Epstein-Barr virus early antigen inhibition

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... 

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... 

Tetradecanoylphorbol 13-acetate (TPA) and other diterpene esters from the plant family Euphorbiaceae are well-known as tumor-promotion agents [85]. Thus, inhibition of the biological effects induced by TPA has been considered as a promising strategy [68]. To date, two short-term cell-based in vitro bioassays using TPA as a tumor-promoter have been developed to evaluate the potential cancer chemopreventive activities of several lignans isolated from Hernandia species, namely, inhibition of Epstein-Barr virus early antigen activation [6] and the inhibition of the transformation of JB6 mouse epidermal cells [7]. 

In recent years, the anti-tumor-promoting activities of several natural products [102] have been investigated for inhibition of 12-0-tetradecanoylphorbol-13-acetate (TPA) induced Epstein-Barr virus early antigen (EBV-EA) activation [103]. Compounds isolated from T. wilfordii var. regelii were assayed by Takaishi and coworkers [27] on... 

Procyanidin B2 (dimer), isolated from loquat leaves, was found to inhibit the 12-0-tetradecanoylphorbol-13-acetate (TPA)-induced activation of Epstein-Barr virus early antigen in Raji cells [108]. Animal studies and cell models suggest that flavonoids act as anticarcinogens through influencing molecular events in the initiation, promotion, and progression stages of cancer [109]. 

The lignans asarinin and xanthoxylol isolated from Asiasarum heterotropoides var. mandshuricum [104], inhibited Epstein-Barr virus (EBV) early antigen activation induced by TP A. 

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