• Journal of Energy Engineering
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• v.20 no.1
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• pp.36-43
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• 2011

Plant biomass has been proposed as an alternative source of petroleum-based chemical compounds. Especially, aromatic chemical compounds can be obtained from lignin by depolymerization processes because the lignin consist of complex aromatic materials. In this study, kraft lignin, the largest emitted substance among several kinds of lignin in Korea, was used as a starting material and was characterized by solid-state $^{13}C$-Muclear Magnetic Resonance($^{13}C$-NMR), Fourier Transform Infrared Spectroscopy(FT-IR), Elemental Analysis(EA). The depolymerization of kraft lignin was studied at water-phenol mixture solvent in near critical region and the experiments were conducted using a batch type reactor. The effects of water-to-phenol ratio and reaction temperature($300-400^{\circ}C$) were investigated to determine the optimum operating conditions. Additionally, the effects of formic acid as a hydrogen-donor solvent instead of $H_2$ gas were examined. The chemical species and quantities in the liquid products were analyzed using gas chromatography-mass spectroscopy(GC-MS), and solid residues(char) were analyzed using FT-IR. GC-MS analysis confirmed that the aromatic chemicals such as anisole, o-cresol(2-methylphenol), p-cresol(4-methylphenol), 2-ethylphenol, 4-ethylphenol, dibenzofuran, 3-methyl cabazole and xanthene were produced when phenol was added in the water as a co-solvent.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.367-371
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• 2013

The half maximal inhibitory concentration ($IC_{50}$) values and trolox equivalent antioxidant capacity (TEAC) values were calculated by a 2,2'-diphenylpicrylhydrazyl (DPPH) assay and a 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^{+{\cdot}}$) assay, in order to determine the antioxidative activities of the compounds. On the basis of the DPPH assay, quercetin had the strongest antioxidative potential of the flavonoids, followed in order by fisetin, 7,8-dihydroxyflavone, morin and kaempferol. Quercetin, fisetin and 7,8-dihydroxyflavone had higher antioxidant potentials than butyl hydroxyl anisole. Quercetin had the highest TEAC value amongst the flavonoids and isoflavonoids, followed in order by 3-hydroxyflavone, fisetin, 7,8-dihydroxyflavone and morin. Comparatively, isoflavonoids were found to have significantly weaker antioxidative potential than the flavonoids.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.251.2-251.2
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• 2010

Plant biomass has been proposed to be an alternative source for petroleum-based chemical compounds. Especially, phenolic chemical compounds can be obtained from lignin by chemical depolymerization processes because lignin consists of complex aromatic polymer such as trans-p-coumaryl, coniferyl and sinapyl alcohols, etc. Phenolic chemical compounds from lignin were usually produced in super critical water. However, we applied Near-critical water (NCW) system because NCW is known as a good solvent for lignin depolymerization. Organic matter like lignin can be solved in NCW system and the system has a unique acid-base property without conventional non-eco-friendly chemicals such as sulfuric acid and sodium hydroxide. In this work, we tried to optimize the NCW depolymerization system by adjusting the processing variables such as reaction time, temperature and pressure. Moreover, the amount of additional phenol was optimized by changing the molar ratio between water and phenol. Phenol was used as capping agent to prevent re-polymerization of active fragment such as formaldehyde. Alkali-lignin was used as a starting material and characterized by a Solid State 13C-NMR, FT-IR and EA (Elemental Analysis). GC-MS analysis confirmed that o-cresol, p-cresol, anisole and 4-hydroxyphathalic acid were the main product and they were quantitatively analyzed by HPLC.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1685-1691
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• 2011

The molecular structures of thiacalix[4]biscrown-5 (1) and p-tert-butylthiacalix[4]biscrown-5 (2) and their alkali-metal-ion complexes were optimized using the DFT BLYP/6-31G(d) and mPW1PW91/6-31G(d,p) (hybrid HF-DF) calculations. The total electronic energies, the normal vibrational modes, and the Gibbs free energies of the mono- and di-topic complexes of each host with the sodium and potassium ions were analyzed. The $K^+$-complexes exhibited relatively stronger binding efficiencies than $Na^+$-complexes for both the monoand di-topic complexes of 1 and 2 comparing the efficiencies of the sodium and potassium complexes with an anisole and phenol. The mPW1PW91/6-31G(d,p) calculated distances between the oxygen atoms and the alkali metal ions were reported in the alkali-metal-ion complexes ($1{\cdot}Na^+$, $1{\cdot}2Na^+$, $1{\cdot}K^+$, $1{\cdot}2K^+$, $2{\cdot}Na^+$, $2{\cdot}Na^+$, $2{\cdot}K^+$, $2{\cdot}2K^+$). The BLYP/6-31G(d) calculated IR spectra of the host 1 and its mono-topic alkali-metal-ion complexes are compared.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.500-504
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• 2004

This study was designed to investigate the possible utilization of Zanthoxylum schinifolium as a source of decontamination agents. The antimicrobial effect of Zanthoxylum schinifolium extract was investigated against Vibrio parahaemolyticus which is food-born disease organism. Ethanol extract of Zanthoxylum schinifolium was compared with water extract of Zanthoxylum schinifolium to test antimicrobial activities against Vibrio parahaemolyticus by disk method. Ethanol extract was more effective than water ,extract on the antimicrobial activities. It had remarkable antimicrobial activities against Vibrio parahaemolyticus. It was very stable on the wide range of temperature and pH. It turned out by GC-MS that estragole (4-allyl anisole) was a major antimicrobial component of Zanthoxylum schinifolium extract. These results indicated that Zanthoxylum schinifolium extract could protect against bacterial contamination and inhibit a growth of Vibrio parahaemolyticus.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.516-521
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• 2014

The purpose of this study was to examine the skin regeneration ability of Lespedeza cuneata extract (LC) as well as verify its wound healing effects on an open wound in rats. Rats were divided into six groups (NO, saline treated group; CO, 1% carboxy methyl cellulose (CMC) treated group; PC, fucidin treated group; LCL, 1% LC treated group; LCM, 3% LC treated group; LCH, 5% LC treated group), and the experimental material was applied for 5 weeks. Elastase inhibition rate of the LCM group was 2.7% lower than that of butylated hydroxy anisole (BHA), which is an antioxidant. Futher, the collagenase inhibition rate of the LCM showed 7% higher activity than that of BHA. The left wound areas in the LCL group, LCM group, and LCH group after the 21st day were noticeably reduced in wound area by 54.2%, 53.5%, and 48.7%, respectively, compared to the CO group. This suggests that Lespedeza cuneata extract has healing effects on surgical wounds by promoting regeneration of skin epithelial tissue and synthesis of collagen.

• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.235-240
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• 2006

We investigated the antioxidant activities such as DPPH radical scavenging capacity, xanthine oxidase inhibitory activity, and superoxide radical scavenging capacity of the aqueous EtOH extract and its solvent fractions of Artemisia scoparia. The ethyl acetate fraction showed high antioxidant activity, compared to positive controls such as ascorbic acid, butylated hydroxy anisole (BHA), trolox, and allopurinol in these assay systems. Moreover, we examined the inhibitory effect of solvent fractions of A. scoparia on the production of pro-inflammatory factors that the nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and prostaglandin E2 $(PGE_2)$ production activated with LPS $(1{\mu}g/ml)$ in murine macrophage cell line RAW264.7. The amounts of protein levels were determined by immunoblottting. Tn the sequential fractions of hexane and dichloromethane inhibited the NO and $PGE_2$ production and the protein level of iNOS and COX-2. These results suggest that A. scoparia may have anti-inflammatory activity through the antioxidant activity and inhibition of pro-inflammatory factors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1252-1256
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• 2004

Radiolytic characteristics of phytic acid by gamma irradiation were investigated, and the antioxidative activity between irradiated phytic acid and commonly used antioxidants including ascorbic acid, tocopherol and butylated hydroxyl anisole (BHA) was evaluated. Phytic acid sodium salt dissolved in a deionized distilled water was irradiated at 0, 5, 10, 15 and 20 kGy. It was found that the level of irradiation had an effects on the degree of degradation. After irradiation, stable DPPH radical scavenging capacity of phytic acid was newly observed, and it was significantly increased by dose-dependent manners (p<0.05). Antioxidant activity of phytic acid in the oil models was higher than that of the other antioxidant during storage, and phytic acid (400 $\mu\textrm{g}$/mL) irradiated at 20 kGy especially showed the highest antioxidative ability among the antioxidants tested during 3 weeks. Results indicated that irradiation induced the radiolysis of phytic acid in an aqueous model system, and the antiradical and antioxidative activities of irradiated phytic acid increased.

• KSBB Journal
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• v.15 no.2
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• pp.150-155
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• 2000

Antioxidative activity of c비ture of Streptomyces sp. BH-405 was investigated. After removal of pellets of Streptomyces sp. B BH-405, antioxidative substances were is미ated and suc$\infty$sively purified from culture of Streptomyces sp. BH-405 by by thin | layer chromatography $\pi$LC) or silica gel column chromatography. The fraction 3 obtained from ethylether fractionation of the C culture appeared highest level of anti oxidative activity as determined by thiocyanate method. Band 2 obtained by further P purification of this fraction showed higher anti oxidation level than that of same concentration of dl- $\alpha$ -tocopherol, butylated h hydroxy anisole (BHA). The band 2 showed higher rate of 1, 1.diphenyl 2-picrylhydrazyl (DPPH) decolorization than dl-$\alpha$-tocopherol. In the rat liver microsomes, band 2 rapidly inhibited lipid peroxidation which was initiated enzymatically by r reduced nicotinamide adenine dinucleotide phosphate (NADPH) or non-enzymatically by Fenton’s reagent. Band 2 inhibited on | lipid peroxidation of mitochondria or the linoleic acid hydro peroxide induced peroxidation system. It is concluded that band 2 obtained by fractionation of Streptomyces sp. BH-405 cultivation contained antioxidants with the capacity to inhibit oxidative m modification.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.146-153
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• 2012

In this study, the antioxidant property of leaf and callus extracts of five selected in vitro grown Ocimum species (Ocimum sanctum, Ocimum kilimandscharicum, Ocimum gratissimum, Ocimum basilicum, and Ocimum americanum) and their respective callus extracts was investigated. The callus cultures were successfully initiated on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (1mg L) combined with different concentrations (0.1-0.4 mg L) of kinetin as plant growth regulators. Total phenolic contents were estimated using the Folin-Ciocalteu reagent. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power, $Fe^{2+}$ chelating activity, and ${\beta}$-carotenelinoleic acid bleaching assays were used to determine the biological effects of the extracts. Interestingly, all the callus extracts exhibited significant (p<0.05) increase in phenolic contents and antioxidant activity. Furthermore, a liner correlation was obtained between the total phenolic contents and free radical scavenging activity ($R^2$ = 0.783). The extracts of leaves and calluses of Ocimum species exhibited activity in all the in vitro antioxidant assays, but its extent was less potent that the positive controls butylated hydroxyl anisole (BHA) and ascorbic acid. A higher accumulation of phenolics in the callus extracts suggests that isolation of high-concentration materials with antioxidant activivity is possible from in vitro callus cultures rather than field-grown plant organs. Furthermore, these extracts may be used as an effective preservative in the food industry.