• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.567-582
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• 2015

Botrytis cinerea infects stems, leaves and fruits of greenhouse tomato and can cause serious economic losses. This study was conducted to develop organic farming control method against tomato gray mold. Twenty two organic farming materials including mineral and plant extracts were screened for the suppressive activity against Botrytis cinerea, in vitro and in vivo. Among the organic farming materials, sulfur, copper, Chinese twinleaf extract and rhubarb extract decreased by 51.7-90% of the spore germination of Botrytis cinerea. Also, gray mold incidence was reduced more than 90% on tomato stems by treating sulfur, seaweed extracts, rhubarb root extracts and Chinese twinleaf extract. After the selected four organic farming materials were applied on tomato cultivated in greenhouse, their control effects against the tomato gray mold were tested. When the water soluble sulfur was foliar-sprayed on the tomato leaves infected by artificial inoculation with spore suspension of Botrytis cinerea, it showed 87.9% of control value. Also, control activity of the water soluble sulfur was paralleled with chemical fungicide, diethofencarb+carbendazim. The above mentioned results indicate the sulfur formulation can be used as chemical fungicide alternatives for controlling tomato gray mold in the greenhouse.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.323-329
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• 2016

Water extract from spent mushroom substrate (WESMS) of Pleurotus eryngii suppressed bacterial wilt disease of tomato caused by Ralstonia solanacearum by 70% without any direct antibacterial activity against the pathogen. WESMS-treated tomato had increased contents of free phenolic compounds (increased by 3%) and total salicylic acid (increased by 75%), and significantly enhanced plant height, leaf number, and fresh weight compared to those of a water-treated tomato sample. These results suggest that the treatment of tomato with WESMS can suppress bacterial wilt disease by enhancing plant defense factors and overall plant health.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.976-982
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• 2005

Abilities of various edible plants and natural antioxidants to protect brain against oxidative damages were evaluated using brain homogenate of perfused Sprague-Dawley rat. Oxidative damage, expressed as lipid peroxidation (LPO), indicating total quantity of malondialdehyde and 4-hydroxyalkenal, increased from 4.1 to 6.9nmol/mg protein by treatment of $2.5{\mu}M$ ferrous sulfate and 7.5mM hydrogen peroxide as source of reactive oxygen species (ROS) on brain homogenate for 10min at $37^{\circ}C$ Mallow(88%) in leafy vegetables, small potato (93%) in root vegetables, green red pepper (76%) in fruit vegetables, and avocado (96%) in fruits showed highest LPO inhibition capacities. Ability of mushrooms decreased in order of nameko, shiitake, pine mushroom, oyster mushroom, and new type pine mushroom. Among natural antioxidants tested, (+)catechin (91%), (-)epigallocatechin gallate (85%), (-)epicatechin gallate (83%), and kaempferol(83%) showed high LPO inhibition capacities.

• Research in Plant Disease
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• v.21 no.4
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• pp.309-314
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• 2015

Xylogone ganodermophthora (Xg) is an ascomycetous fungus that causes yellow rot on cultivated Ganoderma lucidum. Previously, we reported in vitro antifungal activities of a Xg culture extract against several watermelon pathogens. In 2014, we conducted greenhouse experiments to evaluate the control efficacy of a water extract of cultured Xg on watermelon powdery mildew (WPM). The test material (stock solution, ca. $4,000{\mu}g/ml$) was prepared by an autoclaved Xg culture in water at a ratio of 800 g of culture per 6 liter of water, and then filtering it through filter paper. Six foliar applications of the solutions (diluted 100- and 1,000-fold) significantly suppressed the formation of conidiophores and conidia. The inhibitory effect of aqueous potassium phosphonate solution on the disease and its phytotoxicity was tested. Phytotoxicity on watermelon plants was observed at concentrations of 1,000 and $2,000{\mu}g/ml$ as irregular brownish spots. The control efficacies against WPM were 91.9% at $2,000{\mu}g/ml$, 64.9% at $1,000{\mu}g/ml$, and 62.2% at $500{\mu}g/ml$.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.14-19
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• 2004

Aerial parts of Compositae plants were harvested from pastures and crop fields of Sunchon area at vegetative stage to determine their antioxidant activity. Among 13 species, three species Taraxacum officinate, Breea segeta, and Artemisia princeps were selected as potent plant materials. Through measurement by Rancimat and TBARS method, antioxidative effect was the greatest in Taraxacum officinate among plant species. Antioxidative index (AI) investigated by Rancimat showed Siegesbeckia glabrescensi was 1.51 while commonly-used antioxidants, BHT and ascorbic acid were 3.86 and 2.43, respectively. The highest TBARS value was also obtained from Taraxacum officinate(0.18) at 4 weeks after storage, indicating the plant had the strongest antioxidant activity during long time. Even though TBARS value (0.18) in Taraxacum officinate sample showed lower in all plants than two synthetic antioxidants(0.05-0.09), antioxidant activities of the plants were much higher than that of a control (1.01). The results suggest that the plants have antioxidant potential as an alternative natural antioxidant based on natural plant resources.

• Journal of Plant Biotechnology
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• v.49 no.2
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• pp.145-149
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• 2022

Airborne fine dust (FD) particles smaller than 10 ㎛ in diameter (PM10) are one of the major causes of air pollution in East Asia, including Korea, and have become a major contributor to respiratory and skin problems. FD inordinately promotes the production of reactive oxygen species and inflammatory response in macrophages, leading to cell damage and death. Rosa rugosa, a deciduous shrub of the Rosa genus, has been used in traditional East Asian herbal medicine to treat various illnesses. The present study investigated the anti-inflammatory effects of R. rugosa organ extracts on PM10-stimulated RAW264.7 macrophages. Compared to non-treated RAW264.7 cells, treatment with 100 ㎍.ml^-1 PM10 resulted in increased nitric oxide (NO) production, similar to lipopolysaccharide treatment. Additionally, 100 ㎍/ml stem extract reduced NO production by more than 45% compared to mock treatment. Furthermore, PM10-induced expression of interleukin (IL)-1β, IL-6, inducible NO synthase, and cyclooxygenase-2 was significantly reduced by stem extract treatment, indicating that the anti-inflammatory effect of the stem extract is mediated by the inhibition of pro-inflammatory mediators in PM10-stimulated RAW 264.7 cells. These results indicate that the R. rugosa stem could be considered a natural remedy with a protective effect against inflammatory responses induced by harmful airborne dust.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.232-239
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• 2012

A laboratory experiment was conducted to determine the content of phenolics and flavonoids, antioxidant activity and cytotoxicity from methanol extracts of different plant parts of $T.$ $officinale$ F. H. Wigg. Total phenolics [mg chlorogenic acid equivalents (FAE) $kg^{-1}$ DW] was highest in flower extracts (72.0 mg $kg^{-1}$), followed by leaf, root, and stalk extracts of $T.$ $officinale$ ($p$ < 0.05). The result of total flavonoid level [mg naringin equivalents $kg^{-1}$ DW] had same tendency to differential total phenolics contents among plant parts, but showed lower ranges of amount. The antioxidant activity of the methanol extracts from all the plant parts dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was highest in flower extracts ($IC_{50}$ value = 624.3 mg $kg^{-1}$ ), and followed by leaf, root, and stalk extracts of $T.$ $officinale$ ($p$ < 0.05). By means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell viability of Calu-6 for human pulmonary carcinoma and SNU-601 for human gastric carcinoma showed the lowest $IC_{50}$ value in the flower extracts ($IC_{50}$ value = 85.7 and 311.4 mg $kg^{-1}$, respectively), indicating the highest cytotoxicity. The results suggested that total phenolics content and total flavonoids level in different plant parts of $T.$ $officinale$ were highly correlated with antioxidative ($r^2$=0.7280 to 0.9971) or with cytotoxic activities ($r^2$=0.5795 to 0.9515).

• Korean Journal of Environmental Agriculture
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• v.4 no.2
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• pp.114-117
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• 1985

A new method for micro-quantification of abscisic acid from plant tissue is described. GLC-ECD method of abscisic acid pertafluorobenzyl ester synthesized by reaction of plant extract with pentafluorobenzyl bromide showed higher sensitivity than that of abscisic acid methyl ester, and the detection limit of abscisic acid by the described method was as low as 5 pg.

• Journal of Life Science
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• v.33 no.7
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• pp.538-548
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• 2023

The research has been conducted on the isolation of antimicrobial compounds from plant natural extracts and their potential application in oral health care products. This study aimed to investigate the antimicrobial mechanism by analyzing the changes in gene expression of Streptococcus mutans, a major oral pathogen, in response to complex compounds extracted from Aralia continentalis and Arctii Semen using organic solvents. Transcriptome analysis (RNA-seq) revealed that both natural extracts commonly upregulated or downregulated the expression of various genes associated with different metabolic and physiological activities. Three genes (SMU_1584c, SMU_2133c, SMU_921), particularly SMU_921 (rcrR), known as a transcription activator of two sugar phosphotransferase systems (PTS) involved in sugar transport and biofilm formation, exhibited consistent high expression levels. Additionally, component analysis of the A. continentalis extract was performed to compare its effects on gene expression changes with the A. Semen extract, and two active compounds were identified through gas chromatography-mass spectrometry (GC-MS) analysis of the active fraction. The n-hexane fraction (ACEH) from the A. continentalis extract exhibited antibacterial specificity against S. mutans, leading to a significant reduction in the viable cell counts of Streptococcus sanguinis and Streptococcus gordonii among the tested multi-species bacterial communities. These findings suggest the broad-spectrum antibacterial activity of the A. continentalis extract and provide essential foundational data for the development of customized antimicrobial materials by elucidating the antibacterial mechanism of the identified active compounds.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.194-200
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• 2011

Diamondback moth (DBM, Plutella xylostella L.) is known as the most destructive pest of cruciferous crops worldwide. As most insecticides targeted to mainly larval stage, new insecticides which have hatching-inhibitory or ovicidal activity could be more efficient to control DBM. Therefore, we developed an easy and efficient method for screening ovicidal activity of DBM eggs using aluminum foil. The aluminum foil ($4{\times}12$ cm) coated with filtered juice of chinese cabbage leave (hereinafter called oviposition foil) exposed to 300 newly-emerged adults for 24 hours inside the rearing container. The oviposition foils were replaced every 4 days consecutively after mating, but it was better to discarded over then. Oviposition foil were divided into 6 to 12 pieces depending on egg mass volume. After dipping into test solutions for 10 seconds using faucet, oviposition foil pieces were placed into common petri dish, and then investigated hatchability. The effect of methanol solvent (50%) for 10 seconds dipping on the toxicity against DBM eggs was negligible. In addition, whether covering the petri dish or not should be dependent on nature of active compounds tested. With applying the new bioassay method, methanol extracts from 50 plants were tested the ovicidal activity to DBM eggs. Among them, four plant extracts; Angelica tenuissima root, Lycium chinense root, Cnidium officinale root and Polygala tenuifolia root, showed high ovicidal activity of over 90% control efficacy, against DBM eggs.