[论文解读] Antibacterial and antifungal activity of various extracts of Bacopa monnieri

Fazlul Mkk, Deepthi Sp+4 more|arXiv (Cornell University)|Sep 3, 2019

Medicinal Plants and Neuroprotection被引用 10

一句话总结

本研究通过琼脂纸片扩散法评估了马钱子（Bacopa monnieri）的乙醇、二乙醚、乙酸乙酯和水提取物的抗菌和抗真菌活性。乙醇提取物对黄曲霉菌（Aspergillus flavus）和白色念珠菌（Candida albicans）表现出强效抗真菌活性，而二乙醚提取物抑制了金黄色葡萄球菌（Staphylococcus aureus），乙酸乙酯提取物在300 µg/mL浓度下对大肠杆菌（Escherichia coli）产生抑制作用，表明不同溶剂提取物具有选择性抗菌潜力。

ABSTRACT

Bacopa monnieri was also known as Brahmi. Theses plant has been considered as medicinal plants in Ayurvedic systems for centuries. This present study was carried out to evaluate the antibacterial and antifungal properties of ethanolic, diethyl ether, ethyl acetate, and aqueous extracts of B. monnieri. Agar disc diffusion tests were carried out to determine the antimicrobial effects of ethanolic, diethyl ether, ethyl acetate and aqueous extracts of B. monnieri against Gram-positive (Staphylococcus aureus ATCC 25923), Gram-negative (Escherichia coli ATCC 25922) bacterial strains and antifungal strains (Aspergillus flavus, and Candida albicans). Among the various extracts, diethyl ether extracts of B. monnieri has an antibacterial potency against Staphylococcus aureus (gram positive), and ethyl acetate extract showed effects on E. coli (gram negative) at higher concentrations of 300 microgam mL-1. The ethanolic extract has potent antifungal activity against the fungus (Aspergillus flavus, and Candida albicans) compared to diethyl ether and ethyl acetate-ether. Both extracts (diethyl ether and ethyl acetate) has a minimum antifungal effect while these extracts showed more inhibitory effects on tested bacteria. Inhibitory effects of the aqueous extract were not observed at all concentration (100 microgam mL-1, 200 microgam mL-1and 300 microgam mL-1) against the entire examined bacterial and fungal species. The finding of this study indicates the antibacterial and antifungal activity exhibited by the ethanolic, diethyl ether, and ethyl acetate extract of B. monnieri can be validated to the management of medicinal plant throughout the world.

研究动机与目标

• 评估马钱子不同溶剂提取物的抗菌潜力。
• 比较乙醇、二乙醚、乙酸乙酯和水提取物对革兰氏阳性菌和革兰氏阴性菌及真菌的疗效。
• 确定最有效的提取物及溶剂体系以抑制微生物生长。
• 通过体外抗菌测试验证阿育吠陀医学中马钱子的传统用途。

提出的方法

• 制备马钱子地上部分的乙醇、二乙醚、乙酸乙酯和水提取物。
• 采用琼脂纸片扩散法评估对金黄色葡萄球菌、大肠杆菌、黄曲霉菌和白色念珠菌的抗菌活性。
• 在100、200和300 µg/mL浓度下测试提取物。
• 测量抑菌圈直径以确定抗菌活性强度。
• 比较不同溶剂提取物的结果，以识别最有效的化合物类别。

实验结果

研究问题

• RQ1 马钱子的哪种溶剂提取物对革兰氏阳性菌和革兰氏阴性菌的抗菌活性最强？
• RQ2 乙醇提取物是否对黄曲霉菌和白色念珠菌表现出显著的抗真菌活性？
• RQ3 二乙醚和乙酸乙酯提取物在抑制细菌和真菌菌株方面有何差异？
• RQ4 为何水提取物在测试浓度下无抑制作用？
• RQ5 马钱子提取物的抗菌活性是否可与特定溶剂组分中的特定植物化学物质相关联？

主要发现

• 二乙醚提取物在300 µg/mL浓度下对金黄色葡萄球菌（革兰氏阳性菌）表现出显著的抗菌活性。
• 乙酸乙酯提取物在300 µg/mL浓度下对大肠杆菌（革兰氏阴性菌）表现出抑制作用。
• 乙醇提取物对黄曲霉菌和白色念珠菌表现出强效抗真菌活性。
• 水提取物在100、200和300 µg/mL浓度下对所有测试的细菌或真菌菌株均无抑制作用。
• 二乙醚和乙酸乙酯提取物的抗菌效果强于抗真菌效果。
• 乙醇提取物总体效果最佳，尤其对真菌种类表现出优异活性。