α-Amylase inhibition of a certain dietary polyphenol is predominantly affected by the concentration of α-1, 4-glucosidic bonds in starchy and artificial substrates.

The inhibitory mechanism of gallic acid (GA) on α-amylase was investigated through enzymatic inhibition assays, multi-spectroscopy, Job plot analysis and in-silico molecular docking. The results reveal that GA competitively binds to the active site of α-amylase in a 1:1 stoichiometry, dominantly via four hydrogen bonds and one hydrophobic interaction. The α-amylase-GA complex showed an increased thermal stabilisation, accompanied by a rise in α-helical and β-sheet components, resulting in a partial folding of the protein structure. The compact structure prevents substrate binding and inhibits enzyme activity. The self-quenching ability of GA was considered in the intrinsic fluorescence analysis, revealing a distinct loss in fluorescence intensity with a blueshift in the α-amylase-GA complex spectra. This observation suggests a direct interaction between GA and tryptophan amino acid residues, as the residues move to a more hydrophobic environment. Findings in this study provide insights into the interaction mechanism between GA and α-amylase, which will aid in understanding the inhibitory mechanism of their complex forms found in nature. 

Mechanistic insights into α-amylase inhibition, binding affinity and structural changes upon interaction with gallic acid

The inhibitory mechanisms of purified bound polyphenols extracted from mung bean coat dietary fiber (pMBDF-BP) on porcine pancreatic α-amylase (PPA) were investigated through inhibition kinetics, fluorescence spectroscopy, circular dichroism, differential scanning calorimetry and molecular docking. It was shown that pMBDF-BP exerted significant reversible inhibition on PPA in a mixed-type inhibition manner (IC50 = 18.57 ± 0.30 μg/mL), and the combination of the three major components exhibited a synergistic inhibitory effect on PPA. Further, pMBDF-BP bound to the active site or form a polyphenol-enzyme complex at the inactive site through hydrogen bonding and hydrophobic forces, via enhancing the hydrophobicity of the microenvironment surrounding tryptophan and tyrosine residues and promoting the secondary structure of PPA towards a more stable conformation, eventually reducing the enzyme activity. This study provided theoretical evidences for the utilization of bound polyphenols extracted from mung bean coat dietary fiber as a functional component in natural inhibitors of α-amylase. 

The inhibition mechanism of bound polyphenols extracted from mung bean coat dietary fiber on porcine pancreatic α-amylase: kinetic, spectroscopic, differential scanning calorimetric and molecular docking

Identification of coniferyl ferulate as the bioactive compound behind the xanthine oxidase inhibitory activity of Chuanxiong Rhizome

Inhibition of α-amylase activity to limit the rise in postprandial glucose is one of the most notable effects of dietary plant (poly)phenols. The rate and extent of inhibition depend on many factors, including the structure of (poly)phenols and the substrate used for the inhibition study. While soluble/gelatinised starch is widely used as a substrate for studying inhibition mechanisms, the formation of (poly)phenol-amylose complexes can reduce its susceptibility to α-amylase catalysis. Therefore, the extent of inhibition may not truly represent the inhibition of α-amylase by (poly)phenols. To elucidate mechanisms of interactions between a (poly)phenol and the enzyme, this study compared the inhibition of porcine pancreatic α-amylase (PPA) by three differently structured (poly)phenols: p-coumaric acid, quercetin, and cyanidin-3-glucoside, using solid maize starch as a substrate, that limits the formation of starch-(poly)phenol complexes due to the compact structure of starch granules. The inhibition kinetics were investigated and supported by complementary techniques: in silico analysis (molecular docking and molecular dynamic simulation), fluorescence quenching, circular dichroism and differential scanning calorimetry. Quercetin exhibited the strongest inhibition, followed by cyanidin-3-glucoside and p-coumaric acid, with apparent modes of mixed, mixed, and competitive inhibition, respectively. The specific binding of (poly)phenols to PPA involved hydrogen bonds and hydrophobic interactions, as indicated by in-silico studies. Multi-spectroscopic analysis of the PPA structure unveiled changes or peak shifts due to ligand binding, resulting in structural alterations. These findings were consistent with the kinetic data, emphasising the importance of the structural aspects of each individual (poly)phenol in relation to their interaction with PPA. The study articulated the in-depth mechanism of molecular interaction mechanism between (poly)phenols and enzymes and provided evidence that the structural alterations of enzymes are not a strong indicator of inhibition efficacy, but rather inhibition is due to the binding of (poly)phenols to the enzyme structure limiting the catalysis. 

Molecular interactions between polyphenols and porcine α-amylase: An inhibition study on starch granules probed by kinetic, spectroscopic, calorimetric and in silico techniques

Caffeoyl substitution decreased the binding and inhibitory activity of quinic acid against α-amylase: The reason why chlorogenic acid is a relatively weak enzyme inhibitor.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Xiaoke Peng

Author Tools

Chat about Author

Papers

Caffeoyl substitution decreased the binding and inhibitory activity of quinic acid against α-amylase: The reason why chlorogenic acid is a relatively weak enzyme inhibitor.