Hypoglycaemic Effects of an Aqueous Leaves Extract of Combretum micranthum in Normoglycaemic Rats

Background: In order to promote the Ivorian pharmacopoeia, we undertook the study of Combretum micranthum (Combretaceae), a plant commonly used in Ivory Coast for the treatment of diabetes. The aim of this study was to evaluate the hypoglycemic effects of an aqueous leaves extract of Combretum micranthum (EaqCM) in Wistar rats.

Methods and Materials: A phytochemical screening study was performed. The pharmacological test on normoglycaemic rats was carried out in 4 groups of 5 rats per group. Rats in group 1 received 2 ml of distilled water, and rats in the test groups received doses ranging at 100 to 300 mg/kg B.W. of the EAqCM. Tests in pre-treated temporarily hyperglycemic rats were performed in 4 groups of 5 rats per group. The rats in groups 1 and 2 received 2ml of distilled water, the rats in test groups (3 and 4) received the dose of 10-2g/kg B.W. and 100 mg/kg B.W. respectively glibenclamide and EAqCM. Thirty minutes later, all rats except those in group 1 received anhydrous glucose. The protocol for testing post-treated hyperglycaemic rats is the same as that for pretreated rats, except that in this experiment glucose is administered to the animals before the test substances. Blood glucose is measured in the rats at regular intervals of 30, 60, 90, 120, 150, and 180 minutes after administration of the substances.

Results: Qualitative phytochemical analysis of EAqCM revealed the presence of polyphenols, flavonoids, catechic, tannins, quinonic compounds, alkaloids, sterols, and polyterpenes. Pharmacological tests on the glycemia of normoglycemic rats showed that EAqCM has hypoglycemic properties at a dose of 100 mg/kgB.W. with a percentage reduction of 30%. In hyperglycemic rats, EAqCM and glibenclamide exhibited anti-hyperglycemic activity with respective percentages reduction of 57.47 % and 58.82 %.

Conclusion: Antihyperglycemic effect of EAqCM in post-treated rats would probably be due to the presence of polyphenols and flavonoids in this extract. These results support the use of this plant in traditional medicine for the treatment of diabetes.