Inhibition of tumour promotion by various palm‐oil tocotrienols

Inhibition of tumour promotion by various vitamin E compounds (tocopherols and tocotrienols) and some of their dimers was examined by an in vitro assay utilizing the activation of Epstein-Barr virus (EBV) early antigen (EA) expression in EBV-genome-carrying human lymphoblastoid cells. The results reveal that γ- and δ-tocotrienols derived from palm oil exhibit a strong activity against tumour promotion by inhibiting EBV EA expression in Raji cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). However, α- and γ-tocopherols and dimers of γ-tocotrienol or γ-tocopherol lack this activity. © 1994 Wiley-Liss, Inc.