Bioassay-Guided Isolation and Structure Elucidation of Bioactive Phytoconstituents with Inhibitory Activity against Carbohydrate-Hydrolyzing Enzymes from the Aerial Parts of Premna odorata Blanco

Indian Journal of Pharmaceutical Education and Research

  • Ronel Abad Mendoza1School of Chemical, Biological and Materials Engineering and Sciences, Mapúa University, Metro Manila, PHILIPPINES.
  • Chien-Chang Shen2National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, TAIWAN.
  • Po-Wei Tsai3Department of Medical Sciences Industry, College of Health Sciences, Chang Jung Christian University, Tainan, TAIWAN.
  • Kathlia Aguila De Castro-Cruz1School of Chemical, Biological and Materials Engineering and Sciences, Mapúa University, Metro Manila, PHILIPPINES.

Volume 55 Issue 3 Pages 846-856

DOI: 10.5530/ijper.55.3.158

Abstract

Background: This study aimed to isolate the bioactive components from the aerial parts of Premna odorata Blanco and to evaluate the hypoglycemic potentials of the crude extracts, sub-fractions and final isolate. Materials and Methods: The plant material underwent a series of enzyme assay-guided isolation and purification having the fractions assayed for inhibitory activity against α-amylase using 3,5-dinitrosalicylic acid (DNS) colorimetric method for each stage. H.1 isolate was tested for α-amylase and α-glucosidase inhibitory activity and glucose uptake by yeast cells. Phytochemical characterization and 1H and 13C NMR spectral analysis were done for the structure elucidation of H.1. Results: In vitro amylase studies revealed that at 100 μg/mL concentrations, hexane crude extract, fraction F (20%/80% and 10%/90% n-hexane/dichloromethane fractions) and F.3 (10:1 v/v petroleum ether/ethyl acetate sub-fraction) exhibited 34.38±0.116%, 71.86± 4.909% and 42.16±1.257% inhibition against α-amylase (at 1000 μg/mL concentration), respectively. H.1 isolate exerted significant inhibition (p < 0.05) of 55.99± 2.202% and 72.43±3.988% against α-amylase and α-glucosidase enzyme (both at 1000 μg/ mL concentration), respectively and significant glucose uptake of 13.85± 0.368%. The purified isolate was spectroscopically confirmed as a 5:1 mixture of β- sitosterol (H.1a) and stigmasterol (H.1b). Conclusion: The compounds have significant inhibitory activity against carbohydrate-hydrolyzing enzymes and may be potentially developed as adjuvant pharmacotherapy for type 2 diabetes.

Keywords

  • Premna odorata
  • α-amylase
  • α-glucosidase
  • Bioassay
  • Hyperglycemia
  • Inhibition
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