• Food Science and Preservation
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• v.30 no.1
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• pp.170-178
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• 2023

We investigated the free radical scavenging and digestive enzyme inhibitory activities of the hot water extract of peach twig (Prunus persica L. Bastch). This extract of the peach twigs was further split up into n-hexane, ethyl acetate (EtOAc), and n-butyl alcohol(n-BuOH), which resulted in three solvent-soluble fractions. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) assay systems, while hypoglycemic effect of the peach twig extract and the solvent-soluble fractions were tested using α-glucosidase and α-amylase inhibition assays. Accordingly, the EtOAc layer showed a greater free radical scavenging activity compared to other solvent-soluble fractions. Furthermore, based on the α-glucosidase and α-amylase assays, the IC₅₀ values were determined to be 38.2±1.6 and 69.6±6.1 ㎍/mL for the EtOAc-soluble fractions, respectively. Taken together, these results suggest that the fractions obtained from the peach twig extract can be considered as a potential source of natural antioxidant and hypoglycaemic constituents.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.136-140
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• 2011

• Food Science and Preservation
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• v.14 no.6
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• pp.709-715
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• 2007

Korean green tea has been claimed to have health-promoting effects, which may be related to the antioxidant activity in vitro. Korean green teas (Woojeon, WJ ; Sejak, SJ ; Jungjak, JJ ; Daejak, DJ) were subjected to different harvested times and yet little research has examined their bioactive compounds. To assess the effect of this different harvested times on nutritional and health-related properties such as Korean green tea polyphenols, flavonoids, theanine and free amino acids, antioxidant activities and radical scavenging activities were determined. Total polyphenols in JJ (37.16 mg/g) was higher than in other products (WJ, 19.55 ; SJ 24.65 ; DJ, 23.28 mg/g). Contents of flavonol and flavone glycosides were the highest at DJ (350.83 mg%) as compared to WJ (220.81), SJ (256.88) and JJ (270.36 mg%). Contents of theanine and total free amino acids were the highest at WJ (14.11, 23.62 mg/g, respectively), but decreased thereafter. Antioxidant activities were higher in JJ and DJ, using the linoleic acid peroxidation, DPPH and ABTS free radical-scavenging activities. However, WJ and SJ had less active antioxidant activity and free radical-scavenging activity. Reducing powers were increased depend on the concentration of extracts. Antioxidant activity and free radical-scavenging activity of JJ and DJ seemed to relate with total polyphenol and flavonoid contents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.115-118
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• 2003

This study was conducted to determine optimal extraction condition and free radical scavenging effect of ethanol extracts of Campell Early grape seeds and skins at different temperatures, and of organic solvent fractionated from ethanol extracts of grape seeds and skins. The free radical scavenging effect was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and expressed as dose required for a 50% reduction of DPPH radical (RC$_{50}$). The extraction yields were increased with increasing the extraction temperature but it was not related with ethanol concentrations. The ethanol extract of grape seeds obtained at 5$0^{\circ}C$ showed the more stronger RC$_{50}$ (16.8 $\mu\textrm{g}$/mL) than those of both 3$0^{\circ}C$ and 78$^{\circ}C$. The ethylacetate fraction obtained from ethanol extract of grape seed showed the strongest RC$_{50}$ (15.4 $\mu\textrm{g}$/mL). Overall, both ethanol extracts and their fractions of grape seeds showed significantly stronger free radical scavenging effect than those of skin extracts.racts.

• Journal of Life Science
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• v.20 no.5
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• pp.768-774
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• 2010

In this study, we investigated the antioxidant activities, alcohol metabolizing activities, nitrite scavenging ability, angiotensin converting enzyme (ACE), and elastase inhibitory effects of hot water extract from Makgeoly (HWM). Antioxidant activities were measured by using 2,2.diphenyl.1.picryl.hydrazyl (DPPH) free radical scavenging activity and SOD (superoxide dismutase).like activity. The DPPH radical scavenging activity and SOD.like activity of HWM were remarkably increased in a dose.dependent manner and were 48.0% and 98.7% at 10 mg/ml, respectively. To determine the influence of HWM on alcohol metabolizing activity, the generating activities of reduced.nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured. The facilitating rates of ADH and ALDH activity by HWM were remarkably increased in a dose.dependent manner and were 70.2% and 64.1% at 10 mg/ml, respectively. The inhibitory activity against angiotensin converting enzyme (ACE) of HWM was increased in a dose.dependent manner and was 74.2% at 10 mg/ml. The nitrite scavenging ability of HWM showed the most remarkable effect at pH 1.2 and 2 mg/ml. These results indicated that HWM may have valuable biological properties owing to their antioxidant activities, ADH and ALDH activity, nitrite scavenging ability, and ACE inhibitory activity.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.539-546
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• 2016

The aim of this study was to analyze antioxidant activity, total phenolics, and vitamin C content in unripe and ripe jujube cultivar and to investigate correlation between antioxidant and chemical constituents including total phenolics and vitamin C. The antioxidant activity was measured by the DPPH radical scavenging activity, ABTS radical scavenging activity, and reducing power. Although, the weight, diameter and soluble solids of Zyziphus jujuba fruit were increased with the progress of ripening, antioxidant activity and total phenolics were decrease during ripening. The highest free-radical scavenging activity (at 2.5 ㎎/㎖) and reducing power (at 1 ㎎/㎖) in fruit were 81.75% (Bokjo, unripe) and 0.80 (Mudeung, unripe), respectively. The highest total phenolic content in unripe fruit of Mudeung was 62.50 ㎍/g. A linear correlation (r=0.911) was shown between DPPH radical scavenging activity and total phenolic content.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.928-935
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• 2000

This study was carried out to examine the antioxidative, antimicrobial and nitrite scavenging effects of various solvent extracts and different solvent fractions from Schizandra chinensis RUPRECHT(Omija) seed. The results were as follows; The antioxidative activities using lard, soybean oil and linoleic acid were the highest in methanol, ethanol and methanol extract from omija seed, respectively. The free radical scavenging activity using DPPH method was the strongest in acetate fraction of methanol extract from seed. The methanol extract from omija seed had the strongest antimicrobial activities to L. plantarum, B. subtilis, E. coli and P. citrinum, while ethyl acetate extract had the strongest against S. aureus and S. typhimurium. The buthanol fraction from methanol extract had the highest antimicrobial activities, followed by B. subtilis, L. plantarum, E. coli, S. aureus and S. typhimurium. The nitrite scavenging ability was pH dependent, highest at pH 1.2 and lowest at pH 6.0. The buthanol fraction of methanol extract from omija seed had more effective nitrite scavenging ability than other fractions of extracts.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.141-147
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• 2000

Interrelation between the antioxidative activity of hot-water extracts of 130 medicinal plants and their cellular antimutagenic activity was investigated. Antioxidative activity was evaluated by assaying electron-donation to DPPH free radical and scavenging of hydroxyl radical $({\cdot}OH)$ generated through Fenton rection, respectively. All medicinal plants examined in this study exhibited markedly electron-donating ability and radical scavenging ability in each assay system. The results demonstrated the fact that Pilbal (Piper longum L.) is the strongest in electron-donating activity, on the other hand, that Seokgok (Dendrobium moniliforme L.) is the strongest in ${\cdot}OH$ scavenging activity. When evaluated their antioxidative activities, 24 medicinal plants including Jimo (Anemarrhena asphodeloides Bunge) were found to be the medicinal plants carrying strong antioxidative activity, which exhibited more than 50% activity compared to the control group in both electron-donating and free radical scavenging. The experiment was also performed to examine whether 11 medicinal plants having significant antimutagenicity damage DNA in the presence of $Cu^{2+}$, showing the fact that all samples tested, except Taeksa (Alisma canaliculatum All. Br.), Paekjain (Nitraria sibirica Pall) and Ohyak (Lindera strychifolia Sieb. et Zucc. Villar) are capable of inducing DNA strand break. We also found that Taeksa and Paekjain strongly block DNA strand break induced by chemical mutagen mitomycin C.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.481-486
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• 2010

The nutraceutical role of omija (Schizandra chinensis Baillon) water extract (OWE) was determined through the analysis of antioxidant activity, nitrite scavening activity, and xanthine oxdiase and $\alpha$-glucosidase inhibitory effects. Antioxidant activity of OWE was measured by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and superoxide dismutase-like activity (SODA). DPPH radical scavenging activity and SODA increased in a dose-dependent manner, and was about 49.0% at 2.5 mg/mL and 69.2% at 5 mg/mL, respectively. The xanthine oxidase and $\alpha$-glucosidase inhibitory activities of OWE were about 88.8% and 86.2% at 1 mg/mL, respectively. Nitrite scavenging activity of OWE was about 54.9%, 42.4%, and 34.2% on pH 1.2, 3.0, and 6.0 at 1 mg/mL, respectively. These results suggest that OWE has a strong antioxidant activity, and xanthine oxidase and $\alpha$-glucosidase inhibitory effects.

• Journal of Life Science
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• v.18 no.3
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• pp.357-362
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• 2008

The dried roots of Aralia continentalis Kitagawa is known to have the potential for anti-inflammation and anti-rheumatic, but their effects on thrombosis are not clear. In this study, we evaluated the anti-platelet and antioxidative activities of A. continentalis Kitagawa. Methanol extract and its various fractions of A. continentalis Kitagawa inhibited ADP-induced platelet aggregation, and EtOAc fraction showed strongest inhibition in a concentration-dependent manner with a $IC_{50}$ value of 217.7 ${\mu}g/ml$. Moreover, the EtOAc fraction contained 77.7% of 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 43.1% of 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity at 0.1 mg/ml. In addition, the methanol and EtOAc fraction dose-dependently inhibited thrombin-stimulated platelet adhesion to collagen or fibrinogen. Collectively, these results suggest that the polyphenol-rich EtOAc fraction from A. continentalis Kitagawa can reduce platelet hyperactivation by scavenging free radicals. Thus, the EtOAc fraction of A. continentalis Kitagawa is a potential source for inhibition of platelet-dependent thrombosis.