• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.874-880
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• 2010

A series of 13- and 14-membered cyclic enkephalin analogs based on the moderately $\mu$ selective prototype compound Tyr-C[D-$A_2bu$-Gly-Phe-Leu] 8a were synthesized to investigate the structure-activity relationship. The modifications of sequence were mainly focused on two positions 3 and 5, critical for the selective recognition for $\mu$ and $\delta$ opioid receptors. The substitution of hydrophobic $Leu^5$ with hydrophilic $Asp^5$ derivatives led to Tyr-C[D-$A_2bu$-Gly-Phe-Asp(N-Me)] 7 and Tyr-C[D-Glu-Phe-gPhe-rAsp(O-Me)] 5, the peptides with a large affinity losses at both $\mu$ and $\delta$ receptors. The substitution of $Phe^3$ with $Gly^3$ led to Tyr-C[D-Glu-Gly-gPhe-rLeu] 3 and Tyr-C[D-Glu-Gly-gPhe-D-rLeu] 4, the peptides with large affinity losses at $\mu$ receptors, indicating the critical role of phenyl ring of $Phe^3$ for $\mu$ receptor affinities. One atom reduction of the ring size from 14-membered analogs Tyr-C[D-Glu-Phe-gPhe-(L and D)-rLeu] 6a, 6b to 13-membered analogs Tyr-C[D-Asp-Phe-gPhe-(L and D)-rLeu] 1, 2 reduced the affinity at both $\mu$ and $\delta$ receptors, but increased the potency in the nociceptive assay, indicating the ring constrain is attributed to high nociceptive potency of the analogs. For the influence of D- or L-chirality of $Leu^5$ on the receptor selectivity, regardless of chirality and ring size, all cyclic diastereomers displayed marked $\mu$ selectivity with low potencies at the $\delta$ receptor. The retro-inverso analogs display similar or more active at $\mu$ receptor, but less active at $\delta$ receptor than the parent analogs.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1814-1822
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• 2018

Most people use cosmetics to protect their skin. Preservatives are often used to prevent their contamination upon use. There has been a great demand for natural preservatives due to recent reports on the side effects of parabens. Therefore, we evaluated the antimicrobial activities of Lonicera japonica and Magnolia obovata extracts and determined their potential as natural preservatives. We found that the 50% ethanol extract from L. japonica had antibacterial activity only against S. aureus and P. aeruginosa, while the ethyl acetate fraction showed antimicrobial activity against all six microbial strains tested. On the other hand, the 70% ethanol extract and the ethyl acetate fraction from M. obovata showed antimicrobial activity against all six strains. A synergistic effect against S. aureus, B. subtilis, and C. albicans was confirmed when two ethyl acetate fractions having antimicrobial activity against all six strains were used in combination. Synergistic activity against B. subtilis was also confirmed through kill-time analysis. High-performance liquid chromatography was performed to identify the components of each extract. Based on the minimum inhibitory concentration and the results of a disc diffusion assay, we confirmed that caffeic acid and luteolin influenced the antimicrobial activity of L. japonica and that the antimicrobial activity of M. obovata was influenced by the interaction of magnolol and honokiol with other components. Therefore, this study suggests that the combination of L. japonica and M. obovata extracts may be used as a plant-derived natural preservative.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.1
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• pp.75-81
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• 2013

Chrysin (5,7-dihydroxyflavone) is a natural flavonoid found in various plants and foods such as propolis and honey. It has been reported that chrysin has various biological effects including antioxidant, anti-aging, anti-inflammatory and anti-cancer. In this study, we investigated the effect of chrysin on the transcriptional activity of VDR in human epidermal keratinocytes by performing dual-luciferase assay. Chrysin significantly induced the transcriptional activity of VDR in a concentration-dependent manner. The VDR mRNA expression was investigated by quantitative real time PCR and chrysin increased the VDR mRNA expression in normal human epidermal keratinocytes. We also found that chrysin increased the expression of keratinocyte differentiation markers such as keratin 10, involucrin and filaggrin. Therefore, the results suggest that chrysin can stimulate the differentiation of human keratinocytes by increasing transcriptional activity of VDR.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2375-2378
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• 2010

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.522-523
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• 2006

• Applied Biological Chemistry
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• v.44 no.1
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• pp.35-37
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• 2001

• YAKHAK HOEJI
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• v.53 no.5
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• pp.298-302
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• 2009

Mume Fructus extract is used in folk medicine in Eastern Asian countries including Korea. However, its therapeutic effect on thrombosis is not known. Mume Fructus methanol extract (ME) dose-dependently inhibited ADP-induced platelet aggregation and also exhibited about 130% fibrinolytic activity compared to the natto. Oral administration of ME to mice significantly extended tail-bleeding time. ME prolonged both aPTT and PT in human citrated plasma also. These results suggest that the methanol extract from Mume Fructus have antithrombosis activity.

• Proceedings of the Technology Innovation Conference
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• 2002.06a
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• pp.238-256
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• 2002

Competitiveness of a nation can be explained by the concept of national innovation systems(NIS). As components of NIS, industry clusters become the issue in analysing innovative activity of an economy. Innovative clusters can be identified by the innovation survey or other economic activity data. Input-output Table was used widely as a tool for quantitative analysis, This paper classifies seven clusters in Korean industry based on inter-industries trade of intermediary goods and services, Maximizing procedure method is used in analysing input-output table. Identified clusters are Textiles/chemicals, Construction/Material, Instrument/Equipment, Automobile, Services, Energy, and Agriculture/Food cluster, Among these clusters, some different characteristics in R&D portfolios are detected. R&D investment characteristics of each cluster give us significant implications in understanding innovative dynamics of Korean industry.

• YAKHAK HOEJI
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• v.34 no.6
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• pp.434-438
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• 1990

The methanolic extract of the root-bark of Morus alba L.(Mulberry tree) has the potent antibacterial activity against Streptococcus mutans. Its active component was identified to be sanggenon C. The active component had stronger anti-bacterial activity than berberine, having minimum inhibitory concentration(MIC) of $25\;{\mu}g/ml$. Moreover, the inhibitory effect of this component on the cellular adherence of Streptococcus mutans to glass surfaces also was more remarkable than that of berberine in the presence of glucosyltransferase(GTase) and sucrose in vitro. These results indicate that sanggenon C may play an important role in inhibiting plaque formation and caries incidence.

• Natural Product Sciences
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• v.7 no.2
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• pp.45-48
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• 2001

The antioxidative effect of the extracts from the leaves and fruits of Acer ginnala against free radicals was studied by two different methods using DPPH radical-generating system, and hydroxyl radical-generating system $(Cu^{++}/H_2O_2\;system)$ which induces DNA strand breaking. Compared with well known antioxidative plants, green tea, Scutellaria baicalensis, the Acer ginnala extracts showed excellent radical-scavenging activity in DPPH radical-generating system and inhibited effectively hydroxyl radical induced-DNA strand breaking in a concentration-dependent manner in $Cu^{++}/H_2O_2$ system whereas the green tea extract stimulated the strand breaking at a low concentration. These results suggest that he extracts from the leaves and fruits of Acer ginnula could be good antioxidative agents.