3-Epicabraleahydroxylactone and Other Triterpenoids from Camellia Oil and Their Inhibitory Effects on Epstein–Barr Virus Activation

Abstract

The structure of a triterpenoid isolated from the nonsaponifiable lipid (NSL) of the seed oil of the camellia (Camellia japonica L.; Theaceae) was established to be (20S)-3β-hydroxy-25,26,27-trisnordammaran-24,20-olide (1; 3-epicabraleahydroxylactone) on the basis of spectroscopic and chemical methods. Six other triterpenoids isolated from the NSL were identified as 3-epicabraleadiol (2), ocotillol II (3), ocotillol I (4), dammarenediol II (5), (20R)-taraxastane-3β,20-diol (6), and lupane-3β,20-diol (7). Upon evaluation of the seven triterpenoids (1—7) with respect to their inhibitory effects on the induction of Epstein–Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, three compounds (5—7) showed potent inhibitory effects against EBV-EA induction (IC₅₀ values of 277—420 mol ratio/32 pmol TPA).