Anti-inflammatory activities of crude ethanol extract of Combretum zenkeri Engl. & Diels leaves

To augment orthodox anti-inflammatory drugs, which are scarce in some areas, local dwellers in some parts of Nigeria and Asia rely on herbal products such as Combretum zenkeri Engl. & Diels leaves for the treatment of inflammatory diseases. This study investigated the anti-inflammatory activities of crude ethanol extract of C. zenkeri leaves (EECZ). EECZ was prepared and subjected to anti-inflammatory activity tests. The ability of EECZ to inhibit the release of inflammatory mediators in rats was used as a measure of its anti-inflammatory property. The inhibitory effects of EECZ on phospholipase A2 (PLA2) activity, platelet aggregation and haemolysis of human red blood cells (HRBCs) were determined using standard methods. The phytochemical constituents and acute toxicity profile were also evaluated. EECZ at oral doses of 50 and 100 mg/kg b.w. and at 6 h inhibited egg albumin-induced rat paw oedema by 67.36% and 86.19% respectively. The extract similarly inhibited PLA2 activity causing 58.23% and 60.24% inhibition at concentrations of 400 and 800 μg/ml, respectively. At 100–800 μg/ml, EECZ also significantly inhibited haemolysis of HRBCs. In a concentration-dependent manner, EECZ significantly inhibited CaCl2-induced platelet aggregation. The presence of flavonoids, terpenoids, alkaloids, phenol, saponins, steroids, tannins and glycosides were detected in EECZ. The acute toxicity test showed that EECZ is safe at doses less than 5,000 mg/kg b.w. This study shows that EECZ possess anti-inflammatory activities that could be through the inhibition of PLA2 activity and platelet aggregation, and membrane stabilization.