Maltoheptaoside hydrolysis with chromatographic detection and starch hydrolysis with reducing sugar analysis: Comparison of assays allows assessment of the roles of direct α-amylase inhibition and starch complexation

Rizliya Visvanathan, Michael J. Houghton, Gary Williamson

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The aim was to determine inhibition of human α-amylase activity by (poly)phenols using maltoheptaoside as substrate with direct chromatographic product quantification, compared to hydrolysis of amylose and amylopectin estimated using 3,5-dinitrosalicylic acid. Acarbose exhibited similar IC50 values (50% inhibition) with maltoheptaoside, amylopectin or amylose as substrates (2.37 ± 0.11, 3.71 ± 0.12 and 2.08 ± 0.01 µM respectively). Epigallocatechin gallate, quercetagetin and punicalagin were weaker inhibitors of hydrolysis of maltoheptaoside (<50% inhibition) than amylose (IC50: epigallocatechin gallate = 20.41 ± 0.25 µM, quercetagetin = 30.15 ± 2.05 µM) or amylopectin. Interference using 3,5-dinitrosalicylic acid was in the order punicalagin > epigallocatechin gallate > quercetagetin, with minimal interference using maltoheptaoside as substrate. The main inhibition mechanism of epigallocatechin gallate and punicalagin was through complexation with starch, especially amylose, whereas only quercetagetin additionally binds to the α-amylase active site. Interference is minimised using maltoheptaoside as substrate with product detection by chromatography, potentially allowing assessment of direct enzyme inhibition by almost any compound.

Original languageEnglish
Number of pages14
JournalFood Chemistry
DOIs
Publication statusAccepted/In press - 26 Oct 2020

Keywords

  • 3,5-Dinitrosalicylic acid (PubChem CID: 11873)
  • Epigallocatechin gallate (PubChem CID: 65064)
  • Flavonoid
  • Interference
  • Maltoheptaose (PubChem CID: 4444637)
  • Maltopentaose (PubChem CID: 124005)
  • Maltose monohydrate (PubChem CID: 23615261)
  • Maltotetraose (PubChem CID: 439639)
  • Maltotriose (PubChem CID: 439586)
  • Phenolics
  • Polyphenol
  • Punicalagin (PubChem CID: 44584733)
  • Quercetagetin (PubChem CID: 5281680)
  • Reducing sugar
  • Sugar quantification
  • α-amylase inhibition

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