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Molecules (Basel, Switzerland) Apr 2022Inhibiting the intestinal α-glucosidase can effectively control postprandial hyperglycemia for type 2 diabetes mellitus (T2DM) treatment. In the present study, we...
Inhibiting the intestinal α-glucosidase can effectively control postprandial hyperglycemia for type 2 diabetes mellitus (T2DM) treatment. In the present study, we reported the binding interaction of betulinic acid (BA), a pentacyclic triterpene widely distributed in nature, on α-glucosidase and its alleviation on postprandial hyperglycemia. BA was verified to exhibit a strong inhibitory effect against α-glucosidase with an IC value of 16.83 ± 1.16 μM. More importantly, it showed a synergistically inhibitory effect with acarbose. The underlying inhibitory mechanism was investigated by kinetics analysis, surface plasmon resonance (SPR) detection, molecular docking, molecular dynamics (MD) simulation and binding free energy calculation. BA showed a non-competitive inhibition on α-glucosidase. SPR revealed that it had a strong and fast affinity to α-glucosidase with an equilibrium dissociation constant () value of 5.529 × 10 M and a slow dissociation. Molecular docking and MD simulation revealed that BA bound to the active site of α-glucosidase mainly due to the van der Waals force and hydrogen bond, and then changed the micro-environment and secondary structure of α-glucosidase. Free energy decomposition indicated amino acid residues such as PHE155, PHE175, HIE277, PHE298, GLU302, TRY311 and ASP347 of α-glucosidase at the binding pocket had strong interactions with BA, while LYS153, ARG210, ARG310, ARG354 and ARG437 showed a negative contribution to binding affinity between BA and α-glucosidase. Significantly, oral administration of BA alleviated the postprandial blood glucose fluctuations in mice. This work may provide new insights into the utilization of BA as a functional food and natural medicine for the control of postprandial hyperglycemia.
Topics: Animals; Diabetes Mellitus, Type 2; Glycoside Hydrolase Inhibitors; Hyperglycemia; Mice; Molecular Docking Simulation; Pentacyclic Triterpenes; alpha-Glucosidases; Betulinic Acid
PubMed: 35458714
DOI: 10.3390/molecules27082517 -
Food Chemistry Mar 2022Phenolic acids are involved in modulating the activity of starch digestive enzymes but remains unclear if their interaction with enzymes or starch is governing the...
Phenolic acids are involved in modulating the activity of starch digestive enzymes but remains unclear if their interaction with enzymes or starch is governing the inhibition. The potential inhibition of nine phenolic acids against α-amylase and α-glucosidase was studied applying different methodologies to understand interactions between phenolic acids and either enzymes or substrates. Vanillic and syringic acids were prone to interact with α-amylase requiring low half-maximum inhibitory concentration (IC) to inhibit starch hydrolysis. Nevertheless, the initial interaction of phenolic acids with starch somewhat obstructed their interaction with starch, requiring 10 times higher IC, with the exception of chlorogenic and gallic acid. The study demonstrates that 10% of the phenolic acids were retained during starch gelatinization. Those effects were not really evident with α-glucosidase, likely due to the small molecular size of maltose substrate. Phenolic acids with > 1 hydroxyl group like caffeic and protocatechuic acids showed the lowest IC against α-glucosidase.
Topics: Glycoside Hydrolase Inhibitors; Hydrolysis; Maltose; Starch; alpha-Amylases; alpha-Glucosidases
PubMed: 34624776
DOI: 10.1016/j.foodchem.2021.131231 -
Molecules (Basel, Switzerland) Jul 2021-glucosidase is a major enzyme that is involved in starch digestion and type 2 diabetes mellitus. In this study, the inhibition of hypericin by α-glucosidase and its...
-glucosidase is a major enzyme that is involved in starch digestion and type 2 diabetes mellitus. In this study, the inhibition of hypericin by α-glucosidase and its mechanism were firstly investigated using enzyme kinetics analysis, real-time interaction analysis between hypericin and -glucosidase by surface plasmon resonance (SPR), and molecular docking simulation. The results showed that hypericin was a high potential reversible and competitive α-glucosidase inhibitor, with a maximum half inhibitory concentration (IC) of 4.66 ± 0.27 mg/L. The binding affinities of hypericin with -glucosidase were assessed using an SPR detection system, which indicated that these were strong and fast, with balances dissociation constant (KD) values of 6.56 × 10 M and exhibited a slow dissociation reaction. Analysis by molecular docking further revealed that hydrophobic forces are generated by interactions between hypericin and amino acid residues Arg-315 and Tyr-316. In addition, hydrogen bonding occurred between hypericin and -glucosidase amino acid residues Lys-156, Ser-157, Gly-160, Ser-240, His-280, Asp-242, and Asp-307. The structure and micro-environment of α-glucosidase enzymes were altered, which led to a decrease in α-glucosidase activity. This research identified that hypericin, an anthracene ketone compound, could be a novel α-glucosidase inhibitor and further applied to the development of potential anti-diabetic drugs.
Topics: Anthracenes; Binding Sites; Fungal Proteins; Glycoside Hydrolase Inhibitors; Humans; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Hypoglycemic Agents; Kinetics; Molecular Docking Simulation; Nitrophenylgalactosides; Perylene; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Saccharomyces cerevisiae; Surface Plasmon Resonance; alpha-Glucosidases
PubMed: 34361714
DOI: 10.3390/molecules26154566 -
Marine Drugs Dec 2021polysaccharide (GLP) exhibits good physiological activities, and it is more beneficial as it is degraded. After its degradation by hydrogen peroxide combined with...
polysaccharide (GLP) exhibits good physiological activities, and it is more beneficial as it is degraded. After its degradation by hydrogen peroxide combined with vitamin C (HO-Vc) and optimized by Box-Behnken Design (BBD), a new product of GLP-HV will be generated. While using GLP as control, two products of GLP-H (HO-treated) and GLP-V (Vc-treated) were also produced. These products chemical characteristics (total sugar content, molecular weight, monosaccharide composition, UV spectrum, morphological structure, and hypolipidemic activity in vitro) were assessed. The results showed that the optimal conditions for HO-Vc degradation were as follows: HO-Vc concentration was 18.7 mM, reaction time was 0.5 h, and reaction temperature was 56 °C. The total sugar content of GLP and its degradation products (GLP-HV, GLP-H and GLP-V) were more than 97%, and their monosaccharides are mainly glucose and galactose. The SEM analysis demonstrated that HO-Vc made the structure loose and broken. Moreover, GLP, GLP-HV, GLP-H, and GLP-V had significantly inhibition effect on α-glucosidase, and their IC value were 3.957, 0.265, 1.651, and 1.923 mg/mL, respectively. GLP-HV had the best inhibition effect on α-glucosidase in a dose-dependent manner, which was the mixed type of competitive and non-competitive. It had a certain quenching effect on fluorescence of α-glucosidase, which may be dynamic quenching.
Topics: Animals; Aquatic Organisms; Gracilaria; Hypolipidemic Agents; Inhibitory Concentration 50; Polysaccharides; alpha-Glucosidases
PubMed: 35049867
DOI: 10.3390/md20010013 -
Bioscience, Biotechnology, and... Aug 1997The hydrolysis of glucosidic linkage catalyzed by every carbohydrate-hydrolase is a reaction in which the product retains (alpha-->alpha or beta-->beta) or inverts... (Review)
Review
The hydrolysis of glucosidic linkage catalyzed by every carbohydrate-hydrolase is a reaction in which the product retains (alpha-->alpha or beta-->beta) or inverts (alpha-->beta or beta-->alpha) the anomeric configuration of the substrate. alpha-Glucosidase and glucoamylase are essentially distinguished by releasing alpha-glucose and beta-glucose, respectively, from the common substrates having alpha-glucosidic linkage. The distinction in the substrate specificities of the two enzymes was explained by the subsite affinities in their active sites. The amino acid sequences of the regions containing the catalytic sites were compared in alpha-glucosidases and glucoamylases from various sources. alpha-Glucosidases were suggested to be grouped into two families by their primary structures. The catalytic reaction mechanisms of carbohydrate-hydrolases were discussed in the two significant models of a nucleophilic displacement mechanism and an oxocarbenium ion intermediate mechanism.
Topics: Amino Acid Sequence; Animals; Fungi; Glucan 1,4-alpha-Glucosidase; Humans; Molecular Sequence Data; Substrate Specificity; alpha-Glucosidases
PubMed: 9301101
DOI: 10.1271/bbb.61.1233 -
BMC Complementary and Alternative... Jan 2016Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications...
BACKGROUND
Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications of diabetes. One approach of controlling blood glucose in diabetes targets at reducing the postprandial spikes of blood glucose. The objectives of this study were to assess the in vitro inhibitory effects of Costus speciosus (COS) leaves on α-amylase and α-glucosidase activities, fructosamine formation, protein glycation and glycation-induced protein cross-linking.
METHODS
Methanol extracts of COS leaves were used. Inhibitory effects on enzyme activities were measured using porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae in the presence of COS extract. Percentage inhibition of the enzymes and the IC50 values were determined. In vitro protein glycation inhibitory effect of COS leaves on early and late glycation products were measured using bovine serum albumin or chicken egg lysozyme with fructose. Nitroblue tetrazolium was used to assess the relative concentration of fructosamine and polyacrylamide gel electrophoresis was used to assess the degree of glycation and protein cross-linking in the reaction mixtures.
RESULTS
α-Glucosidase inhibitory activity was detected in COS leaves with a IC50 of 67.5 μg/ml which was significantly lower than the IC50 value of Acarbose (p < 0.01). Amylase inhibitory effects occurred at a comparatively higher concentration of extract with a IC50 of 5.88 mg/ml which was significantly higher than the IC50 value of Acarbose (p < 0.01). COS (250 μg/ml) demonstrated inhibitory effects on fructosamine formation and glycation induced protein cross-linking which were in par with 1 mg/ml aminoguanidine were detected.
CONCLUSION
Methanol extracts of COS leaves demonstrated in vitro inhibitory activities on α-glucosidase, fructosamine formation, glycation and glycation induced protein cross-linking. These findings provide scientific evidence to support the use of COS leaves for hypoglycemic effects with an added advantage in slowing down protein glycation.
Topics: Costus; Fructosamine; Glycation End Products, Advanced; Glycoside Hydrolase Inhibitors; Glycosylation; Plant Leaves; alpha-Amylases; alpha-Glucosidases
PubMed: 26727889
DOI: 10.1186/s12906-015-0982-z -
Molecules (Basel, Switzerland) May 2021Medicinal plants offer imperative sources of innovative chemical substances with important potential therapeutic effects. Among them, the members of the genus have been...
Medicinal plants offer imperative sources of innovative chemical substances with important potential therapeutic effects. Among them, the members of the genus have been widely used in traditional medicine for the treatment of several diseases. The present study investigated the antioxidant (DPPH, ABTS and FRAP assays) and the in vitro anti-hyperglycemic potential of aerial parts of (L.) () extracts through the inhibition of digestive enzymes (α-amylase and α-glucosidase), responsible of the digestion of poly and oligosaccharides. The polyphenolic profile of the (L.) EtOAc extract was also investigated using HPLC-DAD/ESI-MS analysis, whereas the volatile composition was elucidated by GC-MS. The chemical analysis resulted in the detection of twenty-one polyphenolic compounds, whereas the volatile profile highlighted the occurrence of forty-eight different compounds. (L.) presented values as high as 87.2 ± 0.50 mg GAE/g and 78.6 ± 0.55mg CE/g, for gallic acid and catechin, respectively. The EtOAc extract exhibited the higher antioxidant activity compared to methanol and chloroform extracts in different tests with (IC = 0.6 ± 0.03 µg/mL; IC = 8.6 ± 0.08 µg/mL; 634.8 mg ± 1.45 AAE/g extract) in DPPH, ABTS and FRAP tests. Moreover, (L.) leaves did show an important inhibitory effect against α-amylase and α-glucosidase. On the basis of the results achieved, such a species represents a promising traditional medicine, thanks to its remarkable content of functional bioactive compounds, thus opening new prospects for research and innovative phytopharmaceuticals developments.
Topics: Antioxidants; Inula; Phytochemicals; Plant Leaves; alpha-Amylases; alpha-Glucosidases
PubMed: 34073905
DOI: 10.3390/molecules26113134 -
International Journal of Molecular... Feb 2023Controlling post-prandial hyperglycemia and hyperlipidemia, particularly by regulating the activity of digestive enzymes, allows managing type 2 diabetes and obesity....
Controlling post-prandial hyperglycemia and hyperlipidemia, particularly by regulating the activity of digestive enzymes, allows managing type 2 diabetes and obesity. The aim of this study was to assess the effects of TOTUM-63, a formulation of five plant extracts ( L., L., subsp. B.L.Turner, L., and L.), on enzymes involved in carbohydrate and lipid absorption. First, in vitro inhibition assays were performed by targeting three enzymes: α-glucosidase, α-amylase, and lipase. Then, kinetic studies and binding affinity determinations by fluorescence spectrum changes and microscale thermophoresis were performed. The in vitro assays showed that TOTUM-63 inhibited all three digestive enzymes, particularly α-glucosidase (IC of 13.1 µg/mL). Mechanistic studies on α-glucosidase inhibition by TOTUM-63 and molecular interaction experiments indicated a mixed (full) inhibition mechanism, and higher affinity for α-glucosidase than acarbose, the reference α-glucosidase inhibitor. Lastly, in vivo data using leptin receptor-deficient (db/db) mice, a model of obesity and type 2 diabetes, indicated that TOTUM-63 might prevent the increase in fasting glycemia and glycated hemoglobin (HbA1c) levels over time, compared with the untreated group. These results show that TOTUM-63 is a promising new approach for type 2 diabetes management via α-glucosidase inhibition.
Topics: Animals; Mice; alpha-Amylases; alpha-Glucosidases; Diabetes Mellitus, Type 2; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; Kinetics; Lipase; Obesity; Plant Extracts
PubMed: 36835060
DOI: 10.3390/ijms24043652 -
Cellular Immunology Aug 2019Pompe disease is caused by mutations in acid alpha glucosidase (GAA) that causes accumulation of lysosomal glycogen affecting the heart and skeletal muscles, and can be... (Review)
Review
Pompe disease is caused by mutations in acid alpha glucosidase (GAA) that causes accumulation of lysosomal glycogen affecting the heart and skeletal muscles, and can be fatal. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) improves muscle function by reducing glycogen accumulation. Limitations of ERT include a short half-life and the formation of antibodies that result in reduced efficacy. By harnessing the immune tolerance induction properties of the liver, liver-targeted gene delivery (with an adeno-associated virus vector containing a liver specific promoter), suppresses immunity against the GAA introduced by gene therapy. This induces immune tolerance to rhGAA by activating regulatory T cells and simultaneously, corrects GAA deficiency. Potentially, liver-targeted gene therapy can be performed once with lasting effects, by administering a relatively low dose of an adeno-associated virus type 8 vector to replace and induce immune tolerance to GAA.
Topics: Animals; Dependovirus; Enzyme Replacement Therapy; Genetic Therapy; Glycogen Storage Disease Type II; Humans; Immunomodulation; Liver; Mice; Transduction, Genetic; alpha-Glucosidases
PubMed: 29295737
DOI: 10.1016/j.cellimm.2017.12.011 -
European Journal of Pharmaceutical... Jan 202218β-Glycyrrhetinic acid (18β-GA) is known for several biological activities, and has been the focus of extensive research for the development of therapeutic agents. In...
18β-Glycyrrhetinic acid (18β-GA) is known for several biological activities, and has been the focus of extensive research for the development of therapeutic agents. In the current study, 18β-GA-peptide conjugates 2-11 were evaluated for their in vitro α-glucosidase inhibitory and antiglycation activities. Structure-activity relationship (SAR) established and molecular interactions of active bioconjugates with the enzyme's binding sites were predicted through molecular modeling approach. In tripeptide moiety of conjugates 2-11, peptide residue at position 1 was found to have a significant role on α-glucosidase inhibition. The most active 18β-GA-peptide conjugates 5 (18β-GA-Cys-Tyr-Gly), and 8 (18β-GA-Pro-Tyr-Gly) exhibited several-fold potent α-glucosidase inhibition (IC values 20-28 μM), as compared to standard drug acarbose (IC = 875.8 ± 2.10 µM). Kinetic studies of potent compounds, 4-8 revealed that conjugate 5 exhibits competitive-type of inhibition, while conjugates 6-8 showed a non-competitive type of inhibition. The simulation studies also supported the kinetic results that conjugate 5 (18β-GA-Cys-Tyr-Gly) inhibits the α-glucosidase enzyme by blocking its substrate binding site. AGEs-induced NO inhibitors play an important role in controlling the inflammation associated with diabetes mellitus. The peptide conjugates 2-11 were also evaluated in vitro for AGEs-induced NO inhibition using RAW 264.7 macrophage cell line. Our data revealed that conjugates 7-10 were the more potent AGEs-induced NO inhibitors, comparable to standards rutin, and PDTC. The peptide conjugate 5 (a competitive inhibitor of α-glucosidase) also exhibited a strong inhibitory activity against AGEs-induced NO production. Furthermore, peptide conjugates 2-11 were found non-cytotoxic to mouse fibroblast NIH-3T3, and murine macrophages RAW 264.7 cell lines. In conclusion, our data demonstrates that besides possessing strong α-glucosidase inhibition, the newly synthesized peptide conjugates also alleviated the AGEs-induced NO production in RAW macrophages. Dual inhibition of α-glucosidase enzyme, and AGEs-induced NO production by 18β-GA-peptide conjugates qualify them for further research in anti-diabetic drug discovery.
Topics: Animals; Glycoside Hydrolase Inhibitors; Glycyrrhetinic Acid; Kinetics; Mice; Molecular Docking Simulation; Peptides; Structure-Activity Relationship; alpha-Glucosidases
PubMed: 34666184
DOI: 10.1016/j.ejps.2021.106045