scholarly journals Inhibitory Properties of Aqueous Ethanol Extracts of Propolis on Alpha-Glucosidase

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hongcheng Zhang ◽  
Guangxin Wang ◽  
Trust Beta ◽  
Jie Dong
Keyword(s):  
Aqueous Ethanol ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Postprandial Hyperglycemia ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Ethanol Extracts ◽  
Alpha Glucosidase ◽  
Mammalian Intestine ◽  
Intestinal Sucrase

The objective of the present study was to evaluate the inhibitory properties of various extracts of propolis on alpha-glucosidase from baker’s yeast and mammalian intestine. Inhibitory activities of aqueous ethanol extracts of propolis were determined by using 4-nitrophenyl-D-glucopyranoside, sucrose and maltose as substrates, and acarbose as a positive reference. All extracts were significantly effective in inhibitingα-glucosidase from baker’s yeast and rat intestinal sucrase in comparison with acarbose (P<0.05). The 75% ethanol extracts of propolis (75% EEP) showed the highest inhibitory effect onα-glucosidase and sucrase and were a noncompetitive inhibition mode. 50% EEP, 95%, EEP and 100% EEP exhibited a mixed inhibition mode, while water extracts of propolis (WEP) and 25% EEP demonstrated a competitive inhibition mode. Furthermore, WEP presented the highest inhibitory activity against maltase. These results suggest that aqueous ethanol extracts of propolis may be used as nutraceuticals for the regulation of postprandial hyperglycemia.

Phenylalanine Analogues: Potent Inhibitors of Phenylalanine Ammonia-Lyase Are Weak Inhibitors of Phenylalanine-tRNA Synthetases

1994 ◽  
Vol 49 (11-12) ◽  
pp. 781-790 ◽  
Author(s):  
Gerhard Leubner Metzger ◽  
Nikolaus Amrhein
Keyword(s):  
Wheat Germ ◽  
Phenylalanine Ammonia Lyase ◽  
Inhibitory Effect ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Exchange Reactions ◽  
Trna Synthetases ◽  
Different Sources

(1-Amino-2-phenylethyl)phosphonic acid (APEP), (1-amino-2-phenylethyl)phosphonous acid (APEPi), α-aminooxy-β-phenylpropionic acid (AOPP) and several other phenylalanine analogues are potent inhibitors of (S)-phenylalanine ammonia-lyase (PAL) in vitro and in vivo. The ability of these compounds to inhibit (S)-phenylalanine-tRNA synthetases (PRSs) from wheat germ, soybean, and baker’s yeast has been investigated and compared to the inhibition of PAL. APEP and APEPi were found to inhibit the tRNAphe-aminoacylation reactions catalyzed by the three PRSs studied in vitro in a competitive manner with respect to (5)-phenylalanine. (R)-APEP inhibits the PRSs with apparent Ki values of 144 μᴍ for wheat germ (app. Km for (S)-phe 5.2 μᴍ) , 130 μᴍ for soybean (app. Km for (S)-phe 0.9 μᴍ) , and 1096 μᴍ for baker’s yeast (app. Km for (S)-phe 5.5 μᴍ ) . The apparent Ki values for (R)-APEPi are 315 μᴍ , 160 μᴍ , and 117 μᴍ , respectively. APEP and APEPi inhibit the ATPpyrophosphate exchange reactions catalyzed by the PRSs from wheat germ and baker’s yeast, but they are not activated and do not serve as substrates in these reactions. AOPP has no affinity to any of the three PRSs, whereas it is a potent inhibitor of PAL. In light of our in vitro results with PRSs from different sources it appears unlikely that the PAL inhibitors we have studied have any significant inhibitory effect on this essential step in protein synthesis in vivo.

scholarly journals Inhibitory Effect of the Stem Bark Extracts of Albizia chevalieri Harms on the Activity of Alpha-glucosidase Obtained from Aspergillus niger

2019 ◽  
pp. 1-10
Author(s):  
Abdulhafiz Damilola Oso ◽  
Idris Bello ◽  
Yusuf Sa’idu ◽  
Onu Andrew
Keyword(s):  
Ethyl Acetate ◽  
Competitive Inhibition ◽  
Stem Bark ◽  
Inhibitory Effect ◽  
Acetate Buffer ◽  
Bark Extract ◽  
Methanol Extracts ◽  
Glucosidase Activity ◽  
Alpha Glucosidase

The aim of the current study is to evaluate the inhibition of α-glucosidase activity by stem bark extract of Albizia chevalieri. The activity of alpha glucosidase was assayed in vitro using 50 mM acetate buffer pH 6.0 (prepared from acetic acid and sodium acetate) and various concentration of maltose (0.5 mM to 10 mM). Five test tubes, labeled TA – TE, each containing 1.5 ml of acetate buffer, 0.5 ml of alpha glucosidase and 0.5 ml of a known concentration of plant extract and control tubes (CA – CE) were assessed for Alpha glucosidase activity. The results showed that hexane, ethyl acetate and methanol extracts inhibited α-glucosidase activity. The results further indicated that the extracts act by competitive inhibition with inhibition constant of 232 mg/ml, 157 mg/ml and 67 mg/ml for hexane, ethyl acetate and methanol extracts, respectively. The value for the inhibition constants shows that there is a strong binding of the enzyme to the inhibitor as the polarity of solvent increases. The inhibitory activity of Albizia chevalieri may be due one or more of the phytochemicals present in the extracts.

scholarly journals The Effects of Nucleotides on the alpha-Glucosidase Formation in Baker's Yeast Protoplasts.

1973 ◽  
Vol 27 ◽  
pp. 3126-3128
Author(s):  
Sampsa Haarasilta ◽  
Erkki Oura ◽  
Randi Winsnes ◽  
Petri Pajunen ◽  
Jouko Koskikallio ◽  
...  
Keyword(s):  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Yeast Protoplasts ◽  
Alpha Glucosidase

scholarly journals Preliminary Analysis of the Antidiabetic Activity of Indonesian Polyherbal Formulation

2021 ◽  
Vol 21 (3) ◽  
pp. 219
Author(s):  
Syamsudin Abdillah ◽  
Apriala Gita Lestari ◽  
Priskila Monika ◽  
Wahono Sumaryono ◽  
Kartiningsih Hisyam
Keyword(s):  
Stevia Rebaudiana ◽  
Inhibitory Effect ◽  
Antidiabetic Activity ◽  
Smallanthus Sonchifolius ◽  
Polyherbal Formulation ◽  
Diabetes In Mice ◽  
Ethanol Extracts ◽  
Alpha Glucosidase

This study aims to prepare polyherbal formulations and also analyze the antidiabetic potentials of the prepared polyherbal in animals. The ethanol extracts of the leaves of <em>Smallanthus sonchifolius</em>, <em>Stevia rebaudiana, Syzygium polyanthum</em>, and <em>Camellia sinensis</em> were used in this study. The extracts of the aforementioned plants were prepared in the ratio of 2:1:1:1. The formulation was tested for antidiabetic activity <em>in vitro</em> through the inhibition of alpha-glucosidase and <em>in vivo</em> using alloxan-induced diabetes in mice. The polyherbal has an inhibitory effect with the IC<sub>50</sub> value of 26.23 μg/mL compared to acarbose (control) was 17.02 μg/mL. The diabetic animals were observed to show an obvious decline in glucose level when compared with control (P&lt; 0.001) after treatment.

scholarly journals ISOLATION OF HEXOKINASE FROM BAKER'S YEAST

1946 ◽  
Vol 29 (6) ◽  
pp. 379-391 ◽  
Author(s):  
Louis Berger ◽  
Milton W. Slein ◽  
Sidney P. Colowick ◽  
Carl F. Cori
Keyword(s):  
Specific Activity ◽  
Proteolytic Enzymes ◽  
Protective Action ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Thiol Compounds ◽  
Protective Proteins ◽  
Yeast Hexokinase

1. A method is described for the isolation of hexokinase from baker's yeast. The method is based mainly on fractionation with alcohol and results See PDF for Structure in a 30-fold increase in specific activity. The final product could be crystallized from ammonium sulfate without change in specific activity. 2. The enzyme catalyzes a transfer of phosphate from adenosinetriphosphate to glucose, fructose, or mannose, the relative rates with these three sugars being 1:1.4:0.3. 3. With glucose as substrate, the turnover number for the crystalline enzyme is 13,000 moles of substrate per 105 gm. of protein per minute at 30° and pH 7.5. The temperature coefficient (Q10°) between 0 and 30° is 1.9. 4. Magnesium ions are necessary for the activity, the dissociation constant for the Mg++ -protein complex being 2.6 x 10–3. Fluoride in concentrations as high as 0.125 M has no inhibitory effect on the enzyme when the Mg++ and orthophosphate concentrations are 6.5 x 10–3 M and 1 x 10–3 M, respectively. 5. The crystalline enzyme shows a loss in activity when highly diluted. This loss in activity can be prevented by diluting in the presence of small amounts of other proteins. Of the various protective proteins tested, insulin was the most effective, providing complete protection in a concentration of 6 micrograms per cc.; with serum albumin, a concentration of 60 micrograms per cc. was necessary. Thiol compounds (cysteine, glutathione) exerted no protective action. 6. The inactivation of the crystalline enzyme on incubation with trypsin can be prevented to a marked degree by the presence of glucose. The instability of crude preparations of yeast hexokinase may be attributed to the presence of proteolytic enzymes, since glucose or fructose has a remarkable protective effect on such preparations.

scholarly journals Effects of adenosine phosphates and nicotinamide nucleotides on pyruvate carboxylase from baker's yeast

1969 ◽  
Vol 112 (5) ◽  
pp. 755-762 ◽  
Author(s):  
J. J. Cazzulo ◽  
A. O. M. Stoppani
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Carboxylase ◽  
Physiological Role ◽  
Inhibitory Effect ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Acetyl Coa ◽  
Competitive Inhibitors ◽  
Adenosine Phosphates ◽  
Regulation Of Enzyme Activity

1. Pyruvate carboxylase from baker's yeast is inhibited by ADP, AMP and adenosine at pH8·0 in the presence of magnesium chloride concentrations equal to or higher than the ATP concentration. The adenine moiety is essential for the inhibitory effect. 2. In the absence of acetyl-CoA (an allosteric activator) ADP, AMP and adenosine are competitive inhibitors with respect to ATP. In the presence of acetyl-CoA, besides the effect with respect to ATP, AMP competes with acetyl-CoA, whereas ADP and adenosine are non-competitive inhibitors with respect to the activator. 3. Pyruvate carboxylase is inhibited by NADH. The inhibition is competitive with respect to acetyl-CoA and specific with respect to NADH, since NAD+, NADP+ and NADPH do not affect the enzyme activity. In the absence of acetyl-CoA, NAD+, NADH, NADP+ and NADPH do not inhibit pyruvate carboxylase. 4. Pyruvate carboxylase is inhibited by ADP, AMP and NADH at pH6·5, in the presence of 12mm-Mg2+, 0·75mm-Mn2+ and 0·5mm-ATP, medium conditions similar to those existing inside the yeast cell. The ADP and NADH effects are consistent with a regulation of enzyme activity by the intracellular [ATP]/[ADP] ratio and secondarily by NADH concentration. These mechanisms would supplement the already known control of yeast pyruvate carboxylase by acetyl-CoA and l-aspartate. Inhibition by AMP is less marked and its physiological role is perhaps limited.

Antioxidant capacity, anti-acetylcholinesterase activity and inhibitory effect on lipid peroxidation in mice brain homogenate of Achillea millefolium

2017 ◽  
Vol 42 (4) ◽  
Author(s):  
Elif Nur Barut ◽  
Burak Barut ◽  
Seçkin Engin ◽  
Sercan Yıldırım ◽  
Ahmet Yaşar ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Inhibitory Activity ◽  
Competitive Inhibition ◽  
Antioxidant Activities ◽  
Brain Homogenate ◽  
Acetylcholinesterase Activity ◽  
Inhibitory Effect ◽  
Achillea Millefolium ◽  
Mice Brain ◽  
Ethanol Extracts

AbstractObjective:(Methods:Methanol extracts (ME) and ethanol extracts (EE) ofResults:ME had higher antioxidant activities compared to EE. Both extracts displayed a competitive inhibition of acetylcholinesterase; however, the inhibitory activity of ME was higher than EE. The inhibitory constant (KConclusions:Our results showed that

Effects of Dipyrone on Prostaglandin Production by Human Platelets and Cultured Bovine Aortic Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 132-137 ◽  
Author(s):  
A Eldor ◽  
G Polliack ◽  
I Vlodavsky ◽  
M Levy
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Ionophore A23187 ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
Aortic Endothelial

SummaryDipyrone and its metabolites 4-methylaminoantipyrine, 4-aminoantipyrine, 4-acetylaminoantipyrine and 4-formylaminoan- tipyrine inhibited the formation of thromboxane A2 (TXA2) during in vitro platelet aggregation induced by ADP, epinephrine, collagen, ionophore A23187 and arachidonic acid. Inhibition occurred after a short incubation (30–40 sec) and depended on the concentration of the drug or its metabolites and the aggregating agents. The minimal inhibitory concentration of dipyrone needed to completely block aggregation varied between individual donors, and related directly to the inherent capacity of their platelets to synthesize TXA2.Incubation of dipyrone with cultured bovine aortic endothelial cells resulted in a time and dose dependent inhibition of the release of prostacyclin (PGI2) into the culture medium. However, inhibition was abolished when the drug was removed from the culture, or when the cells were stimulated to produce PGI2 with either arachidonic acid or ionophore A23187.These results indicate that dipyrone exerts its inhibitory effect on prostaglandins synthesis by platelets or endothelial cells through a competitive inhibition of the cyclooxygenase system.

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