Alpha-glucosidase Inhibitory and Antigylcation Effects of Compounds Isolated from Detarium microcarpum Stem Bark

Abstract

Diabetes is a leading cause of death and accounted for about 2 million deaths globally in 2019 alone. The disease is characterized by  hyperglycaemia and protein glycation. This study was designed to examine the antidiabetic potential of Detarium microcarpum stem  bark. The plant material was extracted into 70% methanol by cold maceration. The extract was concentrated in vacuo and partitioned into  n-hexane, dichloromethane, and ethyl acetate soluble fractions. The crude extract and fractions were subjected to alpha-glucosidase  inhibitory assay. The active fractions were subjected to a combination of chromatographic techniques, and the isolated  compounds were characterized using spectroscopic data. In vitro alpha-glucosidase inhibitory and anti-glycation activities of the isolated  compounds were evaluated. The crude extract, dichloromethane, ethyl acetate, and aqueous soluble fractions displayed potent alpha- glucosidase inhibitory activity with IC₅₀ values of 8.93±2.03, 24.67±1.32, 12.89±2.41 and 7.69±1.09 µg/mL, respectively. The isolated  compounds were identified as methyl gallate, quebrachitol, catechin, catechin gallate, and gallic acid. The compounds all displayed potent  alpha-glucosidase inhibitory activity. Methyl gallate and catechin displayed the highest activity with IC₅₀ values of 83.43±2.68 and  106.27±2. 98 μM compared to acarbose (377.75±1.34 μM). Catechin and catechin gallate displayed antiglycation activity with IC₅₀ values  of 108±0.30 and 576.34±22.92 μM, respectively. However, a catechin that displayed the highest activity produced about 50% of the  antiglycation activity of rutin (54.59±2.20 μM) used as standard. Detarium microcarpum stem bark displayed alpha-glucosidase inhibition  and the compounds isolated from the ethyl acetate fraction showed protective effects against glucose-induced protein glycation