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

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.

Antioxidant Molecules from Plant Waste: Extraction Techniques and Biological Properties

“…However, natural alternatives are sought due to this medication's adverse effect, such as gastrointestinal discomfort, steatorrhea, oily feces, fecal incontinence, and potentially liver damage [209]. Zhou, Zhou, Liu, Zhang, and Cai [33] performed a docking analysis on the inhibitory capacity of caffeic acid and catechin against pancreatic lipase. Their computational analysis using the software SYBYL-X 2.1.1 showed that catechin has more affinity towards the enzyme, as catechin binds to pancreatic lipase with the amino acid residues Ala197, Pro194, Ser195, and Lys198 at the active site by hydrogen bonds.…”

“…On the other hand, caffeic acid binds to the amino acid residues Ala197, His224, and Lys198 at the active site. However, caffeic acid shows shorter hydrogen bond distances than catechin, which usually represent tight bounds and stronger inhibitory ability [33].…”

Inhibitory Effects of Myricetrin and Dihydromyricetin toward α-Glucosidase and Pancreatic Lipase with Molecular Docking Analyses and Their Interaction

“…Carbohydrates and fats in food are the main contributors to the body's energy intake, and therefore reducing carbohydrate and/or fat intake is considered an effective way to suppress energy intake [5][6][7]. In the digestive system, carbohydrates and fats need to be digested before they can be absorbed.…”

“…Although these clinical drugs are effective, they all have serious side effects. A large number of previous studies have found that many secondary metabolites of edible plants, especially phenolic compounds, have good inhibitory effects toward α-glucosidase and/or pancreatic lipase [6,7,10,12,13].…”

“…Phenolic compounds in plants are generally polyphenols, which contain multiple hydroxyl groups on the benzene ring. A certain edible plant commonly contains a variety of phenolic substances, and these phenolics often interact with each other when they exert their biological activities, such as synergistic or antagonistic effects [6,10].…”