Evaluation of the analgesic, anti‐inﬂammatory and anti‐diabetic properties of Sclerocarya birrea (A. Rich.) Hochst. stem‐bark aqueous extract in mice and rats
Authors: Ojewole John A. O. 
Published: October 2004

In order to appraise some of the ethnomedical uses of Sclerocarya birrea (A. Rich.) Hochst., subspecies caffra (Sond.) Kokwaro [family: Anacardiaceae], the present study was undertaken to investigate the analgesic, anti‐inﬂammatory and anti‐diabetic properties of the plant's stem‐bark aqueous extract in experimental models of pain, inﬂammation and diabetes mellitus. The analgesic effect of Sclerocarya birrea stem‐bark aqueous extract was evaluated in mice, while its anti‐inﬂammatory and anti‐diabeticic effects were investigated in rats. Diclofenac (DIC, 100 mg/kg p. o.) and chlorpropamide (250 mg/kg p. o.) were used respectively as reference analgesic, anti‐inﬂammatory and anti‐diabetic agents for comparison. Like diclofenac (DIC, 100 mg/kg p. o.), Sclerocarya birrea stem‐bark aqueous extract (SBE, 100–800 mg/kg p. o.) produced dose‐dependent, signiﬁcant protection (p < 0.05–0.001) against electrical heat‐induced pain. The plant extract (SBE, 25–800 mg/kg p. o.) also produced dose‐ and time‐related, sustained and signiﬁcant reductions (p < 0.05–0.001) in the fresh egg albumin‐induced acute inﬂammation of the rat hind paw oedema. However, the analgesic and anti‐inﬂammatory effects of the plant's extract were found to be approximately 10–15 times less than that of diclofenac. In one set of experiments involving hypoglycaemic/antidiabetic evaluation of the plant's extract, graded doses of Sclerocarya birrea stem‐bark aqueous extract (SBE, 25–800 mg/kg p. o.) were separately administered to groups of fasted normal and fasted diabetic rats. In another set of experiments, a single dose of the plant's aqueous extract (SBE, 800 mg/kg p. o.) was used. The hypoglycaemic effect of this single dose of Sclerocarya birrea stem‐bark aqueous extract (SBE, 800 mg/kg p. o.) was compared with that of chlorpropamide (250 mg/kg p. o.) in both fasted normal and fasted streptozotocin (STZ)‐treated diabetic rats. Following acute treatment, relatively moderate to high doses of Sclerocarya birrea stem‐bark aqueous extract (SBE, 25–800 mg/kg p. o.) produced dose‐dependent, signiﬁcant reductions (p < 0.05–0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. Chlorpropamide (250 mg/kg p. o.) also produced signiﬁcant reductions (p < 0.05–0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. Administration of the single dose of Sclerocarya birrea stem‐bark aqueous extract (SBE, 800 mg/kg p. o.) signiﬁcantly reduced (p < 0.01–0.001) the blood glucose levels of both fasted normal (normoglycaemic) and fasted STZ‐treated, diabetic rats. The results of this experimental animal study indicate that Sclerocarya birrea stem‐bark aqueous extract possesses analgesic, anti‐inﬂammatory and hypoglycaemic properties. These experimental ﬁndings lend pharmacological support to the suggested folkloric uses of the plant's stem‐bark in the management and/or control of pain, inﬂammatory conditions, and adult‐onset, type‐2 diabetes mellitus in some communities of South Africa. Copyright © 2004 John Wiley & Sons, Ltd.