Effects of an Aqueous Extract of Vernonia Amygdalina Del. (Asteraceae) Leaves on Blood Glucose Levels in Rats
Diabetes mellitus is a major public health problem, which has spurred research into plant-derived substances that may help control blood glucose levels. This study aimed to evaluate the hypoglycemic and antihyperglycemic activities of an aqueous extract of Vernonia amygdalina leaves in Rattus norvegicus rats. The leaves, harvested in Djébonoua (Côte d’Ivoire), were dried, ground, and then extracted with distilled water. A phytochemical screening was performed to identify the different groups of secondary metabolites. An acute toxicity study was conducted in female rats in accordance with OECD Test Guideline 423, using a single dose of 2,000 mg/kg body weight. Hypoglycemic and antihyperglycemic activities were evaluated in male rats, under normoglycemic conditions and after an oral glucose load, respectively, using glibenclamide as a reference drug. The aqueous extract of V. amygdalina leaves contained sterols, polyterpenes, polyphenols, flavonoids, alkaloids, and saponins, with polyphenols, flavonoids, and alkaloids being particularly abundant. At a dose of 2,000 mg/kg, no deaths, no clinical signs of toxicity, and no significant changes in body weight were observed after 14 days. Under normoglycemic conditions, the extract did not cause any significant reduction in blood glucose levels at doses ranging from 100 to 1,000 mg/kg. However, following a glucose overload, doses of 100, 200, and 500 mg/kg significantly reduced the induced hyperglycemia, with the maximum effect observed at 200 mg/kg. These results demonstrate the antihyperglycemic activity of the aqueous extract of V. amygdalina leaves, associated with good acute tolerance.