Linear polyketides produced by co-culture of and .

Unlabelled: Two new polyketides, penifellutins A () and B (), possessing a 22 carbon linear skeleton, were isolated from a co-culture of the deep-sea-derived fungi PRB-2 and HDN14-323. Meanwhile, two esterification products of , penifellutins C () and D (), were obtained because compound could be esterified spontaneously when stored in methanol. Their configurations were difficult to determine because of chiral central crowdedness, structural flexibility and instability. As such, we solved this issue by comprehensively using Mo(OAc)-based CD experiments, density functional theory calculation of C NMR, DP4 + probability analysis and many chemical reactions, including making acetonide derivative, Mosher's method, PGME method, etc. Compounds and show obvious inhibitory activity on the liver hyperplasia of zebrafish larvae at a concentration of 10 μmol/L, while and show no activity, indicating that two carboxyls in the structure are important active sites.

Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-021-00125-8.