Effect of combination on the antioxidant and inhibitory properties of tropical pepper varieties against α-amylaseand α-glucosidase activities in vitro

Pepper used as a spice for food preparations is usually a single type or a combination of several different varieties. This choice is usually based on individual preferences, without consideration of health benefits. Therefore, the present study investigated the health benefits of a combination of 3 pepper varieties commonly consumed in Nigeria. Aqueous extracts (1:100 w/v) of Capsicum annuum var. grossum, C. annuum var. abbreviatum, and C. annuum var. accuminatum and a combination of the 3 varieties (1:1:1) were assayed for phenolic content (total phenol and flavonoid), antioxidant activities (reducing power and 1,1-diphenyl-2-picrylhydrazyl radical-scavenging abilities), inhibitory effect on Fe²⁺-induced lipid peroxidation in rat pancreas in vitro, and the ability of the extracts to inhibit key enzymes linked with type 2 diabetes (α-amylase and α-glucosidase). The combination of peppers showed additive effects in their phenolic content and displayed antioxidant properties. However, the inhibition of pancreatic α-amylase activity showed an additive effect, whereas α-glucosidase inhibitory activity was antagonistic with the combination. C. annuum var. accuminatum contributed most to the activities of the combined peppers. Strong inhibitory activities of the peppers against key enzymes linked to type 2 diabetes and Fe²⁺-induced lipid peroxidation in rat pancreas in vitro, coupled with their antioxidant properties, suggest that pepper could be used in the prevention and management of type 2 diabetes. The pepper combination showed additive tendencies of these properties.