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BACKGROUND Ethnopharmacological practitioners in Nigeria have used aqueous and ethanol extracts of Bridelia micrantha leaves to manage conditions associated with inflammation, and these include diabetes, chest pain, edema, arthritis and joint pains. This study aimed to evaluate the effects of methanol leaf extract of B. micrantha on chronic inflammation and oxidative stress which accompany diabetic conditions, in streptozotocin-induced diabetic Albino Wistar rats. METHODS The dried leaves were extracted by percolation in 80% methanol:water for 72 h after which the mixture was filtered using Whatman No. 1 (11 μm) filter papers. Acute toxicity studies were done using Wistar rats and given orally up to a dose of 2,000 mg/kg. The animals were monitored for 48 h. The experimental design involved five (5) groups of six (6) albino Wistar diabetic rats each. Groups A, B and C rats received 100, 200 and 400 mg/kg B. micrantha respectively while groups D (negative control) and E (positive control) rats received 10 mL/kg normal saline and 200 mg/kg acetylsalicylic acid (ASA) respectively by gastric gavage for 7 days. Two sterilized cotton pellets (10 mg each) were implanted subcutaneously into both sides of the dorsal area of each diabetic rat in all the groups. Post cotton pellet implantation, rats in three groups (A, B and C) were treated with 100, 200 and 400 mg/kg B. micrantha extract, while those in two groups (D and E) were treated with acetyl salicylic acid (ASA 200 mg/kg) and normal saline (10 mL/kg) respectively by gastric gavage for 7 days. Serum obtained from the animals on Day 8 of the cotton pellet test were used for malondialdehyde (MDA), catalase, superoxide dismutase (SOD) and glutathione (GSH) assays. RESULTS The administration of the leaf extract up to a dose of 2,000 mg/kg to rats produced absolutely no death or observable signs of toxicity in 48 h. The cotton pellet granuloma weights in 200 mg/kg (44.88±1.2 mg), 400 mg/kg (42.10±1.2 mg) B. micrantha extract treated groups and ASA at 200 mg/kg (43.25±1.8 mg) were significantly lower compared to weight of granuloma (85.50±3.2 mg) obtained in the group treated with normal saline. Serum malondialdehyde (MDA) level in the 200 mg/kg (3.32±0.72 nmol/mL) and 400 mg/kg (1.88±1.27 nmol/mL) B. micrantha extract treated groups were significantly (p more...

The methanolic leaf extract of Bridelia micrantha was tested for subacute antidiabetic and in vivo antioxidant effects in alloxan-induced hyperglycaemic rats. The subacute treatment of the extract (125, 250 and 500 mg/kg) produced 75, 68 and 63% reduction in fasting blood sugar level respectively, on day 14 of treatment. The extract produced time-dependent effect, but did not show a dose-dependent effect. Its optimum antidiabetic activity was noted at the dose of 125 mg/kg and this was comparable to glibenclamide 2 mg/kg (positive control). The extract (125 mg/kg) showed good oral glucose tolerance test (OGTT) effect in both normoglycaemic and hyperglycaemic rats. The OGTT effect of the extract (125 mg/kg) did not differ significantly (p>0.05) from glibenclamide (2 mg/kg). The antioxidant effect of the extract was assayed through the determination of the level of thiobarbituric acid reactive substance (TBARS) and catalase activity. The extract produced a dose-dependent decrease in the serum level of TBARS and gave its optimum catalase activity at the dose of 500 mg/kg. This study suggests that the B. micrantha extract has antihyperglycaemic and antioxidant activities. Therefore, could be a potential source of novel antidiabetic and antioxidant agent for the management of diabetes mellitus. more...