• Journal of the Korean Wood Science and Technology
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• 제34권2호
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• pp.88-94
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• 2006

The purpose of this study is to examine the relationship between antioxidant activities and chemical structures of various chalcones. Twenty-two chalcones were assessed for their radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Of 22 compounds tested, the most active on DPPH radical was 2',4-dihydroxy-3,3'5-trimethoxy-5'-propylchacone (4) (72.6% at 100 ppm). It was followed by 3',4'-dihydroxy-3,4,5-trimethoxy-6'-methylchalcone (6), 2',4,4'-trihydroxy-3-methoxy-5-propenylchalcone (7) and 2',4,4'-trihydroxy-3,5-dimethoxychalcone (13). Based on the results, we concluded that the scavenging activity is controlled by the number and the position of the substitution in the compound.

• 대한화장품학회지
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• 제15권1호
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• pp.1-36
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• 1989

The protective effects of 24 flavonoids against singlet oxygen - induced photohemolysis of rabbit erythrocytes were investigated and compared with their antioxidant activities. 1. All the flavonoid aglycons investigated besides flavone and 7,8-benzoflavone showed tad dose-dependant Protective effects. Especially galagin showed the most Pronounced effect under the experimental condition. 2. The order of the radical-scavenging activities of flavonoids was as follow (-)-EGCG > flavonols > flavonols > flavones > flavanonols. The radical-scavenging activities of flavonoid glycosides were not different from those of their aglycons. 3. When added after irradiation, flavonoids did not alter the photohemolysis pattern of control. In this study, several antioxidant were found and it was newly found that Photohemolysis experiment is a convenient, reproductive diagnostic method in the screening and researching the compound which has antioxidant activity or protective effect on cell membrane against active oxygen species.

• Journal of Ginseng Research
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• 제13권2호
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• pp.189-197
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• 1989

A new quaternary ammonium compound, hydrolyzed ginseng-saponin quaternary (HGSQ), from Korean ginseng saponin and 2,3-epoxypropyltrimethylammonium chloride has been developed as a conditioning agent in cosmetics. This structure has a hydrophobic group from the aglycone of ginseng saponin which is biologically active and considered to be the most important component of the Korean ginseng. Its properties : surface tension, critical micelle concentration (CMC), eye irritation, sorption onto hair, force reduction(%) and moisture retention effect were studied. Its cationic character allows the molecule to be more substantive than ginseng saponin. HGSQ had good physical properties and was safe. enough as a cosmetic raw material. Also half-head tests of HGSQ-containing shampoo were carried out to compare the conditioning effects in shampoos. HGSQ was an excellent conditioning agent in shampoo..

• Biomolecules & Therapeutics
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• 제18권2호
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1472-1478
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• 2008

The synthesis of a new series of 1$\beta$-methylcarbapenems having spiro[2,4]heptane moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents at the pyrrolidine ring was investigated. Most of the compounds were found to be more active compared to imipenem against Gram-negative bacteria. A particular compound (IIIc) having 7-oxo-5- azaspiro[2,4]heptane moiety showed the most potent antibacterial activity.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.322-328
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• 1993

During the screening of antifungal compounds from microbial secondary metabolites to control phytophthora blight of red pepper caused by Phytophthora capsici, a soil isolate, strain 38D10 was selected. Based on taxonomic studies, this strain was identified as Streptomyces neyagawaensis. The antifungal compound was purified from culture broth by HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, HPLC and identified as concanamycin B by UV. $^1H$-NMR, $^{13}C$-NMR, SIMS analysis. Concanamycin B has strong antifungal activity against some phytopathogenic fungi but not antivacterial activity and preventive value were 50% and 100% at 125ppm and 250ppm in pot assay.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.217-217
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• 1994

Calcium entry blockers, capable of inhibiting transmembrane influx of extracellular calcium through specific calcium channels, are useful drugs in the treatment of angina pectoris, hypertension, cardiac arrythmia, and various cardiovascular disorders. Compounds having isoquinoline structures have recently been reported to possess calcium antagonistic action. Therefore, in the present study, we have attempted to synthesize some isoquinoline and related compound.; in order to search for potentially effective chemicals acting on cardiovascular system, and evaluated their pharmacological properties focusing on calcium antagonistic actions. Almost all of the compounds so far synthesized, had inhibitory action against phenylephrine or high potassium-induced contraction in vascular smooth muscle with different degrees of potencies depending on their structures, However, some of tetrahydroisoquinoline analogs showed directly inhibit calcium current in isolated rabbit cardiac myocytes examined by patch clamp techniques. The pharmacological properties of these compounds need more intensive investigation as to whether these chemicals may have developed as a new cardiovascular active drugs. Therefore, we are now under investigation of the mechanism of action of these compounds.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.41-49
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• 1994

The most common conventional method of discovering a drug involves a massive screening of a large number of compounds in chemical libraries or in the extracts from natural sources such as plants or microbial broths followed by chemical modification of one or more active compounds to improve their properties as a drug. When the three-dimensional structure of the target molecule for which the drug is searched is known the drug discovery process can be significantly simplified, This is especially true when the three-dimensional structure of a complex between the target and a lead compound is known. In this lecture our experience on the structure-based drug design for human CDK2(cyclin-dependent protein kinase 2) will be discussed with special emphasis on the strength and weakness of this approach of drug discovery. The regulation of the activity of CDK2 plays an important role in the cell proliferation of normal and cancer cells.

• Biomolecules & Therapeutics
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• 제11권1호
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• pp.5-7
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• 2003

The purpose of this study was to evaluate tyrosinase inhibitory activity of plant for extracts for cosmetic use. When 80 plant extracts were tested, the methanol extracts of Allium thunbergi, Asparagus oligoclonos, Ixeris dentate, Salvia plebeia, Sophora flavescens and Sophora japonica showed more than 30% inhibition of mushroom tyrosinase activity at 100 $\mu\textrm{g}$/mL. Although less active than the reference compound, kojic acid ($IC_{50}$=7.0-16.3 $\mu\textrm{g}$/mL), these plant extracts may be used as tyrosinase inhibitors in cosmetics.

• 생약학회지
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• 제45권1호
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• pp.35-40
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• 2014

In this study, in order to search for new functional materials from natural products, was carried out the study of antioxidant active ingredients in persimmon calyx(calyx of Diospyros kaki Thunberg). I have experimented with the effect of antioxidant activity of five different extract(MeOH, n-hexane, EtOAc, n-BuOH and $H_2O$ extract) obtained from persimmon calyx. As a result, the butanol extract, that is the main component fraction of antioxidant activity was found. Three compounds were isolated by silica gel column chromatography from the n-BuOH extract of persimmon calyx. Their structures of compound 1, 2 and 3 isolated from n-BuOH extract of persimmon calyx were identified as quercetin, (+)-catechin and gallic acid by using the TLC, $^1H$-NMR and $^{13}C$-NMR.