• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.148-152
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• 2006

Comparison of four phenolic compounds among three different parts of Panax ginseng C.A. Meyer was performed in this study. Contents of esculetin, p-coumaric acd, quercetin, maltol in the ethyl acetate fraction were determinated by HPLC analysis. The main root has a highest concentration of p-coumaric acid and the leave has a highest concentration of quercetin and esculetin. This ethyl acetate fraction of the leaves exhibited higher depigmenting activity and lower cell toxicity than the other parts of ginseng. In addition, it showed that quercetin and esculetin among phenolic compounds highly inhibited melanin biosynthesis in ginseng. It implies that leaves of ginseng may be used as skin whitening herb. Quercetin and esculetin proved to be active compounds in the leaves of ginseng.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.355-362
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• 2010

In this study, the anticoagulant compounds in Korean red ginseng (KRG) were investigated. KRG powder was extracted using hot methanol, and the methanol extract was fractionated into n-hexane, ethylacetate, n-butanol, and aqueous fractions by solvent partitioning. The remains from the methanol extraction were further extracted with water and then dialyzed to obtain low and high molecular weight fractions. The anticoagulant activities of the seven fractions were evaluated in terms of thrombin time, prothrombin time, and activated partial thromboplastin time. Among these fractions, the ethylacetate fraction showed the most potent anticoagulant activity. The active components in the ethylacetate fraction were identified as the phenolic compounds vanillic, caffeic, ferulic, and p-coumaric acid via TLC and HPLC. These findings suggest that the anticoagulant activities of phenolic compounds contribute to the cardiovascular effects of KRG.

• Korean Journal of Medicinal Crop Science
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• v.18 no.6
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• pp.373-378
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• 2010

In order to obtain basic data for utilization of the aerial parts of Cnidium officinale Makino (APCO), the antioxidant properties of the aerial parts and rhizomes of C. officinale were measured using DPPH and ABTS radicals, and nitrite scavenging assays. The ethyl acetate (EA) fraction prepared from the aerial parts of APCO showed the strongest antioxidant activities, and contained high level of total phenolic compounds (325.81 mgTE/g) and flavonoids (259.16 mgRE/g). The concentrations for 50% reductions ($RC_{50}$) values of the DPPH and ABTS radicals, and nitrite by the EA fraction of APCO were $11.27\;{\mu}g/m{\ell}$, $14.34\;{\mu}g/m{\ell}$, and $10.26\;{\mu}g/m{\ell}$, respectively. APCO exhibited approximately 3-9 times higher antioxidant activity than rhizomes of C. officinale. The antioxidant capacities of APCO were positively correlated with its total phenolic contents. Therefore, it was concluded that the aerial parts of C. officinale can be a useful and cost-effective source of natural antioxidant for food or cosmetics.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.220-223
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• 2013

In the course of screening tyrosinase inhibitory activity, total methanolic extract and EtOAc-soluble fraction of Smilax china leaves showed significant inhibitory activity. Further fractionation and isolation of the EtOAc-soluble fraction resulted in 12 phenolic compounds, which were identified as 4-hydroxybenzoic acid (1), 3,4-dihydroxybenzaldehyde (2), 3,4-dihydroxybenzoic acid (3), 3,4-dihydroxyacetophenone (4), 3-hydroxy-4-methoxy benzoic acid (5), trans-p-hydroxycinnamic acid (6), cis-p-hydroxycinnamic acid (7), trans-resveratrol (8), cis-resveratrol (9), dihydroresveratrol (10), moracin M (11) and kaempferol (12). Compounds 1-11 were first reported from this plant. Among the isolated compounds, compounds 2, 8, 9 and 12 showed strong inhibition on tyrosinase activity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.143-146
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• 2004

Pultrusion process of phenolic foam composite is investigated. Phenolic foam composites provide heat and flame resistance with less weight. When made into foam, a variety of properties can be obtained with different bubble size and number density. In this study, effect of process variables on the foaming characteristics of phenolic resin composites during pultrusion process has been studied experimentally. The process variables considered are the heating temperature and the pulling speed as well as the mass fraction of blowing agent. Experiments were performed using a laboratory scale pultrusion apparatus. Optimal process condition was found by observing the micro-morphology.

• Macromolecular Research
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• v.13 no.3
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• pp.194-205
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• 2005

The network structure of Ni-coated carbon black (NCB) composites filled with phenolic resin was investigated by means of using scanning electron microscopy, viscosity, interfacial tension, shrinkability, Flory-Huggins interaction parameters, and swelling index. The electrical properties of the composites have been characterized by measurement of the specific conductivity as a function of temperature. Additionally, the variation of conductivity with temperature for the composites has been reported and analyzed in terms of the dilution volume fraction, relative volume expansion, and barrier heights energy. The thermal stability of phenolic-NCB composites has been also studied by means of the voltage cycle processes. The experimental data of EMI wave shielding were analyzed and compared with theoretical calculations. The mechanical properties such as tensile strength, tensile modulus, hardness and elongation at break (EB) of NCB-phenolic resin composites were also investigated.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.186-192
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• 1990

This study was conducted to further purify and characterize a polysaccharide fraction from whole parts of Duchesnea indica (Andr.) Focke, which was previously reported to show an antitumor activity by us. Mild acid-treatment of the fraction by 5% acetic acid yielded three subtractions (Fr. A,B and C) on a Sephadex G-25. Fr. A was composed of uronic acid, hexose, pentose and phenolic substance, Fr. C mainly phenolic substance, and Fr. B contained hexose. All three fractions exhibited colony stimulating factor activity.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.1-5
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• 2015

In the course of screening tyrosinase inhibitory activity, EtOAc-soluble fraction of Nelumbinis Semen (Seeds of Nelumbo nucifera) showed significant inhibition. Further fractionation of the EtOAc-soluble fraction resulted in 12 compounds, which were identified as 4-(hydroxymethyl)phenol (1), tyrosol (2), 4-(hydroxymethyl)benzaldehyde (3), 4-hydroxybenzoic acid (4), 4-(2-methoxyvinyl)benzene-1,2-diol (5), 2,6-dihydroxybenzoic acid (6), (2R-trans)-2,3-dihydro-3,5,7,8-tetrahydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (7), (+)-catechin (8), elephantorrhizol (9), (+)-dehydrovomifoliol (10), (-)-boscialin (11) and uridine (12). Compounds 5 and 7 were first reported from this plant. Among the isolated compounds, compound 7 showed strong inhibition on tyrosinase activity with mixed mechanism of competitive and noncompetitive inhibition.

• Korean Journal of Medicinal Crop Science
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• v.25 no.1
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• pp.10-15
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• 2017

Background: We investigated the antioxidative and tyrosinase inhibitory activities of 70% ethanol extract, and its fractions, of the root of Rumex japonicus HOUTT. Methods and Results: The total phenolic compound contents of the 70% ethanol extract and ethyl acetate fraction were 168.99 mg/g and 651.78 mg/g, respectively. The antioxidant activity was compared through the DPPH radical and nitric oxide (NO) scavenging assays. The ethyl acetate fraction showed the highest DPPH radical and NO scavenging abilities, which confirmed the antioxidant activity. Specifically, the ethyl acetate fraction showed a higher DPPH radical scavenging ability than ascorbic acid. These results were related to the total phenolic compound content of the ethyl acetate fraction. Moreover, in the tyrosinase inhibition assay, the ethyl acetate fraction exhibited stronger inhibitory activity than arbutin, which was used as the positive control. The cell viability of L929 cells was analyzed by MTT assay after treatment with 70% ethanol extract and all fractions; no changes in viability were observed, which demonstrated the nontoxic nature of the extract and fractions. Conclusions: These results suggested that the extract from the root of R. japonicus and its ethyl acetate fraction could be a novel resource for the development of a cosmetic with antioxidant and tyrosinase inhibitory activity.

• Archives of Pharmacal Research
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• v.4 no.1
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• pp.53-58
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• 1981

The effective components of Korean ginseng showing the lipid-peroxide depressing activity were isolated. From the ether-soluble acidic fraction of fresh ginseng three phenolic acids were obtained. Salicylic acid and vanilic acid exhibited the potent antioxidant activity, where p-hydroxycinnamic acid did not.