Soluble dietary fibres decrease α-glucosidase inhibition of epigallocatechin gallate through affecting...

Area of Science:

• Biochemistry
• Food Science
• Nutritional Science

Background:

• Epigallocatechin gallate (EGCG) is a polyphenol with α-glucosidase inhibitory properties.
• Soluble dietary fibers (SDFs) are complex carbohydrates found in plant-based foods.
• The interaction between SDFs and EGCG's inhibitory effects on α-glucosidase is not fully understood.

Purpose of the Study:

• To investigate how different types of SDFs affect EGCG's inhibition of α-glucosidase.
• To elucidate the mechanisms behind these interactions.
• To determine the implications for evaluating dietary polyphenol efficacy.

Main Methods:

• Studied the effects of three arabinoxylans, polygalacturonic acid (PGA), and two β-glucans on EGCG's α-glucosidase inhibition.
• Assessed changes in EGCG's inhibitory activity, competitive inhibition character, and fluorescence quenching.
• Analyzed the particle size and turbidity of EGCG-enzyme complexes formed in the presence of SDFs.

Main Results:

• Arabinoxylans and PGA significantly reduced EGCG's α-glucosidase inhibitory activity.
• β-glucans had minimal impact on EGCG's inhibition.
• SDFs formed ternary complexes with EGCG and the enzyme, altering particle size and turbidity; arabinoxylans and PGA showed stronger interactions with EGCG, leading to greater inhibition reduction.

Conclusions:

• SDFs, particularly arabinoxylans and PGA, can modulate the α-glucosidase inhibitory effects of EGCG.
• The interactions involve the formation of ternary complexes, influenced by SDF structure and chemical properties.
• SDFs are a crucial factor to consider when assessing the efficacy of dietary polyphenols like EGCG.