p-Terphenyl alcohols from a marine sponge-derived fungus, Aspergillus candidus OUCMDZ-1051

In order to discover structurally new and bioactive compounds from marine life,we studied the secondary metabolites of the marine-derived fungi associated with a marine sponge (XS-3) from the Xisha islands. As a result,4-O-methylcandidusin A (1),a new p-terphenyl alcohol,along with nine known analogs (2-10),were isolated and identified from the marine sponge-derived fungus Aspergillus candidus OUCMDZ-1051. The structures of these compounds were determined by analyzing spectroscopic data,especially 1D and 2D NMR. The new compound 1 selectively inhibited the growth of the MDA-MB-468,BT474 and A431 human cancer cell lines with the IC₅₀ values of 1.84,6.05 and 0.98 μmol/L,respectively. Compound 1 also displayed a selective antimicrobial activity against Escherichia coli with an MIC value of 27.3 μmol/L. The results indicated 4-O-methylcandidusin A (1) as a potential lead in the new drug discovery for triple negative breast cancer,invasive ductal breast cancer and epidermoid cancer. The antimicrobial metabolites also evidenced a clue for chemical defense of sponges by their associated microorganisms.