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1
Schmidt, Sabine, Sandra Rainieri, Simone Witte, Ulrich Matern, and Stefan Martens. "Identification of aSaccharomyces cerevisiaeGlucosidase That Hydrolyzes Flavonoid Glucosides." Applied and Environmental Microbiology 77, no. 5 (January 7, 2011): 1751–57. http://dx.doi.org/10.1128/aem.01125-10.
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ABSTRACTBaker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-β-glucoside revealed considerable β-glucosidase activity, which impairs any strategy to generate or modify flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in theS. cerevisiaegenome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic α- or β-glucosides identified three efficient β-glucosidases (EXG1, SPR1, and YIR007W), which were further assayed with natural flavonoid β-glucoside substrates and product verification by thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Preferential hydrolysis of 7- or 4′-O-glucosides of isoflavones, flavonols, flavones, and flavanones was observedin vitrowith all three glucosidases, while anthocyanins were also accepted as substrates. The glucosidase activities of EXG1 and SPR1 were completely abolished by Val168Tyr mutation, which confirmed the relevance of this residue, as reported for other glucosidases. Most importantly, biotransformation experiments with knockout yeast strains revealed that only EXG1 knockout strains lost the capability to hydrolyze flavonoid glucosides.
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Fogarty, William M., Catherine T. Kelly, and Sunil K. Kadam. "Separation and characterization of an α-glucosidase and maltase from Bacillus amyloliquefaciens." Canadian Journal of Microbiology 31, no. 8 (August 1, 1985): 670–74. http://dx.doi.org/10.1139/m85-127.
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A novel α-glucosidase and a maltase were isolated from Bacillus amyloliquefaciens. The formation of both enzymes was induced by trehalose, sucrose, or lactose in the growth medium. Trehalose is by far the most efficient inducer of both systems. The α-glucosidase and maltase were separated and purified by ion-exchange chromatography on DEAE Bio-Gel A. Purified α-glucosidase hydrolysed p-nitrophenyl-α-D-glucoside, isomaltose, and isomaltotriose but sucrose, maltose, or related saccharides were not attacked. β-Glucosides and polymeric glucosides were not degraded. The optimum temperature for α-glucosidase activity was 40 °C and its pH optimum was 5.3. The molecular weight and isoelectric point (pI) of the enzyme were 27 000 and 4.6, respectively. Purified maltase attacked maltose and sucrose, while maltotriose and melezitose were hydrolysed at slower rates and p-nitrophenyl-α-D-glucoside was not degraded. Other properties of the maltase were as follows: optimum temperature for activity, 30 °C; pH optimum, 6.5; molecular weight, 64 000; and pI, 4.7.
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Li, Xun, Hua Xiang Gu, Hao Shi, and Fei Wang. "Overexpression and Phylogenetic Analysis of a Thermostable α-Glucosidase from Thermus thermophilus." Advanced Materials Research 1004-1005 (August 2014): 841–48. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.841.
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The α-glucosidase geneaglfromThermus thermophilusHB8 was cloned into expression vector pBV220. The phylogenetic trees of α-glucosidases were constructed using Neighbor-Joining (NJ) and Maximum-Parsimony (MP) methods. Evolution analysis indicated the α-glucosidase fromT. thermophileHB8 was distant from the other glycoside hydrolases 4 and 31 α-glucosidases. By weakening the mRNA secondary structure and replacing the rare codons for the N-terminal amino acids of the target protein, the expression level of theaglwas increased 30-fold. The recombinant AGL was purified by the heat treatment, and had a molecular mass of 61 kDa. The optimal activity was at pH 7.8 and 95°C over a 10 min assay. The purified enzyme was stable over a pH range of 5.4-8.6, and had a 1-h half life at 85°C. Kinetic experiments at 90°C withp-nitrophenyl-α-D-glucoside as substrate gave aKm, andVmaxof 0.072 mM and 400 U/mg. Thus, this report provides an industrial means to produce the recombinant α-glucosidase inE. coli.
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Baiya, Supaporn, Salila Pengthaisong, Sunan Kitjaruwankul, and James R. Ketudat Cairns. "Structural analysis of rice Os4BGlu18 monolignol β-glucosidase." PLOS ONE 16, no. 1 (January 20, 2021): e0241325. http://dx.doi.org/10.1371/journal.pone.0241325.
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Monolignol glucosides are storage forms of monolignols, which are polymerized to lignin to strengthen plant cell walls. The conversion of monolignol glucosides to monolignols is catalyzed by monolignol β-glucosidases. Rice Os4BGlu18 β-glucosidase catalyzes hydrolysis of the monolignol glucosides, coniferin, syringin, and p-coumaryl alcohol glucoside more efficiently than other natural substrates. To understand more clearly the basis for substrate specificity of a monolignol β-glucosidase, the structure of Os4BGlu18 was determined by X-ray crystallography. Crystals of Os4BGlu18 and its complex with δ-gluconolactone diffracted to 1.7 and 2.1 Å resolution, respectively. Two protein molecules were found in the asymmetric unit of the P212121 space group of their isomorphous crystals. The Os4BGlu18 structure exhibited the typical (β/α)8 TIM barrel of glycoside hydrolase family 1 (GH1), but the four variable loops and two disulfide bonds appeared significantly different from other known structures of GH1 β-glucosidases. Molecular docking studies of the Os4BGlu18 structure with monolignol substrate ligands placed the glycone in a similar position to the δ-gluconolactone in the complex structure and revealed the interactions between protein and ligands. Molecular docking, multiple sequence alignment, and homology modeling identified amino acid residues at the aglycone-binding site involved in substrate specificity for monolignol β-glucosides. Thus, the structural basis of substrate recognition and hydrolysis by monolignol β-glucosidases was elucidated.
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Thanakosai, Wannisa, and Preecha Phuwapraisirisan. "First Identification of α-Glucosidase Inhibitors from Okra (Abelmoschus Esculentus) Seeds." Natural Product Communications 8, no. 8 (August 2013): 1934578X1300800. http://dx.doi.org/10.1177/1934578x1300800813.
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Infusion of roasted okra seeds has long been consumed in Turkey for diabetes mellitus therapy. Previous reports of a hypoglycemic effect observed in rats administrated with okra seed extract indicated a possible connection with inhibition of intestinal α-glucosidase. An attempt to identify active components was first herein conducted using α-glucosidase-inhibition-guided isolation, yielding two major flavonol glucosides named isoquercetin (2) and quercetin-3- O-β-glucopyranosyl-(1″′ →6″)-glucoside (3). They selectively inhibited rat intestinal maltase and sucrase, in which isoquercetin (2) was 6–10 times more potent than its related diglucoside 3. This result suggested that an increase in hydrophilicity by the additional glucose residue in 3 led to a significant decline in the inhibitory effect and raised the possible involvement of the free 3-OH in exerting the inhibition. Our postulation was evaluated by examining α-glucosidase inhibition of quercetin (1), and the aglycone of 2 and 3, whose 3-OH is free from any glucose moiety. Interestingly, 1 displayed a broad inhibitory effect toward rat intestinal and baker's yeast α-glucosidases, with improved potency. A kinetic study of 1 indicated that it inhibited maltase by two distinct mechanisms, in competitive ( K i 462 μM) and noncompetitive ( K i 2153 μM) manners, whereas the mechanism underlying the inhibition of sucrase was verified as being of a competitive behavior ( K i 218 μM).
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Flores-Bocanegra, Laura, Rafael Torres-Colín, Martin González-Andrade, José S. Calderón, and Rachel Mata. "In Vivo and In Vitro α-Glucosidase Inhibitory Activity of Perfoliatin a from Melampodium Perfoliatum." Natural Product Communications 14, no. 1 (January 2019): 1934578X1901400. http://dx.doi.org/10.1177/1934578x1901400102.
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As part of our effort to discover new α-glucosidase inhibitors from natural sources, it was found that an aqueous extract from Melampodium perfoliatum (Cavanilles) Kunth (Asteraceae) inhibited the activity of rat-intestinal α-glucosidases in a concentration dependent manner (IC50= 958 μg/mL). Fractionation of the active extract led to the isolation of perfoliatin A (1), which was active against the mammal α-glucosidases and a recombinant α-glucosidase with maltase-glucoamylase activity obtained from Ruminococcus obeum. Kinetic analysis revealed that the interaction of 1 with R. obeum-α-glucosidase was noncompetitive. The calculated Ki was 0.68 ± 0.034 mM. In vivo testing using an oral sucrose tolerance test, in healthy and hyperglycemic mice, revealed that perfoliatin A (1) reduced significantly the postprandial peak, consistent with its α-glucosidase inhibitory activity. The effect was comparable or better to that of acarbose, a therapeutically used α-glucosidase inhibitor. Altogether, these findings clearly supported the α-glucosidase inhibitory activity of melampolide-type of sesquiterpene lactones.
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Zhao, Lin, Yuqiong Pei, Guoxin Zhang, Jiayao Li, Yujie Zhu, Mingjun Xia, Ke Yan, et al. "Efficient Synthesis and In Vitro Hypoglycemic Activity of Rare Apigenin Glycosylation Derivatives." Molecules 28, no. 2 (January 5, 2023): 533. http://dx.doi.org/10.3390/molecules28020533.
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Apigenin is a natural flavonoid with significant biological activity, but poor solubility in water and low bioavailability limits its use in the food and pharmaceutical industries. In this paper, apigenin-7-O-β-(6″-O)-d-glucoside (AG) and apigenin-7-O-β-(6″-O-succinyl)-d-glucoside (SAG), rare apigenin glycosyl and succinyl derivatives formed by the organic solvent-tolerant bacteria Bacillus licheniformis WNJ02 were used in a 10.0% DMSO (v/v) system. The water solubility of SAG was 174 times that of apigenin, which solved the application problem. In the biotransformation reaction, the conversion rate of apigenin (1.0 g/L) was 100% at 24 h, and the yield of SAG was 94.2%. Molecular docking showed that the hypoglycemic activity of apigenin, apigenin-7-glucosides (AG), and SAG was mediated by binding with amino acids of α-glucosidase. The molecular docking results were verified by an in vitro anti-α-glucosidase assay and glucose consumption assay of active compounds. SAG had significant anti-α-glucosidase activity, with an IC50 of 0.485 mM and enhanced glucose consumption in HepG2 cells, which make it an excellent α-glucosidase inhibitor.
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Viigand, Katrin, Kristina Põšnograjeva, Triinu Visnapuu, and Tiina Alamäe. "Genome Mining of Non-Conventional Yeasts: Search and Analysis of MAL Clusters and Proteins." Genes 9, no. 7 (July 16, 2018): 354. http://dx.doi.org/10.3390/genes9070354.
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Genomic clustering of functionally related genes is rare in yeasts and other eukaryotes with only few examples available. Here, we summarize our data on a nontelomeric MAL cluster of a non-conventional methylotrophic yeast Ogataea (Hansenula) polymorpha containing genes for α-glucosidase MAL1, α-glucoside permease MAL2 and two hypothetical transcriptional activators. Using genome mining, we detected MAL clusters of varied number, position and composition in many other maltose-assimilating non-conventional yeasts from different phylogenetic groups. The highest number of MAL clusters was detected in Lipomyces starkeyi while no MAL clusters were found in Schizosaccharomyces pombe and Blastobotrys adeninivorans. Phylograms of α-glucosidases and α-glucoside transporters of yeasts agreed with phylogenesis of the respective yeast species. Substrate specificity of unstudied α-glucosidases was predicted from protein sequence analysis. Specific activities of Scheffersomycesstipitis α-glucosidases MAL7, MAL8, and MAL9 heterologously expressed in Escherichia coli confirmed the correctness of the prediction—these proteins were verified promiscuous maltase-isomaltases. α-Glucosidases of earlier diverged yeasts L. starkeyi, B. adeninivorans and S. pombe showed sequence relatedness with α-glucosidases of filamentous fungi and bacilli.
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Giblin, Mary, Catherine T. Kelly, and William M. Fogarty. "Thermostable α-glucosidase produced by Bacillus caldovelox DSM411." Canadian Journal of Microbiology 33, no. 7 (July 1, 1987): 614–18. http://dx.doi.org/10.1139/m87-107.
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Bacillus caldovelox produces an intracellular α-glucosidase (EC 3.2.1.20). It is the most thermostable microbial α-glucosidase reported to date and a number of its properties are outlined here. It was purified by treatment with protamine sulphate and gel filtration on Sephadex G-150 and gave a single band on SDS–PAGE. The enzyme had highest activity on p-nitrophenyl-α-D-glucoside, which was 2.04 times higher than the activity on maltose, and it was inactive towards isomaltose. It had a molecular weight of 30 000 and an isoelectric point of pH 5.0. The enzyme operated most efficiently at pH 5.5–6.0 and at 50–60 °C. It possessed considerable pH stability, retaining 80% or more activity in the range pH 4.0–9.0. α-Glucosidases tend to be very unstable, but this enzyme was fully stable up to 60 °C for 1 h and retained 51% of its original activity on incubation at 70 °C over the same period. The presence of histidine, cysteine, and manganous ions improved the thermal stability of the enzyme considerably. EDTA, α,α′-dipyridyl, o-phenanthroline, barium, strontium, manganous ions, and glucose stimulated activity, while Tris, ribose, glucono-δ-lactone, and phenyl-α-D-glucoside inhibited activity.
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Alarico, Susana, Milton S. da Costa, and Nuno Empadinhas. "Molecular and Physiological Role of the Trehalose-Hydrolyzing α-Glucosidase from Thermus thermophilus HB27." Journal of Bacteriology 190, no. 7 (January 25, 2008): 2298–305. http://dx.doi.org/10.1128/jb.01794-07.
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ABSTRACT Trehalose supports the growth of Thermus thermophilus strain HB27, but the absence of obvious genes for the hydrolysis of this disaccharide in the genome led us to search for enzymes for such a purpose. We expressed a putative α-glucosidase gene (TTC0107), characterized the recombinant enzyme, and found that the preferred substrate was α,α-1,1-trehalose, a new feature among α-glucosidases. The enzyme could also hydrolyze the disaccharides kojibiose and sucrose (α-1,2 linkage), nigerose and turanose (α-1,3), leucrose (α-1,5), isomaltose and palatinose (α-1,6), and maltose (α-1,4) to a lesser extent. Trehalose was not, however, a substrate for the highly homologous α-glucosidase from T. thermophilus strain GK24. The reciprocal replacement of a peptide containing eight amino acids in the α-glucosidases from strains HB27 (LGEHNLPP) and GK24 (EPTAYHTL) reduced the ability of the former to hydrolyze trehalose and provided trehalose-hydrolytic activity to the latter, showing that LGEHNLPP is necessary for trehalose recognition. Furthermore, disruption of the α-glucosidase gene significantly affected the growth of T. thermophilus HB27 in minimal medium supplemented with trehalose, isomaltose, sucrose, or palatinose, to a lesser extent with maltose, but not with cellobiose (not a substrate for the α-glucosidase), indicating that the α-glucosidase is important for the assimilation of those four disaccharides but that it is also implicated in maltose catabolism.
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Widowati, Wahyu, Maesaroh Maesaroh, Nurul Fauziah, Pande Putu Erawijantari, and Ferry Sandra. "Free Radical Scavenging and Alpha/Beta-glucosidases Inhibitory Activities of Rambutan (Nephelium lappaceum L.) Peel Extract." Indonesian Biomedical Journal 7, no. 3 (December 1, 2015): 157. http://dx.doi.org/10.18585/inabj.v7i3.180.
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BACKGROUND: Diabetes mellitus (DM) is associated with oxidative reaction and hyperglycemic condition. Human body has an antioxidant defense system toward free radical, but overproduction of free radical causing imbalance condition between the free radical and the antioxidant defense in the body that lead to several diseases, including DM. Glucosidase is an enzyme that hydrolize carbohydrates causing increase of blood glucose level, so by inhibiting this enzyme blood glucose level in plasma could be effectively decreased. Rambutan (Nephelium lappaceum L.) peel has been reported to have many potential roles, such as antioxidant and anti-glycemia. Therefore our current study was conducted to evaluate possible effectivity of Rambutan peel to scavenge free radical and to inhibit α- and β-glucosidases. METHODS:Rambutan peel extraction (RPE) was performed based on maceration method. Geraniin was used as control. For antioxidant study, 2,2-diphenyl-1- picrylhydrazyl (DPPH) free radical scavenging test was performed. For glucosidase inhibitory activity study, α- and β-glucosidases inhibitory activity tests were performed. Results were analyzed for median of Inhibitory Concentration (IC50).RESULTS: The scavenging activity of RPE was comparable with Geraniin. Meanwhile, the α-glucosidase inhibitory activity of RPE was higher than the one of Geraniin. The α-glucosidase-inhibitory-activity IC50 of RPE and Geraniin were 0.106±0.080 μg/ml and 16.12±0.29 μg/ml, respectively. The β-glucosidase inhibitory activity of RPE was also higher than the one of Geraniin. The β-glucosidase-inhibitory-activity IC50 of RPE and Geraniin were 7.02±0.99 μg/ml and 19.81±0.66 μg/ml, respectively.CONCLUSION: Since RPE showed comparable free radical scavenging activity with Geraniin and higher α- and β-glucosidases inhibitory activities than Geraniin, RPE could be suggested as a promising antioxidant and antiglycemic agent. KEYWORDS: Nephelium lappaceum L., rambutan, hypoglycemic, antioxidant, free radical, diabetes mellitus, glucosidase, DPPH
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Kato, Naoki, Sachie Suyama, Masao Shirokane, Masashi Kato, Tetsuo Kobayashi, and Norihiro Tsukagoshi. "Novel α-Glucosidase from Aspergillus nidulans with Strong Transglycosylation Activity." Applied and Environmental Microbiology 68, no. 3 (March 2002): 1250–56. http://dx.doi.org/10.1128/aem.68.3.1250-1256.2002.
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ABSTRACT Aspergillus nidulans possessed an α-glucosidase with strong transglycosylation activity. The enzyme, designated α-glucosidase B (AgdB), was purified and characterized. AgdB was a heterodimeric protein comprising 74- and 55-kDa subunits and catalyzed hydrolysis of maltose along with formation of isomaltose and panose. Approximately 50% of maltose was converted to isomaltose, panose, and other minor transglycosylation products by AgdB, even at low maltose concentrations. The agdB gene was cloned and sequenced. The gene comprised 3,055 bp, interrupted by three short introns, and encoded a polypeptide of 955 amino acids. The deduced amino acid sequence contained the chemically determined N-terminal and internal amino acid sequences of the 74- and 55-kDa subunits. This implies that AgdB is synthesized as a single polypeptide precursor. AgdB showed low but overall sequence homology to α-glucosidases of glycosyl hydrolase family 31. However, AgdB was phylogenetically distinct from any other α-glucosidases. We propose here that AgdB is a novel α-glucosidase with unusually strong transglycosylation activity.
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Willis, Laura B., and Graham C. Walker. "A Novel Sinorhizobium meliloti Operon Encodes an α-Glucosidase and a Periplasmic-Binding-Protein-Dependent Transport System for α-Glucosides." Journal of Bacteriology 181, no. 14 (July 15, 1999): 4176–84. http://dx.doi.org/10.1128/jb.181.14.4176-4184.1999.
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ABSTRACT The most abundant carbon source transported into legume root nodules is photosynthetically produced sucrose, yet the importance of its metabolism by rhizobia in planta is not yet known. To identify genes involved in sucrose uptake and hydrolysis, we screened aSinorhizobium meliloti genomic library and discovered a segment of S. meliloti DNA which allows Ralstonia eutropha to grow on the α-glucosides sucrose, maltose, and trehalose. Tn5 mutagenesis localized the required genes to a 6.8-kb region containing five open reading frames which were namedagl, for α-glucoside utilization. Four of these (aglE, aglF, aglG, andaglK) appear to encode a periplasmic-binding-protein-dependent sugar transport system, and one (aglA) appears to encode an α-glucosidase with homology to family 13 of glycosyl hydrolases. Cosmid-borne agl genes permit uptake of radiolabeled sucrose into R. eutrophacells. Analysis of the properties of agl mutants suggests that S. meliloti possesses at least one additional α-glucosidase as well as a lower-affinity transport system for α-glucosides. It is possible that the Fix+ phenotype ofagl mutants on alfalfa is due to these additional functions. Loci found by DNA sequencing to be adjacent toaglEFGAK include a probable regulatory gene (aglR), zwf and edd, which encode the first two enzymes of the Entner-Doudoroff pathway, pgl, which shows homology to a gene encoding a putative phosphogluconolactonase, and a novel Rhizobium-specific repeat element.
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Lim, Jongbin, Do Kyoung Kim, Hansol Shin, Bruce R. Hamaker, and Byung-Hoo Lee. "Different inhibition properties of catechins on the individual subunits of mucosal α-glucosidases as measured by partially-purified rat intestinal extract." Food & Function 10, no. 7 (2019): 4407–13. http://dx.doi.org/10.1039/c9fo00990f.
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Mucosal α-glucosidases from rat intestinal powder were employed, with a step to remove α-amylase, to measure the possibility of different inhibition of catechins, particularly those found in tea, on the four α-glucosidase enzymes.
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BERRIN, Jean-Guy, Mirjam CZJZEK, Paul A. KROON, W. Russell MCLAUCHLAN, Antoine PUIGSERVER, Gary WILLIAMSON, and Nathalie JUGE. "Substrate (aglycone) specificity of human cytosolic beta-glucosidase." Biochemical Journal 373, no. 1 (July 1, 2003): 41–48. http://dx.doi.org/10.1042/bj20021876.
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Human cytosolic β-glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyses certain flavonoid glucosides, with specificity depending on the aglycone moiety, the type of sugar and the linkage between them. Based upon the X-ray structure of Zea mays β-glucosidase, we generated a three-dimensional model of hCBG by homology modelling. The enzyme exhibited the (β/α)8-barrel fold characteristic of family 1 β-glucosidases, with structural differences being confined mainly to loop regions. Based on the substrate specificity of the human enzymes, sequence alignment of family 1 enzymes and analysis of the hCBG structural model, we selected and mutated putative substrate (aglycone) binding site residues. Four single mutants (Val168→Tyr, Phe225→Ser, Tyr308→Ala and Tyr308→Phe) were expressed in Pichia pastoris, purified and characterized. All mutant proteins showed a decrease in activity towards a broad range of substrates. The Val168→Tyr mutation did not affect Km on p-nitrophenyl (pNP)-glycosides, but increased Km 5-fold on flavonoid glucosides, providing the first biochemical evidence supporting a role for this residue in aglycone-binding of the substrate, a finding consistent with our three-dimensional model. The Phe225→Ser and Tyr308→Ala mutations, and, to a lesser degree, the Tyr308→Phe mutation, resulted in a drastic decrease in specific activities towards all substrates tested, indicating an important role of those residues in catalysis. Taken together with the three-dimensional model, these mutation studies identified the amino-acid residues in the aglycone-binding subsite of hCBG that are essential for flavonoid glucoside binding and catalysis.
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Sha, Bi Ying, Qing Shan Liu, Jin Lian Zhang, and Xiao Ying Yin. "Alpha-Glucosidase Immobilization Based on PMMA/Chitosan Core-Shell Microparticles." Advanced Materials Research 887-888 (February 2014): 507–11. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.507.
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Objective To obtain immobilized alpha-glucosidase with good biological activity and improve the utilization rate of alpha-glucosidase. Methods Prepare the core-shell microparticles consisting of poly (methyl methacrylate) (PMMA) cores surrounded by various of chitosan shells, induced by tert-butylhydroperoxide (TBHP). Then fixed the alpha-glucosides N-terminal onto the carriers and studied the optimum immobilization conditions and the property of alpha-glucosidase immobilized.Result Immobilized α-glucosidase enzyme pH stability was higher than the free. In particular, the relative enzyme activity were maintained at 80% in the range of pH4.5 ~ 6.5. Immobilized α-glucosidase optimum temperature is 60 °C, the optimum temperature of the free enzyme is 50 °C. Conclution These Alpha-glucosidase Immobilization can be used as biopolymer and biomaterials in the pharmaceutical and medical application fields.
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William, James, Peter John, Muhammad Waseem Mumtaz, Ayoub Rashid Ch, Ahmad Adnan, Hamid Mukhtar, Shahzad Sharif, Syed Ali Raza, and Muhammad Tayyab Akhtar. "Antioxidant activity, α-glucosidase inhibition and phytochemical profiling of Hyophorbe lagenicaulis leaf extracts." PeerJ 7 (June 20, 2019): e7022. http://dx.doi.org/10.7717/peerj.7022.
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Background Diabetes mellitus type II (DMT-2) is a widely spread metabolic disorder both in developed and developing countries. The role of oxidative stress is well established in DMT-2 pathogenesis. The synthetic drugs for DMT-2 are associated with serious side complications. Antioxidant and α-glucosidase inhibitory actions of phytochemicals from various plant species are considered as an alternative to synthetic drugs for DMT-2 management. The present study aimed to evaluate the antioxidant activity, α-glucosidase inhibitory potential and phytochemical profiling of Hyophorbe lagenicaulis. Methods The total phenolic and flavonoid contents, in vitro antioxidant activity (α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging and phosphomolybdenum method) and α-glucosidase inhibition of ultrasonicated hydroethanolic H. lagenicaulis leaf extracts were determined spectrophotometrically. The results of DPPH assay and α-glucosidase inhibition were reported in terms of IC50 value. The phytochemical profiling was accomplished by UHPLC-Q-TOF/MS/MS technique. Results and Discussion Findings leaped 60% ethanolic extract as rich fraction regarding total phenolic and flavonoid contents. The 60% ethanolic fraction was a promising source of natural antioxidants and α-glucosidase inhibitory agents as indicated by anti-radical and enzyme inibitory activities. Kaempferol, rutin, hesperetin 5-O-glucoside, kaempferol-coumaroyl-glucoside, luteolin 3-glucoside, Isorhamnetin-3-O-rutinoside, trimethoxyflavone derivatives and citric acid were identified by UHPLC-Q-TOF-MS/MS. These compounds were believed to be responsible for the strong antioxidant and enzyme inhibitory activity of plant extracts. The extensive metabolite profiling of H. lagenicaulis was carried out the first time as never reported previously. The H. lagenicaulis might be an appropriate choice to manage diabetes mellitus in an alternate way. The findings may be further exploited extensively for toxicity evaluation to proceed with functional food development having antidiabetic attributes.
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Rasool, Nasir, Muhammad Abid Rashid, Saleha Suleman Khan, Zulfiqar Ali, Muhammd Zubair, Viqar Uddin Ahmad, Shamsun Nahar Khan, M. Iqbal Choudhary, and Rasool Bakhsh Tareen. "Novel α-Glucosidase Activator from Pulicaria undulata." Natural Product Communications 8, no. 6 (June 2013): 1934578X1300800. http://dx.doi.org/10.1177/1934578x1300800618.
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A new ent –kaurane type diterpene glucoside, pulicarside (1), together with three known terpenoids, paniculoside IV (2, diterpene), ent–16, 17-dihydroxy-(-)-kauran-19–oic acid (3, diterpene), and 2α–hydroxy alantolactone (4, sesquiterpene) have been isolated from Pulicaria undulata L. Their structures were determined with the help of spectral studies. Pulicarside (1) showed α-glucosidase activator activity, whereas its hydrolyzed product ent-16, 17-dihydroxy-(-)-kauran-19-oic acid (3) exhibited strong α-glucosidase inhibitory activity. Paniculoside IV (2) also shows high inhibitory potency compared with the standard drug acarbose.
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Shen, Xing, Wataru Saburi, Zuoqi Gai, Koji Kato, Teruyo Ojima-Kato, Jian Yu, Keisuke Komoda, et al. "Structural analysis of the α-glucosidase HaG provides new insights into substrate specificity and catalytic mechanism." Acta Crystallographica Section D Biological Crystallography 71, no. 6 (May 23, 2015): 1382–91. http://dx.doi.org/10.1107/s139900471500721x.
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α-Glucosidases, which catalyze the hydrolysis of the α-glucosidic linkage at the nonreducing end of the substrate, are important for the metabolism of α-glucosides.Halomonassp. H11 α-glucosidase (HaG), belonging to glycoside hydrolase family 13 (GH13), only has high hydrolytic activity towards the α-(1→4)-linked disaccharide maltose among naturally occurring substrates. Although several three-dimensional structures of GH13 members have been solved, the disaccharide specificity and α-(1→4) recognition mechanism of α-glucosidase are unclear owing to a lack of corresponding substrate-bound structures. In this study, four crystal structures of HaG were solved: the apo form, the glucosyl-enzyme intermediate complex, the E271Q mutant in complex with its natural substrate maltose and a complex of the D202N mutant with D-glucose and glycerol. These structures explicitly provide insights into the substrate specificity and catalytic mechanism of HaG. A peculiar long β→α loop 4 which exists in α-glucosidase is responsible for the strict recognition of disaccharides owing to steric hindrance. Two residues, Thr203 and Phe297, assisted with Gly228, were found to determine the glycosidic linkage specificity of the substrate at subsite +1. Furthermore, an explanation of the α-glucosidase reaction mechanism is proposed based on the glucosyl-enzyme intermediate structure.
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Tanaka, Kelly SE, Jiang Zhu, Xicai Huang, Francesco Lipari, and Andrew J. Bennet. "Glycosidase-catalyzed hydrolysis of 2-deoxyglucopyranosyl pyridinium salts: effect of the 2-OH group on binding and catalysis." Canadian Journal of Chemistry 78, no. 5 (May 1, 2000): 577–82. http://dx.doi.org/10.1139/v00-061.
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Three 2-deoxy-α-D-glucopyranosyl pyridinium tetrafluoroborates were tested for their binding affinity to a range of α-glucosidases and α-mannosidases. The α-isoquinolinium salt (11) binds approximately 275-fold more tightly to yeast α-glucosidase than does the isomeric quinolinium salt (12). In addition, compound 11 binds to the yeast enzyme approximately two-fold tighter than the corresponding glucopyranosyl isoquinolinium salt (9). The (kcat/khyd) values for the yeast α-glucosidase-catalyzed reactions of 11 and 9 are 1.6 × 105 and 2.0 × 109, respectively, when compared to the spontaneous uncatalyzed reactions. Thus, the interaction of the 2-OH group in compound 9 with the yeast enzyme's active site generates a relative transition state stabilization of about 23.5 kJ mol-1. For both compounds 11 and 12, the observed rate accelerations for the yeast α-glucosidase-catalyzed hydrolysis, relative to the spontaneous reaction in solution, (kcat/khyd) are identical within experimental error.Key words: glycosidase, inhibitor, 2-deoxyglucose, pyridinium, catalysis.
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Kelly, Catherine T., Mary Giblin, and William M. Fogarty. "Resolution, purification, and characterization of two extracellular glucohydrolases, α-glucosidase and maltase, of Bacillus licheniformis." Canadian Journal of Microbiology 32, no. 4 (April 1, 1986): 342–47. http://dx.doi.org/10.1139/m86-066.
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Two extracellular α-glucosidases (EC 3.2.1.20, α-D-glucoside glucohydrolase) of Bacillus licheniformis NCIB 8549 were separated, purified, and partially characterized. Resolution of the complex into two separate enzymes was achieved using Sephadex G-150. The first of these activities, a maltase, hydrolysed maltose preferentially. It had slight activity on isomaltose, p-nitrophenyl-α-D-glycopyranoside, and sucrose. The pH optimum was 6.0 and the molecular weight determined on Sephadex G-200 was 160 000. This enzyme did not display any transglucosylation activity. The second enzyme was an α-glucosidase. It displayed highest activity on p-nitrophenyl-α-D-glucopyranoside, followed by isomaltose, sucrose, and maltose. As with the maltase, the pH optimum was 6.0 and the molecular weight as determined on Sephadex G-150 was 66 000. With isomaltose and maltotriose as substrates, transglucosylation activity was evident.
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Liu, Yang, Xue Zhou, Dan Zhou, Yongxing Jian, Jingfu Jia, and Fahuan Ge. "Isolation of Chalcomoracin as a Potential α-Glycosidase Inhibitor from Mulberry Leaves and Its Binding Mechanism." Molecules 27, no. 18 (September 6, 2022): 5742. http://dx.doi.org/10.3390/molecules27185742.
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Diabetes is a chronic metabolic disease, whereas α-glucosidases are key enzymes involved in the metabolism of starch and glycogen. There is a long history of the use of mulberry leaf (the leaf of Morus alba) as an antidiabetic herb in China, and we found that chalcomoracin, one of the specific Diels–Alder adducts in mulberry leaf, had prominent α-glucosidase inhibitory activity and has the potential to be a substitute for current hypoglycemic drugs such as acarbose, which have severe gastrointestinal side effects. In this study, chalcomoracin was effectively isolated from mulberry leaves, and its α-glucosidase inhibition was studied via enzymatic kinetics, isothermal titration (ITC) and molecular docking. The results showed that chalcomoracin inhibited α-glucosidase through both competitive and non-competitive manners, and its inhibitory activity was stronger than that of 1-doxymycin (1-DNJ) but slightly weaker than that of acarbose. ITC analysis revealed that the combination of chalcomoracin and α-glucosidase was an entropy-driven spontaneous reaction, and the molecular docking results also verified this conclusion. During the binding process, chalcomoracin went into the “pocket” of α-glucosidase via hydrophobic interactions, and it is linked with residues Val544, Asp95, Ala93, Gly119, Arg275 and Pro287 by hydrogen bonds. This study provided a potential compound for the prevention and treatment of diabetes and a theoretical basis for the discovery of novel candidates for α-glycosidase inhibitors.
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Xue, Hongkun, Xiaohan Zhu, Jiaqi Tan, Linlin Fan, Qian Li, Jintian Tang, and Xu Cai. "Counter-Current Fractionation-Assisted Bioassay-Guided Separation of Active Compound from Blueberry and the Interaction between the Active Compound and α-Glucosidase." Foods 10, no. 3 (March 1, 2021): 509. http://dx.doi.org/10.3390/foods10030509.
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An efficient strategy for the selection of active compounds from blueberry based on counter-current fractionation and bioassay-guided separation was established in this study. Blueberry extract showed potential α-glucosidase inhibitory activity. After extraction by different solvents, the active components were enriched in water. The water extract was divided into six fractions via high-speed counter-current chromatography to further track the active components. Results indicated that the α-glucosidase inhibition rate of F4 was remarkable higher than the others. Cyanidin-3-glucoside (C3G) with a purity of 94.16% was successfully separated from F4 through column chromatography, and its structure was identified by ultraviolet spectral, Fourier-transformed infrared spectroscopy, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, 1H nuclear magnetic resonance (NMR), and 13C NMR. The interaction mechanism between C3G and α-glucosidase was clearly characterized and described by spectroscopic methods, including fluorescence and circular dichroism (CD) in combination with molecular docking techniques. C3G could spontaneously bind with α-glucosidase to form complexes by hydrogen bonds. The secondary structure of α-glucosidase changed in varying degrees after complexation with C3G. The α-helical and β-turn contents of α-glucosidase decreased, whereas the β-sheet content and the irregular coil structures increased. Molecular docking speculated that C3G could form hydrogen bonds with α-glucosidase by binding to the active sit (Leu 313, Ser 157, Tyr 158, Phe 314, Arg 315, and two Asp 307). These findings may be useful for the development of functional foods to tackle type 2 diabetes.
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Mosén, Henrik, Albert Salehi, Ragnar Henningsson, and Ingmar Lundquist. "Nitric oxide inhibits, and carbon monoxide activates, islet acid α-glucoside hydrolase activities in parallel with glucose-stimulated insulin secretion." Journal of Endocrinology 190, no. 3 (September 2006): 681–93. http://dx.doi.org/10.1677/joe.1.06890.
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We have studied the influence of nitric oxide (NO) and carbon monoxide (CO), putative messenger molecules in the brain as well as in the islets of Langerhans, on glucose-stimulated insulin secretion and on the activities of the acid α-glucoside hydrolases, enzymes which we previously have shown to be implicated in the insulin release process. We have shown here that exogenous NO gas inhibits, while CO gas amplifies glucose-stimulated insulin secretion in intact mouse islets concomitant with a marked inhibition (NO) and a marked activation (CO) of the activities of the lysosomal/vacuolar enzymes acid glucan-1,4-α-glucosidase and acid α-glucosidase (acid α-glucoside hydrolases). Furthermore, CO dose-dependently potentiated glucose-stimulated insulin secretion in the range 0.1–1000 μM. In intact islets, the heme oxygenase substrate hemin markedly amplified glucose-stimulated insulin release, an effect which was accompanied by an increased activity of the acid α-glucoside hydrolases. These effects were partially suppressed by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one. Hemin also inhibited inducible NO synthase (iNOS)-derived NO production probably through a direct effect of CO on the NOS enzyme. Further, exogenous CO raised the content of both cGMP and cAMP in parallel with a marked amplification of glucose-stimulated insulin release, while exogenous NO suppressed insulin release and cAMP, leaving cGMP unaffected. Emiglitate, a selective inhibitor of α-glucoside hydrolase activities, was able to markedly inhibit the stimulatory effect of exogenous CO on both glucose-stimulated insulin secretion and the activityof acid glucan-1,4-α-glucosidase and acid α-glucosidase, while no appreciable effect on the activities of other lysosomal enzyme activities measured was found. We propose that CO and NO, both produced in significant quantities in the islets of Langerhans, have interacting regulatory roles on glucose-stimulated insulin secretion. This regulation is, at least in part, transduced through the activity of cGMP and the lysosomal/vacuolar system and the associated acid α-glucoside hydrolases, but probably also through a direct effect on the cAMP system.
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Berthelot, Karine, and Francis M. Delmotte. "Purification and Characterization of an α-Glucosidase from Rhizobium sp. (Robinia pseudoacacia L.) Strain USDA 4280." Applied and Environmental Microbiology 65, no. 7 (July 1, 1999): 2907–11. http://dx.doi.org/10.1128/aem.65.7.2907-2911.1999.
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ABSTRACT A novel α-glucosidase with an apparent subunit mass of 59 ± 0.5 kDa was purified from protein extracts of Rhizobium sp. strain USDA 4280, a nodulating strain of black locust (Robinia pseudoacacia L), and characterized. After purification to homogeneity (475-fold; yield, 18%) by ammonium sulfate precipitation, cation-exchange chromatography, hydrophobic chromatography, dye chromatography, and gel filtration, this enzyme had a pI of 4.75 ± 0.05. The enzyme activity was optimal at pH 6.0 to 6.5 and 35°C. The activity increased in the presence of NH4 +and K+ ions but was inhibited by Cu2+, Ag+, Hg+, and Fe2+ ions and by various phenyl, phenol, and flavonoid derivatives. Native enzyme activity was revealed by native gel electrophoresis and isoelectrofocusing-polyacrylamide gel electrophoresis with fluorescence detection in which 4-methylumbelliferyl α-glucoside was the fluorogenic substrate. The enzyme was more active with α-glucosides substituted with aromatic aglycones than with oligosaccharides. This α-glucosidase exhibited Michaelis-Menten kinetics with 4-methylumbelliferyl α-d-glucopyranoside (Km , 0.141 μM; V max, 6.79 μmol min−1 mg−1) and withp-nitrophenyl α-d-glucopyranoside (Km , 0.037 μM; V max, 2.92 μmol min−1 mg−1). Maltose, trehalose, and sucrose were also hydrolyzed by this enzyme.
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Devkota, Hari Prasad, Ayumi Kurizaki, Kazuki Tsushiro, Anjana Adhikari-Devkota, Kengo Hori, Mikiyo Wada, and Takashi Watanabe. "Flavonoids from the leaves and twigs of Lindera sericea (Seibold et Zucc.) Blume var. sericea (Lauraceae) from Japan and their bioactivities." Functional Foods in Health and Disease 11, no. 1 (January 29, 2021): 34. http://dx.doi.org/10.31989/ffhd.v11i1.769.
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Background: The leaves and twigs of Lindera sericea (Seibold et Zucc.) Blume var. sericea (Lauraceae) are used as traditional medicines for treating indigestion, stomachache, anxiety, etc. In recent years, there has been a growing interest in these plant materials as a source of healthy drinks and functional foods. The main aim of this study was to characterize the major phenolic compounds from the leaves and twigs and to evaluate their free radical scavenging and α-glucosidase inhibitory activities.Methods: The dried leaves and twigs were extracted with 70% methanol. The dried extract was then subjected to repeated column chromatography to isolate eight flavonoids. The compounds were then evaluated for their 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and α-glucosidase inhibitory activity.Results: The isolated compounds were identified as (-)-epicatechin (1), taxifolin 3-O-glucoside (2), quercetin (3), quercitrin (4), quercetin 3-O-neohesperidoside (5), pinocembrin (6), pinostrobin (7) and pinostrobin chalcone (8) based on their nuclear magnetic resonance (NMR), spectroscopic data and comparison with literature values. All these compounds were isolated for the first time from this plant. All flavonoids except pinocembrin (6), pinostrobin (7) and pinostrobin chalcone (8) showed potent free radical scavenging activity. In α-glucosidase inhibitory activity assay, quercetin (4), quercitrin (5) and taxifolin 3-O-glucoside (2) showed potent activity.Conclusions: Eight flavonoids were reported for the first time from the leaves and twigs of the title plant. Some of these compounds showed potent free radical scavenging and α-glucosidase inhibitory activities.Keywords: Lindera sericea var. sericea; Lauraceae; Kekuromoji; free radical; α-glucosidase
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Hoelzle, Inger, and John G. Streeter. "Stimulation of α-glucosidases from fast-growing rhizobia and Agrobacterium tumefaciens by K+, NH+4, and Rb+." Canadian Journal of Microbiology 36, no. 3 (March 1, 1990): 223–27. http://dx.doi.org/10.1139/m90-038.
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Extracts from cultured fast-growing rhizobia and Agrobacterium tumefaciens contain enzymes for hydrolysis of the α-glucosides maltose, sucrose, and α,α-trehalose. The hydrolysis of all three sugars was stimulated by the presence of K+, Rb+, or [Formula: see text]. This stimulation varied from less than 2-fold to more than 12-fold, depending on the bacterial species, culture conditions, and experimental conditions, such as type of enzyme, buffer, and ion concentration. Eight other ions tested, including several divalent cations, did not have any stimulatory effect. Other sources of enzyme (Escherichia coli, Saccharomyces cerevisiae, Oryza sativa, porcine kidney, and Medicago sativa and Glycine max nodule cytosol) contained α-glucosidases that differed in both substrate specificity and pH optima and were not affected by K+, Rb+ or [Formula: see text] ions. Bacteroids from G. max and Phaseolus vulgaris nodules did not have detectable α-glucosidase activity. Growth of Rhizobium leguminosarum biovar phaseoli USDA 2667 with one of the α-glucosides as carbon source increased Vm and substrate affinity for all three disaccharidase activities. The pH optimum for all three enzyme activities in R. leguminosarum bv. phaseoli USDA 2667 was 6.6. Stimulation by specific monovalent cations appears to be a novel property of α-glucosidases in the bacterial family Rhizobiaceae. Key words: maltose, sucrose, trehalose, disaccharidases, Rhizobiaceae.
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Gondokesumo, Marisca Evalina, Hanna Sari Widya Kusuma, and Wahyu Widowati. "α-/β-Glucosidase and α-Amylase Inhibitory Activities of Roselle (Hibiscus sabdariffa L.) Ethanol Extract." Molecular and Cellular Biomedical Sciences 1, no. 1 (March 1, 2017): 34. http://dx.doi.org/10.21705/mcbs.v1i1.3.
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Background: Diabetes mellitus is a metabolic disease, characterized by hyperglycemia due to disturbance in both insulin secretion and function. One of theurapeutic approaches is to reduce blood glucose levels by inhbiting α-/β-glucosidase and α-amylase involved in carbohydrate digestion. Thus, inhibition of these enzymes play important role in the treatment of diabetes mellitus. Roselle (Hibiscus sabdariffa L.) has been known to have several medicinal properties and potency as an antidiabetics agents. This reseacrh aimed to observe antidiabetic properties of roselle ethanol extract (REE) towards α-glucosidase, β-glucosidase and α-amylase.Materials and Methods: REE was done with maceration technique using diluent of 70% ethanol. Antidiabetic properties were measured by inhibitory activity of α-amylase, α-glucosidase and β-glucosidase.Results: REE was able to inhibit α-/β-glucosidase and α-amylase in the highest concentration with inhibition percentage of 72.68, 47.34 and 73.08% respectively, and were comparable with Acarbose of 81.49, 50.97, 73.08%. The median inhibitory concentration (IC50) of α-/β-glucosidase and α-amylase of REE were 15.81, 41.77, 18.09 μg/mL respectively, and Acarbose were 9.45, 22.57, 3.64 μg/mL respectively.Conclusions: REE inhibits α-/β-glucosidase and α-amylase.Keywords: Roselle, Acarbose, α-glucosidase, β-glucosidase, α-amylase, antidiabeticBackground: Diabetes mellitus is a metabolic disease, characterized by hyperglycemia due to disturbance in both insulin secretion and function. One of theurapeutic approaches is to reduce blood glucose levels by inhbiting α-/β-glucosidase and α-amylase involved in carbohydrate digestion. Thus, inhibition of these enzymes play important role in the treatment of diabetes mellitus. Roselle (Hibiscus sabdariffa L.) has been known to have several medicinal properties and potency as an antidiabetics agents. This reseacrh aimed to observe antidiabetic properties of roselle ethanol extract (REE) towards α-glucosidase, β-glucosidase and α-amylase.Materials and Methods: REE was done with maceration technique using diluent of 70% ethanol. Antidiabetic properties were measured by inhibitory activity of α-amylase, α-glucosidase and β-glucosidase.Results: REE was able to inhibit α-/β-glucosidase and α-amylase in the highest concentration with inhibition percentage of 72.68, 47.34 and 73.08% respectively, and were comparable with Acarbose of 81.49, 50.97, 73.08%. The median inhibitory concentration (IC50) of α-/β-glucosidase and α-amylase of REE were 15.81, 41.77, 18.09 μg/mL respectively, and Acarbose were 9.45, 22.57, 3.64 μg/mL respectively.Conclusions: REE inhibits α-/β-glucosidase and α-amylase.Keywords: Roselle, Acarbose, α-glucosidase, β-glucosidase, α-amylase, antidiabetic
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Shimoda, Kei, Manabu Hamada, Masaharu Seno, Tadakatsu Mandai, and Hiroki Hamada. "Chemo-Enzymatic Synthesis of Glycolyl-Ester-Linked Taxol-Monosaccharide Conjugate and Its Drug Delivery System Using Hepatitis B Virus Envelope L Bio-Nanocapsules." Biochemistry Insights 5 (January 2012): BCI.S9824. http://dx.doi.org/10.4137/bci.s9824.
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Chemo-enzymatic synthesis of glycolyl-ester-linked taxol-glucose conjugate, ie, 7-glycolyltaxol 2′- O-α-D-glucoside, was achieved by using α-glucosidase as a biocatalyst. The water-solubility of 7-glycolyltaxol 2′- O-α-D-glucoside (21 μM) was 53 fold higher than that of taxol. The hepatitis B virus envelope L particles (bio-nanocapsules) are effective for delivering 7-glycolyltaxol 2′- O-α-D-glucoside to human hepatocellular carcinoma NuE cells.
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WIMMER, Bernhard, Friedrich LOTTSPEICH, Johannes RITTER, and Karin BRONNENMEIER. "A novel type of thermostable α-D-glucosidase from Thermoanaerobacter thermohydrosulfuricus exhibiting maltodextrinohydrolase activity." Biochemical Journal 328, no. 2 (December 1, 1997): 581–86. http://dx.doi.org/10.1042/bj3280581.
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An α-glucosidase with the ability to attack polymeric substrates was purified to homogeneity from culture supernatants of Thermoanaerobacter thermohydrosulfuricus DSM 567. The enzyme is apparently a glycoprotein with a molecular mass of 160 kDa. Maximal activity is observed between pH 5 and 7 at 75 °C. The α-glucosidase is active towards p-nitrophenyl-α-D-glucoside, maltose, malto-oligosaccharides, starch and pullulan. Highest activity is displayed towards the disaccharide maltose. In addition to glucose, maltohexaose and maltoheptaose can be detected as the initial products of starch hydrolysis. After short incubations of pullulan, glucose is found as the only product. At high substrate concentrations, maltose and malto-oligosaccharide, but not glucose, are used as acceptors for glucosyl-transfer. These findings indicate that the T. thermohydrosulfuricus enzyme represents a novel type of α-glucosidase exhibiting maltase, glucohydrolase and ‘maltodextrinohydrolase’ activity.
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Hakamata, Wataru, Makoto Muroi, Toshiyuki Nishio, Tadatake Oku, and Akira Takatsuki. "Recognition Properties of Processing α‐Glucosidase I and α‐Glucosidase II." Journal of Carbohydrate Chemistry 23, no. 1 (December 26, 2004): 27–39. http://dx.doi.org/10.1081/car-120030022.
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Tan, Kemin, Christine Tesar, Rosemarie Wilton, Robert P. Jedrzejczak, and Andrzej Joachimiak. "Interaction of antidiabetic α-glucosidase inhibitors and gut bacteria α-glucosidase." Protein Science 27, no. 8 (July 10, 2018): 1498–508. http://dx.doi.org/10.1002/pro.3444.
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Ojima, Teruyo, Wataru Saburi, Takeshi Yamamoto, and Toshiaki Kudo. "Characterization of Halomonas sp. Strain H11 α-Glucosidase Activated by Monovalent Cations and Its Application for Efficient Synthesis of α-d-Glucosylglycerol." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 1836–45. http://dx.doi.org/10.1128/aem.07514-11.
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ABSTRACTAn α-glucosidase (HaG) with the following unique properties was isolated fromHalomonassp. strain H11: (i) high transglucosylation activity, (ii) activation by monovalent cations, and (iii) very narrow substrate specificity. The molecular mass of the purified HaG was estimated to be 58 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). HaG showed high hydrolytic activities toward maltose, sucrose, andp-nitrophenyl α-d-glucoside (pNPG) but to almost no other disaccharides or malto-oligosaccharides higher than trisaccharides. HaG showed optimum activity to maltose at 30°C and pH 6.5. Monovalent cations such as K+, Rb+, Cs+, and NH4+increased the enzymatic activity to 2- to 9-fold of the original activity. These ions shifted the activity-pH profile to the alkaline side. The optimum temperature rose to 40°C in the presence of 10 mM NH4+, although temperature stability was not affected. The apparentKmandkcatvalues for maltose andpNPG were significantly improved by monovalent cations. Surprisingly,kcat/KmforpNPG increased 372- to 969-fold in their presence. HaG used some alcohols as acceptor substrates in transglucosylation and was useful for efficient synthesis of α-d-glucosylglycerol. The efficiency of the production level was superior to that of the previously reported enzymeAspergillus nigerα-glucosidase in terms of small amounts of by-products. Sequence analysis of HaG revealed that it was classified in glycoside hydrolase family 13. Its amino acid sequence showed high identities, 60%, 58%, 57%, and 56%, toXanthomonas campestrisWU-9701 α-glucosidase,Xanthomonas campestrispv. raphani 756C oligo-1,6-glucosidase,Pseudomonas stutzeriDSM 4166 oligo-1,6-glucosidase, andAgrobacterium tumefaciensF2 α-glucosidase, respectively.
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Pavan Kumar Kurakula, Tharun D, Mahantesh S, Krishna O, Sudheer A, Mujahid SM, and Sai vikas S. "Evaluation of in-vitro antidiabetic activity of leaf juice of Plectranthus amboinicus (lour.)." International Journal of Novel Trends in Pharmaceutical Sciences 10, no. 1 (June 17, 2020): 9–17. http://dx.doi.org/10.26452/ijntps.v10i1.1143.
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Diabetes mellitus ‘the disease of modern civilization’ is characterized by chronic hyperglycaemia. The management of elevated post prandial glucose is critical to control the sequale of complications and α-amylase, α-glucosidases are responsible for elevated plasma glucose. Enzyme inhibitors in current clinical practice like acarbose, voglibose etc. are known to cause various gastrointestinal side effects. The present study was aimed to screen for potential α-amylase and α-glucosidase inhibitors from natural sources by in–vitro antidiabetic assays to overcome the side effects and toxicity. Different concentrations of leaf juice of Plectranthus amboinicus Lour. (20, 40, 60, 80 &100 μg/ml) were tested against fungal α-amylase and α-glucosidases isolated from albino rat small intestine and a prominent dose dependent inhibition of the enzymes was observed comparable with the marketed product, Acarbose. The IC50 values of LJPA and acarbose on fungal α-amylase was found to be 83.15 &52.15 μg/ml respectively. The IC50 values of LJPA and acarbose on α-glucosidase was found to be 92.44 &54.84 μg/ml respectively. The protein concentration of leaf juice was found to be 10.6 mg/ml.
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Yuan, Hao, Hong Wan, Yi-Kao Hu, Emmanuel Ayodeji Ayeni, Qiang Chang, Chao Ma, and Xun Liao. "Fishing of α-Glucosidase’s Ligands from Aloe vera by α-Glucosidase Functionalized Magnetic Nanoparticles." Molecules 26, no. 19 (September 26, 2021): 5840. http://dx.doi.org/10.3390/molecules26195840.
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α-Glucosidase was immobilized on magnetic nanoparticles (MNPs) for selective solid-phase extraction of the enzyme’s ligands present in Aloe vera, which is a medicinal plant used for the treatment of various diseases and possesses anti-diabetic activity. One new compound, aloeacone (2), together with two known compounds, aloenin aglycone (1) and aloin A (3), were fished out as the enzyme’s ligands. The structure of 2 was determined by HR-MS and comprehensive NMR techniques. Compound 3 exhibited a weak inhibitory effect on α-glucosidase, while compounds 1 and 2 were found to possess activation effects on the enzyme for the first time. It is interesting that both an inhibitor and agonists of α-glucosidase were fished out in one experiment.
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Muthukrishnan, Soundararajan, and Sivakkumar T. "IN VITRO STUDIES TO ASSESS THE ANTIDIABETIC POTENTIAL OF SCHLEICHERA OLEOSA (LOUR) OKEN LEAVES." Asian Journal of Pharmaceutical and Clinical Research 10, no. 7 (July 1, 2017): 280. http://dx.doi.org/10.22159/ajpcr.2017.v10i7.18549.
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Objective: The aim of this research is to establish the antidiabetic properties of sequential extracts of Schleichera oleosa (lour) Oken leaves thru α-amylase and α-glucosidase inhibitory assay.Methods: The extracts of S. oleosa (Lour) Oken were prepared by continuous hot percolating the dried powder of the plant leaves. The various solvents were used for the extraction and qualitative assay for the phytochemical test using standard protocols. Different concentration (1, 2, 4, 6, 12, 25, and 50 mg/ml) of sequential extracts of S. oleosa leaves were used to assess the in vitro α-amylase and α-glucosidase inhibitory assay by Bernfeld and Apostolidis method.Results: In the α-amylase assay, the ethanolic extract produced 52.76% inhibition at 4 mg/ml concentration, but in ethyl acetate and aqueous extracts case 50% inhibition attained only at the concentration of 50 mg/ml, and acarbose 0.9 mg/ml was found 89.24% inhibition. In the α-glucosidase assay, the all extracts show the decent inhibitory effect in 50 mg/ml. The ethanolic and aqueous extracts exhibited a higher inhibitory effect 72.64% and 59.44% than other extracts at the concentration of 50 mg/ml, respectively, while acarbose 0.9 mg/ml was producing 86.24% inhibition. This result indicates that the inhibition of ethanolic and aqueous extracts on the activity from α-amylase and α-glucosidases is much more potent than that of other extracts.Conclusion: This study revealed that ethanolic and aqueous extracts showed the high content of polyphenols and flavonoids, which was blamed for the α-amylase and α-glucosidases inhibition. Hence, it deserved to elucidate specific components and to evaluate the antidiabetic effect using in vivo animal model.
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Coma, P., L. Gomez-Chacon, B. Garcia-Serrano, E. Fernandez, and M. A. Ortiz-Apodaca. "α-Glucosidase and Ν-Acetyl-α-D-glucosaminidase Isoenzymes in Serum." Clinical Chemistry 38, no. 2 (February 1, 1992): 223–26. http://dx.doi.org/10.1093/clinchem/38.2.223.
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Abstract Using different conditions for incubation and fluorometry with 4-methylumbelliferylglycosides as substrates, we demonstrated the presence of acid alpha-glucosidase, "renal" alpha-glucosidase, N-acetyl-beta-D-glucosaminidase A, and N-acetyl-beta-D-glucosaminidase B in freshly drawn normal human serum. The acid alpha-glucosidase enzymatic activity was determined at pH 4.0 in 0.1 mol/L Tris reagent, whereas the renal isoenzyme activity was determined at pH 5.6 in presence of 0.05 mol/L turanose reagent. N-Acetyl-beta-D-glucosaminidases A and B were determined by their different behaviors on heating. The corresponding reference intervals for each enzyme were calculated from results for 40 controls: acid alpha-glucosidase (0.024 +/- 0.010 U/L), renal alpha-glucosidase (0.035 +/- 0.012 U/L), N-acetyl-beta-D-glucosaminidase A (10.2 +/- 2.9 U/L), and N-acetyl-beta-D-glucosaminidase B (4.4 +/- 2.1 U/L).
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Li, Yan-Hong, Jia-Meng Dai, Cui Yang, Meng-Yuan Jiang, Yong Xiong, Yu-Kui Li, Hong-Rui Li, Kai Tian, and Xiang-Zhong Huang. "Phenylpropanoid and Iridoid Glucosides from the Whole Plant of Hemiphragma heterophyllum and Their alpha-Glucosidase Inhibitory Activities." Planta Medica 86, no. 03 (January 9, 2020): 205–11. http://dx.doi.org/10.1055/a-1081-7220.
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AbstractThree phenylpropanoid glucosides (1 – 3) and one iridoid glucoside (11), together with eleven known glucosides, were isolated from the ethanol extract of the whole plant of Hemiphragma heterophyllum. Their structures were elucidated by means of 1D and 2D NMR spectroscopy, HRMS, and chemical methods. All compounds except 11 and 13 – 15 showed varying degrees of α-glucosidase inhibitory activity. Compounds 5, 9, and 12 were marginally active in the bioassay, while compounds 1 – 4, 6 – 8, and 10 exhibited appreciable inhibitory activity with an IC50 value of 33.6 ~ 83.1 µM, which was much lower than that of the positive control acarbose (IC50 = 310.8 µM).
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Ramadhan, Rico, and Preecha Phuwapraisirisan. "Arylalkanones from Horsfieldia macrobotrys are Effective Antidiabetic Agents Achieved by α-Glucosidase Inhibition and Radical Scavenging." Natural Product Communications 10, no. 2 (February 2015): 1934578X1501000. http://dx.doi.org/10.1177/1934578x1501000230.
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Horsfielda macrobotrys Merr has long been used by Dayak people in East Kalimantan of Indonesia, for diabetes therapy. Inspired by ethnopharmacological use and promising α-glucosidase and radical scavenging activities, an attempt to identify the active components was carried out. Bioassay-guided isolation yielded two related arylalkanones named 1-(2,4,6-trihydroxyphenyl)-9-phenylnonan-1-one (1) and malabaricone A (2). Arylalkanone 1 showed potent radical scavenging comparable with that of the standard antioxidant, ascorbic acid, and promising inhibition against α-glucosidases. Noticeably, arylalkanone 1 was 3-30 times more potent than malabaricone A (2) in all bioassays examined, thus suggesting the critical role in exerting bioactivities of the hydroxy group on the aryl moiety. This hypothesis was also supported by reduction in inhibitory effects of the methyl ether analogues 1a and 2a. Arylalkanone 1 inhibited yeast α-glucosidase in a mixed-type manner in which the noncompetitive pathway was dominant over competitive inhibition. This study is the first report of α-glucosidase inhibition of arylalkenone-type compounds and the first phytochemicals from H. macrobotrys.
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Kato, Atsushi, Izumi Nakagome, Mizuki Hata, Robert J. Nash, George W. J. Fleet, Yoshihiro Natori, Yuichi Yoshimura, Isao Adachi, and Shuichi Hirono. "Strategy for Designing Selective Lysosomal Acid α-Glucosidase Inhibitors: Binding Orientation and Influence on Selectivity." Molecules 25, no. 12 (June 19, 2020): 2843. http://dx.doi.org/10.3390/molecules25122843.
Full textAbstract:
Deoxynojirimycin (DNJ) is the archetypal iminosugar, in which the configuration of the hydroxyl groups in the piperidine ring truly mimic those of d-glucopyranose; DNJ and derivatives have beneficial effects as therapeutic agents, such as anti-diabetic and antiviral agents, and pharmacological chaperones for genetic disorders, because they have been shown to inhibit α-glucosidases from various sources. However, attempts to design a better molecule based solely on structural similarity cannot produce selectivity between α-glucosidases that are localized in multiple organs and tissues, because the differences of each sugar-recognition site are very subtle. In this study, we provide the first example of a design strategy for selective lysosomal acid α-glucosidase (GAA) inhibitors focusing on the alkyl chain storage site. Our design of α-1-C-heptyl-1,4-dideoxy-1,4-imino-l-arabinitol (LAB) produced a potent inhibitor of the GAA, with an IC50 value of 0.44 µM. It displayed a remarkable selectivity toward GAA (selectivity index value of 168.2). A molecular dynamic simulation study revealed that the ligand-binding conformation stability gradually improved with increasing length of the α-1-C-alkyl chain. It is noteworthy that α-1-C-heptyl-LAB formed clearly different interactions from DNJ and had favored hydrophobic interactions with Trp481, Phe525, and Met519 at the alkyl chain storage pocket of GAA. Moreover, a molecular docking study revealed that endoplasmic reticulum (ER) α-glucosidase II does not have enough space to accommodate these alkyl chains. Therefore, the design strategy focusing on the shape and acceptability of long alkyl chain at each α-glucosidase may lead to the creation of more selective and practically useful inhibitors.
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Ponce, Elvira, David P. Witte, Rochelle Hirschhorn, Maryann L. Huie, and Gregory A. Grabowski. "Murine Acid α-Glucosidase." American Journal of Pathology 154, no. 4 (April 1999): 1089–96. http://dx.doi.org/10.1016/s0002-9440(10)65361-8.
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Jin, Hui-Min, Bin Dang, Wen-Gang Zhang, Wan-Cai Zheng, and Xi-Juan Yang. "Polyphenol and Anthocyanin Composition and Activity of Highland Barley with Different Colors." Molecules 27, no. 11 (May 25, 2022): 3411. http://dx.doi.org/10.3390/molecules27113411.
Full textAbstract:
In this research, the composition of free phenols, bound phenols, and anthocyanins and their in vitro antioxidant activity and in vitro α-glucosidase inhibiting activity were observed in different barley colors. The outcomes revealed that the contents of total phenols (570.78 mg/100 gDW), total flavonoids (47.08 mg/100 gDW), and anthocyanins (48.07 mg/100 g) were the highest in purple barley. Furthermore, the structure, composition, and concentration of phenolics differed depending on the colors of barley. The types and contents of bound total phenolic acids and flavonoids were greater than those of free total phenolic acids and flavonoids. The main phenolic acids in blue barley were cinnamic acid polyphenols, whereas in black, yellow, and purple barley, benzoic acid polyphenols were the main phenolic acids, and the main types of flavonoids in black and blue barley were chalcones and flavanones, respectively, whereas flavonol was the main type of flavonoid in yellow and purple barley. Moreover, cornflower pigment-3-glucoside was the major anthocyanin in blue, yellow, and purple barley, whereas the main anthocyanin in black barley was delphinidin-3-glucoside. The dark color of barley indicated richness in the anthocyanins. In addition, the free polyphenol fractions had stronger DPPH and ABTS radical scavenging capacity as compared to the bound ones. In vitro α-glucosidase-inhibiting activity was greater in bound polyphenols than in free polyphenols, with differences between different varieties of barley. Purple barley phenolic fractions had the greatest ABTS radical scavenging and iron ion reduction capacities, as well as the highest α-glucosidase-inhibiting activity. The strongest DPPH radical scavenging capacity was found in yellow barley, while the strongest in vitro α-glucosidase-inhibiting activity was found in anthocyanins isolated from black barley. Furthermore, in different colors of barley, there was a strong association between the concentration of specific phenolic compounds and antioxidant and α-glucosidase-inhibiting activities. The outcomes of this study revealed that all colored barley seeds tested were high in phenolic compounds, and had a good antioxidant impact and α-glucosidase-inhibiting activity. As a result, colored barley can serve as an antioxidant and hypoglycemic food. Polyphenols extracted from purple barley and anthocyanins extracted from black barley stand out among them.
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Sinha, Durgeshnandani, Trilochan Satapathy, Parag Jain, Jhakeshwar Prasad Chandel, Divya Sahu, Bhavna Sahu, Abhishek Verma, Shalini Singh, Khushboo Verma, and Rahul Rathore. "In Vitro Antidiabetic Effect of Neohesperidin." Journal of Drug Delivery and Therapeutics 9, no. 6 (November 15, 2019): 102–9. http://dx.doi.org/10.22270/jddt.v9i6.3633.
Full textAbstract:
Objective: The present study was performed to determine in vitro antidiabetic effect of neohesperidin. To evaluate inhibitory effect of neohesperidin on α-amylase and α-glucosidase diabetes causing enzyme.
Methods and Materials: Invitro carbohydrate metabolizing enzyme based inhibitory methods were used to determine antidiabetic effect of neohesperidin. Alpha (α)-amylase inhibitory assay was performed using different sources i.e. wheat alpha (α)-amylase enzyme, salivary alpha (α)-amylase and fungal alpha (α)-amylase assay. Alpha (α)-glucosidase inhibitory assay was performed using alpha (α)-glucosidase (B. stearothermophil), alpha (α)-glucosidase rat intestine and alpha (α)-glucosidase from baker’s yeast. Sucrase inhibitory assay from rat small intestine.
Result: Neohesperidin possess a potent anti-diabetic by significantly inhibiting alpha amylase activity.
Conclusion: It was concluded that enzyme inhibitory activity of neohesperidin shown a significantly higher inhibitory activity on alpha-amylase in comparision to alpha-glucosidase & Sucrase enzymes.
Keywords: Neohespiridin, acarbose, alpha-amylase, alpha-glucosidase
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Li, Yunbo, Xiaoling Liu, Haoyu Zhou, Bo Li, and Igor Kostiantinovich Mazurenko. "Inhibitory Mechanism of Engeletin Against α-Glucosidase." Natural Product Communications 16, no. 1 (January 2021): 1934578X2098672. http://dx.doi.org/10.1177/1934578x20986723.
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The inhibitory mechanism of engeletin against α-glucosidase was investigated for the first time by fluorescence spectroscopy and molecular docking. The results showed that engeletin could inhibit α-glucosidase in a noncompetitive inhibition mode with a half-maximal inhibitory concentration value of 48.5 ± 6.0 µg/mL (0.11 ± 0.014 mmol/L). It was found that engeletin could cause static fluorescence quenching of α-glucosidase by forming a complex with α-glucosidase. The thermodynamic parameters indicated that the combination of engeletin and α-glucosidase was driven by hydrophobic force. The molecular docking results confirmed that some amino acid residues of α-glucosidase (Trp391, Arg428, Glu429, Gly566, Trp710, Glu771) could interact with engeletin by hydrogen bonding.
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Raamachandran, Jayaraman, and Arul Amuthan. "Neerizhivu kudineer (a traditional siddha polyherbal antidiabetic medicine) inhibits α- amylase enzyme and αglucosidase enzyme." Journal of Ayurvedic and Herbal Medicine 6, no. 1 (April 3, 2020): 21–25. http://dx.doi.org/10.31254/jahm.2020.6106.
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Objective: To investigate the α-amylase and α-glucosidases inhibitory activity of Neerizhivu kudineer (NK). Methods: The polyherbal formulation NK was prepared as per traditional Siddha medical literature and aqueous extract was taken. Invitro α-amylase and α-glucosidases inhibitory activity of NK was evaluated using various concentrations of NK. Acarbose was used as standard drug. The percent inhibition values were determined and the dose verses percent inhibition was plotted in MS excel. Using the linear trend line, the concentration required for 50% inhibition (IC50 value) were calculated. Results: NK exhibited dose dependent inhibition on α- amylase and α-glucosidase with the IC50 value of 6.90 μg/ml and 8.51 μg/ml respectively, whereas the standard drug acarbose exhibited IC50 at 5.04 μg/ml and 5.50 μg/ml respectively. Conclusion: Neerizhivu kudineer has the inhibitory action on α-amylase and α-glucosidases enzyme.
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Qu, Xiaowang, Xiaoben Pan, Jessica Weidner, Wenquan Yu, Dominic Alonzi, Xiaodong Xu, Terry Butters, Timothy Block, Ju-Tao Guo, and Jinhong Chang. "Inhibitors of Endoplasmic Reticulum α-Glucosidases Potently Suppress Hepatitis C Virus Virion Assembly and Release." Antimicrobial Agents and Chemotherapy 55, no. 3 (December 20, 2010): 1036–44. http://dx.doi.org/10.1128/aac.01319-10.
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ABSTRACTα-Glucosidases I and II are endoplasmic reticulum-resident enzymes that are essential for N-linked glycan processing and subsequent proper folding of glycoproteins. In this report, we first demonstrate that downregulation of the expression of α-glucosidase I, II, or both in Huh7.5 cells by small hairpin RNA technology inhibited the production of hepatitis C virus (HCV). In agreement with the essential role of α-glucosidases in HCV envelope glycoprotein processing and folding, treatment of HCV-infected cells with a panel of imino sugar derivatives, which are competitive inhibitors of α-glucosidases, did not affect intracellular HCV RNA replication and nonstructural protein expression but resulted in the inhibition of glycan processing and subsequent degradation of HCV E2 glycoprotein. As a consequence, HCV virion assembly and secretion were inhibited. In searching for imino sugars with better antiviral activity, we found that a novel imino sugar, PBDNJ0804, had a superior ability to inhibit HCV virion assembly and secretion. In summary, we demonstrated that glucosidases are important host factor-based antiviral targets for HCV infection. The low likelihood of drug-resistant virus emergence and potent antiviral efficacy of the novel glucosidase inhibitor hold promise for its development as a therapeutic agent for the treatment of chronic hepatitis C.
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Lestari, Wening, Rizna Triana Dewi, Leonardus Broto Sugeng Kardono, and Arry Yanuar. "Docking Sulochrin and Its Derivative as α-Glucosidase Inhibitors of Saccharomyces cerevisiae." Indonesian Journal of Chemistry 17, no. 1 (April 1, 2017): 144. http://dx.doi.org/10.22146/ijc.23568.
Full textAbstract:
Sulochrin is known to have an activity as inhibitors of the α-glucosidase enzyme. In this report interaction of sulochrin to the active site of the α-glucosidase enzyme from Saccharomyces cerevisiae was studied by docking method. The crystal structure of α-glucosidase from S. cerevisiae obtained from the homology method using α-glucosidase from S. cerevisiae (Swiss-Prot code P53341) as a target and crystal structure of isomaltase from S. cerevisiae (PDB code 3A4A) as a template. These studies show that sulochrin and sulochrin-I could be bound in the active site of α-glucosidase from S. cerevisiae through the formation of hydrogen bonds with Arg213, Asp215, Glu277, Asp352. Sulochrin-I has stability and inhibition of the α-glucosidase enzyme better than sulochrin. The iodine atom in the structure of sulochrin can increase the activity as an inhibitor of the α-glucosidase enzyme.
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Dewi, Rizna Triana, Yulia Anita, Enade Perdana Istyastono, Akhmad Darmawan, and Muhamad Hanafi. "THE APPLICABILITY OF THE CRYSTAL STRUCTURE OF TERMOTOGA MARITIMA 4--GLUCANOTRANSFERASE AS THE TEMPLATE FOR SULOCHRIN AS -GLUCOSIDASE INHIBITORS." Indonesian Journal of Chemistry 9, no. 3 (June 24, 2010): 479–86. http://dx.doi.org/10.22146/ijc.21520.
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Interaction of sulochrin to active site of glucosidase enzyme of Termotoga maritime has been studied by employing docking method using Molecular Operating Environment (MOE), in comparison with those are reports of established inhibitor α-glucosidase such as acarbose, miglitol and voglibose, and salicinol, as reference compounds. The crystal structure T. maritima α-glucanotransferase (PDB code: 1LWJ) can be employed to serve as the template in the virtual screening of S. cerevisiae α-glucosidase. The comparison between the binding pocket residues of Thermotoga maritima α-glucanotransferase and Saccharomyces cerevisiae α-glucosidase show a high sequence identity and similarity. The result showed that sulochrin could be located in the binding pocket and formed some interactions with the binding residues. The ligands showed proper predicted binding energy (-6.74 - -4.13 kcal/mol) and predicted Ki values (0.011 - 0.939 mM). Sulochrin has a possibility to serve as a lead compound in the development of new α-glucosidase inhibitor. Keywords: Docking, sulochrin, α-glucosidase Inhibitor, Thermotoga maritime α-glucotransferase, Saccharomyces cerevisiae α-glucosidase, MOE
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Alqahtani, Ali S., Syed Hidayathulla, Md Tabish Rehman, Ali A. ElGamal, Shaza Al-Massarani, Valentina Razmovski-Naumovski, Mohammed S. Alqahtani, Rabab A. El Dib, and Mohamed F. AlAjmi. "Alpha-Amylase and Alpha-Glucosidase Enzyme Inhibition and Antioxidant Potential of 3-Oxolupenal and Katononic Acid Isolated from Nuxia oppositifolia." Biomolecules 10, no. 1 (December 30, 2019): 61. http://dx.doi.org/10.3390/biom10010061.
Full textAbstract:
Nuxia oppositifolia is traditionally used in diabetes treatment in many Arabian countries; however, scientific evidence is lacking. Hence, the present study explored the antidiabetic and antioxidant activities of the plant extracts and their purified compounds. The methanolic crude extract of N. oppositifolia was partitioned using a two-solvent system. The n-hexane fraction was purified by silica gel column chromatography to yield several compounds including katononic acid and 3-oxolupenal. Antidiabetic activities were assessed by α-amylase and α-glucosidase enzyme inhibition. Antioxidant capacities were examined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) scavenging assays. Further, the interaction between enzymes (α-amylase and α-glucosidase) and ligands (3-oxolupenal and katononic acid) was followed by fluorescence quenching and molecular docking studies. 3-oxolupenal and katononic acid showed IC50 values of 46.2 μg/mL (101.6 µM) and 52.4 μg/mL (119.3 µM), respectively against the amylase inhibition. 3-oxolupenal (62.3 µg/mL or 141.9 μM) exhibited more potent inhibition against α-glucosidases compared to katononic acid (88.6 µg/mL or 194.8 μM). In terms of antioxidant activity, the relatively polar crude extract and n-butanol fraction showed the greatest DPPH and ABTS scavenging activity. However, the antioxidant activities of the purified compounds were in the low to moderate range. Molecular docking studies confirmed that 3-oxolupenal and katononic acid interacted strongly with the active site residues of both α-amylase and α-glucosidase. Fluorescence quenching results also suggest that 3-oxolupenal and katononic acid have a good affinity towards both α-amylase and α-glucosidase enzymes. This study provides preliminary data for the plant’s use in the treatment of type 2 diabetes mellitus.
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Hasan, Akhmad Endang Zainal, Dimas Andrianto, and Rara Annisaur Rosyidah. "Uji Penghambatan α-Glukosidase dari Kombinasi Ekstrak Kunyit, Teh Hitam dan Jahe." JURNAL AGROINDUSTRI HALAL 8, no. 1 (April 27, 2022): 137–46. http://dx.doi.org/10.30997/jah.v8i1.5608.
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Traditional medicines that can be used as α-glucosidase inhibitors are turmeric (Curcuma longa L.), black tea (Camellia sinensi L), and ginger (Zingiber officinale). It is necessary to research the use of a combination of tea, turmeric, and ginger in inhibiting the α -glucosidase enzyme. This study aims to determine the optimal combination of extracts of turmeric, black tea, and ginger in inhibiting the α-glucosidase enzyme. The research carried out was the measurement of IC50 values for the inhibition of α-glucosidase of each extract, and the inhibition of the enzyme α-glucosidase in combination. The results of the test of ethanol extract of turmeric, ginger and black tea water extract obtained the inhibition value of α-glucosidase with IC50 values of 9.48±0.05 g/mL, 66.64±0.44 g/mL and 9.52±0.25, respectively. F7 is a combination of turmeric, ginger and black tea which produces the highest α-glucosidase inhibition, which is 67.86±0.93%.