homoharringtonine and xanthone

Rare and endangered plants (REPs) and their associated endophytes survived in unique habitats are promising sources for natural product-derived drug discovery. In this study, six new (cephaloverines A-F, 1-6, resp.) and 16 known (11-26) cephalotaxine-type alkaloids, together with three new (oliverbiflavones A-C, 7-9, resp.) and 11 known (27-37) biflavonoids were isolated and characterized from the twigs and leaves of Cephalotaxus oliveri, an endangered plant endemic to China. Meanwhile, a preliminary investigation on the secondary metabolites from a selected fungal endophyte (i.e., Alternaria alternate Y-4-2) associated with the title plant led to the isolation of 21 structurally distinct polyketides including one new dimeric xanthone (10). The new structures (1-10) with the absolute configurations were determined by detailed spectroscopic analyses, electronic circular dichroism (ECD) or Na

Topics: Alternaria; Antineoplastic Agents; Biflavonoids; Cell Line, Tumor; Cephalotaxus; Drug Screening Assays, Antitumor; Endophytes; Homoharringtonine; Humans; Molecular Structure; Plant Leaves; Polyketides; Secondary Metabolism; Structure-Activity Relationship; Xanthones