R. Ranganathan and R. Vijayalakshmi
In the present investigation, the effect of Anisomeles malabarica (L.) R.Br. whole plants extract has been studied on cellular redox status during hamster buccal pouch carcinogenesis. The animals were randomized into experimental and control groups and divided into 8 groups of six animals each. In group 1, the right buccal pouches of hamsters were painted three times per week with a 0.5 percent solution of DMBA in liquid paraffin . Hamsters in groups 2 - 4 painted with DMBA as in group 1, received in addition, intragastric administration of Anisomeles malabarica methanolic extract of concentration 125, 250 and 500 mg/kg body weight respectively three times a week on days alternate to DMBA. Animals in groups 5 through 7 were administered Anisomeles malabarica metabolic extract alone (125, 250 and 500 mg/kg body weight respectively). Group 8 animals received the same volume of water and served as controls. Administration of AMME to DMBA - painted hamsters reduced the incidence of SCC and mean tumour burden in addition to preneoplastic lesions. In the buccal pouch, AMME reversed the susceptibility to lipid peroxidation while simultaneously increasing GSH-dependent antioxidant enzyme activities, whereas in the liver and erythrocytes, the extent of lipid peroxidation was reduced with elevation of antioxidants. Thus, modified oxidant status together with antioxidant adequacy in the target organ as well as in the liver and erythrocytes induced by AMME may significantly reduce cell proliferation and block tumour development in the HBP. The results of the present study are consistent with the free radical scavenging properties of AMME reported in literature. AMME has been shown to prevent the increase in lipid peroxidation and protect against oxidative DNA damage by improving antioxidant defences. Among the doses used in the present study, the medium dose and higher dose of AMME (250 mg/kg bw and 500 mg/kg bw) were found to be more effective in inhibiting HBP carcinogenesis compared to low dose. The protective effects of AMME against HBP carcinogenesis observed in the present study may be related to the antioxidant and antiproliferative properties of phytochemicals such as flavonoids present in the plant.
