• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.730-739
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) causes severe infections and poses a global healthcare challenge. The utilization of novel molecules which confer synergistical effects to existing MRSA-directed antibiotics is one of the well-accepted strategies in lieu of de novo development of new antibiotics. Thymol is a key component of the essential oil of plants in the Thymus and Origanum genera. Despite the absence of antimicrobial potency, thymol is known to inhibit MRSA biofilm formation. However, the anti-MRSA activity of thymol analogs is not well characterized. Here, we assessed the antimicrobial activity of several thymol derivatives and found that 4-chloro-2-isopropyl-5-methylphenol (chlorothymol) has antimicrobial activity against MRSA and in addition it also prevents biofilm formation. Chlorothymol inhibited staphyloxanthin production, slowed MRSA motility, and altered bacterial cell density and size. This compound also showed a synergistic antimicrobial activity with oxacillin against highly resistant S. aureus clinical isolates and biofilms associated with these isolates. Our results demonstrate that chlorinated thymol derivatives should be considered as a new lead compound in anti-MRSA therapeutics.

• Journal of Acupuncture Research
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• v.40 no.4
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• pp.344-350
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• 2023

Background: 4-carvomenthenol[4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol] is a main component of Origanum vulgare L., Zanthoxylum piperitum (L.) DC., and other plants. It has been reported to exhibit anti-inflammatory, antibacterial, and anti-tumor effects. Furthermore, it is necessary to conduct a toxicity test on 4-carvomenthenol to ensure its safety. Methods: This study included 5-week-old Institute of Cancer Research mice that were categorized into 3 treatment groups (12, 25, and 50 mg/kg 4-carvomenthenol dose levels) and a control group (10% dimethyl sulfoxide, 40% polyethylene glycol 300, 5% Tween 80, and 45% normal saline injection of the final volume), with 5 male mice and 5 female mice per group. All groups were observed for clinical symptoms and body weight in a period of 14 days and were subjected to gross necropsy after euthanasia. Results: No deaths were recorded. No test substance-related clinical signs in the female mice of the 12 mg/kg dose group were observed. Abnormal gait was observed in 1 male from day 1 to day 3 in the 12 mg/kg dose group; 1-3 males from day 1 to day 7 and 1-5 females from day 1 to day 15 in the 25 mg/kg dose group; and 2-5 males and 2-5 females from day 1 to day 15 in the 50 mg/kg dose group. No test substance-related effect on the body weight and necropsy findings was observed. Conclusion: The results of this study suggested that the lethal dose of 4-carvomenthenol could be greater than 50 mg/kg. However, further research is needed, especially repeated-dose toxicity studies, to confirm the efficacy and safety of 4-carvomenthenol.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.315-321
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• 2010

Malassezia furfur is an important causal factor for seborrheic dermatitis. Nowadays, the drugs available to treat this fungal infection are few. Several studies have documented the biological activity of essential oils. However, its antifungal properties are not completely understood, especially its anti-Malassezia activity. The aim of this study were to evaluate the effect of the plant essential oils on the growth of M. furfur using disk diffusion method and analyze by Gas chromatography-mass spectrometry (GC-MS) most active essential oils. In first screening, the 17 plant essential oils have possesses inhibitory activity against M. furfur at 2 mg/mL. Among the plant essential oils, oil of Citrus auranifoli was most active against M. furfur and its activity showed dose dependency. This anti-malassezial activity was high than that of itraconazole at 2 mg/mL. Oil of Citrus auranifolia also was phytochemically examined by GC-MS analysis, its main constituents were identified as limonene, ${\gamma}$-terpinene and terpinolene. It can be concluded that essential oils of Citrus auranifolia may have interesting applications to control fungal-derived diseases.