<i><scp>I</scp>n vitro</i> inhibitory effects of cranberry bean (<i><scp>P</scp>haseolus vulgaris </i><scp>L</scp>.) extracts on aldose reductase, α‐glucosidase and α‐amylase

Abstract

Summary The in vitro inhibitory activities of different seed extracts prepared from cranberry bean mutant SA ‐05 and its wild‐type variety H wachia against aldose reductase, α‐glucosidase and α‐amylase were examined. The results indicated that the polyphenolics‐rich extracts obtained using 800 g kg −1 methanol and 500 g kg −1 ethanol demonstrated inhibitory activities against aldose reductase ( IC 50 of 0.36–0.46 mg mL −1 ) and α‐glucosidase ( IC 50 of 1.32–1.94 mg mL −1 ). The 500 g kg −1 ethanol extracts also showed α‐amylase inhibitory activities ( IC 50 of 70.11–80.22 μg mL −1 ). Subsequent extracts, prepared further with NaCl and H 2 O from precipitates of 800 g kg −1 methanol or 500 g kg −1 ethanol extracts, exhibited potent α‐amylase inhibitory activities ( IC 50 of 17.68–38.68 μg mL −1 ). A combination of 500 g kg −1 ethanol extraction plus a subsequent H 2 O extraction produced highest polyphenolics and α‐amylase inhibitors. The SA ‐05 α‐amylase inhibitor extracts showed greater inhibitory activities than that of H wachia. Thus, cranberry bean mutant SA ‐05 is an advantageous choice for producing anti‐hyperglycaemic compounds.