Abstract

The anti-inflammatory effect of the extract of Parinari kerstingii leaves was investigated using egg albumin-induced rat paw oedema, leukocyte mobilization, and acetic acid-induced vascular permeability assay methods. Heat and hypotonicity-induced heamolysis of human red blood cell membrane were also used to assess its membrane stabilizing effect and to determine its inhibitory property on phospholipase A2 activity. Acute toxicity and phytochemical tests were also determined using standard methods. The methanol crude extract (MCE) of P. kerstingii reduced (p<0.05) the acetic acid-induced vascular permeability and increased agar-induced leukocyte mobilization in rats dose-dependently. Vascular permeability was inhibited by 24.85, 26.04 and 48.52% with 100, 200 and 400 mg/kg of the MCE, respectively. The total leukocyte count of the treated groups increased significantly (p<0.05) relative to the control group. The percentage membrane stability exhibited by the MCE was comparable with drug control, indomethacin. The MCE contains principles that protected the erythrocyte membranes effectively. More so, the extract inhibited (p<0.05) the activities of phospholipase A2 and showed no significant difference in the phospholipase A2 inhibitory effect as compared to the standard drug, prednisolone. The extract showed no toxicity at 5000 mg/kg. Phytochemical screenings revealed the presence of tannins, saponins, reducing sugars, phenols, soluble carbohydrates, alkaloids, terpenoids, steroids, hydrogen cyanide glycosides and flavonoids. This study indicated that the MCE of P. kerstingii leaf is relatively safe for consumption and has anti-inflammatory property. Also, it could prevent the haemolysis of human erythrocyte membrane.

Key words: Anti-inflammatory, Parinari kerstingii, acute toxicity, phytochemicals, membrane stability.