Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The methanol extract of Sophora flavescens showed a potent glycosidase inhibitory activity. Active components were identified as well-known flavonoid antioxidants: kushenol A (1), (-)-kurarinone (2), sophoraflavanone G (3), 2'-methoxykurarinone (4), kurarinol (5), 8-prenylkaempferol (6), isoxanthohumol (7), kuraridin (8) and maackian (9). All flavonoids were effective inhibitors of alpha-glucosidase and beta-amylase. Interestingly, lavandulylated flavanones 1-5 had strong alpha-glucosidase inhibitory activities, with IC(50) values of 45 microM, 68 microM, 37 microM, 155 microM and 179 microM, respectively. Kushenol A (1) which does not bear a 4'-hydroxy group showed selective alpha-glucosidase inhibitory activity. Lavandulylated chalcone, kuraridine (8), exhibited IC(50) value of 57 microM against beta-glucosidase, which is the first report of a chalcone displaying glycosidase inhibition. Results showed that 8-lavandulyl group in B-ring was a key factor of the glycosidase inhibitory activities. The inhibition pattern was noncompetitive for alpha-glucosidase, whereas mixed inhibition was observed for beta-amylase.
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PMID:Glycosidase inhibitory flavonoids from Sophora flavescens. 1646 36

2-O-alpha-D-glucopyranosyl-6-O-hexadecanoyl-L-ascorbic acid (6-sPalm-AA-2G), a novel stable lipophilic ascorbic acid derivative, was hydrolyzed to 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), ascorbyl 6-palmitate (6-sPalm-AA) and ascorbic acid (AA) with alpha-glucosidase and lipase. An HPLC method for the simultaneous determination of AA, AA-2G, 6-sPalm-AA and 6-sPalm-AA-2G was developed using a cyanopropyl column with an isocratic solution of methanol-phosphate buffer (pH 2.1) (65:35, v/v) containing 20mg/l of dithiothreitol at a detection wavelength of 240 nm. The calibration curves were found to be linear in the range of 10-200 microM. Linear regression analysis of the data demonstrated the efficacy of the method in terms of precision and accuracy. This method was satisfactorily applied to the determination of 6-sPalm-AA-2G and its three metabolites in a 6-sPalm-AA-2G solution treated with purified enzymes or a small intestine post-mitochondrial supernatant and to the separation of novel stable lipophilic AA derivatives other than 6-sPalm-AA-2G and their metabolites. AA, AA-2G and other well-known stable AA derivatives, ascorbic acid 2-phosphate and ascorbic acid 2-sulfate, were also separated under the same conditions. The results show that the procedure is rapid and simple and that it can be employed for in vitro metabolic analysis of various AA derivatives.
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PMID:An isocratic HPLC method for the simultaneous determination of novel stable lipophilic ascorbic acid derivatives and their metabolites. 1682 27

Barringtonia racemosa presents a wide range of therapeutic applications. In the course of identifying bioactives from Indian medicinal plants it was observed that the hexane, ethanol and methanol extracts of B. racemosa seeds displayed potent yeast and intestinal alpha-glucosidase inhibitory activities. The methanol extract was found to be superior among them. However, none of the extracts exhibited pancreatic alpha-amylase inhibitory activity, rather the ethanol and methanol extracts accelerated the alpha-amylase enzyme activity. Interestingly, however, bartogenic acid isolated from the methanol extract inhibited alpha-amylase also. This is the first report identifying alpha-glucosidase inhibitory activity in B. racemosa seed extracts and assigning to bartogenic acid an alpha-glucosidase and amylase inhibitory property. The presence of bartogenic acid in B. racemosa seeds as a major compound is also reported for the first time in this communication.
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PMID:Inhibition of alpha-glucosidase and amylase by bartogenic acid isolated from Barringtonia racemosa Roxb. seeds. 1753 38

Triterpenoids and flavonoids isolated from Alnus firma S. Z. were found to inhibit HIV-1 virus replication and controlled its essential enzymes. In this study, the inhibition of HIV-1 viral replication and its essential enzymes, such as reverse transcriptase, protease and alpha-glucosidase, were observed using 18 Korean plant extracts. Among the extracts, the methanol extract of Alnus firma leaves showed potent inhibition against the HIV-1 induced cytopathic effect (CPE) in MT-4 cells on microscopic observation (the minimum concentration for complete inhibition of HIV-1 induced CPE, IC=50 microg/mL). Thus, 14 compounds were isolated and identified from the methanol extract of Alnus firma leaves. Of these compounds, the alnustic acid methyl ester exhibited inhibition against HIV-1 protease, with an IC50 of 15.8 microM, and quercetin, quercitrin and myricetin 3-O-beta-D-galactopyranoside displayed inhibition against HIV-1 reverse transcriptase, all with IC50 values of 60 microM. Based on these results, the viral replication inhibition of the methanol extract of Alnus firma leaves was adjudged to be acutely related to the protease inhibition activation of the alnustic acid methyl ester as well as the reverse transcriptase inhibition activation of flavonoids.
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PMID:Effects of triterpenoids and flavonoids isolated from Alnus firma on HIV-1 viral enzymes. 1770 32

Momordica charantia (bitter melon) is commonly known as vegetable insulin, but the mechanisms underlying its hypoglycemic effect remain unclear. To address this issue, the effects of bitter melon extracts on postprandial glycemic responses have been investigated in rats. An aqueous extract (AE), methanol fraction (MF) and methanol insoluble fraction (MIF) were prepared from bitter melon. An oral sucrose tolerance test revealed that administration of AE, MF or MIF each significantly suppressed plasma glucose levels at 30 min as compared with the control. In addition, the plasma insulin level at 30 min was also significantly lower after MF administration than in the control in the oral sucrose tolerance test. By contrast, these effects of bitter melon extracts were not observed in the oral glucose tolerance test. In terms of mechanism, bitter melon extracts dose-dependently inhibited the sucrase activity of intestinal mucosa with IC(50) values of 8.3, 3.7 and 12.0 mg/mL for AE, MF and MIF, respectively. The fraction with a molecular weight of less than 1,300 (LT 1,300) obtained from MF inhibited the sucrase activity most strongly in an uncompetitive manner with an IC(50) value of 2.6 mg/mL. Taken together, these results demonstrated that bitter melon suppressed postprandial hyperglycemia by inhibition of alpha-glucosidase activity and that the most beneficial component is present in the LT 1,300 fraction obtained from MF.
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PMID:Extracts of Momordica charantia suppress postprandial hyperglycemia in rats. 1820 35

The synthesis of a series of 2-deoxy-2,2-dihaloglycosyl halides as potential alpha-glycosidase inactivators has been achieved via the halogenation of protected 2-fluoroglycal precursors. Direct chlorination of per-O-acetylated 2-fluoro-d-glucal and 2-fluoromaltal followed by basic deprotection yielded the corresponding 2-chloro-2-deoxy-2-fluoroglycosyl chlorides. Reaction of the per-O-acetylated 2-fluoroglycals with acetyl hypofluorite or Selectfluor yielded the 2-deoxy-2,2-difluoroglycosyl derivatives, which were converted to their alpha-chlorides using thionyl chloride and deprotected under basic conditions. Trinitrophenyl glycosides of the 2-deoxy-2,2-difluoro mono- and disaccharides were synthesized by arylation of the hemiacetals with picryl fluoride, then deprotected with HCl in methanol. All three monosaccharide derivatives caused active site-directed, time-dependent inactivation of yeast alpha-glucosidase via the trapping of covalent glycosyl-enzyme intermediates, and kinetic parameters for inactivation by each compound were determined. Surprisingly neither of the 2-deoxy-2,2-dihalomaltosyl chlorides caused time-dependent inactivation of human pancreatic alpha-amylase, despite the fact that the trinitrophenyl 2-deoxy-2,2-difluoromaltoside functioned in that mode. The trinitrophenyl glycosides appear to be approximately 1000-fold more reactive than the corresponding chlorides in the enzyme active sites.
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PMID:Synthesis and testing of 2-deoxy-2,2-dihaloglycosides as mechanism-based inhibitors of alpha-glycosidases. 1834 85

The methanol extract of kiwifruit leaf suppressed the postprandial blood glucose level after an oral administration of soluble starch or sucrose in mice. The mechanism of action is proposed to be due to the alpha-amylase-inhibiting activity in the 90% aqueous methanol fraction and alpha-glucosidase-inhibiting activity in the n-buthanol fraction, based on the results of in vitro experiments.
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PMID:Anti-hyperglycemic activity of kiwifruit leaf (Actinidia deliciosa) in mice. 1839 41

Activity-guided fractionation of the methanol extract of Chinese aloes led to the isolation of aloeresin A, which demonstrated significant dose dependent alpha-glucosidase inhibitory activities, with IC(50) values of 11.94 and 2.16 mM, against rat intestinal sucrase and maltase, respectively.
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PMID:Alpha-glucosidase inhibitor from Chinese aloes. 1850 5

Lipids extracted from tsao-ko were separated into three fractions with silica gel column chromatography and fed to mice (3 mo old) for 90 d to clarify their inhibitory activity on digestive enzyme activity. The diets contained the following: control--no tsao-ko, 0.05% total lipid of tsao-ko (TL), 0.0109% chloroform fraction (CF), 0.0245% acetone fraction (AF), or 0.00365% methanol fraction (MeF). Although CF and AF slightly inhibited the activities of alpha-glucosidase, alpha-amylase, and lipase, intakes of these fractions had little influence on plasma and liver lipid concentrations when compared with the control diet. MeF did not inhibit alpha-glucosidase but had DPPH radical scavenging activity and the mice fed this fraction had the most marked reduction in plasma glucose and TBARS concentrations compared with the other diet groups. These results suggest that the fat-soluble polar components of tsao-ko contain an active component that might be associated with decreased plasma glucose and TBARS concentrations in mice.
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PMID:Effect of lipid extracted from tsao-ko (Amomum tsao-ko Crevost et Lemaire) on digestive enzyme activity, antioxidant activity, plasma and liver lipids, and blood glucose levels of mice. 1900 69

The compounds that could inhibit the activity of a-glucosidase are potentially used for antidiabetic by suppressing postprandial hyperglycemia. This research aimed to investigate the hypoglycemic activity in A. terreus koji extracted by ethyl acetate. The extracts was dissolved in methanol: water (1:4), followed by fractionations with n-hexane, methylene chloride and ethyl acetate. Each fraction was assayed for its activity against a-glucosidase. The active fraction was purified by column chromatography using silica gel and resin as adsorbent. The kopi extract showed potential as alpha-glucosidase inhibition with IC50 <10 microg mL(-1) and showed combination of non-competitive and uncompetitive inhibition mode against a-glucosidase. Ethyl acetate fraction showed potential as inhibitor alpha-glucosidase with IC50 = 8.6 microg mL(-1). In animal experiment, active fraction (F10-4) of ethyl acetate fraction suppressed the increase of postprandial blood glucosidase level compare to the control. Thus it showed potential as alpha-glucosidase inhibitor and demonstrated depressed postprandial blood glucose level and may have potential use in the management of type 2 diabetes.
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PMID:Inhibitory effect of koji Aspergillus terreus on alpha-glucosidase activity and postprandial hyperglycemia. 1909 Jan 11


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