Silphiperfolene-Type Terpenoids and Other Metabolites from Cultures of the Tropical Ascomycete Hypoxylon rickii (Xylariaceae)

摘要

AbstractA culture isolated from ascospores of Hypoxylon rickii, a xylariaceous ascomycete collected in Martinique, had yielded botryane, noreremophilane and abietane-type terpenoids in a preceding study, but additional metabolites were detected by extensive HPLC–MS analysis in other fractions. Herein we report the further isolation of four new sesquiterpenoids with a silphiperfol-6-ene skeleton from extracts of H. rickii. The planar structures were elucidated by NMR and HRMS data as 13-hydroxysilphiperfol-6-ene (>1), 9-hydroxysilphiperfol-6-en-13-oic acid (>2), 2-hydroxysilphiperfol-6-en-13-oic acid (>3) and 15-hydroxysilphiperfol-6-en-13-oic acid (>4). For compounds >2–>4 we propose the trivial names rickinic acids A–C. Their stereochemistry was assigned by ROESY correlations as well as by the specific optical rotation. Additionally, the known compounds, botryenanol, dehydrobotrydienol, cyclo(Phe-Pro), cyclo(Pro-Leu), (+)-ramulosin and α-eleostearic acid were isolated. The antimicrobial and cytotoxic activities of the new compounds are also reported.