In vitro Free Radical Scavenging and Analgelsic Activities of Parinari Kerstingii Leaves

Abstract

The study was aimed to investigate in vitro free radical scavenging activity and Analgelsic Activities of Parinari Kerstingii Leaves Extract.

The in vitro free radical scavenging activity of Parinari kerstingii leaf extract was studied through DPPH radical scavenging assay, Ferric reducing antioxidant power ability (FRAP), Nitric oxide (NO) radical scavenging assay and total antioxidant capacity, using ascorbic acid and gallic acid as standard. The analgesic activity of the plant extract was also evaluated using acetic-acid-induced mice writhing and hot plate tests. The phytochemical constituents of the extract were also determined. The extract showed high DPPH radical scavenging activity as shown by the high percentage inhibition (86 %) and lowest value of EC50 (79.23 μg/mL), indicating the strong hydrogen-donating ability. The extract manifested significant reducing power (0.745) which exceeded even that of gallic acid (0.710) at a concentration of 1000 μg/mL. At a maximum concentration of 1000 μg/mL, the extract showed 97.2 % inhibition of nitric oxide and also exhibited a scavenging effect of 78.9 % on total antioxidant capacity. The results also showed that the extract (100-400 mg/kg) significantly (P<0.05) and dose-dependently prolonged the pain reaction time in hot-plate pain model, and reduced acetic acid-induced writhing.

Phytochemical analysis revealed the presence of tannins, saponins, reducing sugars, phenols, soluble carbohydrates, alkaloids, terpenoids, steroids, hydrogen cyanide glycosides and flavonoids. These findings indicate that the leaf extract of Parinari kerstingiimay play an important role in chemical protection from oxidative damage by possessing endogenous antioxidants, such as phenolics, tannins and flavonoids.