Induction of apoptosis in mouse and human carcinoma cell lines by Emblica officinalis polyphenols and its effect on chemical carcinogenesis

Plant-derived phenolic compounds manifest many beneficial effects and can potentially inhibit several stages of carcinogenesis. In the present study, we investigated the efficacy of Emblica officinalis (E. officinalis) polyphenol fraction (EOP) on the induction of apoptosis in mouse and human carcinoma cell lineses and its modulatory effect on N- nitrosodiethylamine (NDEA) induced liver tumors in rats. The results indicate that EOP treatment could induce apoptosis in Dalton's Lymphoma Ascites (DLA) and CeHa cell lines At 200 microg/ml dose EOP induced membrane blebbing, chromatin condensation and intenucleosomal breaks as evident from the morphology and DNA ladder pattern obtained in gel electrophoresis. The results also suggested that EOP treatment could decrease the liver tumour development induced by NDEA. Animals administered (oral) with NDEA (0.02%, 2.5 ml/rat, 5 days a week, 20 weeks) developed visible liver tumours by the end of the 20th week and the liver weight raised to 5.2 +/- 1.1 g/ 100 g body weight. Only 11% of the animals treated with EOP (60 mg/kg, oral, 5 days a week for 20 weeks) developed visible liver tumours by this period and the liver weights were reduced to 3.2 +/- 0.7 g/ 100 g body weight. gamma-glutamyl transpeptidase activity was raised to 88.4 +/- 16.2 U/l in serum of NDEA treated group was reduced to 48.4 +/- 14.8 U/l by EOP treatment. Elevated levels of serum alkaline phosphatase (ALP), glutamate pyruvate transaminase (GPT), bilirubin, liver glutathione S-transferase (GST) and glutathione (GSH) in the NDEA administered group were significantly reduced by EOP treatment. The EOP was found to scavenge superoxide and hydroxyl radicals and inhibit lipid peroxidation in vitro. EOP also inhibited DNA topoisomerase I in Saccharomyces cervisiae mutant cell cultures and the activity of cdc25 tyrosine phosphatase.