Inhibitory Actions of Lupinifolin Isolated from Derris reticulata Stem against Carbohydrate‑Digesting Enzymes

Background: Postprandial hyperglycemia is linked with the development of diabetic complications. Inhibition against the carbohydrate‑digesting enzymes, specifically pancreatic α‑amylase and intestinal α‑glucosidase, delays carbohydrate digestion and subsides postprandial plasma glucose (PPG) levels. Objectives: This study aimed to examine the effects of lupinifolin, purified from Derris reticulata stem, a medicinal plant traditionally used for the treatment of diabetes mellitus, on in vitro α‑amylase and α‑glucosidase enzyme activities and enzyme kinetics. Subjects and Methods: The identification of the isolated phytochemical was performed using nuclear magnetic resonance–mass spectrometry (NMR‑MS) spectrometry. In vitro pancreatic α‑amylase and α‑glucosidase activities and enzyme kinetics were determined using the enzymatic colorimetric methods. Results: The purified phytochemical was identified as lupinifolin from the NMR‑MS spectrometry. The isolated lupinifolin produced a significant α‑amylase and α‑glucosidase inhibitory actions with the median inhibitory concentrations of 3.43 ± 0.77 and 56.29 ± 11.64 μg/mL, respectively. The study of enzyme kinetics showed that lupinifolin exhibited the mode of non-competitive and mixed enzyme inhibitions against α‑amylase and α‑glucosidase, respectively. Conclusion: The potent α‑amylase and α‑glucosidase inhibitory actions of lupinifolin derived from D. reticulata stem evidently suggest its potential use as an alternative for the control of PPG.