Two new resveratrol tetramers isolated from Cayratia japonica (Thunb.) Gagn. with strong inhibitory activity on fatty acid synthase and antioxidant activity

Abstract

Two new resveratrol tetramers, cajyphenol A (1) and cajyphenol B (2), together with two known resveratrol dimers, quadrangularin A (3) and pallidol (4), and resveratrol (5) were isolated from the stems of Cayratia japonica (Thunb.) Gagn. Their structures were established by means of NMR (¹H,¹H-COSY, ¹H, ¹³C-HSQC, HMBC, and NOESY) and ESI-MS analyses. Compounds 1-5 showed fast-binding inhibitory activities on fatty acid synthase with the IC₅₀ values of 1.63±0.02, 1.49±0.03, 7.50±0.01, 11.1±0.01, and 10.2±0.01 μM, respectively. Compounds 1-5 also exhibited antioxidant activities in the ORAC assay.