Anti-tumour promoter activity in Malaysian ginger rhizobia used in traditional medicine

Zingiberaceae rhizomes commonly used in the Malaysian traditional medicine were screened for anti-tumour promoter activity using the short-term assay of inhibition of 12-O-tetradecanoyl phorbol-13-acetate (TPA) induced Epstei n-Barr virus early antigen (EBV-EA) in Raji cells. The inhibition of TPA-in duced EBV-EA was detected using the indirect immunofluorescence assay (IFA) and Western blot technique, The indirect IFA detected the expression/inhib ition of EBV-EA-D (diffused EA antigen). whereas the Western blot technique detected the expression/inhibition of both EBV-EA-D and EA-R (restricted E A antigen), Seven rhizomes were found to possess inhibitory activity toward s EBV activation, induced by TPA; they are: Curcuma domestica, C. xanthorrh iza, Kaempferia galanga, Zingiber cassumunar, Z. officinale, Z. officinale (red variety), and Z. zerumbet. A cytotoxicity assay was carried out to det ermine the toxicity of the Zingiberaceae rhizome extracts, The rhizome extr acts that exhibited EBV activation inhibitory activity had no cytotoxicity effect in Raji cells. Therefore, the present study shows that several Zingi beraceae species used in Malaysian traditional medicine contain naturally o ccurring non-toxic compounds that inhibit the EBV activation, which, if fur ther investigated, could contribute in the development of cancer prevention methods at the tumour-promoting stage.