• Archives of Pharmacal Research
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• v.22 no.2
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• pp.213-218
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• 1999

The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at $37^{\circ}C$, using 2-thiobarbituric acid (TBA). The methanol extract and its factions of Eriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCl gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH fraction and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and$ 2{\alpha}$-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.

• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.165-174
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• 2019

Oregonin is known as a representative active substance of plants of the Alnus species. In this study, we will show the results of establishing a method for extracting trace amounts of useful substances in plants. Additionally, a variety of physiological activity studies were conducted with extracts containing high content of useful substances. In this study, anti-oxidant, anti-inflammatory and anti-allergic activities of supercritical fluid residue 60% EtOH extracts of Alnus sibirica (ASCFR) were investigated in vitro. To explore anti-oxidant and anti-inflammatory characteristics of supercritical extract, DPPH radical scavenging, and ABTS radical scavenging activity, inhibition of nitric oxide production in LPS-stimulated RAW 264.7 cells and ${\beta}$-hexosaminidase release in IgE-stimulated RBL-2H3 cells were examined, respectively. Results showed a concentration-dependent increase in DPPH and ABTS radical scavenging activity. Cells stimulated with LPS produced more nitric oxide than normal control cells. However, cells treated with supercritical fluid residue 60% EtOH extract decreased production in a concentration-dependent manner. In anti-allergic activity studies, ASCFR showed concentration-dependentanti-allergic activity. Based on results and strong antioxidant activity, ASCFR has potential as basic research materials for development of therapeutic supplements-based medicines or functional cosmetics related to chronic inflammatory skin immunity diseases.

• Bulletin of the Korean Chemical Society
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• v.6 no.6
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• pp.362-366
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• 1985

The hydrogen atom transfer reaction between substituted methane, $CH_3X,$ and its radical, $CH_2X(X=H,F,CH_3,CN,OH\;and\;NH_2$ was studied by MINDO/3 method. The transition state(TS) structure and energy barriers were determined and variation of the transition state and of the reactivity due to the change of X were analyzed based on the potential energy surface characteristics. It was found that the greater the radical stabilization energy. the looser the TS becomes; the TS occurs at about 15% stretch of the C-H bond, which becomes longer as the radical stabilization energy of $CH_2X$ increasers. The intrinsic barrier, ${\Delta}E*_{x.x},$ of the reaction with X was found to increase in the order $H The degree of bond stretch of the C-H bond stretch of the C-H bond at the TS also had the same order indicating that the homolytic bond cleavage of the C-H bond is rate-determining. Orbital interactions at the TS between LUMO of the fragment $C{\ldots}H{\ldots}C$ and the symmetry adapted pair of nonbonding, $n{\pm}(=n_1{\pm}n_2),$ or pi orbitals of the two X atoms were shown to be the dominant contribution in determining tightness or looseness of the TS. The Marcus equation was shown to apply to the MINDO/3 barriers and energy changes of the reaction.

• Toxicological Research
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• v.25 no.4
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• pp.243-251
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• 2009

Present study was conducted to evaluate the anti oxidative activity of the Agrimonia pilosa-Ledeb leaves on non-lipid oxidative damage. The antioxidative activity of methanolic (MeOH) extract of the Agrimonia pilosa-Ledeb leaves on non-lipid oxidation, including liposome oxidation, deoxyribose oxidation, protein oxidation, chelating activity against metal ions, scavenging activity against hydrogen peroxide, scavenging activity against hydroxyl radical and 2'-deoxyguanosine (2'-dG) oxidation were investigated. The MeOH extract of the Agrimonia pilosa-Ledeb leaves exhibited high anti oxidative activity in the liposome model system. Deoxyribose peroxidation was inhibited by the MeOH extract of the Agrimonia pilosa-Ledeb leaves and MeOH extract of the Agrimonia pilosa-Ledeb leaves provided remarkable protection against damage to deoxyribose. Protective effect of MeOH extracts of the Agrimonia pilosa-Ledeb leaves on protein damage was observed at $600{\mu}g$ level (82.05%). The MeOH extracts of the Agrimonia pilosa-Ledeb leaves at $300{\mu}g$ revealed metal binding ability (32.64%) for hydrogen peroxide. Furthermore, the oxidation of 2'-deoxyguanosine (2'-dG) to 8-hydroxy-2-deoxyguanosine (8-OH-2'dG) was inhibited by MeOH extracts of the Agrimonia pilosa-Ledeb leaves and scavenging activity for hydroxyl radical exhibited a remarkable effect. From the results in the present study on biological model systems, we concluded that MeOH extract of the Agrimonia pilosa-Ledeb leaves was effective in the protection of non-lipids against various oxidative model systems.

• The Korea Journal of Herbology
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• v.32 no.4
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• pp.39-46
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• 2017

Objectives : This study aims to provide basic data about Portulacae Herba (PH) extracts as natural antioxidants by considering diverse antioxidant activities of PH depending on solvents. Methods : The samples of PH were pulverized, and A hot water and a 70% EtOH were stir-extracted for two hours three times repeatedly in a water bath with a temperature of 95 degrees and at room temperature respectively to measure 7 kinds of antioxidant activities. Results : There were significant differences in total phenol content, because the total phenol content of the 70% EtOH extract was higher than the hot water extract's, and the total flavonoid content of the 70% EtOH extract($4.40{\mu}g/mg$) was nearly 3.8 times higher than the hot water extract's($1.16{\mu}g/mg$). DPPH and ABTS radical scavenging activities were 70% EtOH extract showed a little higher activity than the hot water extract, and at a concentration of $500{\mu}g/mg$, the highest scavenging activity was found in the 70% EtOH extract, not in the control group. Hydroxyl radical and $Fe^{2+}$ chelatingactivities were slightly higher in hot water extract than in 70% EtOH extract, and increased in a dose-dependent manner. Nitrite scavenging activities increased dose-dependently in the hot water and the 70% EtOH extract, regardless of the pH level, and scavenging activity of the 70% EtOH extract was higher at pH 1.2 than at pH 3.0. Conclusions : In conclusion, it is thought that PH hot water and 70% EtOH extract have antioxidant activities, and can be used as natural antioxidants in future.

• Journal of Life Science
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• v.24 no.4
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• pp.386-392
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• 2014

Haw (Crataegus pinnatifida $B_{UNGE}$) is a medicinal plant commonly used in Korea due to its beneficial health effects. This study was performed to investigate the antioxidative activity of bioactive components from haw seed. Freeze-dried seed was processed with various solvents such as 70% methanol, 70% ethanol, a mixture of chloroform and methanol (2:1, v / v), n-butanol and ethyl acetate (EA). DPPH, reducing power, ferric reducing antioxidant power (FRAP), and ABTS radical scavenging activity decreased in this order: 70% methanol, 70% ethanol, EA, CM, n-butanol extracts. NO radical scavenging activity was high in the n-butanol extract (36.73% in 0.8 mg/ml concentration) and low in the 70% ethanol extract (24.96% in 0.8 mg/ml concentration). $OH^-$ radical scavenging activity of n-butanol extract (40.42% in 0.8 mg/ml concentration) was higher than the other extracts, but EA extract was the lowest (13.39%) at the same concentration. The results show that each extract contained various antioxidative substances and it seemed that different influence at each antioxidative activity.

• Journal of Life Science
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• v.23 no.5
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• pp.643-649
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• 2013

In this study, we examined the antioxidative activities of ethanol extracts obtained from three plants; Lithospermum erythrorhizon Siebold & Zucc., Xanthium strumarium Linn, and Lonicera japonica, which have traditionally been used as drugs in Eastern medicine in Korea. Their extraction yields were 7.01%, 2.92%, and 7.95% in Lithospermum erythrorhizon Siebold & Zucc., Xanthium strumarium L, and Lonicera japonica, respectively. The contents of the phenolic compounds were $4.3{\pm}0.1{\mu}g/ml$, $5.4{\pm}0.1{\mu}g/ml$, and $4.6{\pm}0.1{\mu}g/ml$ in Lithospermum erythrorhizon Siebold & Zucc., and Xanthium strumarium L, respectively. Furthermore, the radical scavenging activity measured through the DPPH assay appeared highest in the Lonicera japonica's extract, and its $EC_{50}$ was 0.24 mg/ml. Compared to the control, the xanthine oxidase inhibiting activities of all extracts were effective at 0.01 mg/ml concentration. Superoxide radical scavenging activity in Lithospermum erythrorhizon Siebold & Zucc. and Lonicera japonica was more than 80%, with a concentration of 50 mg/ml. OH radical scavenging activity was 40% in the three plants, with a concentration of 50 mg/ml scavenging activity. From our results, we demonstrated that the ethanol extracts of three medicinal plants have antioxidant activities and could be potential candidates for natural antioxidants.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.647-655
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• 2016

Lead dioxide ($PbO_2$) is an electrode material that is effective for organic pollutant degradation based on hydroxyl radical ($^{\bullet}OH$) attack. Representative parameters for $PbO_2$ electrodeposition are summarized to current, temperature, reaction time, concentration of Pb(II) and electrolyte agent. In this study, $Ti/PbO_2$ electrodes were fabricated by electrodeposition method under controlled reaction time, current density, temperature, concentration of $HNO_3$ electrolyte. Effects of deposition parameters on $^{\bullet}OH$ evolution were investigated in terms of electrochemical bleaching of p-Nitrosodimethylaniline (RNO). As major results, the $^{\bullet}OH$ evolution was promoted at the $PbO_2$ that was deposited in longer reaction time (1-90 min), lower current density ($0.5-50mA/cm^2$), higher temperature ($5-65^{\circ}C$) and lower $HNO_3$ concentration (0.01-1.0 M). Especially, the $PbO_2$ which was deposited in 0.01 M of lowest $HNO_3$ concentration by applying $20mA/cm^2$ for above 10 min was most effective on $^{\bullet}OH$ evolution. The performance gap between $PbO_2$s that was best and worst in $^{\bullet}OH$ evolution was about 41%. Among the properties of $PbO_2$ related on $^{\bullet}OH$ evolution performance, conductivity of $Ti/PbO_2$ significantly influenced on $^{\bullet}OH$ evolution. The increase in conductivity promoted $^{\bullet}OH$ evolution. In addition, the increase in crystal size of $PbO_2$ interfered $^{\bullet}OH$ evolution at surface of some $PbO_2$ deposits.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.323-326
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• 2019

The flowers of Coreopsis lanceolata were extracted with 80% aqueous MeOH and the concentrates were partitioned into EtOAc, n-BuOH, and H₂O fractions. The repeated silica gel (SiO₂) and octadecyl silica gel column chromatographies for the EtOAc fraction led to isolation of one flavonol and one benzoyl compounds. The chemical structures of the compounds were respectively determined as melanoxetin (1) and protocatechuic acid methyl ester (2) based on spectroscopic analyses including NMR, IR, and MS. These two compounds were isolated for the first time from C. lanceolata flowers in this study. All fractions and the isolated compounds were evaluated for 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activities.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.988-993
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• 2003

The ethyl acetate-soluble acidic fraction of juice, hot water, and MeOH extract of Allium fistulosum L. showed DPPH radical-scavenging activity. Each fraction was purified through silica gel adsorption column chromatography, and the active substances in the juice and hot water extract were identified as succinic acid, fumaric acid, 4-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxycinnamic acid, and 4-hydroxy-3-methoxycinnamic acid. For the MeOH extract, 4-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxycinnamic acid, and 4-hydroxy-3-methoxycinnmic acid were identified as the active substances by GC-MS. The contents of these compounds were determined by GC analysis, and their anti-oxidative activities were measured using the DPPH radical-scavenging assay. The results obtained showed that 4-hydroxy-3-methoxycinnamic acid was the dominant antioxidant in Allium fistulosum L.