Evaluation of antioxidant and anti-inflammatory activity of methanol extract of Oxalis corniculata

Oxalis corniculata (family: Oxalidaceae) is used in folk medicine for the treatment of dysentery, fever, cardiopathy, hepatopathy, and various inflammatory aliments 1. Free radicals have been implicated in a variety of conditions including inflammation, atherosclerosis, diabetes, ageing and hepatic toxicities 2. Thus the aim of the present study was to investigate antioxidant and anti-inflammatory activity of methanol extract of whole plant Oxalis corniculata (MOX) using different techniques. In vitro antioxidant activity was studied by DPPH (1,1-Diphenyl-2-Picrylhydrazyl) radical 3, nitric oxide radical scavenging activity 4 and TBARS (Thiobarbituric acid Reactive Substances) methods 5. Experiment was performed in triplicate to minimize the errors. In vivo anti-inflammatory activity was studied using carrageenan induced rat paw edema 6 and cotton pellet induced granuloma formation in rats 7 at the dose levels of 125, 250 and 500mg/kg. Indomethacin (10mg/kg) was used as a positive control in in vivo activity. Results were analyzed by One-way ANOVA followed by Dunnet's test, and considered statistically significant at P<0.05 when compared with negative control. MOX showed significant antioxidant activity by scavenging DPPH (IC50=296.40µg/ml) and NO radicals (IC50=200.45µg/ml) and TBARS (IC50=165.43µg/ml) method. Oral administration of MOX showed significant (p<0.01) biphasic response by decrease in paw inflammation induced by carrageenan. MOX also showed significant percent inhibition viz. 35.12, 56.45, and 68.45 in granuloma formation at the doses of 125, 250 and 500mg/kg respectively. It is concluded that, methanol extract of whole plant of Oxalis corniculata exhibited significant antioxidant and anti-inflammatory activity in acute and chronic phase of inflammation.