University of Wolverhampton
Investigation of insulin releasing and glucose lowering effects of extract of selected plants used in African traditional medicinal practice
Abstract
dc:description.abstractOcimum basilicum, Vernomia amygadalina, Moringa oleifera and Gongronema latifolium have been used traditionally in the treatment of diabetes globally, especially in developing countries where there is little or no access to drugs. However, information about the efficacy and mechanisms underlying biological activities of these plants are poorly understood. This work assessed insulinotropic actions of aqueous and methanolic extracts of selected plants. Plants extraction was carried out using Soxhlet extractor and vacuum evaporator with methanol or water as solvent. Phytochemical screening, total flavonoids and total phenolics content was carried out. Effects of extracts on insulin secretion at various glucose concentrations, in the presence of established modulators of insulin secretion and in the absence of extracellular calcium were also investigated. Cytotoxicity and effects of extracts on cell viability and cell proliferation were assessed in cells treated with the various plant extracts. Protein glycation and antioxidant properties of the extracts were also assessed. Acute, delayed and long-term effects of M. oleifera extracts in animals with diet-induced obesity were assessed. For acute in vivo studies, mice were administered with glucose alone or in combination with glibenclamide or plant extracts (50 mg/kg bw and 100 mg/kg bw). Results obtained in this study confirmed the presence of phytochemicals in all plant extracts. However, phytochemicals were more concentrated in aqueous extract than methanolic extract. All plant extract stimulated insulin secretion at concentration ≥0.1 mg/ml in a dose-dependent manner. The aqueous extract of Moringa oleifera produced the highest insulin-releasing effects on BRIN-BD11 cells (7.2-fold at 1000 μg/ml, P<0.001). The investigation of mechanisms underlying the insulin-releasing effects of these extracts revealed that the ATP-dependent pathway is likely involved in the actions of these extracts. All tested plants significantly inhibited protein glycation. Significantly improved glucose tolerance and enhanced plasma insulin levels were observed in mice acutely administered aqueous extracts of all selected plants with O. basilicum producing the most potent effects (P<0.001). These results indicated beneficial effects of the consumption of the selected plants and their traditional use in the management of diabetes.
Degree
thesis:*- Name dc:type.qualificationname
- PhD
- Grantor dc:publisher.institution
- University of Wolverhampton
- Year dc:date.issued
- 2025
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Falana, Ayokunle Benjamin
- Advisor dc:contributor.advisor
-
- Ojo, Opeolu