Punctaporonins N-S, New Caryophyllene Sesquiterpenoids from Cytospora sp.

Six new caryophyllene sesquiterpenoids, punctaporonins N-S (1-6), and three known ones, 6-hydroxypunctaporonins B (7), A (8), and E (9), have been isolated from solid cultures of Cytospora sp. The structures of 1-6 were elucidated primarily by NMR spectroscopy. The absolute configuration of 1 was assigned by X-ray crystallographic analysis of its S-MTPA ester. Compounds 2, 5, and 6 showed modest cytotoxicity against HeLa cells.