Anti-inflammatory and antioxidant activities of ethanolic leaf extract of Brownlowia tersa (L.) Kosterm

Abstract

The present study was designed to investigate the inflammatory and antioxidant activities of ethanolic leaf extract of Brownlowia tersa (L.) Kosterm. The anti-inflammatory activity of leaf extract was studied using carrageenan and histamine-induced rat paw edema test at different doses (200 and 400 mg/kg body weight). DPPH free radical scavenging, nitric oxide scavenging, reducing power, Fe++ ion chelating ability and total phenolic content were used for determining antioxidant activities. The extract, at the dose of 400 mg/kg, showed a significant anti-inflammatory activity (P < 0.01) both in the carrageenan and histamine-induced edema test models in rats showing 54.76 % and 56.96 % reduction in the paw volume comparable to that produced by the standard drug indomethacin (64.88 % and 67.09 %) at 4 h respectively. In DPPH free radical scavenging test, IC50 value for ethanolic extract was found fairly significant 39.33 μg/ml when compared to the IC50 value of the reference standards ascorbic acid and Butylated Hydroxy Anisole (BHA) (3.16 and 5.81 μg/ml) respectively. The IC50 values of the extract and ascorbic acid were 99.06 and 39.35 μg/ml, respectively in nitric oxide scavenging assay. The maximum absorbance for reducing power assay was found to be 1.276 at 100 μg/ml when compared to 2.821 and 1.231 for standard ascorbic acid and BHA respectively. The IC50 value of the extract as percentage of Fe++ ion chelating ability was also found significant compared to that of EDTA. The total phenolic content was 211.82 mg/g of gallic acid equivalent. Acute toxicity test showed that the plant might be safe for pharmacological uses up to a dose level of 3,200 mg/kg of body weight in rats. Therefore, the obtained results suggest the acute anti-inflammatory and antioxidant activities of the ethanolic extract of Brownlowia tersa leaves and thus provide the scientific basis for the traditional uses of this plant part as a remedy for pain and inflammations.