Inhibition by Phyllanthus amarus of hepatocarcinogenesis induced by N-nitrosodiethylamine

Abstract

The extract of Phyllanthus amarus (Syn. P. niruri) was found to be a potent inhibitor of the hepatocarcinogenesis induced by N-nitrosodiethylamine (NDEA). None of the P. amarus extract-treated animals developed any tumors even 32 weeks after the NDEA administration, whereas all of the animals died due to tumor burden in the control group. Liver weight was significantly increased in the NDEA-treated group, whereas it was not altered after treatment with NDEA and P. amarus. Liver γ-glutamyl transpeptidase (GGT), glutamyl-S-transferase (GST), reduced glutathione (GSH) and aniline-4-hydroxylase P450 enzyme were elevated in NDEA-treated animals, whereas they were almost normal in animals treated with the carcinogen plus P. amarus extract. The serum parameters indicative of liver injury such as bilirubin, lipid peroxides, alkaline phosphatase, and glutamate-pyruvate transaminase, which were elevated by NDEA treatment, were also normal in the NDEA and P. amarus-treated group. Even though the exact mechanism of action is not known at present, the observed antitumor activity may be due to the inhibition of P450 enzyme activity and subsequent inhibition of the production of the ultimate carcinogen as well as scavenging of oxygen free radicals during promotion of the transformed cell.