Research on the Influences of Five Food-Borne Polyphenols on In Vitro Slow Starch Digestion and the Mechanism of Action

Abstract

Inhibiting starch digestion can effectively control postprandial blood sugar level. In this study, the in vitro digestion differences among the mixtures of five polyphenols (i.e., procyanidins [PAs], catechin [CA], tannic acid [TA], rutin [RU], and quercetin [QU]) and starch were analyzed through an in vitro simulation test of starch digestion. The interaction characteristics of these five polyphenols with α-amylase and α-glucosidase were investigated in terms of the inhibition effect, dynamics, fluorescence quenching, and circular dichroism (CD). The results revealed that the rapidly digestible starch (RDS) contents decreased, while the resistant starch (RS) contents increased. All five polyphenols inhibited the α-amylase activity through the noncompetitive approach but inhibited the α-glucosidase activity through the competitive approach. Five polyphenols combined with α-amylase spontaneously by using the hydrophobic effect. The interaction of PAs and QU with α-glucosidase were recognized as van der Waals forces and H bonding, whereas CA and TA interacted with α-glucosidase through the hydrophobic effect. All five polyphenols can cause conformational changes in enzymes.

In Vitro Inhibitory Effects of Viburnum opulus Bark and Flower Extracts on Digestion of Potato Starch and Carbohydrate Hydrolases Activity

“…The observed differences in the inhibitory activity of the extracts against digestive enzymes may result from the different affinities of polyphenolic compounds for amylase and glucosidase. For example, procyanidin dimer was a better α-amylase inhibitor than catechin, and the order was reversed in the α-glucosidase-containing system [ 55 ]. Moreover, the authors showed a higher efficiency of inhibiting the activity of these enzymes for rutin and quercetin than for the above-mentioned flavanols.…”

Influence of gardenia yellow on in vitro slow starch digestion and its action mechanism

“…This type was similar with the inhibition of polyphenols for digestive enzymes. 17,30 However, some phenolic acids were mixed inhibitory effects on α-amylase and α-glucosidase, such as naked oat phenolic acid. 31…”

“…The results showed that the inhibitory effect of gardenia yellow on α-glucosidase activity was greater than that on α-amylase activity, that mean it is a mild α-amylase inhibitor but a strong α-glucosidase inhibitor, which was similar with polyphenols. 17 In addition, acarbose exerted more outstanding inhibitory effects on α-amylase and α-glucosidase than gardenia yellow. However, as a natural plant extract, gardenia yellow integrates various merits, such as usage safety, and it could effectively prevent phenomena such as abdominal distension, which may be generated when acarbose is used.…”

“…Its volume was made constant at 25 mL using deionized water after being cooled to room temperature, and the absorbance was determined via ultraviolet-visible (UV-vis) spectrophotometer (UV-1600B, Shanghai Mapada Instruments Co., Ltd., Shanghai, China) at 540 nm. 17 The α-amylase inhibitory activity was measured under different concentrations of gardenia yellow, and the IC 50 value was calculated. The inhibitory effect was calculated using the following formula: α-Amylase inhibition rate (%) = [1 − ( A sample − A sample control )/( A blank − A blank control )] × 100%, where A sample is the absorbance of mixture of gardenia yellow, substrate, enzyme, and DNS color developing agent; A sample control is the absorbance of mixture of gardenia yellow, substrate, and DNS color developing agent, and the enzymatic solution is replaced by PBS; A blank is the absorbance of mixture of substrate, enzyme, and DNS color developing agent, and gardenia yellow is replaced by PBS; and A blank control is the absorbance of mixture of enzyme-free substrate and DNS color developing agent.…”

In vitro evaluation of digestive enzyme inhibition and antioxidant effects of naked oat phenolic acid compound (OPC)

“…Epidemiological studies have shown that dietary polyphenols are able to regulate carbohydrate or glucose homeostasis and control blood glucose by reducing the rate of glucose release and absorption in the small intestine (Hanhineva et al , ). The phenolic‐rich extracts or food‐borne phenolic acid (procyanidins, catechin, tannic acid, rutin and quercetin) has good inhibitory effects on α‐amylase, α‐glucosidase and slow starch digestion (Figueiredo‐Gonzalez et al , ; Ren et al , ).…”