Comparative Evaluation of the Digestive Enzyme Inhibition, Protein, and Starch Components of Ten Macrotyloma uniflorum (Lam.) Verdc. Accessions

Digestive enzymes play a crucial role in carbohydrate hydrolysis and subsequent glucose absorption, and their inhibition can contribute to improved glycemic regulation. Legumes, with their inherent enzyme-inhibitory properties, offer a natural approach for achieving this. In this study, accessions of <i>M. uniflorum</i> (Lam.) Verdc, an underutilized legume, were evaluated <i>in vitro</i> for their α-amylase and α-glucosidase inhibitory activities, as well as their protein, amylose, and resistant starch contents. The results revealed significant variation among the accessions. PI 174827 01 SD (IC₅₀ = 23.29 ± 0.01 µg/mL) and PI 173901 01 SD (IC₅₀ = 24.60 ± 0.01 µg/mL) demonstrated strong inhibition of α-amylase and α-glucosidase, respectively. Protein content ranged from 13.81 to 27.08%<i>w</i>/<i>w</i> d.w., with PI 180437 01 SD showing the highest percentage. Total starch content ranged from 27.48 to 54.70%<i>w</i>/<i>w</i> d.w., amylose from 27.05 to 48.13%<i>w</i>/<i>w</i> d.w., and resistant starch from 5.89% to 7.09%<i>w</i>/<i>w</i> d.w., with PI 174827 01 SD exhibiting both higher amylose and resistant starch contents. These findings suggest that <i>M. uniflorum</i> accessions possess enzyme-inhibitory and nutritional components that could be harnessed to develop functional foods, nutraceuticals, and pharmaceuticals for the management of diabetes and obesity.