Secondary metabolites from the karst cave fungus Roussoella sp. LCP1-2 with proangiogenic activity

Six compounds were isolated from the fermentation broth of Roussoella sp. LCP1-2, including four new metabolites: papyracillic acid D (1), 7-epi-4-epi-papyracillic acid B (2), 4-epi-papyracillic acid B (3), and 3-hydroxyl-11α,18-Dihydroxy-7-oxo-13-epi-ent-pimara-8(9),15-diene (5), along with two known compounds, papyracillic acid B (4) and saccharonol A (6). Their planar structures were elucidated through comprehensive analysis of NMR and MS spectroscopic data. The structure of 1 was unambiguously confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of compounds 2, 3, and 5 were established through a combination of experimental ECD spectroscopy and computational ECD calculations. Biological evaluation revealed that compound 3 exhibited moderate proangiogenic activity in a zebrafish model at a concentration of 40 μM.