In vitro antidiabetic and antityrosinase activities of methanolic extracts of four nigerian medicinal plants: A kinetic study
TL;DR
Results demonstrate the dual inhibition property of Berlinia sp.
Abstract
Medicinal plants provide a potential source of enzyme inhibitors to aid in diabetes and hyperpigmentation management. This research assessed the in vitro antidiabetic and antityrosinase effects of methanolic extracts from four Nigerian plants: Euphorbia graminea, Berlinia sp., Tabernaemontana pachysiphon, and Anacardium occidentale. Standard chromogenic tests were used to test the inhibition of diabetic enzymes (α-glucosidase and α-amylase) and the inhibitory effects on tyrosinase were monitored at 30 minutes. Berlinia sp. at 100 µg/mL demonstrated the highest inhibition of α-glucosidase inhibition at 83.46 ± 4.12%, like the 91.12 ± 2.34% inhibition seen with acarbose. It also showed moderate α-amylase inhibition at 66.59 ± 5.01%. Euphorbia graminea showed selective inhibition of α-amylase with 68.39 ± 4.87%. The inhibition of tyrosinase activity was moderate, with Berlinia sp. and E. graminea exhibiting 55.04 ± 3.98% and 53.90 ± 4.21% inhibition, respectively, both significantly less active than kojic acid (99.39 ± 1.02%). Different time-dependent inhibitory patterns were observed by kinetic analysis, indicating different modes of interaction with the enzyme. These results demonstrate the dual inhibition property of Berlinia sp. and reinforce the traditional uses of these plants, highlighting the potential for bioassay-guided extraction of bioactive compounds.