p -Terphenyl and Diphenyl Ether Derivatives from the Marine-Derived Fungus Aspergillus candidus HM5-4.

Two undescribed p -terphenyl derivatives, asperterphenylcins A-B ( 1 - 2 ), and two undescribed diphenyl ether derivatives, asperdiphenylcins A-B ( 3 - 4 ), together with three previously described p -terphenyl derivatives-4″-deoxyterprenin ( 5 ), terphenyllin ( 6 ), and 3″-hydroxyterphenyllin ( 7 )-were obtained from the solid-rice culture of the marine-derived fungus Aspergillus candidus HM5-4, which was isolated from sponges from the South China Sea. Their structures were elucidated by HRESIMS data and NMR spectroscopic analysis. Compound 1 showed a strong inhibitory effect on Neoscytalidium dimidiatum , with an inhibition circle diameter of 31.67 ± 2.36 mm at a concentration of 10.0 µg/disc. Compounds 5 and 7 displayed cytotoxic activity against human chronic myeloid leukemia cells (K562), human liver cancer cells (BEL-7402), human gastric cancer cells (SGC-7901), human non-small cell lung cancer cells (A549) and human HeLa cervical cancer cells, with IC ₅₀ values ranging from 3.32 to 60.36 µM, respectively. Compounds 2 , 6 and 7 showed potent inhibitory activity against α -glucosidase, with IC ₅₀ values of 1.26 ± 0.19, 2.16 ± 0.44 and 13.22 ± 0.55 µM, respectively.