Antibacterial Metabolites Of Endophytic Fungi From Eucommia Ulmoides

Eucommia ulmoides Oliv., the only variety in eucommia genus, eucommia family, is one kind of peculiar cash tree in our country. As one kind of plant in the second class which is protected in China, the resources of E. ulmoides need protection on the basis of full utilization. Hoping for not destroying E. ulmoides resources we have now and exploiting natural anti-biotic substances, our research group have isolated and identified endophytic fungi from E. ulmoides, screened antibacterial activity of some strains, isolated and elucidated four natural compounds from one of these endophytic fungi, and tested for antibacterial activity of 3 natural compounds. The results are as the follows: 80 strains of endophytic fungi were separated from roots, stems, and leaves of E. ulmoides by tissue isolation method for the first time. 72 strains in 13 genuses were identified according to their morphological and micro-structure characters; Alternaria sp., Fusarium sp., and Phoma sp. are dominant endophytic fungi population in E. ulmoides which occupy 52.78% in 72 strains. 33 strains in 9 genuses, 45.83% of the identified, were from roots. Antibacterial activity of 20 strains endophytic fungi and of their secondary metabolites was screened with Staphylococcus aureus, Bacillus subtilis and Escherichia coli as tested bateria. We chose DL04 (Alternaria sp.), DR01(Phoma sp.)and DR02(Paecilomyces sp.)as our target strains according to analysis of activity screening results. DL04 strain with antibacterial activity was fermented in liquid culture medium, and extracted for its crude metabolites (25.0g). The crude metabolites were subjected to silica gel column, C18 column, SephdexLH-20 column, chromatography thin layer preparation and re-crystallization. 4 compounds were elucidated as 3?-hydroxy-5a,8a-epidioxyergosta-6,22-diene(â… ), one steroid(â…¡), one aliphatic compound(â…¢), and one glycoside(â…£), and compound(â… ) was derived from DL04 of E. ulmoides for the first time. MIC(minimum inhibition concentration) and inhibition rate of compound â…¡,â…¢and â…£against Staphylococcus aureus, Escherichia coli, Candida albicans, Pseudomonas aerugi-nosa(Schroeter)Migula were determined qualitatively and quantitively. Results showed that compound â…¡, â…£, â…¢have inhibition effect on tested bacteria to a certain extent, and worth of further study.