Phenolic Acids from Lycium barbarum Leaves: In Vitro and In Silico Studies of the Inhibitory Activity against Porcine Pancreatic α-Amylase

Abstract

Nowadays, bioactive compounds from vegetable food and waste are of great interest for their inhibitory potential against digestive enzymes. In the present study, the inhibitory activity of methanolic extract from Lycium barbarum leaves on porcine pancreas α-amylase has been studied. The α-amylase inhibitory activity of the constituent phenolic acids was also investigated. The leaves were extracted by ultrasound-assisted method, one of the most efficient techniques for bioactive extraction from plant materials, and then the phenolic acids were identified by Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) Liquid Chromatography/Mass Spectrometry (LC/MS). Chlorogenic and salicylic acids were the most abundant phenolic acids in L. barbarum leaf extract. The inhibitory effect against α-amylase, determined for individual compounds by in vitro assay, was higher for chlorogenic, salicylic, and caffeic acids. L. barbarum leaf extract showed an appreciable α-amylase inhibitory effect in a concentration-dependent manner. Docking studies of the considered phenolic acids into the active site of α-amylase suggested a conserved binding mode that is mainly stabilized through H-bonds and π-π stacking interactions.

Glycoside Hydrolases and Non-Enzymatic Glycation Inhibitory Potential of Viburnum opulus L. Fruit—In Vitro Studies

“…This study also showed weaker inhibitory activity of this phenolic acid on α-amylase porcine pancreas (IC 50 = 13.17 mg/mL) which is in line with our results. However, Pollini et al [ 26 ] demonstrated that chlorogenic acid had higher inhibitory activity against α-amylase than other phenolics acids (e.g., caffeic acid, p -coumaric acid, sinapic acid, and syringic acid) and 5-fold lower activity compared to acarbose. In addition, the inhibitory activities of the V. opulus fruit samples against both α-amylase and α-glucosidase were lower than the acarbose, probably due to the complexity of the chemical composition of fruit matrices, and weak inhibitory activity of chlorogenic acid—quantitatively the main component of the tested samples.…”

“…These secondary plant metabolites have the capacity to inhibit activity of carbohydrate hydrolyzing digestive enzymes, modulate the glucose transport, stimulate insulin secretion from pancreatic β -cells, reduce insulin resistance, increase insulin sensitivity, inhibit the activity of protein tyrosine phosphatase, reduce the production of protein glycation products, and improve antioxidant defenses [ 15 , 21 , 22 , 23 ]. The listed activities of phenolic compounds largely depend on their structure [ 24 , 25 , 26 , 27 ]. For example, the hydroxylation on aromatic rings of flavonoids improved the inhibition against α-amylase and α-glucosidase while the glycosylation of hydroxyl group on flavonoids weakened the inhibitory potential [ 24 ].…”

Arnica montana Cell Culture Establishment, and Assessment of Its Cytotoxic, Antibacterial, α-Amylase Inhibitor, and Antioxidant In Vitro Bioactivities

“…In Cota fulvida (Asteraceae), the methanolic extract of its aerial parts demonstrated significant inhibition of α-amylase with an IC 50 of 0.35 mg/mL, an effect attributed to flavonoid concentration in the extract [55]. Phenolic acids in species belonging to the Asteraceae family showed capability to inhibit α-amylase, whose IC 50 was reported in mg/mL (6.0 mg/mL for syringic acid, 0.5 mg/mL for chlorogenic acid, 1.8 mg/mL for salicylic acid, 3.5 mg/mL for caffeic acid, 6.2 mg/mL for vanillic acid, 5.6 mg/mL for p-coumaric acid, and 8.3 mg/mL for sinapic acid) [56]. In this work, the fractions of the methanolic extract of A. montana cell culture showed inhibition of this enzyme of almost 10% at 10 µg/mL.…”

Going from Digestion to Microstructure of Starch-Based Food Products: Understanding the Role of Polyphenols

“…Preincubating acarbose with α-amylase caused enzyme inhibition in the range 3.95 to 67.72%, on varying its concentration from 0.004 to 0.031 mM. Acarbose is a pseudo-tetra saccharide usually employed as a positive control in inhibition studies of α-amylase and α-glucosidase (Pollini et al, 2020). Also, vanillic and syringic acids showed high inhibitory effect when previously incubated with the α-amylase (M1AM).…”

“…Therefore, results agree with reported statements affirming that phenolic acids and starch digestive enzymes interact by non-covalent interactions, being responsible of their inhibitory activity . Particularly, hydrogen binding, cation-π interactions, salt bridge interactions or electrostatic forces have been described for chlorogenic, caffeic, p-coumaric, vanillic and syringic and the enzyme (Pollini et al, 2020). The differences in the inhibitory concentration observed with the methodologies tested (M1AM, M2AM, M3AM) suggests that starch somewhat hinders the phenolic acids-enzyme interaction, and in consequence greater concentration of phenolic acids are required for the inhibition.…”