Digestive Enzyme Inhibition of Different Phenolic Fractions and Main Phenolic Compounds of Ultra-High-Pressure-Treated Palm Fruits: Interaction and Molecular Docking Analyses

Qingfeng Zhou,Xiaojing Liu,Shengbao Cai,Jiexin Zhou,Yan-Bing Zhang

doi:10.1155/2020/8811597

Abstract

The purpose of the present work was to evaluate the inhibitory effects of different phenolic extracts from non- and ultra-high-pressure- (UHP-) treated palm fruits and their main phenolic compounds against pancreatic lipase and α-glucosidase and to further analyze the interaction and inhibitory mechanisms of two main phenolics (caffeic acid and catechin). Results showed that the free, esterified, and insoluble-bound phenolic fractions from the non- and UHP-treated fruits demonstrated good inhibitory effects towards two enzymes. The insoluble-bound phenolic fraction, regardless of UHP treatment, presented the strongest inhibitory capacities, and UHP treatment significantly upgraded the inhibitory effects of these phenolic fractions (lipase IC50 : 78.01 vs. 72.50 μg/mL; α-glucosidase IC50 : 76.42 vs. 64.51 μg/mL). Catechin and caffeic acid, main phenolic compounds detected in all phenolic fractions of the fruits, showed similar efficiencies on inhibiting the two enzymes, which were consistent with the findings observed by molecular docking analysis. Moreover, these two phenolic compounds exhibited a synergy effect on inhibiting pancreatic lipase and α-glucosidase at a relatively high combination concentration with the ratio of 1 : 1. Therefore, the present work may be helpful for further application of palm fruits as food supplements or nutraceuticals to control energy intake to improving some chronic metabolic diseases.

Highlights

With the continuous improvement of people’s material life, long-term consumption high-glucose and high-fat diet results in glucose and lipid metabolic disorders, causing severe problems to human health [1]
As for UHP-treated oil palm fruits, the inhibitory effects coincided with the order shown in nontreated oil palm fruits, insoluble-bound phenolic fraction > esterified phenolic fraction > free phenolic fraction, and their IC50 value was 72.50 ± 1.36 μg/mL, 95.68 ± 2.37 μg/mL, and 127.57 ± 2.17 μg/mL, respectively
A previous study reported that the insoluble-bound phenolic extract of Sophia seeds had the best inhibitory effect against pancreatic lipase [17]

Summary

Introduction

With the continuous improvement of people’s material life, long-term consumption high-glucose and high-fat diet results in glucose and lipid metabolic disorders, causing severe problems to human health [1]. To the best of our knowledge, few studies have been performed to evaluate the inhibitory effects of the free, esterified and insoluble-bound phenolic fractions (F, E, and IB) from oil palm fruits against the pancreatic lipase and α-glucosidase.

Results

Conclusion