Three new orcinol-conjugated hydrolysable tannins from the leaves of Cleyera japonica.

Three new orcinol (3-hydroxy-5-methylphenol)-conjugated hydrolysable tannins, together with two known compounds were isolated from the leaves of Cleyera japonica (CJ), and have been tentatively named cleyeratannin A (1), cleyeratannin B (2) and cleyeratannin C (3). The chemical structures of these compounds were elucidated using 1 dimensional (1D)/2D NMR and high resolution FAB-MS, and the absolute configuration was confirmed by circular dichroism (CD). To evaluate their anti-oxidative activities, 1,1-diphenyl-2-picrylhydrazyl (DPPH)/free radical scavenging activity and nitroblue tetrazolium (NBT)/superoxide anion scavenging activity were determined.