Abstract
Phomaketals A(1)and B(2),two tropolonic meroterpenoids with the unprecedented pentacyclic skele-tons,were isolated from the solid-substrate fermentation cultures of a eupC overexpressed mutant strain of the fungus Phoma sp.,together with a biogenetically related secondary metabolite pughiinin B(3),and the known one noreupenifeldin B(4).The structures of 1-3 were elucidated primarily by nuclear magnetic resonance(NMR)experiments.The absolute configurations of 1 and 2 were assigned by elec-tronic circular dichroism calculations and the calculated NMR with DP4+analysis,while that of 3 was established by single-crystal X-ray diffraction analysis using Cu Kα radiation.Biogenetically,phomaketals A(1)and B(2)could be derived from the hypothetical tropolonic sesquiterpene intermediates neose-tophomone B(6)and 9-R-neosetophomone B(6′),respectively,via different reactions cascades.Com-pound 1 showed antiproliferative effect only against the SUPB15 cells,with an 50% inhibitory concentra-tion(IC50)value of 4.85μmol/L,while the co-isolated known meroterpenoid 4 displayed potent effects against three tumor cell lines,SUPB15,EL4,and H9,showing IC50 values of 0.36-27.08 μmol/L.
基金项目
National Natural Science Foundation of China(82003628)
CAMS Innovation Fund for Medical Sciences(2021-I2M-1-030)
CAMS Innovation Fund for Medical Sciences(2021-I2M-1-028)
CAMS Innovation Fund for Medical Sciences(2021-1-I2M-2-002)
维普
万方数据