In Vitro Antioxidant and Alpha-glucosidase Inhibition Activity of Polygonatum verticillatum of Karnali, Nepal

Abstract

Background: Diabetes mellitus is a metabolic disorder that has become a major health issue in the modern era due to long-term health consequences. α-amylase and α-glucosidase are the key enzymes involved in the digestion of starchy foods, and the inhibition of these enzymes is regarded as a postprandial hyperglycemia control strategy. Objective: The primary goal of this work is to examine the antioxidant activity as well as α- glucosidase inhibitory activity of Polygonatum verticillatum rhizomes via in vitro test. Method: The in vitro α-glucosidase inhibition activity was performed using p-nitrophenyl-α- Dglucopyranoside (PNPG) substrate. 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay was performed to estimate the antioxidant activity. Results: The in vitro α-glucosidase inhibitory activity of Polygonatum verticillatum was investigated for the very first time. Of the three fractions and a crude extract, the ethyl acetate (EA) fraction disclosed potent inhibition activity against α-glucosidase enzyme with an IC50 value of 22.3 ± 0.1 μg/mL. Likewise, the IC50 values for dichloromethane (DCM) fraction and the crude extract against α- glucosidase were reported at 34 ± 0.1 μg/mL and 402.2 ± 0.2 μg/mL, respectively. Similarly, the EA fraction, crude extract, and DCM fraction disclosed promising antioxidant activity with IC50 = 55 ± 0.3 μg/mL, 171.5 ± 0.6 μg/mL, and 164.1 ± 3.4 μg/mL, respectively. Conclusion: These findings concluded that among the crude extract and fractions of Polygonatum verticillatum of Nepalese origin, the EA fraction constituted a potent α-glucosidase inhibiting and antioxidant agent. Further research is required to expose the inhibiting compounds.