The present study was designed to investigate the antioxidant activity of aqueous and methanol extracts of Erythrina indica Lam leaves by in vitro methods viz. 1, 1-Diphenyl-2-Picrylhydrazyl, nitric oxide radical scavenging activity, and inhibition of lipid peroxidation by thiobarbituric acid reactive substances (TBARS) method on isolated rat liver tissues. Quantitative analysis of antioxidative components like total amount of phenolics, flavonoids, and flavonols were estimated using the spectrophotometric method. Linear regression analysis was used to calculate the IC50 value. Results showed that the aqueous and methanol extracts exhibited significant DPPH radicals scavenging activity with an IC50 value 342.59 + 19.59, 283.24 + 12.28 mg/mL respectively. Nitric oxide radicals were significantly scavenged by the aqueous and methanol extracts (IC50 = 250.12 + 10.66; 328.29 + 3.74 mg/mL). Lipid peroxidation induced by the Fe2+ was inhibited by the aqueous extract with low IC50 value (97.29 +2.05 mg/mL) as compared to methanol extract (IC50 = 283.74 + 5.70 mg/mL). Both the extracts were exhibited similar quantities of total phenolics. Total flavonoids were found to be in higher quantities than total flavonols in aqueous extract as compared to methanol extract. From the results, it is concluded that the aqueous and methanol extracts of E. indica leaves possesses significant antioxidant activity that may be due to the presence of flavonoids and related polyphenolic compounds.
Key words: Antioxidant, Erythrina indica, gallic acid, polyphenols, radicals, rutin.
