Penicacids E−G, three new mycophenolic acid derivatives from the marine-derived fungus Penicillium parvum HDN17-478

Three new mycophenolic acid derivatives, penicacids E−G ( 1 − 3 ), together with three known analogues, mycophenolic acid ( 4 ), 4′-hydroxy-mycophenolic acid ( 5 ) and mycophenolic methyl ester ( 6 ), were isolated from a marine-derived fungus Penicillium parvum HDN17-478 from a South China Sea marine sediment sample. The structures of compounds 1 − 3 were elucidated by HRMS, NMR, and Mosher’s method. Among them, compounds 1 and 2 were the first examples of mycophenolic acid analogs with a double bond at C-3′/C-4′ position. The cytotoxicity of 1 − 6 was evaluated against the HCT-116, BEL-7402, MGC-803, SH-SY5Y, HO-8910 and HL-60 cell lines, and compounds 4 and 6 showed potent cytotoxicity with IC₅₀ values ranging from 1.69 to 12.98 μmol·L^–1.