• Natural Product Sciences
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• 제17권2호
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• pp.65-79
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• 2011

Reactive oxygen species potentially cause damage to cellular components including lipids, protein and DNA; this oxidative damage plays a key role in the pathogenesis of neurodegenerative disease, cardiovascular disease, metabolic disease and cancer. On the basis of the oxidative stress hypothesis, a number of studies have been performed to search for an efficient and safe antioxidant. Although in vitro studies have provided promising results, only a limited number of natural and synthetic antioxidants have been developed for clinical application due to their low efficacy and side-effects. Thus, the discovery of new antioxidants with marked efficacy and safety has attracted worldwide attention in recent decades. Since plants are recognized as important sources of natural antioxidants, our research has focused on the discovery of new naturally occurring antioxidants from medicinal plants. The purpose of this review is to open a new prospect in the field of search for natural antioxidants from medicinal plants by summarizing our recent findings. Using in vitro bioassay systems such as 2,2-diphenyl-1-picrylhydrazyl, superoxide radical scavenging tests and lipid peroxidation models, we have tested over than 350 species of medicinal plants for their antioxidant activity and selected several of them for further investigation. During the research on the discovery of effective natural antioxidants from the medicinal plants selected, we have isolated several new and known antioxidant compounds that include stilbene glycosides, phenolic glycosides, flavonoids, oligostilbenes, and coumarins. Our results suggest that the presence of antioxidant compounds in the medicinal plants might be associated with the traditional use to treat inflammation, cardiovascular disease and various chronic diseases.

• 한국자원식물학회지
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• 제25권4호
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• pp.363-371
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• 2012

본 연구에서는 딱총나무의 항산화 활성을 조사해 보았다. 딱총나무 잎과 줄기의 물추출물에는 6.6 mg/g과 2.0 mg/g의 phenolic compound가 함유되어 있었다. 추출물의 항산화 활성 실험에서 전자공여능은 딱총나무 잎의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 99.5%, 89.7%, 줄기의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 92.2%, 94.3%의 높은 항산화 효과를 나타내었다. 또한 ABTS radical cation decolorization 측정에서도 딱총나무 잎의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 79.8%, 99.1%, 줄기의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서 90.8%, 97.2%의 매우 높은 항산화 효과를 나타내었다. Antioxidant protection factor에서는 딱총나무 잎의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 1.1과 1.1 PF, 줄기의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 1.4와 1.0 PF의 항산화효과를 나타내었다. Thiobarbituric acid reaction substance 측정에서도 딱총나무 잎의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 88.7%, 98.1%, 줄기의 물과 에탄올 추출물 phenolic 200 ${\mu}g/mL$의 함량에서는 93.6%, 90.6%로 positive control인 BHT 및 vitamin C보다 우수한 항산화 효과를 나타내었다. 본 연구의 결과로 딱총나무의 항산화 활성을 이용한 천연 기능성 식품소재로서의 활용이 가능할 것으로 판단되었다.

• 한국환경보건학회지
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• 제5권1호
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• pp.21-24
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• 1978

This study was conducted to find out the co-operative effect of antioxidants (butyl hydroxy anisol, dibutyl hydroxy toluene, propyl gallate, dl-$\alpha$-tocopherol) and organic acid (citric acid, tartaric acid, succinic acid) on the stability of soybean oil by active oxygen method. The results obtained were summarized as follows: 1. When antioxidants and organic acid were used together, the antioxidants activity was more strong than antioxidants were used only. 2. The co-operative effect of citric acid for antioxydants was the strongest whereas succinic acid was the weakest. 3. The co-operative effect of phenolic antioxydants for organic acid was more strong than dl-$\alpha$-tocopherol.

• 대한화학회지
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• 제24권5호
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• pp.337-341
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• 1980

페놀계 산화방지제들의 라디칼 생성반응을 분자궤도론적으로 고찰하였다. 결과로 페놀계 산화방지제는 전자공여성인 알킬기의 치환으로 phenoxy 라디칼 생성이 용이해지며, 따라서 산화방지 능력이 증가함을 알았다. 이것은 electrophilic 라디칼의 작용으로 형성되는 양이온을 안정화시켜 주기 때문임을 밝혔다

• 한국작물학회지
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• 제49권2호
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• pp.116-120
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• 2004

In order to investigate low molecular antioxidants synthesized by enhanced UV-B radiation, we used the seedlings of two rice varieties. Woonjangbyeo, UV-tolerant, and Hwajoongbyeo, UV-susceptible, were subjected under supplemental UV-B irradiation. When rice seedlings were irradiated with UV light for short period, biosynthesis of total phenolic compound, ascorbate and glutathione were momently reduced. With an increase of UV-B radiation, however, those were slightly synthesized. The content of lipid peroxides in UV-challenged rice leaves was considerably increased after 12 hrs of UV-B treatment. Lipoxygenase activity under supplemental UV-B radiation was differently responded on rice varieties.

• 생약학회지
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• 제41권2호
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• pp.130-135
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• 2010

This study was performed to the activity of antioxidant and anti-diabetic from Zanthoxylum schnifolium fruit. The Zanthoxylum schnifolium fruits were extracted with water, 100% methanol, 100% ethanol, 70% methanol and 70% ethanol. The activities of each extracts were measured by antioxidant tests, such as total phenolic contents, total flavonoid contents, hydroxyl radical activity, DPPH radical scavenging activity, reducing power and $\alpha$-glucosidase inhibition activity assay. The water extract represented the highest activity in the antioxidants properties in vitro, including hydroxyl radical activity, DPPH radical scavenging activity, reducing power. Furthermore, water extract also showed significantly high total phenolic contents but the 100% methanol extract showed high total flavonoid contents estimated as $196.48{\mu}g/mg$. The $IC_{50}$ values for $\alpha$-glucosidase inhibition activity of the 100% ethanol and 100% methanol extracts were $275.66{\mu}g/mg$ and $261.44{\mu}g/mg$. Our results indicated that the Zanthoxylum schnifolium fruit expected to be useful as antioxidants.

• 셀메드
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• 제5권2호
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• pp.14.1-14.6
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• 2015

Antioxidative and free radical scavenging properties of different stem extracts of Euphorbia trigona were evaluated and correlated with its total phenolic content. Aqueous, acetone and methanolic extracts of shade dried stem were obtained and were concentrated in vacuo. The antioxidant and free radical scavenging activities of stem extracts was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, reducing power assay, deoxyribose degradation assay and $Fe^{2+}$ chelating assay. Total phenolic contents (TPC) were evaluated using Folin-Ciocalteu reagent. The results confirmed that the plant is a rich source of polyphenolic compounds which are invariably higher compared to other herbs. All extracts showed TPC in the range of 146.6 - 168.6 mg/g gallic acid equivalents at $300{\mu}g/ml$ of extract. Among the three extracts ME showed highest scavenging activity as evidenced by maximum scavenging of DPPH (83.2%), $OH{\bullet}$ radicals (94.81%), $Fe^{2+}$ chelating activity (88.59%) and a high reducing power 0.623 at $300{\mu}g/ml$. Our results demonstrate that Euphorbia trigona, an unexplored xerophytic plant could be potential source of natural antioxidants and phytotherapeutic agents. The plant possess invariably high amount of polyphenolic compounds with a broad spectrum of antioxidant properties and could be further used for food, feed and pharmaceutical applications.

• Preventive Nutrition and Food Science
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• 제4권4호
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• pp.221-225
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• 1999

Antioxidative compounds contained in roasted safflower seeds were investigated. Six phenolic compounds, N-feruloylserotonin, N-(p-coumaroyl) serotonin, matairesinol, 8'-hydroxyarctigenin, acacetin 7-Ο-β-D-glucoside(tilianine) and acacetin were isolated and identified from the extract of seeds. The inhibitory effects of six phenolic compounds on 1,1-dipheny1-2-picrylhydrazyl(DPPH) radical and lipid peroxidation induced by H₂O₂/FeSO₄in rat liver microsomes were determined. Two serotonins showed more potent DPPH radical scavenging activity, and a stronger inhibitory effect on the lipid peroxidation than that of α-tocopherol. In addition, acacetin and matairesinol also considerably inhibited lipid peroxidation, while 2-hydroxy-arctigenin and tilianine were inactive. These results suggest that phenolic compounds, including serotonins, lignans and flavonoids in the roasted safflower seeds can be used as potential dietary natural antioxidants.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.827-831
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• 2007

Bioassay-directed fractionation of Draba nemorosa led to the isolation of two new phenolic glycosides, 1-O- (sinapoyl)-glucitol (2) and 1,3-disinapoylgentiobiose (5) along with five known phenolic glycosides (1, 3, 4, 6, and 7). Their structures were characterized based on spectroscopic methods (2D NMR, HRTOFMS, IR, and UV). The isolated compounds showed antioxidant activities (IC50) in the range of 14-98 mM which were estimated by DPPH radical-scavenging assay.

• 한국작물학회지
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• 제50권5호
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• pp.336-339
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• 2005

Common thistle contains water-soluble substances that are antioxidative to foods. Antioxidant activities measured by DPPH method for the ground samples were the greatest in leaves, although was less than that of commonly used antioxidants, BHT and ascorbic acid. Methanol extracts and fractions from Xanthium occidentale plants dose-dependently increased DPPH free radical scavenging activity, in vitro test. The extracts from leaves showed the strongest antioxidant activity. DPPH scavenging activity of the individual fraction was in order of n-butanol>water>ethyl acetate>n-hexane fraction. By means of HPLC analysis, leaf samples of Xanthium occidentale had the highest amount of phenolic compounds, related with antioxidant activity, and followed by stems and roots. Total content of these antioxidant phenolic com­pounds for leaves extracts were detected in water fraction (36.7 mg 100 $g^{-1}$) as the greatest amount, especially chlorogenic acid (39.4 mg 100 $g^{-1}$) was the greatest component. These results suggest that Xanthium occidentale plants had potent antioxidant activity, and their activities were differently exhibited depending on plant part and fraction.