Inhibitory effects of 12-O-tetradecanoylphorbol-13-acetate and teleocidin B induced Epstein-Barr virus by saponin and its related compounds.

The inhibitory effects of triterpene glycosides and monoterpene glycosides on 12-O-tetradecanoylphorbol-13-acetate (TPA) and teleocidin B in the Epstein-Barr virus (EBV) activation in Raji cells were studied. Concomitant treatment of Raji cells with TPA or Teleocidin B and these glycosides showed the inhibition of EBV activation. We herein report in vitro structure-activity studies using a biological test system on a variety of triterpene glycosides having 1 sugar chain (monodesmoside), 2 sugar chain (bisdesmoside) and an acyl side-chain. Among these glycosides, triterpene 3-O-glycosides and acylated saponin exhibited an effective inhibition of EBV activation; therefore, the sugar chain at C-3 of the triterpene and/or the acyl side-chain were determined to be essential to the inhibitory activities in this test system. The data suggested that these triterpenoid glycosides which were originally used as herbal drugs and folk remedies in many areas of the world, were in fact inhibitory compounds, thus explaining the EBV activation in the in vitro test system.