• Journal of Life Science
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• v.25 no.1
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• pp.29-36
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• 2015

Prodigiosin, a member of natural red pigment family, is produced by Serratia marcescens, and characterized by a common pyrrolylpyrromethane skeleton. This pigment has been reported with the effects of anticancer, immunosuppressant, antifungal, and algicidal activities. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital infections. In this study, anti-MRSA properties of prodigiosin isolated from Serratia sp. PDGS 120915 were investigated. We identified and purified prodigiosin using high performance liquid chromatography (HPLC) and evaluated anti-MRSA activity. Purified prodigiosin inhibited the growth of MRSA. The minimum inhibitory concentrations (MICs) of prodigiosin were determined to $32{\mu}g/ml$ against the MRSA strains. Fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were indicated synergistic effects of prodigiosin on MRSA.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3219-3222
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• 2011

Three types of ${\beta}$-ketoacyl acyl carrier protein synthase (KAS) are important for overcoming the bacterial resistance problem. Recently, we reported the discovery of a antimicrobial flavonoid, YKAF01 (3,6-dihydroxyflavone), which exhibits antibacterial activity against Gram-positive bacteria through inhibition of ${\beta}$-ketoacyl acyl carrier protein synthase III (KAS III). In this report, we suggested that YKAF01 can be an inhibitor ${\beta}$-ketoacyl acyl carrier protein synthase I (KAS I) with dual inhibitory activity for KAS I as well as KAS III. KAS I is related to the elongation of unsaturated fatty acids in bacterial fatty acid synthesis and can be a good therapeutic target of designing novel antibiotics. We performed docking study of Escherichia coli KAS I (ecKAS I) and YKAF01, and determined their binding model. YKAF01 binds to KAS I with high binding affinity ($2.12{\times}10^6$) and exhibited an antimicrobial activity against the multidrug-resistant E. coli with minimal inhibitory concentration (MIC) value of 512 ${\mu}g$/mL. Further optimization of this compound will be carried out to improve its antimicrobial activity and membrane permeability against bacterial cell membrane.

• Korean journal of food and cookery science
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• v.25 no.4
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• pp.496-505
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• 2009

The influence of roasting time on antibacterial and antioxidative effects of methanol and water coffee extracts was investigated. Extract yield differed with roasting time. The maximum yield of methanol extract was 20.02% and 24.00% at respective roasting times of 12 and 20 min. The maximum yield of water extracts was 2.70% and 18.58% at 5 and 25 min roasting time, respectively. Antibacterial effects of each extract were determined by the classical minimal inhibitory concentration (MIC) paper disc diffusion method. Methanol extracts of different coffee samples inhibited growth of various strains except Escherichia coli. Extracts obtained following roasting times of 12, 14, 16, 20, and 25 min in particular displayed the most potent activity against Staphylococcus aureus. Among these extracts, that obtained from 12 min roasted coffee samples produced a MIC of $16.125{\mu}g$/mL against S. aureus. Water extracts applied at $1,000{\mu}g$/mL were growth inhibitory except against Salmonella choleraesuis and Prevotella intermedia. However, growth inhibition by water extracts was weak, with inhibitory zones of only 6-8 mm diameter produced. Determinations of free radical elimination for the different coffee extracts using 1,1-diphenyl-2-picrylhydrazyl were compared with ascorbic acid and butylated hydroxytoluene positive controls. Methanol and water extracts of different coffee samples ($100{\mu}g$/mL) showed $67.1{\sim}92.3%$ and $66.4{\sim}93.3%$ radical scavenging activity, respectively. However, longer roasting time (especially >20 min) tended to somewhat lower free radical elimination using both extracts. Total phenol in different coffee samples measured by the Folin-Denis method revealed the highest level of phenol contents with non-roasted coffee, whereas phenol content differed with different roasting time, ranging from $87.{\sim}126.5\;mg/g$ in methanol extracts. In water extracts, the phenol content was maximum at 8 min roasting time, whereas in other samples the content was varied from $95.0{\sim}199.1\;mg/g$.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.1
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• pp.47-57
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• 2021

Objectives This study was conducted to confirm the possibility of Clostridium difficile infection (CDI) treatment through natural herbal medicines. Methods After screening a total of 77 herbal medicines through the paper disc agar diffusion method, we selected the herbal medicines that showed a effectiveness compared to the positive control vancomycin. Afterwards, drugs that showed inhibitory effects compared to C. difficile without inhibition of Bifidobacterium bifidum and Lactobacillus plantarum, known as beneficial bacteria, were selected and minimal inhibitory concentration (MIC) was confirmed by applying the Broth microdilution method. Results The Coptidis Rhizoma, well known for its antimicrobial effect, was found to have antimicrobial effects on C. difficile, but also had inhibitory effects on the beneficial bacterium B. bifidum. 30% ethanol extraction Crataegi fructus, Corni fructus and Mume fructus had antimicrobial effects on C. difficile without inhibiting the beneficial bacteria B. bifidum and L. plantarum. The MIC values of 30% ethanol extraction Crataegi fructus, Corni fructus and Mume fructus were found to be 10 mg/mL, 20 mg/mL and 5 mg/mL, respectively. Conclusions Crataegi fructus, Corni fructus and Mume fructus were identified as candidate medicines for C. difficile. Further researchs will need to be done in vivo, and to find an optimal extraction method accompanied by economic evaluation.

• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.372-377
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• 2009

The chemical compositions and antibacterial and antifungal activities of essential oils extracted from Abies holophylla and A. koreana were investigated. GC-MS analysis revealed that 38 compounds comprised 95.88% of the A. holophylla essential oil, with the main components being bicyclo[2.2.1]heptan-2-ol(28.05%), ${\delta}3$-carene(13.85%), $\alpha$-pinene(11.68%), camphene(10.41%), dl-limonene(7.61%), $\beta$-myrcene(7.11%), trans-caryophyllene(5.36%), and $\alpha$-bisabolol(3.67%). In the essential oil from A. koreana, 36 compounds comprised 98.67% of the oil, and the main compounds were bornyl ester(41.79%), camphene(15.31%), $\alpha$-pinene(11.19%), dl-limonene(8.58%), fenchyl acetate(5.55%), and $\alpha$-terpinene(2.29%). Both essential oils showed great potential of antibacterial activity against several bacteria tested, in the range of 2.2-$8.8{\mu}g$ per disc by the agar disc diffusion method, and minimal inhibitory concentration(MIC) values of 5.5-21.8 mg/ml by the microdilution method. Both oils showed very effective antifungal activities toward all pathogenic strains tested, including Candida glabrata, with MIC values in the range of 0.5-2.2 mg/ml. As a whole, A. koreana oil showed better antibacterial and antifungal properties than A. holophylla oil.

• Korean Journal of Pharmacognosy
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• v.27 no.4
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• pp.309-315
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• 1996

As part of our search for less toxic antimicrobial agents from natural resources, antimicrobial activity of rutin isolated from Sophora japonica was tested in vitro against four kinds of gram positive bacteria and four kinds of gram negative bacteria by serial broth dilution method. Among eight kinds of bacteria tested, the antimicrobial activity of rutin was the most potent against Mycobacterium smegmatis showing MIC of $375\;{\mu}g/ml$. The acute toxicity of rutin was examined in mice and rats. and $LD_{50}$ value administered intraperitoneally in mice was 650 mg/kg(Confidence limit: 894-1,473 mg/kg). There were no significant changes in serum biochemical values and histopathological changes as compared with those of control after intraperitoneal administration with rutin in rats.

• Journal of Life Science
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• v.9 no.4
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• pp.348-357
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• 1999

Seventy-two strains of Pseudomonas aeruginosa isolated from the patients were tested for pigment production, exoenzyme production and antimicrobial susceptibility. In the pigment production test, 23.6% of total 72 strains produced both pyocyanine and pyoverdin. Pyoverdin and pyomelanin producing strains were in 9.7%, and 5.5% produced pyoverdin and pyorubin. Strains producing of all of exoenzyme, protease, elastase and lecithinase were in 5.6%. The most common type of exoenzyme production was both protease and elastase producing. Protease producing strain were 23.6%, Among the 72 strains, 50% produced protease. As the result of antimicrobial susceptibility in the isolated 20 strain, most strain were resistant to sulfamethoxazole(90%), but sensitive to other tested antibiotics more than 60%. The MIC50 and MIC90 level of tested antibiotics to 70 strains were 128 $\mu\textrm{g}$/$m\ell$, 512 $\mu\textrm{g}$/$m\ell$ for KM, 8,256 $\mu\textrm{g}$/$m\ell$ for GM, 8, 128 $\mu\textrm{g}$/$m\ell$ for CPZ, and 8, 64 $\mu\textrm{g}$/$m\ell$ for PIPC respectively.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.111-114
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• 2004

This study was carried out to evaluate the inhibition of growth and collagenase activity of Salvia miltiorrhiza Bunge against microorganisms causing periodontal diseases. The ethanol extract of Salvia miltiorrhiza showed sig-nificant growth inhibition against microorganisms causing periodontal diseases. Ethanol extract was further fractionated with organic solvents in the order of hexane, chloroform and ethyl acetate. Among the fractions tested, the hexane fraction showed the highest cell growth inhibition. The minimal inhibitory concentration (MIC) of the extract against C. curvus, C. rectus, E. corrodens, F nucleatum, P. gingivalis, P. intermedia and W. succinogenes were 200, 50, 50, 250, 150, 250 and 200 ${\mu}g$/ml, respectively. The inhibition of collagenase activity by organic solvent fractions were higher than that of minocycline, and the inhibition ratio of collagenase activity was $88.2{\pm}2.1$ % in the chloroform fraction.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.252-252
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• 1994

현재 시판되고 있는 정장용 생균 제제에 함유되어있는 정장균주의 하나인 Bifidohacterium bifidum은 항결핵제 중 rifampicin에 감수성으로 rifimpicin과 병용 투여시 본래의 정장 효과를 기대할 수 없다. 따라서, rifampicin에 내성인 돌연변이 균주를 얻기 위해 B. bifidum을 N-methyl-N'-nitro-N-nitroso- -guanidine(MNNG)로 처리하여 rifampicin에 내성인 30종의 균주를 선별 하였고, rifampicin에 대한 Minimal Inhibitory Concentration(MIC)를 측정해 본 결과 내성이 1,000배 이상 상승하였다. 또한 rifampicin에 내성인 균주 RFR61을 자연 돌연변이시켜 ofloxacin에도 내성인 돌연변이 균주 20종을 선별 하였고, MIC를 측정한 결과 내성이 4배 이상 증가하였다. 또, fructose-6-phosphate phosphoketolase test를 실시해 본 결과, 모두 Bifidobacterium임이 확인되었다. 유기산 생성량을 측정하여 모균주의 유기산 생성량과 가장 유사한 3균주, B. bifidum RFRll, RFR21, RFR61 그리고 OFR9을 선별하였다. 이 네 균주의 E. coli 생육 억제능을 측정한 결과 모두 모균주와 유사한 E. coli 생육 억제능을 가지고 있었다. Rifampicin 내성균주들에 대하여 내성 유지 시험을 한 결과 복귀 돌연변이에 의해 내성이 소실될 가능성은 없는 것으로 여겨진다. 마지막으로, 내성 균주에 의한 rifampicin 불활성화 여부를 알아 본 결과 rifampicin이 불활성 화되지 않음을 알 수 있었다. 이상의 결과를 통해 본 연구실에서 개발한 B. bifidum RFR11, RFR21 그리고 RFR61 균주들은 rifampicin에 내성이며, B.bifidum OFR9은 rifampicin과 ofloxacin에 이중 내성을 갖는 균주로서 모균주와 유사한 생화학적 특성을 갖는 우수한 정장 세균으로 여겨진다.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.57-63
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• 2013

This study compared the antimicrobial activity and total phenolic content of three Pinus plants (Pinus densiflora, P. thunbergii, P. rigida) for the first time. The antimicrobial activity of the water fraction of methanol extract of fresh leaves was stronger than that of fallen leaves at any concentrations. The water fraction of crude methanol extract from fresh leaves of P. thunbergii showed a higher growth inhibitory activity against gram-positive and gram-negative bacteria than that of P. densiflora and P. rigida. The results from the disc diffusion method followed by measurements of minimal inhibition concentration (MIC) indicate that Bacillus subtilis was the most sensitive microorganism with the lowest MIC value. The highest total phenolic content was found in fresh leaves of P. rigida and P. thunbergii. The assay showed that the fresh leaves of the three Pinus plants contained higher total phenolic content than fallen leaves of the three plants. The antimicrobial activity was related with the total phenolic content.