Brian K Beseni, Kolawole A Olofinsan, Veronica F Salau, Ochuko L Erukainure, Md Shahidul Islam
Although some studies have validated the traditional use of several Celtis species as antidiabetic agents, pharmacological reports on the antidiabetic activity of Celtis africana are scarce. This study investigated the antioxidant capacity of plant leaf extracts; their inhibitory effects on lipid- and carbohydrate-digesting enzymes; modulation of skeletal muscle glucose uptake, hepatic gluconeogenic enzyme activities, and intestinal glucose absorption; and their protective capacity against oxidative damage in cardiac tissue. The C. africana leaf extracts showed good concentrations of both phenolics and flavonoid constituents, along with an array of other bioactive phytocompounds identified by GC-MS analysis. The extracts exhibited antioxidant activity and inhibited the carbohydrate digestive enzymes α-amylase and α-glucosidase. They also retarded intestinal glucose absorption and increased glucose uptake in psoas muscle tissue of rats and in a yeast cell suspension. C. africana reduced lipid peroxidation while concomitantly augmenting reduced glutathione (GSH) levels and the activities of superoxide dismutase (SOD) and catalase (CAT) in iron-mediated oxidative cardiac injury. Methoxy-phenyl-oxime and 3-carboxy-1H-indol-5-olate had the best binding affinities against the digestive protein targets. In silico analysis suggests a link between indole-based compounds and the observed bioactivities. Further, in vivo experiments are necessary to verify these findings and elucidate their underlying modes of action.