Polyketides with anti-inflammatory activity from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7

Seven undescribed polyketides with particular ortho-trisubstituted benzo[c]furan and benzo[c]oxepin spiro structures were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7. Structural elucidations of these compounds were determined mainly by NMR and HR-ESI-MS analysis. An assumed polyketide biosynthetic pathway of these isolates was proposed. Two undescribed compounds and four known compounds showed significant inhibitory effects on LPS-induced NO production in RAW 264.7 cells without cytotoxicity at their effective concentrations.

Automated summary

Seven undescribed polyketides with unique structures were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7. The structures of these compounds were determined using NMR and HR-ESI-MS analysis. Two undescribed compounds and four known compounds demonstrated significant inhibitory effects on LPS-induced NO production in cells without cytotoxicity.