• Korean Journal of Medicinal Crop Science
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• v.18 no.5
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• pp.315-322
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• 2010

This study was carried out to investigate the antimicrobial activities of organic extracts obtained from the fruit of Thuja orientalis L. The native fruits in Korea were collected and extracted by 80% ethanol, and the extract was sequentially fractionated with n-hexane, chloroform, ethylacetate, and butanol. The fraction yields of n-hexane, chloroform, ethylacetate, butanol and water of ethanol extract were 10.15%, 10.05%, 1.45%, 45.35% and 27.55%, respectively. n-Hexane-soluble fraction showed the highest antibacterial activity against gram positive bacteria, while the chloroform, ethylacetate, butanol and aqueous fractions did not show any antibacterial activity. Minimum inhibitory concentration (MICs) on Staphyloycoccus aureus, Bacillus subtilis and Sateptococcus pneumoniae, n-hexane-soluble fraction were $100\;{\mu}g$, $500\;{\mu}g$ and $50\;{\mu}g$/disc, respectively. The antibacterial activity was not destroyed by heating at 80, 100, $120^{\circ}C$ for 30 min and was not affected by pH. In the inhibitory test against the Staphylococcus aureus, Bacillus subtilis and Sateptococcus pneumoniae, n-hexane-soluble fraction showed potent growth inhibition at the concentration of 0.1 and $0.5\;{\mu}g/mL$ for 12~24 hours and n-hexane-soluble fraction did not show any mutagenic activity.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.130-136
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• 2007

Artemisia capillaris THUNB is a perennial herb that belongs to the family Compositae spp and the most common plant among the various herbal folk remedies used in treatment of abdominal pain, hepatitis, chronic liver disease, jaundice and coughing in Korea. In this study, antimicrobial effects of Artemisia capillaris extracts on the food poisoning bacteria were investigated for further clinical application, which is an alternative for the use of antibiotics and their unexpected resistance. Artemisia capillaris extract using ethyl acetate showed the highest antimicrobial effects on S. enteritidis, E. coli O157 : H7, L. monocytogenes and S. aureus. The chloroform extract showed strong effects on all kinds of bacteria; whereas ethanol and methanol extracts showed weaker effects. Finally, ether and water extracts showed the weakest effects under the same conditions. The minimum inhibitory concentration (MIC) of ethyl acetate extract was 1 mg/mL for E. coli O157 : H7 and L. monocytogenes, and 2 mg/mL for S. enteritidis and S. aureus. The inhibitory effects on all the bacteria continued for 12 hours after incubation using 20 mg/mL and 30 mg/mL of ethyl acetate extract. The inhibitory effects continued maximally for 72 hours. The results of these studies indicate Artemisia capillaris extract exhibited excellent antimicrobial and inhibitory effects on the food poisoning pathogenic bacteria; S. enteritidis, E. coli O157 : H7, L. monocytogenes and S. aureus.

• Korean Journal of Organic Agriculture
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• v.22 no.2
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• pp.269-280
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• 2014

This study was performed to test the insecticidal and antimicrobial activity of plant extracts from clove, Sophora flavescens Aiton and neem. As the result of antimicrobial activity test, clove extract showed the strongest activity against Botrytis cinerea. In insecticidal activity test, the extract of Sophora flavescens Aiton was the highest against Nilaparvata lugens. The pyroligneous liquor (10%) and emulsified spreader (10%) were added to the extracts of clove and Sophora, respectively, to apply the environment-friendly rice field. In the field treated clove extract, disease damage occurred 49.1% and insect damage occurred 29.5% compared to control plot (100%). In the field treated Sophora extract, disease damage was 56.7% and insect damage was 21.0% compared to control plot (100%). In conclusion, plant extracts from Sophora and clove could control about 50% of disease and about 70% of insect damage that they could be used as environment-friendly resources to control disease and insect in rice farming.

• Advances in Traditional Medicine
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• v.3 no.4
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• pp.191-195
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• 2003

Euphorbia hirta, locally called 'ara tanah' or 'susun nabi' in Malaysia is a small annual herb common to the tropical countries and belongs to the same family as the tic and tapioca. E. hirta has had a long history of usage in the treatment of various ailments. In this current study, in vitro sensitivity test of crude aqueous and ethanol extracts of leaves and barks of E. hirta was carried out against bacteria (Escherichia coli, Salmonella enteritidis, Staphylocccus aureus and Bacillus subtilis) and fungi (Microsporum canis, Aspergillus fumigatus, Candida albicans and Candida tropicalis) using the discs diffusion method. The extract-impregnated discs (20, 40 and $80\;{\mu}g/{\mu}l$), the E. hirta extracts inhibited the growth of all the bacteria tested. The growth of C. albicans was inhibited in a concentration dependent manner by the aqueous leaves and barks extracts. C. tropicalis was found to be sensitive to the aqueous leaves extracts. The results were compared to antibacterial drugs of chloramphenicol, ampicilin, penicillin G, and enrofloxacine; and to antifungal drug of ketoconazole, itraconazole and miconazole. In this current study, it can be concluded that this plant has antimicrobial activity that is as potent as the standard antimicrobial drugs against certain microorganisms.

• Journal of Life Science
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• v.29 no.6
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• pp.712-723
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• 2019

Chemically synthesized compounds are widely used in oral hygiene products. However, excessively long-term use of these chemicals can cause undesirable side effects such as bacterial tolerance, allergy, and tooth discoloration. To solve these issues, significant effort is put into the search for natural antibacterial agents. The aim of this study was to assess the extracts of foreign native plants that inhibit the growth and biofilm formation of Streptococcus mutans. Among the 300 foreign plant extracts used in this study, Chesneya nubigena (D. Don) Ali extract had the highest antimicrobial activity relatively against S. mutans with a clear zone of 9 mm when compared to others. This plant extract also showed anti-biofilm activity and bacteriostatic effect (minimal bactericidal concentration [MBC], 1.5 mg/ml). In addition, the plant extracts of 19 species decreased the ability of S. mutans to form biofilm at least a 6-fold in proportion to the tested concentrations. Of particular note, C. nubigena (D. Don) Ali extract was found to inhibit biofilm formation at the lowest concentration tested effectively. Therefore, our results reveal that C. nubigena (D. Don) Ali extract is a potential candidate for the development of antimicrobial substitutes, which might be effective for caries control as well, as demonstrated by its inhibitory effect on the persistence and pathogenesis of S. mutans.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.769-775
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• 2012

Among the phenolic compounds that is generally present in strawberry fruits, five simple phenolics, three flavonoids, and a stilbene were tested for their antimicrobial activity against seven fungi and one oomycete. trans-Cinnamic acid showed strong antimicrobial activity, and the antimicrobial effect of the simple phenolics decreased with an increase in the number of hydroxyl groups. Phytophthora capsici was the most susceptible to the phenolic compounds tested in this study. trans-Cinnamic acid, p-hydroxybenzoic acid, and kaempferol were mainly detected in 'Seolhyang' strawberry fruits, and the total phenolic contents of the fruits decreased during their development. Extracts of the green (1-10% red color) and red (above 90% red color) strawberry fruits reduced the mycelial growth and zoospore germination rate of P. capsici, and the extract of red strawberry fruit showed strong antimicrobial activity against the zoospore germination of P. capsici. These results indicate that strawberry fruits contain antimicrobial phenolic compounds and that strawberry fruit extract can be used as a natural fungistat.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.44-44
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• 2003

Leaves from natural populations of Artemisia princeps var. orientalis in Suncheon of South Korea were examined for antimicrobial and antioxidative activities monthly (April through October). The antimicrobial activity of the ethyl acetate and water fractions of crude methanol extract from the plant collected monthly against three gram-positive, two gram-negative and one lactic acid bacteria were studied. The ethyl acetate and water fractions of crude methanol extract from A. princeps var. orientalis collected in August and September had the highest antimicrobial activity. Minimum inhibitory concentrations (MIC) for each strain by ethyl acetate fraction of methanol extract from A. princeps var. orientalis was different depending on strains and sampling months. MIC for each strain was the highest in the sample of April, followed by October. In specific, MIC for Bacillus cereus was around 0.25mg/disc in the sample of April. The MIC for Staphyllococcus aureus was 0.01mg/disc in the sample of July, August, and September. It was the lowest value among tested strains and samples. And the antimicrobial activity for Lactobacillus plantarum was not found at any concentrations and sampling months. The in vitro antioxidative activities of methanol extract from Artemisia princeps var. orientalis collected monthly were determined by the scavenging of DPPH radical and inhibition of xanthine oxidase activity. The DPPH scavenging activity of the extracts from the plant sampled in May, June and July were higher than any other months. The xanthine oxidase activity of the extract of A. princeps var. orientalis collected in April and May showed the greatest activity, it is different with antimicrobial activity.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.46-51
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• 2019

This study was carried out to evaluate antimicrobial effects of a mixture of resin fractionated ethanol extract of Eucalyptus globulus, Yucca recurvifolia, and tea tree (Melaleuca alternifolia). The plant fraction mixture showed low minimum inhibitory concentration (0.24~3.32 mg/ml) against several bacteria and yeast that usually used as the target skin microbes in a cosmetic industry, and it was more effective than antibiotics, triclosan and ampicillin. In a time-kill assay the plant fraction mixture reduced more than 92% of microbial populations during 4 h, and significantly increased leakage of nucleotides from all microorganisms tested. Antimicrobial effect of the plant fraction mixture was not affected by divalent cation ($Mg^{2+}$ and $Ca^{2+}$). These results suggest that the fraction mixture of ethanol extracts of E. globulus, Y. recurvifolia, and M. alternifolia may be utilized as an efficient preservative in cosmetics to prevent contamination by human skin microbes.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.47-52
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• 2008

The plant Eclipta prostrata, a member of the Compositae family, has folkloric reputation of being used as a medicinal agent in Bangladesh. In the present investigation, attempt was taken to explore the antimicrobial potency and cytotoxicity of its extractives and purified compounds. The methanolic extract of the whole plant, its n-hexane, carbon tetrachloride, chloroform, aqueous soluble fractions and two purified compounds, eclalbasaponin I (1) and II (2), obtained from Eclipta prostrata were subjected to screening for inhibition of microbial growth by the disc diffusion method at 300 and 100 ${\mu}g$/disc for extracts and pure compounds, respectively. In this case, the carbon tetrachloride and chloroform soluble fractions of the methanolic extract appeared very potent in terms of both zone of inhibition and spectrum of activity. However, all the extractives were also subjected to brine shrimp lethality bioassay for preliminary cytotoxicity evaluation. Here, the carbon tetrachloride soluble fraction of methanolic extract revealed the strongest cytotoxicity having $LC_{50}$ of 1.318 ${\mu}g$/ml.

• Korean Journal of Medicinal Crop Science
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• v.8 no.2
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• pp.109-116
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• 2000

This study was carried out to screen herbs among herbal plants showing antimicrobial activity against some food spoilage and pathogenic microorganisms. One hundred fifteen kinds of herbal plants were extracted by 70% ethanol, and then they have been screened for antimicroorganisms. Six herbal plants such as Salviae radix, Dryopteris rhizoma, Terminaliae fructus, Araliae radix, Psoraleae fructus and Schisandrae fructus showed strong antimicrobial activities against Bacillus subtilis. Antimicrobial activities were showed in Anemarrhena radix and Dryopteris rhizoma on Candida albicans, and in Anemarrhenae radix, Dryopteris rhizoma and Polygalae radix on Schizosaccharomyces sp. It was revealed that eight herbal plants such as Dryopteris rhizoma, Salviae radix, Sappan ligunum, Sinomeniae radix, Schisandrae fructus, Rhui fructus, Sophorae radix and Inulae radix also showed antimicrobial activities on Streptococcus mutans. In addition, Anemarrhena radix, Curcuma tuber, Inulae radix, Polygonum radix, Sanguisorbae radix, Scutellariae radix and Terminaliae fructus and showed antimicrobial activities on Trichophyton mentagrophytes. Four kinds of herbal plants such as Dropteris rhizoma, Salviae radix, Terminaliae fructus and Scutellariae radix which showed broad antimicrobial spectrums were mixed by 1 : 1 ratio with the other herbal paints showing relatively strong microbial activities such as Terminaliae fructus, Sinomeniae radix and Scutellariae radix etc. The extracts of mixed herbal paints showed higher antimicrobial activities than those of single herbal plant.