Abstract: Isaria farinosa is a widely distributed entomopathogenic fungus in soil-dwelling insects. It has been extensively studied and applied in biological control of insects, and also attracted researchers′ attention for its pharmacological effects and bioactive metabolites. In this study, seven strains of I. farinosa from different origins were selected based on morphological and molecular identification to reveal the variation among strains. Antioxidant effects and antimicrobial activities were tested by crude ethyl acetate extracts from the strains cultivated on rice medium. The results showed that the strains displayed significant variations in the bioactivities tested under the same conditions and strain 2142 had the best performance. In particular, the crude extract (200 mg/mL) from strain 2142 had the similar effect with Bacillus cereus to that of ampicillin sodium (80 μg/mL) used as the positive control in the antimicrobial experiment. Further investigation on the strain was required to explore its potentials. There are broad prospects for the application of I. farinosa in health foods and pharmaceutical product, but the caution should be taken in the selection of strains for such purposes. It is important to evaluate the safety of any strain before its application in the area associated with human health.

Key words: Isaria farinosa, Paecilomyces hepiali, crude ethyl acetate extracts, antioxidant effects, antimicrobial activity, strain variation

摘要： 虫花棒束孢（Isaria farinosa）是一种常见的土栖昆虫病原真菌，在害虫生物防治方面有着广泛研究和应用，其对人体保健、药效和活性成分等方面也有一定的研究。为了揭示不同菌株之间的差异，选择7个来源不同的菌株，经形态和分子鉴定后，通过大米固体培养和乙酸乙酯提取，进行了抗氧化和抗菌活性测定。研究结果表明不同来源的虫花棒束孢菌株，经相同条件的培养和提取得到的产物在抗氧化和抗菌活性方面呈现明显的差异，以菌株2142表现最佳，在抗菌实验中尤其突出。菌株2142乙酸乙酯粗提物（200 mg/mL）对蜡样芽胞杆菌的抗菌活性达到与阳性对照氨苄西林钠（80 μg/mL）相似的水平。该菌株具有较好的应用前景，有待进一步深入研究。利用虫花棒束孢菌株研发保健产品或医药产品具有很好的潜力，但其菌株来源需要十分关注；筛选对人体安全可靠，并有利于产品开发利用的优良菌株是一项非常重要的工作。

关键词: 虫花棒束孢, 蝙蝠蛾拟青霉, 乙酸乙酯粗提物, 抗氧化活性, 抗菌活性, 菌株差异