In vitro antioxidant activities of the methanolic root extract of tissue cultured medicinal plant Pluchea indica( L.) Less

Antioxidants are molecules, which can safely interact with free radicals and terminate the chain reaction before vital molecules are damaged. Generally, synthetic antioxidants(like, butylated hydroxyl anisole) are good free radical scavengers but they may show some carcinogenic effects. Therefore, current interest is growing on in searching for antioxidants of natural origin. The present investigation evaluates the antioxidant activities of the methanolic root extract of tissue cultured Pluchea indica (L.) Less. (Family: Asteraceae) in various in vitro models. The hydrogen donating ability of the methanol extract of Pluchea indica (MEPI) was measured in the presence of 1,1- diphenyl-2-picryl-hydrazyl (DPPH) radical. A 400 μg/ml of MEPI and Ascorbic acid exhibited 91.23% and 96.35% inhibition, respectively, and the IC ₅₀ values were found to be 12.35μg/ml and 67.65 μg/ml for MEPI and ascorbic acid respectively. The effect of MEPI on reducing power was studied according to the reaction of Fe+3 to Fe+2. The reducing power of the extract increased with the increasing amount of the concentration. The methanolic root extract showed effective reducing power, and inhibition of β-carotene bleaching. The total phenolic content with Folin-Ciocalteu reagent using pyrocatechol as the standard and flavonoid content with aluminium nitrate using quercetin as the standard of the MEPI was 15.3 μg/100mg and 22.2-μg/100 mg respectively. The pro-oxidant activity of the fractions was assessed by their effects on bleomycin-induced DNA damage. MEPI inhibited the nitric oxide (NO) at IC50 values of 102.5 μg/ml, against the corresponding standard Curcumine (IC50 = 70.9 μg/ml). The results were observed in a concentration dependent manner. All the above in vitro studies clearly indicate that the methanolic extract of Pluchea indica (MEPI) has a significant antioxidant activity.