Bioactive compounds from fungus Bipolaris oryzae

Abstract

In the course of preliminary screening test for bioactive compounds from 11 plant pathogenic fungi, bipolaris oryzae was selected for further investigation. The chromatographic separation of the ethyl acetate crude extracts results in the isolation of one new and six known compounds. They can be divided into two groups, four ophiobolins; 3-anhydroophiobolin A (1), ophiobolin I (2), ophiobolin A (3) and 6-epi-ophiobolin A (4), and three cochlioquinones; isocochlioquinone A (5), isocochlioquinone C (6) and anhydrocochlioquinone A (7). Compound 7 has to been previously reported in the literature. The structures of all isolated compounds were elucidated on the basis of spectroscopic methods, as well as comparison with previously reported. In addition, the cytotoxic activity against cell line and acetylcholinesterase inhibition were investigated. Compound 2 showed highest cytotoxic activity against Hela and KB cell lines at IC[subscript 50] <0.1 and 0.89 microg./mL, respectively. For the acetylcholinesterase inhibition assay, compound 1, 2, 3, 4, 5 and 7 showed the potential inhibition at concentration of 1 mg/mL.