• BMB Reports
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• v.32 no.1
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• pp.12-19
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• 1999

Gaegurin 4 (GGN4), a broad-spectrum antibiotic, is a 37-amino acid peptide isolated from the Korean frog, Rana rugosa. In this study, we have chemically synthesized and purified GGN4 analogues where the C-terminal portion is truncated and/or substituted with tryptophan. These peptides show significantly different biological activities depending on the location of tryptophan and the number of amino acids truncated from the C-terminal end. While deletion of 9 amino acids from the C-terminal seems to be marginally tolerable in maintaining the antimicrobial activity, further deletion of up to 14 amino acid residues decreases the potency by more than 60-fold towards Gram-positive, and 10-fold towards Gram-negative, bacteria. Surprisingly, the reduced activity of the shorter peptide can be completely restored by a single substitution of aspartic acid 16 to tryptophan 16 (D16W). Also, the truncation seems to decrease the specificity of antibiotic activity more towards Gram-positive than towards Gram-negative bacteria studied. These data suggest a partial role of the C-terminal region in determining the binding specificity and the activity of peptides upon binding to their target cell membranes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.6
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• The Korean Journal of Mycology
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• v.35 no.1
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• pp.58-60
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• 2007

Root of Asarum sieboldii has been used in chinese medicine. It was been known that the extract of A. sieboldii has medicinal effect such as antifebrile, anodyne, and anti-inflammatory. Antifungal activity of the essential oil extracted from A. sieboldii against various epiderman and opportunistic human pathogenic fungi was investigated. Steam-distillated essential oil demonstrated very high antifungal activity against Aspergillus fumigatus, Aspergillus niger, Cryptococcus neoformans, and Candida albicans. MIC (minimum inhibitory concentration) of the essential oil against C. albicans was 5 ul/ml, indicating that the essential oil may be used as natural preserves for cosmetic and nutritional products.

• Advances in Traditional Medicine
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• v.7 no.3
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• pp.286-289
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• 2007

Heracleum nepalense D Don. (Umbelliferae) is a small shrub having high glabrescent stem found in stream banks in Sikkim. Various medicinal properties which include antidiarrhoeal, antiseptic, anti-influenzal etc. have been attributed for this plant in the traditional system of medicine in Sikkim. In present investigation the methanol extract of roots of Heracleum nepalense was subjected for its effectiveness against both Gram-positive and Gram-negative bacteria causing diarrhoea. The roots extract was tested for its minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative organisms causing diarrhoea. Further, the zones of inhibition produced by the crude extract against few sensitive strains was measured and compared with those of standard antibiotic ciprofloxacin. It is evident that the methanol extract is very active against the bacteria causing diarrhoea at low concentrations. The antibacterial efficacy of the root extract was found to decrease in the following order against different tested bacterial strains like Shigella dysenteriae, Escherichia coli, Shigella boydii, Vibrio cholerae, Salmonella typhimurium.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.80-83
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• 2012

The addition of NaBr to the fermentation medium of a marine isolate of the fungus Dothideomycete sp. resulted in induced production of two toluhydroquinone derivatives, 5-bromotoluhydroquinone (1) and 4-O-methyltoluhydroquinone (2), and two known compounds, toluhydroquinone (3) and gentisyl alcohol (4). The structures of 1 and 2 were assigned through the spectroscopic data analyses. Compounds 1-4 showed a potent antibacterial activity against the methicillin-resistant and multidrug-resistant Staphylococcus aureus (MRSA and MDRSA) with MIC (minimum inhibitory concentration) values of 6.2, 12.5, 6.2, and 12.5 ${\mu}g/ml$, respectively. Compounds 1-4 also exhibited a moderate radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with $IC_{50}$ values of 11.0, 17.0, 12.0, and 7.0 ${\mu}M$, respectively, which were more active than the positive control, L-ascorbic acid ($IC_{50}$, 20.0 ${\mu}M$).

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.352-355
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• 2004

The extracts from 70 different plant natural products were used to investigate the antimicrobial activities against Brachyspira hyodrsenteriae, the causative agent of swine dysentery. Among them, the extracts from Terminalia chehula exhibited the highest antimicrobial activities against B. hyodysenteriae. It showed the antimicrobial activity against B. hyodysensteriae mostly in parts of its shell. Minimum inhibitory concentration (MIC) of the water extracts of T chehula was 12.5 mg/ml. After organic solvent extractions, the ethylacetate extracts exhibited higher antimicrobial activities against B. hyodysenteriae, and their antimicroactivities were similar to that of the tannin. In conclusion, these findings suggest that the extracts from T chebula may be used as animal feed additives for their antimicrobial activities against B. hyodysenteriae.

• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.87-93
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• 2013

This study was conducted to investigate the antimicrobial, antivirus properties of Saururus chinensis extracts. The n-hexane extracts from Saururus chinensis showed the active antimicrobial activity against gram-positive bacteria. Minimum inhibitory concentration (MIC) of Saururus chiensis n-hexane extracts was 1.25 mg/ml against B. subtilis and 2.5 mg/ml against S. aureus. The cytotoxicity effects on MDBK (Madin-Darby bovine kidney) cell were observed at the various n-hexane extract concentrations. In $TCID_{50}$ assay, 0.6 mg/ml of n-hexane extracts decreased BVD (bovine viral diarrhea) virus by 1.4 log, whereas other extracts did not show antiviral activity. In this study, The results suggested that n-hexane extracts and fractions of Saururus chinensis can be a candidate materal of feed additive to chemical antibiotics and antivirus substances.

• Journal of Life Science
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• v.9 no.3
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• pp.314-327
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• 1999

This study was investigated to isolate identify the total bacteria and fungi from the indoor air of work-place of the shoes, paint, stainless steel, and plastic industries. The number of bacterial colonies on the nutrient agar plates were calculated by the open petridish method for 30 minutes in indoor air of work-places at the autumn and winter. The isolated bacteria were identified by Gram stain and biochemical test using API Staph and API 20E kits. The isolated fungal colonies were identified by gross appearance of the giant colonies and microscopic examination of their spore and hyphal characteristics on the slide culture method. The minimum inhibitory concentration (MIC) of several antibiotics against isolated bacteria was determined by the microdilution method with Mueller-Hinton broth. The 70-400 colonies in autumn and 54-236 colonies in winter were isolated from the indoor air of work-places of several industry. The isolation rates of Gram positive cocci, Gram positive bacilli, Gram negative bacilli, and Gram negative cocci were 46.3%, 19.8%, 17.3%, and 16.1%, respectively. In Gram positive cocci, the most strains were identified as Aerococcus spp, Micrococcus spp, and Staphylococcus spp. In Gram positive and negative bacilli, and Gram negative cocci were identified as Bacillus spp, Pseudomonas spp, and Neisseria spp, respectively. The frequently isolated fungi were Aspergillus spp, Penicillium spp and Rhizopus spp, respectively. The frequently isolated Aerococcus spp, Micrococcus spp, and Staphylococus spp were highly resistance against ampicillin, erythromycin, methicillin, and tetracycline. These results arouse our attention to microbiologic pollution in the indoor air of work-places of industries.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.586-589
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• 1997

Antifungal activities of 6-[(N-4-bromophenyl)amino]-7-chloro-5,8-quinolinedione (RCK7) were tested. The MIC values of RCK7 were determined for antifungal suceptibility, in vitro against Aspergillus niger, Cryptococcus neoformans and Trichophyton mentagrophyte by standard agar streak method. In vitro, RCK7 showed more potent antifungal activity than fluconazole and ketoconazole. Also, RCK7 was tested for in vivo antifungal activity in the treatment of systemic infection with Candida albicans in normal mice. The therapeutic potential of RCK7 had been assessed by evaluating their survival rate against systemic infections compared with that of ketoconazole. $ED_{50}$ of intraperitoneally administered RCK7 ws $2.05{\pm}0.30mg/kg$ but that of ketoconazole was $8.00{\pm}0.73 mg/kg$, respectively. When RCK7 was administered intravenously at the $ED_{50}$(2.05 mg/kg). the colony counts of Candida albicans in the liver after 7 days and 14 days were reduced as likely as ketoconazole at the $ED_{50}(8.00 mg/kg)$, and the better survival rates than ketoconazole's were achieved after 14 days. The results suggest that RCK7 may be a potent antifungal agent.

• Journal of the Korean Chemical Society
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• v.66 no.3
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• pp.194-201
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• 2022

A simple, efficient, and cost-effective method has been employed for the synthesis of 2,4,5-trisubstituted imidazole derivatives (3a-j) containing quinoline substituent at 2^nd position. Title compounds were obtained by multicomponent reaction (MCR), involving aryl substituted 1,2-diketone, quinoline carbaldehyde and ammonium acetate in the presence of acetic acid solvent under mild reaction conditions. The newly synthesized quinoline containing imidazole derivatives were confirmed through FT-IR, ¹H-NMR, ¹³C-NMR and mass spectral analysis. In-vitro microplate alamar blue assay (MABA) to determine the MIC (minimum inhibitory concentration) values against Mycobacterium tuberculosis H37Rv was performed for the synthesized compounds. The synthesized compounds exhibited activity against Mycobacterium tuberculosis and among which compounds, 3d, 3f and 3i showed good activity. The highest activity was showed with compound 3i. The anti-mycobacterial activity results are well correlated with the computational molecular docking analysis, which was performed for the synthesized compounds prior to the evaluation of the activity.