Inhibition of α-Glucosidase by Abietane-Type Diterpenoids Isolated from Roots of Salvia miltiorrhiza

– Salvia miltiorrhiza is a traditional medicinal plant used in Asian medicine for various therapeutic purposes. This plant contains numerous bioactive secondary metabolites, particularly abietane-type diterpenoids. In this study, 16 abietane-type diterpenoids were isolated from S. miltiorrhiza root extracts and structurally identified through advanced spectroscopic techniques. Among them, tanshinone IIA (6) and 15,16-dihydro-tanshinone I (11) exhibited potent α-glucosidase inhibition, with IC₅₀ values of 48.38 ± 0.57 and 48.02 ± 0.47 µM, respectively. Enzyme kinetic studies revealed that these compounds served as non-competitive inhibitors of α-glucosidase. Our findings indicate that natural compounds from S. miltiorrhiza show promise as safe and effective α-glucosidase inhibitors, providing an alternative approach to diabetes treatment. This study contributes to the growing interest in utilizing natural sources for α-glucosidase inhibition and their potential application in healthcare and disease management.