Antihyperglycemic Activity of Vernonia amygdalina Leaf Extracts, Hibiscus esculentus Fruit Extract and Garcinia kola Seed Extract from Kisangani Plants

Abstract

Objective: Many plants used in traditional medicine still need to be studied scientifically in order to verify their medical usefulness and standardize their pharmaceutical properties. The present study aimed at evaluating the antihyperglycemic activity of aqueous and alcoholic extracts from local species of Vernonia amygdalina Delile (Va), Hibiscus esculentus (He) and Garcinia kola Heckel (Gk). Methods: The tests were done on Va-aqueous, Va-ethanolic, Va-butanolic and Va-saponin leaf extracts; He-aqueous fruit extract and Gk-aqueous seed extract. The extracts were prepared using conventional methods. The activity was evaluated in male rabbits given orally 100 mg of extracts per Kg BW and overloaded with glucose (4 g/Kg) 30 minutes later. Glibenclamide 0.2 mg/Kg was given as reference positive control. A negative control group of untreated animals was also included. Blood samples were collected on the animal ear at different times. The assay was performed using a handheld Glucometer®.  Results: The percentages of reduction in glycemia calculated on the basis of the negative control values were 60.5% for glibenclamide, 70.5% for Va-ethanol, 57.6% for Va-aqueous, 42.2% for Va-butanol, 54.5% for He-aqueous and 58.7% for Gk-aqueous. Va-saponins fraction was inactive; it increased the baseline glycemia instead of reducing. Conclusion: All extracts have a relative reduction activity comparable to glibenclamide with the exception of Va-saponins. Improved tradimedicines can be prepared with ethanolic or polyphenolic dry extracts.