• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.269-275
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• 2010

P-gp plays a critical role in drug disposition and represents a mechanism for the development of multidrug resistance. Flavonoids, a major class of natural compounds widely present in foods and herbal products, have been shown to inhibit P-gp. Therefore, the aim of this study was to identify new candidate chemosensitizers by screening various plant extracts. The ability of natural plant extracts to inhibit P-gp activity was assessed by measuring cellular accumulation of calcein AM, daunorubicin and vincristine in P-gp overexpressing MDCKII-MDR1 cells. Among more than 800 plant extracts, eight were found to inhibit P-gp activity. Curcuma aromatica extract produced greatest inhibition, followed by Curcuma longa and Dalbergia odorifera extracts. Extracts of Aloe ferox, Curcuma zedoariae rhizome, Zanthoxylum planispinum, and Ageratum conyzoides showed moderate inhibitory effects. Curcumin and quercetin exhibited similar inhibition of P-gpmediated efflux of daunorubicin and vincristine, and flavones had a lesser effect. When chemosensitizing effect was evaluated by measuring daunorubicin sensitivity to MDCKII-MDR1 cells in the presence of natural plant extracts, Curcuma aromatica showed the most potent chemosensitizing effect based on daunorubicin cytotoxicity. In conclusion, natural plant extracts such as Curcuma aromatica can potently inhibit P-gp activity and may have potential as a novel chemosensitizers.

• Natural Product Sciences
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• v.14 no.1
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• pp.32-36
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• 2008

The antimicrobial activity of seventy five ethanol extracts obtained from 67 different kinds of plant species of the Mongolian flora were evaluated by means of the disc diffusion method against five species of microorganisms, Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, Micrococcus luteus and Pseudomonas aeruginosa. Among the plant extracts examined, 34 kinds of extracts demonstrated significant antibacterial activity against one or more species of microorganisms, respectively. Especially, the root extract of Paeonia anomala, the whole herb extract of Myricaria alopecuroides, the whole herb extract of comarum zalesovianum, the whole herb extract of Agrimonia pilosa and some other plant extracts demonstrated a particularly potent antimicrobial activity. The ethylacetate fractions obtained from the whole herb extract of Myricaria alopecuroides and from those of Sedum aizoon, Paeonia anomala, Sedum hybridum and Dasiphora fruticosa exhibited a particularly potent antibacterial activity especially against Staphylococcus aureus and Micrococcus luteus.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.227-231
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• 2007

Many of antimicrobial components used in the mouthwash have disadvantages such as coloring of periodontal tissue and homing sensation. To find the more biocompatible antimicrobial agent, we have screened the 2,125 kinds of natural plant extracts obtained from by the Plant Extract Bank (Daejeon, Korea). The antimicrobial activity was determined by spectrophotometric growth inhibition assay for the major dental pathogens. For the Porphyromonas gingivalis, 19 plant extracts had an antimicrobial activity, 17 plant extracts for the Prevotella intermedia, 45 plant extracts for the Haemophilus actinomycetemcomitans and 85 plant extracts for the Streptococcus mutans. Among these effective extracts, 8 kind of natural plant extracts had an antimicrobial activity for more than 3 species of dental pathogens. In our experiment, Cudrania tricuspidata, Morus bombycis and Mallotus japonicas have antibacterial effects on the all kinds of major dental pathogens. Therefore these plant extracts have a possibility to be a candidate for major antibacterial components in dental products.

• Natural Product Sciences
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• v.9 no.1
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• pp.34-37
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• 2003

We examined methanol extracts prepared from the Korean plants for their inhibitory effects on rat lens aldose reductase (RLAR) activity in vitro. Among 41 plant extracts, the extracts of Lagerstroemia indica, Punica granatum, Eurya japonica, Liquidambar styraciflua, and Vitis coignetiae exhibited highest inhibitory potency, even more potent than tetramethylene glutaric acid (TMG), known as one of typical aldose reductase inhibitors $(IC_{50}\;value,\;0.51\;{\mu}g/ml)$. Especially, the extract of Lagerstroemia indica (Lythraceae), exhibited the most inhibitory potency $(IC_{50}\;value,\;0.069\;{\mu}/ml)$ on RLAR.

• Natural Product Sciences
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• v.5 no.4
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• pp.165-171
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• 1999

Since reactive oxygen species (ROS) play an important role in carcinogenesis and other several human diseases, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, potential activity was assessed by determining with inhibition of a xanthine/xanthine oxidase assay system. Approximately 170 plant extracts of Korean herbal medicines were primarily evaluated for the potential of antioxidant activity. As a result, 13 plant extracts were found to be active $(IC_{50}$<$100\;{\mu}g/ml)$. Especially, Juncus effusus, Selaginella tamariscina, Pueraria thunbergiana and Sedum albroseum showed strong inhibitory activity in this process. Further studies for the identification of active principles from these active lead plant extracts might be warranted.

• The Korean Journal of Food And Nutrition
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• v.18 no.3
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• pp.225-228
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• 2005

Effects of natural plant extracts on kochujang and it's sensory evaluation were investigated. Natural plant extracts was added to the general kochujang and then investigated the changes of free amino acids composition after fermentation at $30^{\circ}C$ for 60 days. The content of glutamic acid among the free amino acids was highest, and those of aspartic acid, proline, valine, histidine were also presented higher than the general kochujang, Sensory properties of natural plant extract-added kochujang were unchanged in color, hot taste, salty taste but, properties presented better in flavor, savory taste, sweet taste, overall preperence. Therefore, we may conclude that kochujang added natural plant extracts was more acceptable than general kochujang.

• Natural Product Sciences
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• v.20 no.3
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• pp.170-175
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• 2014

Twenty five methanolic plant extracts were investigated to determine the anticancer activity against sonic hedgehog (shh)/Gli signaling pathway dependent cancer, PANC-1 human pancreatic cancer cells, through three screening programs. All extracts were inspected their inhibitory properties on sonic hedgehog-conditioned medium (shh-CM) induced alkaline phosphatase (ALP) activity in C3H10T1/2 mouse mesenchymal stem cells to examine whether the plant extracts affect the shh/Gli signaling pathway. Next, plant extracts were screened the ability to suppress the cell proliferation of PANC-1 human pancreatic cancer cells. Finally, active plant extracts from the two screening systems were evaluated for the suppressive effect on Gli-mediated transcriptional activity in PANC-1 cells. Among active plants, Cinnamomum cassia suppressed Gli-mediated transcriptional activity leading to the down-regulated expression of Gli-target genes such as Gli-1 and Patched-1 (Ptch-1). This study provides the consideration for the important role of natural products in drug discovery process as well as the basis for the further analysis of active plant and potential identification of novel bioactive compounds as inhibitors of Gli and therapeutic candidates against shh/Gli signaling pathway dependent cancers.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.242-255
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• 2019

In this study, we examined the antimicroboal effect against Actinobacillus actinomycetemcomitans and Prevotella intermedia which were the bacteria causing the Periodontopathic by using 34 types of natural plant extracts. Therefore, this study measures growth inhibition activity and Minimum Inhibition Concentration (MIC) of a sample extract with the use of organic solvent extracts in order to analyze the antibacterial effect of natural plant extracts on periodontopathic bacteria. Each of the 34 types of natural plant extracts were extracted by using the ethanol, and subsequently, the size of growth inhibition zone(clear zone, ㎜) of respective extracts were measured through the disk diffusion method. As a result, it was found that the growth inhibitory activity was found for A. actinomycetemcomitans, which is the bacteria causing the Periodontitis, in 13 types of natural plant extracts such as Raphanus sativus, Akebia quinata, Paeonia lactiflora, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Forsythia saxatilis, Gentiana macrophylla, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus, etc. In the case of P. intermedia, the growth inhibitory activity was found in 13 types of natural plant extracts such as Raphanus sativus, Angelica acutiloba, Akebia quinata, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Cinnamomum cassia, Aster tataricus, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus etc. For A. actinomycetemcomitans, anti-bacterial effect was exhibited in Belamcanda chinensis, Cinnamomum cassia, Kalopanax Pictus, Phellodendron amurense, Coptis chinensis. The Coptis chinensis showed the most excellent growth inhibitory activity in all organic solvent fragment, while P. intermedia showed the growth inhibitory activity in Belamcanda chinensis, Cinnamomum cassia, Meliaazedarach, Phellodendron amurense, and Coptis chinensis.

• Natural Product Sciences
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• v.16 no.4
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• pp.285-290
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• 2010

The inhibition of rat lens aldose reductase (AR) in vitro using methanol extracts from Korean folk plants was investigated. Among them, the extracts of Saussurea grandifolia and Rumex crispus showed highest inhibition of AR. $IC_{50}$ values of the extracts from S. grandifolia and R. crispus were demonstrated 0.07 and 0.05 mg/ml, respectively. Korean folk plants such as S. grandifolia and R. crispus has a possibility of new natural resources for the inhibition of AR.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.319-323
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• 2010

Recently, Korean traditional raw rice wines (RRW) have received attention because they are a nutritious food with health properties. But the rapid deterioration of fermented RRW is one of the serious problems for brewing and marketing in the world beyond Korea. The goal of this study was to develop a way to enhance the quality and to lengthen the period of circulation of the RRW. A lactic acid bacterium was isolated from RRW. It was identified as Lactobacillus fermentum (98%) based on its biochemical properties, and 16S rRNA sequence. Treatments of RRW with gamma radiation and green tea extracts reduced the bacterial population except for yeasts and Lactobacillus in the RRW. This result suggested that the natural plant extracts and catechin products can be used as an effective natural storage agent.