Epstein-Barr virus early antigen EBV-EA

EBV Inhibition of Epstein-Barr virus early antigen (EBV-EA) activation induced by TPA [22-27]... 

Ethanolic extract (50%) of M. oleifera (whole plant excluding roots) shows anti-cancer activity in mice (50). Evaluation of the anticancer potential of 11 plants used in Bangladeshi folk medicine has shown that, only three extracts, among which M oleifera, is considered as a potential source of anticancer compounds (56). Crude ethanol extract of M. oleifera dried seeds inhibits the formation of Epstein-Barr virus-early antigen (EBV-EA) induced by 12-0-tetradecanoylphorbol-13-acetate. At a dosage of 100 pg/mL, the extract inhibits EBV-EA formation by 100% suggesting its antitumor-promoting activity (99). 

Four of the isolates (2), (3), (7) and (8) showed inhibitory activity against Epstein-Barr virus-early antigen (EBV-EA) activation with compounds (2), (3) and (8) having very significant activities (53), indicating higher potential for antitumor activities. Most compounds that inhibit in vitro EBV-EA activation are also known to be antitumor promoters in vivo (12). Niazimicin (3) when... 

The studies were carried out on a primary screening test using their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol- 13-acetate (TPA), a strong promoter, in Raji cells. 

Epstein-Barr virus early antigen induction. Methanol extract of the dried leaf, in cell culture at a concentration of 1 pg/mL, was inactive. The assay was designed for tumor-promoting activity . Two diastere-oisomers of 2,7,1 l-cembratriene-4,6-diol (a- and 3-CBT) from the neutral fractions of cigarette smoke condensate, in Raji cells, produced potent inhibitory effects on the induction of Epstein-Barr virus (EBV)-EA by 12-0-tetradecanoylphorbol-13-acetate (TPA). The doses of a- and P-CBT required for 50% inhibition of EBV-EA induction by TPA were 7.7 and 6.7 mg/mL, respectively. Application of a- and P-CBT to mouse skin before treatment with TPA, inhibited TPA-induced ornithine decarboxylase activity in a dose-dependent manner. Application of 16.5 pM/mouse of a- and p-CBT resulted... 

The effect on EBV- EA (Epstein-Barr virus early antigen) activation of compounds 172 and 210-217, were also examined. Their inhibitory effects on the activation of the early antigen and the viabilities of Raji cells are shown in Table 12. Compounds 172, 210, 216 and 217 showed stronger activities than the other compounds. 

A test of inhibitory effects on Epstein-Barr virus early antigen activation in Raji cells induced by a combination of n-butylic acid and 12-0-tetradecanoylphorbol-13-acetate (TPA) has been employed (EBV-EA test) as a simple primary screening for antitumor promoting agents. In this test, significant inhibitory effect was observed for astilbin and its isomers as well as (+)-taxifolin. Of these dihydroflavonol derivatives, neoastilbin showed the strongest activity. 

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