• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.930-939
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• 2024

Mushroom laccases play a crucial role in lignin depolymerization, one of the most critical challenges in lignin utilization. Importantly, laccases can utilize a wide range of substrates, such as toxicants and antibiotics. This study isolated a novel laccase, named HeLac4c, from endophytic white-rot fungi Hericium erinaceus mushrooms. The cDNAs for this enzyme were 1569 bp in length and encoded a protein of 523 amino acids, including a 20 amino-acid signal peptide. Active extracellular production of glycosylated laccases from Saccharomyces cerevisiae was successfully achieved by selecting an optimal translational fusion partner. We observed that 5 and 10 mM Ca²⁺, Zn²⁺, and K⁺ increased laccase activity, whereas 5 mM Fe²⁺ and Al³⁺ inhibited laccase activity. The laccase activity was inhibited by the addition of low concentrations of sodium azide and ⳑ-cysteine. The optimal pH for the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt was 4.4. Guaiacylglycerol-β-guaiacyl ether, a lignin model compound, was polymerized by the HeLac4c enzyme. These results indicated that HeLac4c is a novel oxidase biocatalyst for the bioconversion of lignin into value-added products for environmental biotechnological applications.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.287-298
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• 2022

This study investigated the changes in the physiochemical property, phytochemical content, nutritional content and antioxidant activity of Polygoni multiflori Radix by steam, aging, and fermentation. After processing Polygoni multiflori Radix (PMR), pH slightly decreased, while acidity increased (pH 5.70→4.78, acidity 0.23→0.29%). The reducing sugar content increased after aging and fermentation from 1.19 mg/g (PMR) to 1.40 (fermented PMR, FPMR), 1.30 (red PMR, RPMR), 1.53 (fermented red PMR, FRPMR), 1.99 (black PMR, BPMR), and 2.33 mg/g (fermented black PMR, FBPMR). Total phenolic content was highest in PMR (6.05 mg/g) and total flavonoids and maillard product were increased after aging and fermentation of PMR, and were the highest in BPMR (1.60 mg/g) and FBPMR (2.76 O.D.), respectively. The major phytochemical was 2,3,5,4'-tetrahydroxystilbene-2-0-α-glucoside, which were highest in PMR (64.9 mg/g) with 46.47 mg/g at FPMR, 33.94 mg/g at RPMR, 48.76 mg/g at FRPMR, 36.68 mg/g at BPMR and 34.35 mg/g at FBPMR. The main fatty acids and free amino acids were detected as palmitic acid (C16:0) and proline, respectively. Generally, 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activities and FRAP reducing powers were shown high in PMR (39.06%, 98.32%, and 2.61 O.D. in extracts concentration 1.0 mg/mL), then were decreased after aging and fermentation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.162-177
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• 2001

The hydrolysis rates of seven kinds of polyol ester base oils 〔POEs〕 of different branch shape were investigated by using a simple apparatus under mild acidic condition. Seven polyol ester base oils were made of poly hydric alcohols of two-four valence, normal or branched fatty acids of different carbon number. p-Toluene sulfonic acid was used as acid catalyst to accelerate the rate of hydrolysis. Partial esters and fatty acid produced by sequential hydrolysis of POEs were identified and their concentrations were determined by calibrated-internal standard method using Gas Chromatography. The rate constants of each step in sequential hydrolysis were determined by the least square method from rate equation and the concentration of each component, were compared with one another. It was shown that the rate of hydrolysis of POEs was strongly affected by whether molecular structure of fatty acid was straight chain or branch chain and which position was branched. The hydrolysis stability for all the POEs can be reasonably explained by using a steric hindrance effect anticipated fi:om their molecular structures affecting as water molecule makes an attack on the carbonyl carbon of POEs.

• Journal of Life Science
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• v.34 no.4
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• pp.245-253
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• 2024

We investigated to analyze total flavonoid content and fatty acid composition of Stachys sieboldii Miq root. In order to determine antioxidant and anti-inflammatory effects of fractions from S. sieboldii Miq. root, we conducted 1.1-Diphenyl-2-picryhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS) assays for antioxidant and measured nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW 264.7 cells. In addition, we examined an inhibitory effect of fractions from S. sieboldii Miq. root on smad signaling induced by transforming growth factor (TGF) β. Among the fractions, n-butanol (n-BuOH) fraction showed the highest flavonoid content (16.67 mg/g), followed by n-Hexane, water and 85% aqueous methanol (85% aq. MeOH) fractions. The fatty acid composition of S. sieboldii Miq. root was in the following order : n-6 fatty acids (54.3%) > n-3 fatty acids (21.2%) > saturated fatty acids (19.7%) > n-9 fatty acids (3.6%). As a result of the antioxidant efficacy, the DPPH and ABTS assays showed that n-BuOH fraction had higher scavenging activity compared to other fractions. Inhibitory effect on NO production showed that all fractions decreased LPS-induced NO production, indicating an anti-inflammatory activity of S. sieboldii Miq. root. 85% aq. MeOH and water fractions showed a higher efficacy in inhibiting transforming growth factor (TGF) β induced smad signaling. From the results, it suggests that food processing products using S. sieboldii Miq. root will be developed as a functional food for promoting health.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.288-298
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• 2024

This study aimed to investigate the amino acid content, fatty acid composition, total flavonoid and phenol contents, and antioxidant activities of Prunus yedoensis Matsum. bark extracts using various extraction solvents. Through amino acid analysis, 13 amino acids were detected in extracts obtained using hot water, 30% ethanol, and 70% ethanol. The major amino acids were identified as aspartic acid, arginine, and proline, and the total amino acid content was 0.17%, 0.16%, and 0.09%, respectively. Fatty acid analysis showed a saturated fatty acid (SFA) ratio of 62.7-66.7% in extracts obtained using hot water, 30% ethanol, and 70% ethanol, with the primary fatty acid identified as palmitic acid. The total flavonoid and polyphenol contents were 727.70-769.87 mg quercetin equivalent (QE)/ g and 309.24-348.09 mg gallic acid equivalent (GAE)/g, respectively, in extracts obtained using hot water, 30% ethanol, and 70% ethanol extracts. Measurements of antioxidant activity confirmed that extracts obtained using hot water, 30% ethanol, and 70% ethanol extracts increased the antioxidant effect in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and ferric reducing antioxidant power (FRAP) in a concentration-dependent manner. A high correlation was observed between the total flavonoid content, total polyphenol content, and antioxidant activities of the extracts. This study provides data and novel insights for the development of functional food materials using P. yedoensis Matsum. bark extracts.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.381-398
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• 1975

Present work was executed to evaluate effects of adjuvants. stabilizers. moisture. pH and heavy metals on the stability of Fenitrothion in the emulsifiable concentrate. In addition, susceptibility ' of Fenitrothion in various formulations, to UV-irradiation has been also examined. The results are summarized as follows; 1. Xylene and benzene were found to be satisfactory solvents for Fenitrothion emulsifiable concentrate. As expected, polar sol vents such as aliphatic alcohols considerably reduced stability of the pesticides. 2. Of the two non-ionic emulsifiers, an alkyl aryl type Sorpol-1200, in contrast to sorbitan type Tweens, substantially reduced decomposition of Fenitrothion in the emulsifiable concentrates. Moisture and pH of emulsifiers. in the ranges studied. affected little if any. on the stabi ity of the Fenitrothion during the experiment periods. 3. Maleic anhydride, p-toluene sulfonic acid, sulfosalicylic acid, maleic anhydride-sulfosalicylic acid reduced decomposition of Fenitrothion in the emulsifiable concentrate. Addition of organic acids, however, increased liability of Fenitrothion in the emulsifiable concentrate. 4. Presence of either zinc or copper metals in the emulsifiable concentrate containing Tween-80 as a emulsifier, reduced stability of the Fenitrothion. 5. UV-irradiation, as expected, brought decomposition of Fenitrothion. The liability of Fenitrothion formulations decreased in the order, wettable powder ${\gg}$ dust > emulsifiable concentrate.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.284-288
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• 2016

To investigate the physiological effect of Hibiscus sabdariffa, in vitro antioxidant activities and neuroprotective effects against high glucose-induced oxidative stress were examined. The ethyl acetate fraction (EtOAc-Fr) from H. sabdariffa contained high total phenolic contents compared with other fractions but total anthocyanin contents were lower than 80% Ethanol extract showed the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activity and malondialdehyde inhibitory effect. Furthermore, the EtOAc-Fr decreased the intracellular reactive oxygen species level, and protected the neuron-like PC12 cells from high glucose-induced cytotoxicity. The EtOAc-Fr also presented inhibitory effects against acetylcholinesterase as an acetylcholine hydrolase enzyme. Finally, chlorogenic acids as main phenolics by high performance liquid chromatography analysis.

• Journal of Life Science
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• v.28 no.8
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• pp.917-922
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• 2018

Centella asiatica is one of the local herbs that is claimed to possess various physiological effects. C. asiatica also accumulates large amounts of pentacyclic triterpenoid saponins known as centelloids. These terpenoids usually include asiatic acid, asiaticoside, madecassoside, and madecassic acids. In the present study, to understand the changes of triterpene glycoside levels in the different shoot tissues of C. asiatica during seasonal cultivation, we investigated the High-Performance Liquid Chromatography (HPLC) analysis via different extraction methods, such as water, 20% ethanol and methanol extracts. Significant increases were observed in the levels of madecassoside and asiaticoside in the leaf extracts by methanol compare with extracts using water or 20% ethanol. Additionally, we also analyzed the various antioxidant activity in the different shoot tissues of C. asiatica using different extracts, such as leaves, petioles and both materials. Among these petiole extracts showed high 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTs) scavenging activity in all extracts, whereas 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity exhibited high activity levels in the leaf part using methanol and ethanol extracts. Levels of total phenolics and flavonoid also showed the highest levels in the leaf tissues using all extracts such as methanol, ethanol and water. Our results indicated that the increased levels of triterpene glycoside and antioxidant activity in the leaf parts of the C. asiatica were indicating that useful metabolites were mainly maintained through seasonal cultivation such as madecassoside, asiaticoside.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.211-224
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• 2008

Characteristics of the esterification reaction between free fatty acid in rice bran oil and methanol was investigated in the presence of catalysts, such as PTS(p-toluene sulfonic acid), Amberlyst 15 dry and SCX(silica gel based strong cation exchange resin). While reaction temperature was kept constant at $65^{\circ}C$, initial feed content of free fatty acid was varied from 100% to 1% by addition of pure free fatty acid which was previously made from rice bran oil. Also, the effect of mole ratio of methanol to fatty acid on the final conversion was examined. When esterification of pure free fatty acid was catalyzed by several acids, final conversions were increased in order of Amberlyst 15 dry, SCX and PTS. Using PTS catalyst, initially the reaction proceeded in homogeneous 2nd oder reaction mechanism. However, phase of reaction mixture changed from homogeneous to heterogeneous along the reaction time and then reaction rate was retarded by mass transfer resistance of methanol. Final conversion of free fatty acid in reaction mixture was depended on initial feed content of free fatty acid, and had maximum value at 30% of initial feed free fatty acid content for all kinds of catalysts used. And the final conversion was increased with mole ratio of methanol by the improvement of reaction rate. When initial feed free fatty acid content below 10% and the reaction was catalyzed by PTS, concentration of free fatty acid in reaction mixture was increased in the middle of reaction time by hydrolysis of triglyceride in reaction mixture. Also, if silica gel was added into the reaction mixture which had initial feed free fatty acid content below 50%, final conversion was increased by the adsorption of moisture produced. The SCX catalyst made the esterification reaction of free fatty acid to progress like in case of PTS catalyst. However, when initial feed free fatty acid content below 10%, concentration of free fatty acid in. reaction mixture was decreased monotonically and not increased in the middle of reaction time on the contrary to the case of PTS. Thus, SCX catalyst accomplished more high value of final conversion than PTS catalyst for the initial feed fatty acid content range from 50% to 5% In case of initial feed free fatty acid content of 1% and mole ratio of methanol was 2, concentration of free fatty acid in reaction mixture increased over the initial feed free fatty acid content for all kind of catalysts used. Although SCX catalyst was added into reaction mixture which had 1% of initial feed fatty acid content, final conversion was hardly raised by mole ratio of methanol.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.258-262
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• 2005

For the purpose of developing natural antioxidant, the antioxidative activity and antimicrobial of phenolics isolated from Baek-bu-ja (Aconiti koreani Rhizoma) were determined. Optimum extracting condition for phenolics were water extracts. HPLC analysis showed that the four major phenolic metabolites were rosemarinic, protocatechuic, caffeic and chlorogenic acids. The water extracts of Baekbuja did not have antimicrobial activity against H. pylori; however, the ethanol extracts revealed higher antimicrobial activity. Electron donation ability on DPPH of Baekbuja ethanol extract was 20% higher than other ethanol extracts. The 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical decolorization (ABTS) and antioxidant protection factor (PF) were determined with extracts from Aconiti koreani Rhizoma. 94% inhibition and 1.14 PF were shown on ABTS and antioxidant protection factor with 60% ethanol extracts. Also, TBARS (thiobarbituric acid reactive substances) showed $0.19\;{\mu}M$ in the control and $0.07\;{\mu}M$ in the 80% ethanol extracts. The result suggests that Baekbuja extract may be useful as potential sources of anti Helicobacter pylori, antioxidant.