• Journal of Microbiology and Biotechnology
• /
• v.16 no.1
• /
• pp.158-162
• /
• 2006

Cyclic dipeptides isolated from Streptomyces sp. have been shown to have antimicrobial activity as well as other potentially useful biological activities. The purpose of this study was to compare the in vitro activity of two cyclic dipeptides combined against anaerobic bacteria with the activity of other antimicrobial agents. Specifically, the in vitro activity of the combination of two cyclic dipeptides was investigated against 140 clinical isolates of anaerobic bacteria by the agar dilution method and was compared with that of erythromycin, cefoxitin, imipenem, clindamycin, and metronidazole. The cyclic dipeptide combination and imipenem were the most active antimicrobial agents tested. In addition, the cyclic dipeptide combination had a radioprotective effect on five normal human lung fibroblast cells, showing survival rates higher $(>90\%)$ than either of the two cyclic dipeptides alone $(<80\%)$.

• The Korean Journal of Food And Nutrition
• /
• v.11 no.6
• /
• pp.629-634
• /
• 1998

1-Deoxynojirimycin which is a potent intestinal ${\alpha}$-glucosidase inhibitor was purified from the culture broth by ion exchange chromatography, Sephadex LH20 column chromatography, TSK gel chromatography and HPLC respectively. Acute toxicity of 1-deoxynojirimycin, which was loaded through the oral as dose of 200mg/kg, was investigated in IRC mouse. None of the tested IRC mice were not dead and increase of body weight showed also the same results in comparison with control mice. The antimicrobial susceptibility of 20 pathogenic strains against 3 antidiabetic compounds (1-deoxynojirimycin, AO-128, acarbose) were obtained by agar dilution method. All of the three antidiabetic compounds has very weak antimicrobial activity (MIC>100$\mu\textrm{g}$/ml).

• YAKHAK HOEJI
• /
• v.21 no.1
• /
• pp.1-16
• /
• 1977

The effect of condensates of phosphates on the preservative activity of the food additives, using eight micro-organisms, has been studied by the agar dilution method. It was found that condensates of phosphates increased the food preserving action of almost all of preservatives and they acted as a synergist for the action of almost all of preservatives. Disodium dihydrogen prrophosphate acted as the strongest synergist in the experiment. But sodium tripolyphosphate anhydrous, sodium poly-phosphate, sodium tripolyphosphate and sodium hexametaphosphate acted as a inhibitor for action of some preservatives on some orgnisms. The preservatives were sodium dehydroacetate (DHA), potassium sorbate and NaNO$_{2}$ etc. The action of sodium meta-phosphate on the preservatives produced a mean difference by their origins. It was supposed that such a difference was produced by the difference of amount of impurities that were contained in sodium metaphosphate, It was also supposed that the does of the preservatives could be reduced by addition of condensates of phosphates, acting as a synergist for the action of almost all of the preservatives.

• Korean Journal of Veterinary Research
• /
• v.17 no.1
• /
• pp.13-16
• /
• 1977

In order to know the current status of sensitivity of Corynebacterium renale to some antimicrobial agents of current use, the sensitivity of 37 strains isolated from urine and vaginal cavity of healthy Korean native cattle and dairy cattle was studied by agar plate dilution method, and their sensitivity according to serological types was compared. The antimicrobial agents tested were streptomycin (SM), erythromycin (EM), oxytetracycline (OT), penicillin G (PC), gentamycin (GM), kanamycin (KM), ampicillin (AP), leucomycin (LM), chloramphenicol (CM), colistin (CL), sulfadimethoxine (SDM) and sulfadiazine (SDZ). Most strains were highly sensitive to PC, GM, AP, LM and KM, and moderate to CM and OT, but resistant to SM, EM, CL, SDM and SDZ. Serological type II was more sensitive to EM, SDM and SDZ than type I and II, but more resistant to SM.

• Archives of Pharmacal Research
• /
• v.28 no.7
• /
• pp.765-769
• /
• 2005

The essential oil fraction of Ostericum koreanum was analyzed by GC-MS. Inhibiting activities of this oil and its main components were tested by the broth dilution assay and disk diffusion test against one antibiotic-susceptible and two resistant strains of Salmonella enteritidis and S. typhimurium, respectively. The GC-MS analysis revealed thirty-four compounds; the main components were $\alpha$-pinene (41.12%), $\rho$-cresol (17.99%) and 4-methylacetophenone (7.90%). The essential oil of O. koreanum and its main components were significantly effective against the tested antibiotic-susceptible strains as well as against the resistant strains of the two Salmonella species, with MICs (minimum inhibitory concentrations) ranging from 2 mg/mL to 16 mg/mL. The anti-Salmonella effects of the oils were dose-dependent on $M\"{u}ller-Hinton$ agar plates in this experiment. Additionally, checkerboard titer test results demonstrated significant combined effects of streptomycin and O. koreanum oil or cresol, one of the main components of this oil, against the two streptomycin resistant strains of S. typhimurium, with FICIs ranging from 0.12 to 0.37.

• Archives of Pharmacal Research
• /
• v.16 no.2
• /
• pp.161-163
• /
• 1993

In order to evaluate the antimicrobial effect of 2,3-disubstituted-1,4-naphthalenedione derivatives, we synthesized several 2-chloro, 2-bromo and 2-hydroxy-3(substituted)-1, 4-naphthalene-diones (1-25). These derivatives were tested for antifugal and antibacterial activities, in vitro, against Candida albicans 10231 and local, Aspergillus niger KCTC 1231, Tricophyton mentagrophytes KCTC 6085, Baciilus subtilis ACTT 6633, Pseudomonas aeruginsa NCTC 10490, Staphylococcus aureus ATCC 6538P, Escherichia coli NIHJ. The MIC values were determined by the two-fold agar dilution/strea method. Among these derivatives, 4, 5 and 6 showed the potent antifungal activities. Also 5 and 6 had the antibacterial activities. 5 with (1,2,4-triazolyl)-amino moirty was the most effective in preventing the growth of fungi, such as Candida albicans, Aspergillus niger and Tricophyton mentagrophytes.

• Biomedical Science Letters
• /
• v.25 no.3
• /
• pp.275-281
• /
• 2019

This study was performed to characterize the chromosomal metallo-${\beta}$-lactamases (MBLs) of Chryseobacterium indologenes isolated from Korea and to propose a clustering method of IND MBLs based on their amino acid similarities. Chromosomal MBL genes were amplified by PCR from 31 clinical isolates of E. indologenes. Nucleotide sequencing was performed by the dideoxy chain termination method using these PCR products. Antimicrobial susceptibilities were determined by the agar dilution method. PCR experiments showed that all 31 E. indologenes isolates contained all $bla_{IND}$ genes. DNA sequence analysis revealed that E. indologenes isolates possessed ten types of $bla_{IND}$ gene, including seven novel variants ($bla_{IND-8}$ to $bla_{IND-14}$). The most common combination of MBL was IND-2 (n = 18). Minimum inhibitory concentrations of imipenem and meropenem for the isolates harboring novel IND MBLs were ${\geq}16{\mu}g/mL$. IND MBLs were grouped in three clusters, based on amino acid similarities.

• Journal of Pharmacopuncture
• /
• v.25 no.2
• /
• pp.101-105
• /
• 2022

Objectives: This study aims to determine the Fractional Inhibitory Concentration Index (FICI) of combinations of Melastoma malabathricum leaf fraction with ciprofloxacin or gentamicin against pathogenic bacteria, Escherichia coli, Staphylococcus aureus, and Bacillus cereus, isolated from Diabetic Foot Ulcer (DFU) patients. Methods: We tested concentrations of 45%, 55%, 65%, and 75% of gentamicin and ciprofloxacin using dilution and agar diffusion methods. The combination of M. malabathricum leaf extract with these antibiotics was tested in vitro against all three bacteria. Results: The combination of M. malabathricum leaf extract and ciprofloxacin gave a FICI value of 0.5, indicating synergistic antibacterial activity against the test bacteria. Conclusion: The results show that the antibacterial effect of a combination of high doses of the leaf extract with either antibiotic is greater than that of the leaf extract and the antibiotics in single use.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.4
• /
• pp.276-286
• /
• 2012

In this study, the antifungal activity of Cryptomeria japonica essential oil against superficial and allergic fungi, Trichophyton schoenleinii, Trichophyton tonsurans, Trichophyton mentagrophytes, Trichophyton rubrum, Epidermophyton floccosum, and Aspergillus fumigatus, was evaluated for determining the potential compound as dermatitis treatment. Minimum Inhibitory Concentration (MIC) measurement, TLC bioassay and agar dilution methods were used for determining the antifungal activity of crude essential oil and its fractions from C. japonica. Also, their major constituents were analyzed by GC/MS. The MICs were below 500 ppm at all superficial fungi, and spot 1 of C. japonica essential oil showed highly effective antifungal activity by TLC bioassay. In antifungal activity by agar dilution methods, crude oil showed high antifungal effect at more than 500 ppm and fraction D was significantly effective at even 100 ppm except for A. fumigatus. The major compounds of spot 1 and fraction D of C. japonica oil determined by GC/MS were elemol, ${\gamma}$-eudesmol, and ${\beta}$-eudesmol, which could be used as atopic dermatitis treatment material.

• The Korean Journal of Pesticide Science
• /
• v.11 no.1
• /
• pp.18-26
• /
• 2007

Fungicidal screening was performed to control soybean black root rot caused by Calonectria ilicicola through in vitro and greenhouse assays. In in vitro assay, 25 fungicides were assessed by an agar dilution method and a 96-well microtiter plate method. While protective fungicides including dithianon, dichlofluanid, mancozeb, and captan showed a very low activity against the mycelial growth C. ilicicola SC03-15 in the agar dilution method, they displayed potent inhibitory activity against spore germination in a 96-well microtiter plate method with $EC_{50}$ values of 4.65, 0.61, 4.64, and $0.29{\mu}g\;mL^{-1}$, respectively. Ergosterol biosynthesis-inhibiting (EBI) fungicides showed different antifungal activity against mycelial growth and spore germination according to molecules. Difenconazole displayed higher antifungal activity against spore germination rather than mycelial growth, and prochloraz inhibited potently both mycelial growth and spore germination with EC50 values less than $1.8{\mu}g\;ml^{-1}$. In contrast, the other EBI fungicides inhibited more highly mycelial growth than spore germination. Carbendazim+diethofencarb and dazomet also inhibited both mycelial growth and spore germination of C. ilicicola SC03-15 at very low concentrations. In greenhouse assay, carbendazim+diethofencarb effectively controlled a soybean black root rot by drenching 2 days before or after inoculation. In addition, tebuconazole showed potent curative activity against soybean black root rot.