Two New Resveratrol Tetramers Isolated from Cayratia japonica ( Thunb. ) Gagn. with Strong Inhibitory Activity on Fatty Acid Synthase and Antioxidant Activity

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 ( 1 H, 1 H‐COSY, 1 H, 13 C‐HSQC, HMBC, and NOESY) and ESI‐MS analyses. Compounds 1 – 5 showed fast‐binding inhibitory activities on fatty acid synthase with the IC 50 values of 1.63±0.02, 1.49±0.03, 7.50±0.01, 11.1±0.01, and 10.2±0.01 μ M , respectively. Compounds 1 – 5 also exhibited antioxidant activities in the ORAC assay.