Modulatory influence of Phyllanthus niruri on oxidative stress, antioxidant defense and chemically induced skin tumors.

The present study evaluates the modulatory potential of Phyllanthus niruri on chemically induced skin carcinogenesis, and its influence on oxidative stress and the antioxidant defense system. Oral administration of P. niruri extract (PNE), during peri- (Gr. III), post- (Gr. IV), or peri- and post- (Gr. V) initiational stages of 7,12-dimethylbenz(a) anthracene (DMBA)-croton oil–induced papillomagenesis considerably reduced tumor burden to 4.20, 4.00, and 3.33(positive control value 6.20); cumulative number of papillomas to 21, 16, and 10, respectively, (positive control value 62); and incidence of mice bearing papillomas to 50, 40, and 30%, respectively (positive control value 100%), but significantly increased the average latent period to 10.14, 10.62, and 11.60, and inhibition of tumor multiplicity to 66, 74,and 83%, respectively. Enzyme analysis of skin and liver showed a significant (p ≤ 0.05, ≤ 0.01, ≤ 0.001) elevation in antioxidant parameters such as superoxide dismutase, catalase, glutathione, and vitamin C in PNE-treated groups (Gr. III–V) when compared with the carcinogen-treated control (Gr. II). The elevated level of lipid peroxidation in the carcinogen-treated positive control group was significantly (p ≤ 0.05, ≤ 0.01, ≤ 0.001) inhibited by PNE administration. These results indicate that P. niruri extract has potentiality to reduce skin papillomas by enhancing antioxidant defense system.