Inhibition of N-Methyl N'-nitro-N-nitrosoguanidine (MNNG) induced gastric carcinogenesis by Phyllanthus amarus extract.

Chemopreventive activity of Phyllanthus amarus Schum & Thonn (Euphorbiaceae) extract was studied with regard to N-methyl N'-nitro-N-nitrosoguanidine (MNNG) induced stomach cancer in Wistar rats. Administration of the extract with MNNG significantly reduced the incidence of gastric neoplasms in rats (44%) as well as their numbers. Moreover, elevated levels of enzymes in the stomach were found to be reduced by P. amarus administration. For example, gamma-glutamyl transpeptidase activity was decreased from 20.3 +/- 6.7 mmol/min/mg protein to almost normal levels (2.8 +/- 0.9) by 750 mg/kg body weight of the extract. Similarly glutathione S-transferase activity (1317.6 +/- 211 n mol/min/mg protein) and glutathione reductase (368 +/- 66) levels in the MNNG treated group were found to be lowered to 494.8 +/- 76 and 192 +/- 45, respectively, while reduced glutathione (GSH) was increased from 4.6+/- 0.9 to 8.5+/-1.4 n mol/min/mg protein. AgNOR dots and clusters, indicators of cellular proliferation, which were increased by MNNG treatment, became near to normal in P. amarus treated animals.

Inhibition of experimental gastric lesion and inflammation by Phyllanthus amarus extract.

Methanolic extract of Phyllanthus amarus Shum & Thonn (Euphorbiaceae) 50, 200, and 1000 mg/kg body weight significantly inhibited gastric lesions, induced by intragastric administration of absolute ethanol (8 ml/kg). Mortality, increased stomach weight, ulcer index, and intraluminal bleeding were reduced significantly by Phyllanthus amarus. Biochemical analysis indicated that reduced glutathione (GSH) of gastric mucosa produced by ethanol administration was significantly elevated by treatment with Phyllanthus amarus extract. Aqueous and methanol extracts of Phyllanthus amarus produced an inhibition of rat paw edema up to 42% compared to control in 3h and continued up to 8h. Anti-oxidant activity of the extract as well as presence of tannins in the extract may be responsible for these observed activities.

Anti-mutagenic activity of Phyllanthus amarus Schum & Thonn in vitro as well as in vivo.

Methanolic extract of Phyllanthus amarus was tested for its anti-mutagenic activity in Salmonella typhimurium strains TA1535, TA100, and TA102 (Ames test). P. amarus extract was able to inhibit the activation and mutagenicity of 2-acetaminofluorene (2-AAF) and aflatoxinB(1) at concentrations of 0.25-2 mg/plate. It was also found to inhibit mutagenicity induced by direct acting mutagens sodium azide (NaN(3)), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), and 4-nitro-0-phenylenediamine (NPD), at concentrations of 1 mg to 0.25 mg/plate. Urinary mutagenicity produced in rats by benzo[a] pyrene was found to be significantly inhibited by the oral administration of Phyllanthus extract. These results indicate significant anti-mutagenicity of the extract in vitro as well as in vivo.

Hypoglycemic effect of methanol extract of Phyllanthus amarus Schum & Thonn on alloxan induced diabetes mellitus in rats and its relation with antioxidant potential.

Methanolic extract of P. amarus was found to have potential anti-oxidant activity as it could inhibit lipid peroxidation, and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 104 microg/ml and the concentrations needed to scavenge hydroxyl and superoxide radicals were 117 and 19 microg/ml respectively. The extract was found to reduce the blood sugar in alloxan diabetic rats at 4th hr by 6% at a dose level of 200 mg/kg body wt and 18.7% at a concentration of 1000 mg/kg body wt. Continued administration of the extract for 15 days produced significant (P < 0.001) reduction in blood sugar. On 18th day after alloxan administration values were almost similar to normal in the group taking 1000 mg/kg body wt.