Department of Basic Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, PMB 31, Ho, VR, Ghana.
Chem Biodivers. 2022 Sep;19(9):e202200296. doi: 10.1002/cbdv.202200296. Epub 2022 Aug 26.
We investigated whether three extractable fractions of lemongrass (Cymbopogon citratus): aqueous and ethanol extracts and lemongrass essential oil exhibited any antimicrobial resistance modulatory effects if used in combination with selected antibiotics ampicillin, tetracycline, streptomycin, cefloxacin and amoxicillin on methicillin-resistant Staphylococcus aureus (MRSA). MRSA growth inhibition (zones of inhibition) was greatest for the lemongrass oil at concentrations of 1, 2, 5, 10 and 20 % (wt/vol). The MIC for lemongrass oil was 0.5 mg/mL, while it was 4 mg/mL for both the aqueous and ethanol extracts. Evaluation of extracts for antibacterial resistance modifying activities when used in combination with either of the five antibiotics at sub-inhibitory concentrations, showed that lemongrass oil highly potentiated the activities of three antibiotics; amoxicillin, streptomycin and tetracycline. The ethanol extract enhanced the activity of tetracycline and ampicillin, while the aqueous extract only increased the activity of tetracycline against MRSA. The activity of cefloxacin with the extracts was either indifferent. Analysis of the lemongrass oil by GC/MS showed the prominence of three compounds: the two isomers neral and geranial of citral and, the acetate geranyl acetate, which together made up 94 % of the composition. The compounds were also observed in the ethanol and water extracts but to a lesser extent when analyzed by HPLC-UV (λ 233 nm). Our study confirms the antibacterial properties of the extracts especially, lemongrass oil. It also demonstrates that lemongrass oil potentiates the activities of three antibiotics against the biofilm-forming MRSA. This biocidal, anti-biofilm disruption and antibiotic potentiating abilities are mainly attributable to citral and geranyl acetate, further evidence of lemongrass oil as a very useful source of phytochemicals, especially citral for the fight against antibiotic resistance.
我们研究了香茅（Cymbopogon citratus）的三种可提取部分：水提物和乙醇提取物以及香茅精油，如果与选定的抗生素氨苄西林、四环素、链霉素、头孢氟沙星和阿莫西林联合使用，是否对耐甲氧西林金黄色葡萄球菌（MRSA）有任何抗菌耐药性调节作用。香茅油在浓度为 1、2、5、10 和 20%（wt/vol）时对 MRSA 的生长抑制（抑制区）最大。香茅油的 MIC 为 0.5mg/mL，而水提物和乙醇提取物的 MIC 均为 4mg/mL。评估提取物在亚抑菌浓度下与五种抗生素中的任何一种联合使用时的抗菌耐药性修饰活性，结果表明香茅油高度增强了三种抗生素的活性；阿莫西林、链霉素和四环素。乙醇提取物增强了四环素和氨苄西林的活性，而水提取物仅增加了四环素对 MRSA 的活性。香茅油与这三种抗生素的活性无明显影响。GC/MS 对香茅油的分析表明，三种化合物突出：柠檬醛的两种异构体柠烯和橙花醛，以及醋酸香叶酯，它们共同构成了 94%的组成。这些化合物也在乙醇和水提取物中被观察到，但用 HPLC-UV（λ 233nm）分析时含量较少。我们的研究证实了提取物，特别是香茅油的抗菌特性。它还表明香茅油增强了三种抗生素对生物膜形成的 MRSA 的活性。这种杀菌、抗生物膜破坏和抗生素增效能力主要归因于柠檬醛和香叶基醋酸盐，进一步证明香茅油是一种非常有用的植物化学物质来源，特别是柠檬醛，可用于对抗抗生素耐药性。
