Anti-inflammatory and antioxidant activities of ethanolic extract of aerial parts of Vernonia patula (Dryand.) Merr

Abstract

Objective: To investigate the inflammatory and antioxidant activities of ethanolic extract of aerial part of Vernonia patula (Dryand.) Merr (EAV).

Methods: The anti-inflammatory activity of EAV was studied using carrageenan and histamine-induced rat paw edema test at different doses (100, 200 and 400 mg/kg body weight). DPPH free radical scavenging, nitric oxide scavenging, reducing power and Fe(2+) ion chelating ability were used for determining antioxidant activities.

Results: The EAV, at the dose of 400 mg/kg, showed a significant anti-inflammatory activity (P<0.01) both in the carrageenan and histamine-induced oedema test models in rats, showing 62.86% and 64.42% reduction in the paw volume comparable to that produced by the standard drug indomethacin (67.26% and 66.01%) at 5 h respectively. In DPPH free radical scavenging test, IC50 value for EAV was found fairly significant 36.59 μg/mL when compared to the IC50 value of the reference standards ascorbic acid 8.97 μg/mL. The IC50 values of the extract and ascorbic acid were 47.72 and 12.39 μg/mL, respectively in nitric oxide scavenging assay. The IC50 value of the EAV (33.59 μg/mL) as percentage of Fe(2+) ion chelating ability was also found significant compared to that of EDTA (9.16 μg/mL). The maximum absorbance for reducing power assay was found to be 1.928 at 100 μg/mL when compared to 2.449 for standard ascorbic acid. The total phenolic content was 198.81 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.

Conclusions: Therefore, the obtained results suggest the acute anti-inflammatory and antioxidant activities of the EAV and thus provide the scientific basis for the traditional uses of this plant part as a remedy for inflammations.

Keywords: Acute toxicity; Anti-inflammatory; DPPH free-radical scavenging; Nitric oxide radical scavenging; Reducing power; Vernonia patula.