saline (control). The measurement of burn contraction proved that TTO-loaded nanolipogel exhibited a significantly accelerated skin healing, this was confirmed by histopathological examination as well as quantitative assessment of inflammatory infiltrate. This study highlighted the success of the proposed nanotechnology approach in improving the efficacy of TTO used for the repair of skin damage induced by burns. [ABSTRACT FROM AUTHOR]

Background: Vulvovaginal candidiasis (VVC) is a disease with high incidence, a huge impact on the quality of life and health of women, and which represents a great challenge to treat. The growing need to apply antifungal intensive therapies have contributed to an emergence of drug-resistant Candida strains. Thus, effective therapeutic options, to meet the antifungal-resistance challenge and to control high resilient biofilms, are urgently needed. This study aimed to investigate the antifungal activity of essentials oils (EOs) on drug-resistant Candida vaginal isolates. Method: Therefore, the antimicrobial effect of tea tree, niaouli, white thyme, and cajeput EOs on the planktonic growth of Candida isolates was initially evaluated by an agar disc diffusion method. Then, the vapor-phase effect of tea tree EO (VP-TTEO) on biofilm formation and on pre-formed biofilms was evaluated by crystal violet staining, XTT reduction assay, colony forming units' enumeration, and scanning electron microscopy. Results: The results revealed high antifungal activity of EOs against drug-resistant Candida isolates. Additionally, the VP-TTEO showed a significant inhibitory effect on the biofilm formation of all tested isolates and was able to provoke an expressive reduction in mature Candida albicans biofilms. Conclusions: Overall, this study suggests that the VP-EO may be a promising solution that is able to prevent biofilm-related VVC caused by antifungal-resistant strains. [ABSTRACT FROM AUTHOR]

Mosquitoes act as vectors for the transmission of various infectious pathogens. The associated diseases are prevalent in tropical and subtropical regions of the world and can be prevented by effective vector control and management. Natural compounds have become a potential alternative to synthetic repellents that are unsafe and harmful to the environment. The repellent activity of trans‐anethole and tea tree [Melaleuca alternifolia (Maiden & E. Betche) Cheel, Myrtaceae] oils was tested against the vector Aedes aegypti (L.) (Diptera: Culicidae) by performing a modified arm‐in‐cage and cloth‐patch repellent assay. Tea tree oil [EC50 = 0.002 mg ml−1, 95% confidence interval (CI) = 0.001–0.003] was found to be a more potent repellent than trans‐anethole (EC50 = 0.003 mg ml−1, 95% CI = 0.001–0.007). Tea tree oil was determined to have a complete protection time of 60 min, which was less than N,N‐dimethyl‐3‐methylbenzamide (DEET), which was used as a control (480 min). The binding affinity of trans‐anethole and terpinen‐4‐ol (a major component of tea tree oil) for the protein target AaegOBP1, a component of the olfactory system of Ae. aegypti, was determined using blind and targeted molecular docking. The results of molecular docking were in accordance with the findings of the repellent assay. OBP1 was found to have a better binding affinity for terpinen‐4‐ol (ΔG = −7.1 kcal per mol) than trans‐anethole (ΔG = −6.9 kcal per mol). In addition, a hydrogen bond of 0.1997 nm (1.997 Å) long was formed between PHE123 of OBP1 and terpinen‐4‐ol as established with Mcule. Further detailed analysis and experimentation of natural products as repellents is required as they may replace currently used synthetic repellents – natural repellents generally have less side effects and lower toxicity while being cost‐effective and easily available. [ABSTRACT FROM AUTHOR]

This study examined the ability of essential oils (EOs) obtained from the Australian native plants, lemon myrtle (Backhousia citriodora) (LM) and lemon scented tea tree (Leptospermum petersonii) (LSTT) to inhibit the in vivo growth of Penicillium digitatum in citrus fruits. The main constituent of LM and LSTT EOs was citral at 85 and 64%, respectively. Citral was included for comparison. Oranges dipped for 120 sec in EO solutions showed less fungal wastage compared to control with efficacy being LM > pure citral > LSTT, with 1000 μL L−1 LM EO the optimal treatment. The greater response of LM over LSTT EO was attributed to its higher concentration of citral but the greater effect over citral suggested some minor constituent(s) of LM EO also had antifungal activity. While the 120 sec dips caused severe rind injury, a 30 sec dip in 1000 µL L−1 LM EO generated only slight injury and inhibited fungal wastage in Valencia and Navel oranges, mandarins and lemons. A 10 sec dip did not cause rind injury but was less effective for mould inhibition. The findings suggest LM EO as an alternative to synthetic fungicides to inhibit wastage in citrus during storage, particularly for organic produce. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eco-friendly Melaleuca alternifolia essential oil Pickering emulsions with strain softening behavior. • High-stable oil-in-water emulsions using cellulose nanofibrils. • Nonlinear viscoelasticity properties of Melaleuca alternifolia essential oil-in-water Pickering emulsions stabilized with cellulose nanofibrils via LAOS measurements. • FT rheology of Melaleuca alternifolia essential oil-in-water Pickering emulsions stabilized with cellulose nanofibrils. • Relationships among nonlinear viscoelasticity, FT rheology coefficients and internal structural changes in Pickering emulsions. Pickering emulsions are suitable technological approaches to stabilize the bioactive compounds of essential oils (EOs) with economic interests for the pharmaceutical, cosmetic and food industries using atoxic and renewable stabilizers, such as cellulose nanostructures. The Melaleuca alternifolia essential oil (MaEO) is recognized for its pronounced antimicrobial performance, which has attracted your interest in developing eco-friendly antiseptic products. In this contribution, we report the nonlinear viscoelasticity behavior of MaEO-in-water Pickering emulsions stabilized by cellulose nanofibrils (CNF) using Large Amplitude Oscillatory Shear (LAOS) tests. The rheological characterizations by Fourier Transform (FT) rheology spectroscopy and Lissajous plots enabled the correlation of the viscous and elastic behaviors with the physical processes involving the deformation of the emulsion. Also, the internal structure of the emulsion was elucidated by fluorescence optical microscopy. Several findings relative to the effects of the shear deformation amplitude over the nonlinear viscoelasticity of the emulsified system are reported here, which are essential to the industrial processes used to develop technological products. [ABSTRACT FROM AUTHOR]

Legionella pneumophila (Lp), responsible for a severe pneumonia called Legionnaires' disease, represents an important health burden in Europe. Prevention and control of Lp contamination in warm water systems is still a great challenge often due to the failure in disinfection procedures. The aim of this study was to evaluate the in vitro activity of Terpinen-4-ol (T-4-ol) as potential agent for Lp control, in comparison with the essential oil of Melaleuca alternifolia (tea tree) (TTO. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of T-4-ol were determined by broth micro-dilution and a micro-atmosphere diffusion method to investigate the anti-Lp effects of T-4-ol and TTO vapors. Scanning Electron Microscopy (SEM) was adopted to highlight the morphological changes and Lp damage following T-4-ol and TTO treatments. The greatest antimicrobial activity against Lp was shown by T-4-ol with a MIC range of 0.06–0.125% v/v and MBC range of 0.25–0.5% v/v. The TTO and T-4-ol MIC and MBC decreased with increasing temperature (36 °C to 45 ± 1 °C), and temperature also significantly influenced the efficacy of TTO and T-4-ol vapors. The time-killing assay showed an exponential trend of T-4-ol bactericidal activity at 0.5% v/v against Lp. SEM observations revealed a concentration- and temperature- dependent effect of T-4-ol and TTO on cell surface morphology with alterations. These findings suggest that T-4-ol is active against Lp and further studies may address the potential effectiveness of T-4-ol for control of water systems. [ABSTRACT FROM AUTHOR]

In order to explore the best extraction process of essential oil of Melaleuca alternifolia by green deep eutectic solvents, four different extraction processes were compared including fresh-steam distillation extraction, dry-steam distillation extraction, freeze thawing-steam distillation extraction and deep eutectic solvents-distillation extraction. The effects of liquid-material ratio, distillation time, molar ratio of deep eutectic solvents, raw material drying time, water content on extraction rate of essential oil of M. alternifolia were investigated by single factor test. Based on single-factor tests, the quadratic regression parasitism model was established through the response surface methodology. The essential oil of M. alternifolia was determined by gas chromatography-mass spectrometry(GC-MS). The results were as follows:(1)Deep eutectic solvents-distillation extraction was the best extraction processes. The optimal extraction conditions were determined to be molar ratio of choline chlorid to 1,3-Butanediol 1:3(mol:mol), water content 52 mol, drying time of raw materials 9 h, material-liquid ratio 1:5 g·mL-1, distillation time 60 min, and the maximum extraction rate of essential oil of M. alternifolia reached 4.06%, which was 383.33%, 290.38% and 497.06% higher than that of fresh-steam distillation extraction, dry-steam distillation extraction and freeze thawing-steam distillation extraction, respectively. Response surface methodology was proved to be applicable for extraction of essential oil from M. alternifolia, the experimental results were in good agreement with the predicted values of the response surface model.(2)The main components of essential oil of M. alternifolia extracted by four different extraction processes were proved to be almost same, while the contents were signifcanthy different.(3)Alcohols and alkenes were confirmed to be the main components in the essential oil of M. alternifolia. The extraction yield and characteristic component content of essential oil of M. alternifolia extracted by deep eutectic solvents-distillation were indicated much higher than those by other three processes,which including eight alcohols, nine alkenes and three other compounds, with the main components of γ-Terpinene,α-Terpinene,α-Pinene,α-Terpineol and alloaromadendrene, and the relative content of alkenes was 45.31%, the content of Terpinen-4-ol and eucalyptol was 30.58% and 0.12%. This study provides the data supporte for the further utilization of M. alternifolia and green extraction of natural products. [ABSTRACT FROM AUTHOR]

Essential oils (EOs) have a long tradition of use in the medical and cosmetic fields based on their versatile properties, including fungicidal, antiparasitic, and bactericidal effects. Nowadays, with the development of industry and electronics, EOs are increasingly being used in the agricultural and food industries; health industries, including pharmacy and dental medicine; and as cosmetic enhancements. The purpose of this study is to develop a compact and portable platform for the detection of EO type and the concentration levels using knitted silver threads. The method is based on measuring the variation in values of the electrical parameters of the silver threads using electrochemical impedance spectroscopy (EIS). The impedance of the solutions applied on the testing platform was measured in the frequency range from 1 Hz to 200 kHz. The platform was tested using three types of essential oils: tea tree; clary sage; and cinnamon bark oil. Increasing the concentration of essential oils resulted in increasing the electrical resistance of the platform, decreasing the capacitance, and consequently increasing the impedance. The proposed cost-effective platform can be used for the fast determination of the type and quality of essential oils. [ABSTRACT FROM AUTHOR]

This study investigated the effects of dietary tea tree oil (TTO) supplementation and feeding patterns on the growth and nonspecific immunity of Macrobrachium rosenbergii. Prawns were randomly assigned into four patterns. Patterns 1 (P1) and 4 (P4): prawns were fed with a basal diet and basal diet supplemented with 100 mg/kg of TTO, respectively; Patterns 2 (P2) and 3 (P3): prawns were fed with the basal diet supplemented with 100 mg/kg of TTO at 1‐ and 2‐week intervals, respectively. A significant increase in growth performance was observed in the P3 and P4 compared with P1. The activities of antioxidant enzyme were significantly elevated in the P3 and P4 compared with the P1. The concentration of haemolymph malondialdehyde was significantly lower in the P3 and P4 than the P1. The haemolymph level of IL‐1 and TNF‐α was significantly lower in the P3 than the P4. The expression of toll and dorsal was significantly lower in the P3 than the P1. However, the expression of peroxiredoxin‐5 was significantly higher in the P3 than the P1. Overall, these findings indicated that feeding 100 mg/kg of TTO at 2‐week intervals significantly improved the growth performance and nonspecific immunity of M. rosenbergii. [ABSTRACT FROM AUTHOR]

The aim was to compare the in-vitro antibacterial effectiveness of two herbal extracts (a) Saussurea-costus (S. costus) and (b) Melaleuca-alternifolia (M. alternifolia) against Porphyromonas gingivalis (P. gingivalis), Streptococcus mutans (S. mutans) and Enterococcus faecalis (E. faecalis). Aqueous extracts from M. alternifolia were prepared by adding 2 grams of S. costus and M. alternifolia, respectively to 100 ml distilled water. Bacterial strains of P. gingivalis, E. faecalis and S. mutans were treated into 3 groups. In groups 1 and 2, bacterial strains were treated with aqueous extracts of S. costus and M. alternifolia, respectively. In the control-group, bacterial strains were exposed to distilled water. Antibacterial activity of the samples and nanoparticles was determined. The minimum-inhibitory-concentration (MIC) values were determined using the microdilution method. P < 0.01 was considered statistically significant. The MIC for all bacterial strains treated with S. costus was significantly higher than that of M. alternifolia (P < 0.001). There was no significant difference in MIC for strains of P. gingivalis, E. faecalis and S. mutans treated with S. costus. For bacterial strains treated with M. alternifolia, the MIC was significantly higher for P. gingivalis compared with E. faecalis and S. mutans strains (P < 0.01). There was no difference in MIC for E. faecalis and S. mutans strains treated with M. alternifolia. The in-vitro antibacterial efficacy of M. alternifolia is higher than S. costus against P. gingivalis, E. faecalis and S. mutans.

Copyright of Journal of Animal & Poultry Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The essential oil of Melaleuca alternifolia, commonly known as tea tree oil, has many beneficial properties due to its bioactive compounds. The aim of this research was to characterize the tea tree essential oil (TTEO) from Slovakia and its biological properties, which are specific to the chemical composition of essential oil. Gas chromatography/mass spectroscopy revealed that terpinen-4-ol was dominant with a content of 40.3%. γ-Terpinene, 1,8-cineole, and p-cymene were identified in contents of 11.7%, 7.0%, and 6.2%, respectively. Antioxidant activity was determined at 41.6% radical inhibition, which was equivalent to 447 μg Trolox to 1 mL sample. Antimicrobial activity was observed by the disk diffusion method against Gram-positive (G+), Gram-negative (G−) bacteria and against yeasts, where the best antimicrobial activity was against Enterococcus faecalis and Candida albicans with an inhibition zone of 10.67 mm. The minimum inhibitory concentration showed better susceptibility by G+ and G− planktonic cells, while yeast species and biofilm-forming bacteria strains were more resistant. Antibiofilm activity was observed against Pseudomonas fluorescens and Salmonella enterica by MALDI-TOF, where degradation of the protein spectra after the addition of essential oil was obtained. Good biological properties of tea tree essential oil allow its use in the food industry or in medicine as an antioxidant and antimicrobial agent. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is one of the most common bacterial isolates found in wounds. Thus, innovative dressings, such as hydrogels, are interesting vehicles for incorporating bioactive compounds like those from Melaleuca alternifolia essential oil (MaEO). In this study, we evaluated the antimicrobial and anti-inflammatory potential of MaEO incorporated into an alginate and chitosan hydrogel for treating wounds infected by S. aureus. The hydrogel incorporated with MaEO 1% (HMa 1%) was homogeneous with a bright pale-yellow color and the characteristic smell of Melaleuca. The incorporation of MaEO 1% does not affect the stability of the hydrogel, which was stable up to 90 days of storage. The Scanning electron microscopy analysis revealed that hydrogels showed irregular surfaces and interconnected porous structures with accumulations of oil crystals distributed throughout the formulation. HMa 1% has a high moisture content (95.1%) and can absorb simulated wound fluid. Regarding the antimicrobial effects, HMa 1% reduced the growth of S. aureus ATCC 6538 in both in vitro conditions and in an ex vivo model of wounds using porcine skin. In addition, the dairy topical treatment of murine skin lesions with HMa 1% induced a significant reduction of the wound area, inflammation score, and bacterial load, as well as tissue re-epithelialization and modulation of inflammatory mediators. Therefore, hydrogel incorporated with MaEO 1% has excellent potential to be used in the pharmacotherapy of infected wounds. [Display omitted] • Essential oil of M. alternifolia inhibits S. aureus in vitro, in vivo and ex vivo. • Hydrogel of Melaleuca reduces the severity of S. aureus- infected wounds. • Treatment with HMa 1% improves re-epithelialization of infected wounds. • Hydrogel of Melaleuca inhibits the production of nitric oxide in mice. • Treatment with HMa 1% stimulates the production of IL-10 in mice. [ABSTRACT FROM AUTHOR]

Sulphate-reducing bacteria are commonly associated with biological causes of oil well souring. Biosulphetogenesis can directly affect oil quality and storage due to the accumulation of sulphides. In addition, these microorganisms can create bio-incrustation that can clog pipes. Sulphite reductase (SIR) is the enzyme responsible for converting ion sulphite into sulphide and several substances may interfere or control such activity. This interference can hinder growth of the sulphate-reducing bacteria and, consequently, it reduces sulphide accumulation in situ. This work focuses on molecular modelling techniques along with in vitro experiments in order to investigate the potential of two essential oils and one vegetable oil as main inhibitors of sulphite reductase activity. Docking simulation identified several substances present in Rosmarinus officinalis, Tea tree and Neem extractable oils as potential inhibitors of SIR. Substances present in Neem vegetable oil are the most potent inhibitors, followed by Rosmarinus officinalis and Tea tree essential oils. The Neem oil mixture showed a superior effectiveness in intracellular SIR inhibitory effects. [ABSTRACT FROM AUTHOR]

Legionella pneumophila (Lp), responsible for a severe pneumonia called Legionnaires’ disease, represents an important health burden in Europe. Prevention and control of Lp contamination in warm water systems is still a great challenge often due to the failure in disinfection procedures. The aim of this study was to evaluate the in vitro activity of Terpinen-4-ol (T-4-ol) as potential agent for Lp control, in comparison with the essential oil of Melaleuca alternifolia (tea tree) (TTO. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of T-4-ol were determined by broth micro-dilution and a micro-atmosphere diffusion method to investigate the anti-Lp effects of T-4-ol and TTO vapors. Scanning Electron Microscopy (SEM) was adopted to highlight the morphological changes and Lp damage following T-4-ol and TTO treatments. The greatest antimicrobial activity against Lp was shown by T-4-ol with a MIC range of 0.06–0.125% v/v and MBC range of 0.25–0.5% v/v. The TTO and T-4-ol MIC and MBC decreased with increasing temperature (36 °C to 45 ± 1 °C), and temperature also significantly influenced the efficacy of TTO and T-4-ol vapors. The time-killing assay showed an exponential trend of T-4-ol bactericidal activity at 0.5% v/v against Lp. SEM observations revealed a concentration- and temperature- dependent effect of T-4-ol and TTO on cell surface morphology with alterations. These findings suggest that T-4-ol is active against Lp and further studies may address the potential effectiveness of T-4-ol for control of water systems.

Leaf-cutting ants are insects of great economic importance which cause economic losses in numerous crops. Compounds that modulate behaviour, and among these natural repellents, show promise in integrated pest management strategies. Tea tree oil has been found to be repellent to certain insect pests, so this study aimed at identifying the effect of tea tree on foraging behaviour in Acromyrmex spp. ants in laboratory as well as in field trials. In laboratory bioassays, a repellent dose response effect of tea tree oil was observed, where concentrations of 0.0001 to 0.1% tea tree did not affect ant behaviour, but concentrations of 1 and 10% repelled ants. In the laboratory, the repellent effect of tea tree was lost after four days and its effect on ant behaviour was evident only at very short distances (less than 1 cm). In the field, ants avoided walking through filter papers treated with tea tree at 1% placed on the foraging trails, and food resources surrounded by tea tree at 1% were not collected. Tea tree is a potent short term leaf-cutting ant repellent and attractive food sources could be protected from leaf-cutting ants attack by this oil. [ABSTRACT FROM AUTHOR]

The presence of microorganisms in skin wounds can lead to infections that hamper the healing process; therefore, growing interest is given to the development of antimicrobial dressing. This study evaluates the ability of tea tree essential oil (EO) to eliminate resistant microorganisms, and new antibacterial bionanocomposites are prepared in two steps, namely sonication followed by melt mixing. Montmorillonite clay (MMT) and poly(acid lactic) (PLA) are chosen for constituting a polymer‐clay bionanocomposite for application in wound dressing. MMT retains and promotes a controlled release of the drug into the wound. Synthetic PLA is approved by the Food and Drug Administration for wound dressing applications. Disk diffusion tests evaluate the antimicrobial properties of tea tree oil, and X‐ray diffraction (XRD) and transmission electron microscopy (TEM) analyzed the extent of clay intercalation/exfoliation. Tea tree essential oil is effective against Escherichia coli and Staphylococcus aureus bacteria. According to the XRD results, the preparation method used can promote oil incorporation into the MMT galleries. TEM micrographs corroborated such results showing the coexistence of intercalated‐exfoliated structures in the bionanocomposites. As a conclusion, the produced bionanocomposites with tea tree essential oil are interesting antibacterial material to be used in wound dressing applications. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to determine the bioactive compounds in rosemary essential oil (REO) and tea tree essential oil (TEO) and to investigate their antibacterial and antibiofilm activities against Staphylococcus aureus and Escherichia coli in vitro. The MIC and MBC assays were performed to assess the antibacterial activity of these two EOs against S. aureus and E. coli with the broth microdilution method. A crystal violet assay was used to ascertain the effects of EOs on the biofilm formation of the test strains, and a tetrazolium bromide (MTT) assay was used to measure the level of inactivation of mature biofilms by EOs. Gas chromatography–mass spectrometry revealed 15 compounds in REO and 27 compounds in TEO, representing 97.78 and 98.13% of the total EO, respectively. Eucalyptol and α-pinene were found in high concentrations in REO, and the two major compounds in TEO were 4-terpineol and terpinolene. The MICs of REO for the two S. aureus and E. coli test strains were both 0.5 mg/mL, and the MICs of TEO for the two strains were both 0.25 mg/mL. Therefore, these EOs can significantly inhibit the formation of biofilms and induced morphological biofilm changes, as verified by scanning electron microscopy. Both EOs had destructive effects on the mature biofilm of the two test strains. TEO was more inhibitory than REO for biofilm formation by the two test strains. 4-Terpineol and terpinolene were characteristic components of TEO. Eucalyptol and α-pinene were characteristic components of REO. The two EOs had antibacterial activity against both gram-positive and gram-negative bacteria. The two EOs had a strong inhibitory effect on S. aureus and E. coli biofilms. [ABSTRACT FROM AUTHOR]

To identify the natural antifungal agents, the antifungal activities of Melaleuca leucadendra (L.) L. essential oil (ML-EO) from Fujian Province of China were assayed. Treatment of ML-EO in combination with the front-line using antibiotics against Candida led to synergistic effects. Electron microscopy analysis on the oil treated C. albicans cells revealed the formation of mesosome-like structures, suggesting well the membrane damage caused by the essential oil. The Griess assay by monitoring NO production in LPS-stimulated RAW264.7 cells indicated the potent anti-inflammatory activity of ML-EO. In comparison with the marked essential oil of Melaleuca alternifolia EO, ML-EO had almost the same chemical components. In general, the antifungal activity of ML-EO and its synergistic interactions with conventional antibiotics were able to lead the development of new treatment strategies on Candida infection. [ABSTRACT FROM AUTHOR]

Highlights • Utilisation of mānuka and kānuka trees for industrial application are discussed. • Products of kānuka as much as mānuka possess almost similar characteristics. • Kānuka oil has viable immuno-stimulatory properties than that of mānuka. • Large avenues, beyond current products to be exploited commercially. Abstract This paper brings to light the current status of products from mānuka , (Leptospermum scoparium J.R.Forst. & G.Forst) and kānuka (Kunzea ericoides (A.Rich) Joy Thomps), and to show that kānuka products also have significant biological potency. Mānuka and kānuka are two native tea tree species found widely within New Zealand. Most research on these two plants was and still is, motivated by the medicinal value identified in the products such as essential oil. It was observed that unlike mānuka, which has extensive and in-depth research and reviews conducted on it, similar studies and appraisals on kānuka is lacking. The few available research outputs available on kānuka have proven that it is superior in terms of anti-inflammatory properties, hence more research and appraisal is required to demonstrate its potency. This review presents evidence that will help promote diversified utilisation of mānuka and kānuka and encourage commercialisation of the latter as much as is done for the former. [ABSTRACT FROM AUTHOR]

Mastitis is the main cause of antibiotic use in dairy sheep. Post-milking teat disinfection is adopted to prevent intra-mammary infections. Use of chemical disinfectants is associated with biocide and antibiotic resistance. Terpinen-4-ol (T-4-ol), component of the Melaleuca alternifolia essential oil, shows antibacterial properties without inducing resistance. Aim of the trial was to evaluate the efficacy of a T-4-ol post-dipping compound in preventing bacterial mastitis in dairy sheep. In two different farms, two groups of 35 ewes were recruited as experimental and control arm (exposed to chlorhexidine-based disinfectant). No differences were observed during the follow-up. In one livestock, during the first year, 30-day incidence of mastitis was significantly lower in the T-4-ol group. Post-milking teat disinfection with T-4-ol showed equivalent efficacy in terms of mastitis incidence. Disinfectants based on natural compounds for mastitis prevention could potentially reduce environmental pollution, avoid drug residues in milk and decrease the antimicrobial resistance development. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the influence of tea tree essential oil (Melaleuca alternifolia) on ochratoxin A synthesis by fungi. Commercially available tea tree essential oil was perched from Infinity Feed Company from Novi Sad, Serbia. Qualitative analyses of tea tree essential oil were performed by GC-MS. The toxigenic activity of the essential oil (7.5; 15.0 and 30.0 μg/ml) was evaluated by inhibiting the production of ochratoxin A by Aspergillus niger. The quantification of the toxin was performed by HPLC. The production of ochratoxin A was dependent on the incubation temperature, 20 and 30°C in the presence of the essential oil. Obtained values from 20°C showed a reduction in ochratoxin A synthesis that ranged from 53.87 to 96.22%, and from 18.36 to 72.85% at 30°C, for the A. niger, respectively. Based on the obtained results from this research, it was concluded that tea tree essential oil as a natural products could serve as potential biocontrol agent against ochratoxin A contamination in feed. [ABSTRACT FROM AUTHOR]

• Essential or vegetable oils showed antiviral properties against SARS-CoV-2. • Melaleuca and cinnamon showed that 0 and 5 min of exposure, respectively, were enough to inactivate SARS-CoV-2. • Cardamom essential oil inactivated the virus after 30 min, and buriti oil after 60 min. • Linalool oil did not present SARS-CoV-2 inactivation. • Essential oils are potential natural active agents to combat the COVID-19 pandemic or other pathogenic microorganisms. The new SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has spread exponentially since the first recognition of the new virus and continues to infect millions of individuals worldwide. The importance of contaminated surfaces in transmission is uncertain. Minimizing surface contact, hand hygiene after surface contact, and cleaning and disinfecting the environment are recommended to reduce the risk of acquiring SARS-CoV-2. As surfaces are prone to transmitting COVID-19 infection, highly exposed surface areas need to be cleaned frequently with a suitable disinfectant. Essential oils have been extensively used as antimicrobial extract for several microorganisms. However, no experimental studies have previously investigated these compounds against the SARS-CoV-2. In this work, we conducted a comprehensive mapping of SARS-CoV-2 protein denaturation using different essential oils (EO) aiming at the future development of natural disinfectants. The tested oils were melaleuca, cinnamon, cardamom, buriti, and linalool. Positive nasopharyngeal samples of COVID-19 patients were exposed in direct contact with EOs, at different times, and the virus elimination efficiency was verified through an immunochromatographic Rapid Antigen Test. The best EOs were Melaleuca alternifolia and Cinnamomum cassia , which denatured SARS-CoV-2 proteins at least with 5 min of contact by interfering with the viral envelope or the spike protein. Cardamom oil probably damaged the virus capsid, and buriti oil disrupted the viral protein envelop. Linalool oil did not denature SARS-CoV-2 proteins. Oils have a considerable potential to produce ecologically friendly disinfectants that can inactivate SARS-CoV-2 in different contact times depending on the mechanism of action and oil-active compounds. [ABSTRACT FROM AUTHOR]

Melaleuca alternifolia essential oil (MaEO) is a green antimicrobial agent suitable for confection eco-friendly disinfectants to substitute conventional chemical disinfectants commonly formulated with toxic substances that cause dangerous environmental impacts. In this contribution, MaEO-in-water Pickering emulsions were successfully stabilized with cellulose nanofibrils (CNFs) by a simple mixing procedure. MaEO and the emulsions presented antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, MaEO deactivated the SARS-CoV-2 virions immediately. FT-Raman and FTIR spectroscopies indicate that the CNF stabilizes the MaEO droplets in water by the dipole-induced-dipole interactions and hydrogen bonds. The factorial design of experiments (DoE) indicates that CNF content and mixing time have significant effects on preventing the MaEO droplets' coalescence during 30-day shelf life. The bacteria inhibition zone assays show that the most stable emulsions showed antimicrobial activity comparable to commercial disinfectant agents such as hypochlorite. The MaEO/water stabilized-CNF emulsion is a promissory natural disinfectant with antibacterial activity against these bacteria strains, including the capability to damage the spike proteins at the SARS-CoV-2 particle surface after 15 min of direct contact when the MaEO concentration is 30 % v/v. • This paper reports the antiviral performance of Melaleuca alternifolia essential oil against SARS-CoV-2. • Melaleuca alternifolia essential oil Pickering emulsions stabilized with cellulose nanofibrils can inactivate SARS-CoV-2. • Bactericidal activities of Melaleuca alternifolia essential oil/water CNF-stabilized Pickering emulsions against different bacteria strains. • Oil-in-water CNF-stabilized Pickering emulsions look like effective and promising eco-friendly disinfectants. [ABSTRACT FROM AUTHOR]

Nanochitins have been explored for preparing Pickering Emulsions, however its application is restricted by its simplex disperse nature. It was hypothesized that zwitterionic nanochitins should be capable of stabilizing oil/water (O/W) interfaces in wider pH range. Furthermore, the control of their size, disperse nature and self-assembly performance suggest the formulation of tunable emulsions. Zwitterionic nanochitins were prepared via Schiff base reaction. A systematic study was performed analyzing the disperse nature, fibril morphology, surface characteristic of modified nanochitins. Oil-in-Water Pickering Emulsions stabilized by modified nanochitins were formulated and emulsion stability was analyzed as function of concentration, pH and self-assembly property and further applied for prolonged antibacterial applications. Comparing freshly prepared nanochitins, neutral/alkaline stably dispersed nanochitins can be prepared while maintaining fibril characteristics such as fibril size, crystallinity, thermal stability and so on. Better suspension stability of modified nanochitins under alkaline conditon together with the self assembly performance resulting from amino groups and carboxyl groups benefit the enhanced emulsion stability under nanochitins concentreation of 0.2 %. Encapsulation of tea tree oil in Pickering Emulsions prolongs the diffusion rate oil in the aqueous environment, thus resulting prolongs its antibacterial performance against E. coli and B. subtilis. [Display omitted] • Dispersibilty of nanochitin can be adjusted by grafting glyoxylic acid. • Stable Pickering emulsion can be prepared using modified nanochitins. • Self-assembly between modified nanochitins improves emulsion stability. • Emulsion encapsulated tea tree oil possess prolonged antibacterial activity. [ABSTRACT FROM AUTHOR]

The growing interest towards essential oils stems from their biological capabilities that include antibacterial and antioxidant effects. Such properties may be extremely useful in the reproductive field; nonetheless essential oils show toxic effects that can lead to cell disruption. The present study aimed to evaluate and compare the effects of tea tree oil (TTO) and its principal component terpinen-4-ol (TER) on the morpho-functional parameters of swine spermatozoa. Experimental samples were prepared by suspending 15 × 107 spermatozoa in 5 mL of medium with different concentrations of the above-mentioned compounds: from 0.2 to 2 mg/mL at an interval of 0.2 for TTO, while TER concentrations were adjusted according to its presence in TTO (41.5%). After 3 h incubation at 16 °C, samples were analyzed for pH, viability, acrosome status, and objective motility. The results highlighted a concentration-dependent effect of TTO with total motility as the most sensitive parameter. TER was better tolerated, and the most sensitive parameters were related to membrane integrity, suggesting a different pattern of interaction. The study confirms the importance of evaluating the effects of natural compounds on spermatozoa before exploiting their beneficial effects. Spermatozoa seem to be good candidates for preliminary toxicological screenings in the light of their peculiar properties.