Pulvinulin A, graminin C, and cis-gregatin B--new natural furanones from Pulvinula sp. 11120, a fungal endophyte of Cupressus arizonica.

Three new natural furanones, pulvinulin A (1), graminin C (2), and cis-gregatin B (3), together with the known fungal metabolites, graminin B (4) and 10-norparvulenone (5), were isolated from Pulvinula sp. 11120, an endophytic fungal strain occurring in healthy foliage of Cupressus arizonica (Arizona cypress). The structures of 1 and 2 were elucidated by the analysis of their spectroscopic data and chemical interconversions, and that of 3 was determined by comparison with data for synthetic cis-gregatin B. Comparison of spectroscopic data of 4 and 5 with those reported identified them as graminin B and 10-norparvulenone, respectively. Metabolites 1-4 exhibited antibacterial activity against E. coli.