ANTIOXIDANT ACTIVITIES OF LASIANTHERA AFRICANA BEAUV. (EDITAN) AND HEINSIA CRINITA AFZEL. (ATAMA) AFTER SIMULATED IN VITRO DIGESTION AND THEIR INHIBITORY ACTION AGAINST ENZYMES LINKED TO DIABETES

Abstract

Diabetes Mellitus is a systemic metabolic disease characterized by hyperglycemia, hyperlipidemia and hyperinsulinemia. As such, this present investigation was aimed at examining the antioxidant indices and antidiabetic potential of Lasianthera africana and Heinsia crinita leaves after simulated in vitro digestion. Preliminary phytochemical screening of the extracts showed that tannins, alkaloids, terpenoids and flavonoids were present in both plants while steroids and phlobatannins were present in H. crinita alone. The non-enzymatic antioxidant assays of both L. africana and H. crinita leaves showed that the in vitro enzyme digested samples have low antioxidant capacity when compared to ethanol-water extract in most of the assays. However, results of the endogenous antioxidant assay showed that both in vitro enzyme digested samples and ethanol-water extract of the vegetal matter possess appreciable level of endogenous enzyme upregulation potential, which are not significantly different. The research has also been able to provide information on the antidiabetic potential of the enzyme-digest and ethanol-water extract of both leaves. The in vitro enzyme digest of both L. africana and H. crinita leaves showed better and appreciable antidiabetic properties (α-amylase, α-glucosidase, non-enzymatic glycosylation of hemoglobin, glucose uptake rate by yeast cell, glucose diffusion inhibitory assay) when compared to the undigested samples. In addition, bioactive compounds in the digested samples of both study plants were more than that of the ethanol-water extract and in silico studies on the bioactive compounds gotten from the samples revealed that bioactive compounds from the in vitro enzyme digest and ethanol-water extract of both study plants have high binding affinity and hence high docking score when compared with acarbose (standard drug) against α-amylase and α-glucosidase which are the key enzymes implicated in Type 2 diabetes. Conclusively, the non-enzymatic antioxidant assays of the L. africana and H. crinita leaves showed that the in vitro enzyme digested 3 samples had low antioxidant capacity when compared to the ethanol-water extract in most of the assays. On the contrary, results of the endogenous antioxidant assay showed that both in vitro enzyme digest and ethanol-water extracts of the medicinal plants possess very appreciable level of endogenous enzyme upregulation potential. Generally, the in vitro enzyme digested samples of both L. africana and H. crinita leaves showed better and appreciable antidiabetic properties when compared to the ethanol-water extract. Therefore, the studied plant can be harnessed as antioxidant bio-resource and antidiabetic agent after passing through the gastro-intestinal tract.