美国山核桃叶的抗菌作用

对美国山核桃Carya illinoensis叶进行体外抗菌作用研究,以期开发出一种新型的天然杀菌剂。美国山核桃叶经体积分数为75%乙醇提取后,采用系统溶剂法将抽提物分为石油醚、氯仿、乙酸乙酯、正丁醇和水等5个不同极性的提取物。采用滤纸片法,检测以上提取物对黄曲霉菌Aspergillus flavus,根霉菌Rhzopus oryzae,青霉菌Penicillium sp.,酵母菌Saccharomyces cerevisiae,大肠埃希菌Escherichia coli和枯草杆菌Bacillus subtilis等的抑菌效果,并计算各提取物对真菌的半数抑菌质量浓度(CE50)。结果表明:乙酸乙酯提取物对青霉菌、根霉菌、黄曲霉菌和枯草杆菌均表现出明显的抑菌效果且差异显著(P<0.05,P<0.01),抑菌圈直径均值分别为9.18,10.86,8.26,10.18mm,但对于黄曲霉菌石油醚提取物(CE500.91 g·L-1)的抑菌效果优于乙酸乙酯提取物(CE50>200 g·L-1);而正丁醇提取物对酵母菌和大肠埃希菌表现出明显的抑菌效果且差异显著(P<0.05,P<0.01),其抑菌圈直径均值分别为11.13,8.83 mm,但对于大肠埃希菌水提物的抑菌效果优于正丁醇提取物,其抑菌圈直径均值为9.13 mm。综上,美国山核桃叶的正丁醇提取物和乙酸乙酯提取物抑菌效果最佳。针对这一实验结果,可以根据防治对象不同,采用不同的提取方法和工艺,研发专菌专治的天然杀菌剂,以提升杀菌剂的作用效果。

Antimicrobial activity of Carya illinoensis leaves

The purpose is to provide theoretical basis for developing a new type of natural antiseptic products. The antimicrobial activity of Carya illinoensis leaves was determined through extraction, in vitro, with 75% ethanol and then fractionated with petroleum ether, chloroform, ethyl acetate, n-butanol, and water in turn. The cup plate method was used to determine antimicrobial activity of the extract and extractants with cultures of Aspergillus flavus, Rhizopus oryzae, Penicillium sp., Saccharomyces cerevisiae, Escherichia coli, and Bacillus subtilis. Then, the half inhibitory concentration （C_E50） were calculated. Results showed that the mean inhibition zone diameter for the ethyl acetate extract of Penicillium sp. was 9.18 mm, of R. oryzae was 10.86 mm, of A. flavus was 8.26 mm, and of B. subtilis was 10.18 mm exhibiting a strong inhibitory effect（P＜0.05，P＜0.01）. However, for A. flavus, the inhibitory effect of the petroleum ether extract （C_E50 0.91 g·L^－1） was better than the ethyl acetate extract （C_E50＞200 g·L^－1）. The mean inhibition zone diameter for the n-butanol extract of S. cerevisiae （11.13 mm） and E. coli （8.83 mm） also showed a strong inhibitory effect（P＜0.05，P＜0.01）; nevertheless, the inhibitory effect of the aqueous extract（9.13 mm） for E. coli was better than the n-butanol extract（8.83 mm）. Thus, the n-butanol extract and the ethyl acetate extract of Carya illinoensis leaves have the best inhibitory effect. For the experimental results, according to different control object, we can use different extraction methods and technology to research and develop the exclusive antiseptic, in order to improve the effect of antiseptic. ［Ch, 2 tab. 1２ ref.］