Amide, cyclohexenone, and cyclohexenone–sordaricin derivatives from the endophytic fungus Xylaria plebeja PSU-G30

Six new compounds, two cyclohexenones, named xylariacyclones A (1) and B (2), three cyclohexenone–sordaricin derivatives, named xylarinonericins A–C (3–5), and one amide derivative, named xylariamide (6), together with 11 known compounds were isolated from the broth extract of the endophytic fungus Xylaria plebeja PSU-G30. The structures were elucidated by analyses of NMR spectroscopic data and chemical methods. Compounds 3–5 are novel and unusual sodaricin derivatives with an ester moiety at C-6 of the sordaricin skeleton. In addition, compound 5 has a unique feature with an ester unit instead of an ether group at C-19. They were evaluated for antifungal activity against Candida albicans ATCC90028 and Cryptococcus neoformans ATCC90113.