• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1799-1804
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• 2012

Anti-Pseudomonas aeruginosa activities for ethanol extract of 34 medicinal plants widely used in the folk medicine were evaluated to screening of anti-Pseudomonas aeruginosa agents. The ethanol extracts of Gardenia jasminoides, Arctium lappa, Citrus unshiu, and Phellodendron amurense showed antimicrobial activities against P. aeruginosa ATCC 27853. The ethanol extracts of Gardenia jasminoides among these medicinal plants showed significant antimicrobial activity against P. aeruginosa. Therefore, we expect that these medicinal plants will be useful for nature antimicrobial agent against P. aeruginosa in future.

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.87-92
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• 2018

A series of pyrimidine annulated dihydropyrano[2, 3-c]pyrazole derivatives were synthesized and screened for their antimicrobial activity. The precursor, dihydropyrano[2, 3-c]pyrazole was synthesised under catalyst free condition using PEG-400 as reaction medium which facilitated improved yield compared to base catalyzed reaction. Wide scope of substrates, simple workup procedure and high yield even in the absence of catalyst are the major highlights of the protocol. Dihydropyrano[2, 3-c]pyrazoles on condensation with formic acid formed pyrimidine annulated dihydropyrano[2, 3-c]pyrazole derivatives. All the products are characterized using FTIR, $^1H-NMR$ and $^{13}C-NMR$ spectroscopic techniques. The molecules have shown good to moderate activity as antimicrobial agents when compared to the standard drug ciprofloxacin.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.934-937
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• 2011

As part of our screening of anticariogenic agents from medicinal plants, the ethanol extracts of 10 herbs widely used in the fork medicine were tested for the antimicrobial activity against a cariogenic bacterium Streptococcus sobrinus. The ethanol extracts of Dryopteris crassirhizoma showed antimicrobial activities against S. sobrinus. These results suggested that the extracts of Dryopteris crassirhizoma could be the potential source of antimicrobial agent against S. sobrinus.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1087-1090
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• 2009

This study was carried out to research antimicrobial agents from medicinal plants, Glycyrrhiza uralensis, Dryopteris crassirhizoma, Dictamnus albus, Paeonia lactiflora, Angelica dahurica, Spirodela polyrhiza, Cimicifuga heracleifolia, Bupleurum falcatum, Magnolia kobus, Artemisia princeps, Arctium lappa, Aster tataricus, Hovenia dulcis, Citrus unshiu, Asparagus cochinchinensis, Gardenia jasminoides, Smilax china, Hovenia dulcis, Prunus sargentii, Scutellaria baicalensis. The ethanol extracts of 20 medicinal plants were tested for the antimicrobial activity against Agrobacterium tumefaciens. The extracts of Glycyrrhiza uralensis, Dryopteris crassirhizoma, Cimicifuga heracleifolia, Bupleurum falcatum showed antimicrobial activities against Agrobacterium tumefaciens.

• Archives of Pharmacal Research
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• v.24 no.1
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• pp.27-34
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• 2001

A series of 2-methylbenzimidazole incorporated to different heterocycles through ethyl or carbamoylethyl groups at position 1 of benzimidazole were synthesized. Also 3-(2-methylbenzimidazol-1-yl)propanoic acid hydrazide incorporated with semicarbazides and thiosemicarbazides were prepared. Moreover, the triazole 5e underwent Michael addition and alkylation reaction. Some of the newly synthesized compounds showed considerable antimicrobial activity against gram positive, negative bacteria and yeast.

• Korean Journal of Pharmacognosy
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• v.34 no.2 s.133
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• pp.142-144
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• 2003

Acetone extracts of 301 strains of marine-derived fungus were tested for antimicrobial activity against three strains of bacteria. The bacteria consisted of three pathogens, Staphylococcus aureus, methicillin-resistant S. Aureus, and multidrug-resistant S. aureus. The acetone extracts of 10 strains (MFA117, MFA130, MFA134, MFA206, MFA217, MFA268, MFA277, MFA291, MFA292, MFA301) showed strong activity, inhibiting 100% of the bacterial growth. These antimicrobial active strains were cultlued in SWS medium on a 1 L scale and the resulting broth and mycelium were extracted to afford mycelium extract (000M) and broth extract (000B), respectively. Antimicrobial activity for all extracts has been tested as the results, the mycelium extract of one strain (217M) and the broth extracts of 9 strains (117B,130B, 134B, 206B, 268B, 277B, 291B, 292B, 301B) exhibited relatively high levels of activity at minimal inhibitory concentration (MIC) values of $500-125\;{\mu}g/mL$ range. Among them, the extracts, 277B, 291B, 292B and 301B showed the most significant antimicrobial activity with $IC_{50}$ values of $125\;{\mu}g/mL$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.137-145
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• 2016

This study screened the biological activity of an acidified gill extract of the Manila clam Ruditapes philippinarum including antimicrobial, hemolytic, membrane permeabilization, and DNA-binding activity, and purified the antimicrobial material. The acidified gill extract showed potent antimicrobial activity against Bacillus subtilis and Escherichia coli without significant hemolytic activity, but showed no membrane permeabilization or DNA-binding ability. An antimicrobial material was purified from the acidified gill extract using C₁₈ reversed-phase and cation-exchange high-performance liquid chromatography (HPLC). Treatment of the purified material with trypsin completely abolished all of the antibacterial activity against Bacillus subtilis, suggesting that the purified material is a proteinaceous antibiotic. The molecular weight of the purified material was 2571.9 Da, but no primary structural information was obtained due to N-terminal blocking. A future study should confirm the primary structure. Our results suggest that the Manila clam gill contains proteinaceous antibiotics that have a role in first-line defense. This information could be used to better understand the Manila clam innate immune system.

• International Journal of Oral Biology
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• v.39 no.4
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• pp.169-176
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• 2014

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format $O_{(1-6)}XXXXX-NH_2$, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-$NH_2$ (pep-1) and WXXXXN-$NH_2$ (pep-2), and one positioned peptide, RRRWRN-$NH_2$ (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic ${\alpha}$-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

• The Korean Journal of Food And Nutrition
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• v.15 no.4
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• pp.300-306
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• 2002

141 methanol extracts from 125 plant species which populate in Korea were screened for antimicrobial activity against various food-borne pathogens and food spoilage microorganisms. Those plants were selected from 3 different plant groups: traditional herbs, edible plants and flowers. The methanol extracts were tested by using the disk diffusion assay against five bacteria: Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter aerogenes, Escherichia coli. From the evaluation of the inhibition zone diameter of microbial growth, the most significant antimicrobial activity against Bacillus subtilis, Staphylococcus auresus, Pseudomonas aeruginosa, Enterobacter aerogenes, Escherichia coli was observed from the extract of Schizandra chinensis (Turcz.) Baill., Rheum officinale Baill., Schizandra chinensis (Turcz.) Baill., Koelreuteria paniculata Lax and Crataegus pinnatifida Bunge, respectively. The extract from many plants - Koelreuteria paniculata Lax, Chaenomeles sinensis Koehne, Scutellaria bacicalensis Georgi, Castanea crenata Sieb. et Zucc., Rosa centifolia L., Allium fistulosum L. var. giganteum Makino, Crataegus pinnatifida Bunge, Schizandra chinensis (Turcz.) Baill., Lonicera japonica - showed antimicrobial activity all four tested bacteria.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.778-782
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• 2007

This study assessed the effects of the antimicrobial substances sulforaphane, grapefruit seed extracts (GSE), and reuterin on the expression of Salmonella HilA and InvF virulence gene using a LacZY assay (${\beta}$-galactosidase assay) with hilA:lacZY and invF:lacZY fusion strains of Salmonella typhimurium SL1344. Salmonella was grown for 8 hr at $37^{\circ}C$ in the presence of diluted antimicrobial substances ($2\;{\mu}g/mL$ sulforaphane, $20\{\mu}g/mL$ GSE, and 0.26 mM reuterin) at concentrations that did not inhibit the cellular growth of Salmonella. Sulforaphane inhibited the expression of HilA and InvF by 50-90 and 20-80%, respectively. GSE also inhibited the expression of both genes, but to a lesser degree. Among the 3 antimicrobial substances, reuterin showed the least inhibition, which was abolished after 3-4 hr. None of the antimicrobial substances inhibited the ${\beta}$-galactosidase enzyme activity of S. typhimurium. The assay used in this study represents a very sensitive method for screening bioactive substances that inhibit the expression of virulence genes in Salmonella.