Methanol extracts of Brachystegia eurycoma and Detarium microcarpum seeds flours inhibit some key enzymes linked to the pathology and complications of type 2 diabetes in vitro

The inhibitory effect of methanol extracts of Brachystegia eurycoma and Detarium microcarpum seeds flours on some key enzymes [α-amylase, α-glucosidase and aldose reductase (AR)] linked to the pathology and complications of type 2 diabetes (T2D); and their antioxidant properties were evaluated. The antioxidant properties evaluated were DPPH and ABTS+ scavenging abilities, reducing power, and antioxidant phytochemicals (total phenolics, tannins, total flavonoids and total saponins). Extracts of both flours inhibited α-amylase, α-glucosidase and AR in a dose-dependent manner. The half-maximal inhibitory concentrations (IC50) of B. eurycoma on α-amylase, α-glucosidase, AR and lipid peroxidation were lower than those of D. microcarpum, indicating that it had stronger inhibitory potency than D. microcarpum. B. eurycoma also had significantly (P < 0.05) higher DPPH and ABTS+ scavenging abilities, and reducing power than D. microcarpum. The antioxidant phytochemicals (total phenolics, tannins, total flavonoids and total saponins) were also significantly (P < 0.05) higher in B. eurycoma than D. microcarpum. The inhibitory effect of B. eurycoma and D. microcarpum extracts on α-amylase, α-glucosidase and AR activities may be attributed to the combined action of their polyphenols and total saponins, and this may be a possible mechanism of action providing support for their use in managing hyperglycemia and the complications of T2D.