• YAKHAK HOEJI
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• v.39 no.5
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• pp.565-568
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• 1995

A new antiplatelett agent, aspalatone ([3-(2-methyl-4-pyronyl)]-2-acetyloxybenzoate) was demonstrated to inhibit MDA generation from arachidonic acid catalyzed by partially purified bovine seminal vesicle cyclooxygenase. This inhibition was also observed with acetylsalicylic acid. The results suggest that the mechanism for the antiplatelet effect of aspalatone is, like acetylsalicylic acid, due to its inhibition of cyclooxygenase.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.279-282
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• 2000

The inhibition mode of S-hydroxy-2-phenylalanylaminomethyl-4-pyron ($IC_{50}=24.6{\;}{\mu}M$) on mushroom tyrosinase was investigated using L-tyrosine as a substrate. This inhibitor is the kojic acid derivative, where the C-7 hydroxyl of kojic acid was replaced by amino group and coupled to the carboxyl of L-phenylalanine. The kinetic data obtained show a competitive inhibition pattern.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.110-113
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• 2006

Prolyl endopeptidase (PEP, EC 3.4.21.26, also referred to as prolyl oligopeptidase) degrades proline containing, biologically active neuropeptides such as vasopressin, substance P and thyrotropin-releasing hormone by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity. Therefore, a specific PEP inhibitor can be a good candidate of drug against memory loss. Upon our examination for PEP inhibitory activity from micronutrients, ascorbic acid (vitamin C) showed small but significant PEP inhibition (13% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$). Palmitic acid showed almost no PEP inhibition. However, 6-O-palmitoyl ascorbic acid ($\underline{1}$) showed 70% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$ indicating that hydrophobic portion of the compound $\underline{1}$ may facilitate the inhibitory effect. $IC_{50}$ value of compound $\underline{1}$ was $12.6{\pm}0.2{\mu}M$. The primary and secondary Lineweaver Burk and Dixon plots for compound $\underline{1}$ indicated that it is a non-competitive inhibitor with inhibition constant (Ki) value of $23.7{\mu}M$.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.297-300
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• 2003

In order to select probiotics with a high survival rate in gut and the growth inhibition of virulent pathogens to human beings or animals, we have screened lactic acid bacteria and yeasts from Jeot-gal to assess resistance against the artificial gastric acid and bile juice. Lactic acid bacteria and yeasts isolated were incubated for 24 h in artificial bile juice after incubation for 2 h in artificial gastric acid. Especially, strain HW 161 and strain NK 181 showed the higher survival for 2 h incubation in artificial gastric acid. All of 3 strains of lactic acid bacteria and 2 strains of yeast were showed higher growth rate than the control in artificial bile. The antimicrobial activity of lactic acid bacteria and yeasts was also investigated to prove efficacy as probiotic organisms. Lactic acid bacteria were shown the inhibition of Gram positive and negative bacteria, but yeasts narrow inhibition.

• Biomolecules & Therapeutics
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• v.9 no.3
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• pp.176-182
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• 2001

Some pharmacological activities of acanthoic acid, isolated from Acanthopanax koreanum root was investigated in animals. It is revealed that the compound had analgesic and anti-inflammatory activities without actions on central nervous system and showed inhibition of lipid peroxidation. The anti-inflammatory activity might be related to inhibition of prostaglandin E$_2$ synthesis in exudates of inflammation.

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.329-332
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• 1997

Cell-free extracts of Streptomyces neyagawaensis SL-387 grown on a chemically defined medium supplemented with DL-3-amino-3-phenylpropionic acid (APP) produced N-acetyl-APP (Ac-APP) in the presence of APP and acetyl coenzyme A. The APP obtained by acid hydrolysis of the Ac-APP was D-configuration: $[\alpha]_D+6.5^{\circ}(H_2O)\;at\;20^{\circ}C$, optical purity 92% enantiomeric excesses (ee). These results suggest that an N-acetyltransferase exists in the cell-free extract as a novel enzyme with specificity for D-APP.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.719-732
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• 2003

A kojic acid derivative, kojic acid 7-O-$\beta$-D-tetraacetylglucopyranoside(KTG) was synthesized. Regio-and stereo-selective glycosylation at 7-postion in kojic acid with $\beta$-D-pentaacetylglucose was achieved with high yield(80％) by the use of Lewis acid and organic base in nonpolar solvent. KTG was hydrolyzed in methanol by the aid of sodium methoxide to give kojic acid 7-O-$\beta$-D-glucopyranoside(KGP). KGP is freely soluble in water and soluble in methanol and ethanol. Its structure was comfirmed by $^1$H-NMR and $^{13}$ C-NMR. Tyrosinase activity inhibition of KGP was measured with mushroom tyrosinase compared with ascorbic acid, kojic acid and arbutin. KGP showed higher tyrosinase inhibition activity($IC_{50}$/=33.3 $\mu\textrm{g}$/ml) than ascorbic acid(63.2 $\mu\textrm{g}$/ml) and arbutin(91.8 $\mu\textrm{g}$/ml) but lower inhibition activity than kojic acid(8.3 $\mu\textrm{g}$/ml). To test free-radical scavenging activity, we used 1, 1-diphenyl-2-picrylhydrazyl(DPPH) as a free-radical source. Free-radical scavenging activity of KGP was very low($SC_{50}$/>1000 $\mu\textrm{g}$/ml) compared with ascorbic acid($SC_{50}$/=2.68 $\mu\textrm{g}$/ml) and arbutin($SC_{50}$/=180$\mu\textrm{g}$/ml). Melanin formation inhibition of KGP was measured in B16 melanoma, compared with kojic acid, arbutin and Vitamin C. Inhibition activity of KGP for melanin formation was not found within test concentrations.

• Journal of Environmental Science International
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• v.31 no.2
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• pp.141-148
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• 2022

In this study, the inhibition of ammonia on anaerobic digestion of butyric acid was evaluated and the potential alleviating effects of such ammonia inhibition by the addition of magnetite particles were investigated. Independent anaerobic batch tests fed with butyric acid as a sole organic source were conducted in twenty 60-mL glass bottles with 10 different treatment conditions, comprising ammonia: 0.5, 2.0, 4.0, 6.0, and 7.0 g total ammonia nitrogen (TAN)/L and magnetite particles: 0 mM and 20 mM. The increase in ammonia concentration did not cause significant inhibition on methane yield; however, a significant inhibition on lag time and specific methane production rate was observed. The IC₅₀ in the control treatments (without magnetite addition) was estimated as 6.2654 g TAN/L. A similar inhibition trend was observed in magnetite-added treatments; however, the inhibition effect by ammonia was significantly alleviated in lag time and specific methane production rate when compared to those in the control treatments. The lag time was shortened by 1.6-46.3%, specific methane production rate was improved by 6.0-69.0%. In the magnetite-added treatments, IC₅₀ was estimated as 8.5361 g TAN/L. This study successfully demonstrated the potential of magnetite particles as an enhancer in anaerobic digestion of butyric acid under conditions of ammonia stress.

• Corrosion Science and Technology
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• v.4 no.5
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• pp.191-200
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• 2005

Two azole compounds viz., Imidazole (IM) and 2-Methylimidazole (2-MIM) were studied to investigate their inhibiting action on corrosion of mild steel in phosphoric acid ($H_3PO_4$) solution by mass loss and polarization techniques at 302K-333K. It has been found that the inhibition efficiency of the all inhibitors increased with increase in inhibitor concentration and decreases with increasing temperature and also with increase in acid concentrations. The inhibition efficiency of these compounds showed very good inhibition efficiency. At 0.5% of IM and 2-MIM in 1N and 5N phosphoric acid solution at 302K to 333K for 5 hours immersion period, the inhibition efficiency of 2-Methylimidazole found to be higher than Imidazole. The adsorption of these compounds on the mild steel surface from the acids has been found to obey Tempkin's adsorption isotherm. The values of activation energy ($E{\alpha}$) and free energy of adsorption (${\Delta}G{\alpha}ds$) were also calculated. The plots of log $W_f$ against time (days) at 302K give straight line which suggested that it obeys first order kinetics and also calculate the rate constant k and half life time $t_{1/2}$. Surface was analyzed by SEM and FITR spectroscopy.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.1
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• pp.52-58
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• 2004

An unstructured mathematical model for lactic acid fermentation was developed. This model was able to predict the inhibition effects of lactic acid and glucose and was con-firmed to be valid with various initial concentrations of lactic acid and glucose. Simulation of energy production was made using this mathematical model, and the relationship between the kinetics of energy metabolism and lactic acid production was also analyzed.