• Microbiology and Biotechnology Letters
• /
• v.25 no.3
• /
• pp.293-297
• /
• 1997

To develope natural food preservatives of pine needle (Pinus densiflora Seib et Zucc.) extract, pine needle sap, ethanol and ether extracts were prepared for investigation of antimicrobial activities against food-related bacteria and yeasts. All extracts exhibited growth inhibiting activities for most of microorganisms tested. However, in general, growth inhibiting activities were higher in ethanol extract than in sap or ether extract. Minimum inhibitory concentrations (MIC) of ethanol extract for Lactobacillus casei, Pseudomonas aeruginosa or Escherchia coli were as low as 0.1 mg/ml, whereas MIC of sap or ether extract for most bacteria and yeasts were 0.25-0.8mg/ml, indicating that the ethanol extract showed the antimicrobial activity by 2.5 $\sim$8 times higher than the sap and ether extract. The antimicrobial activity of the ethanol extract was reduced by heating or alkali treatment. Moreover, growth of Pseudomonas aeruginosa was completely inhibited within 24 hours by the addition of at least 50ppm of ethanol extract. These findings suggest that pine needle, specially the ethanol extrat may play a role for natural food preservatives.

• International Journal of Oral Biology
• /
• v.40 no.1
• /
• pp.41-50
• /
• 2015

The aim of this study was to identify bacteria isolated from the oral cavities and to determine their antimicrobial susceptibility against eight antibiotics. The bacterial strains were obtained from the Korean Collection for Oral Microbiology (KCOM). The bacteria were identified by comparing 16S rDNA sequences at the species level. The data showed that 77 bacterial strains were predominantly identified as streptococci (49.4%) and staphylococci (14.3%). Minimum inhibitory concentrations (MIC) were determined using a broth dilution assay to test the sensitivity of the bacterial strains. The MIC values of the oral bacterial strains against antibiotics were different. Streptococci were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to tetracycline. Staphylococci also were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to penicillin antibiotics. Gramnegative bacterial strains were sensitive to tetracycline and were resistant to clindamycin. These results suggest that the antimicrobial susceptibility test is necessary in deciding the prescription for antibiotics, to prevent the misuse or abuse of antibiotics.

• International Journal of Oral Biology
• /
• v.33 no.4
• /
• pp.197-203
• /
• 2008

It has been reported that the antimicrobial susceptibility patterns of viridans streptococci vary according to geographical region. Although several studies on the antibiotic resistance of viridans streptococci in foreign countries have been reported, little is known about the distribution of resistance among viridans streptococci in Korea. In this study, 88 isolates of viridans streptococci from Korean students' dental plaque were identified as 12 different species. The susceptibility of these isolates to 8 antibiotics was investigated. The in vitro antibiotic activity of penicillin G, ampicillin, vancomycin, streptomycin, gentamicin, erythromycin, amoxicillin, and tetracycline was measured by the broth microdilution method. The range of the minimum inhibitory concentrations (MIC), MIC50, MIC90, and the percentage of the susceptible isolates were determined. Streptococcus mutans and Streptococcus salivarius were susceptible to the 8 antibiotics. Isolates with resistance to vancomycin, streptomycin, and amoxicillin were not found. The overall resistance rates of the 88 isolates to penicillin G, ampicillin, gentamicin, erythromycin, and tetracycline were 12.5%, 62.5%, 62.5%, 26.1%, and 26.1%, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.24 no.3
• /
• pp.89-95
• /
• 1998

The aim of this study is to elucidate the anti-microbial activity and anti-oxidative activity of water-soluble chitosan with a molecular weight of 5,000-200,000. Water-soluble chitosans have demonstrated a regular anti-microbial activity on the tested strians by the paper disk method. In the MIC (Minimum Inhibitory Concentration) test, CC-01 (MW=5,000) with the lower MW showed the higher MIC value than the higher MW chitosan. The MW of chitosan increase, the MIC decreases. MICs of 4 chitosans(CC-02∼CC-05) against S. aureusTCC 65389, E coli ATCC 8739, p. aeruginosa, ATCC 9027 and C. albicans ,ATCC 10231 were 7.0-39.O$\mu\textrm{m}$, whereas MICs of chitosans against A. niger were over 2.OmM. Formula containing chitosan showed higher anti-microbial activities than the formula made with the chemical preservatives(Methylparaben 0.2％ and Imidazolidinyl Urea 0.3％). Among 5 water-soluble chitosans, CC-03(MW=92,163) showed the most potent anti-oxidative activity (IC$\sub$50/ : 0.2mM). In conclusion, the water-soluble low molecular weight chitosan could be served as natural preservatives and antioxidant in cosmetics.

• Research in Plant Disease
• /
• v.12 no.1
• /
• pp.32-39
• /
• 2006

This study has been conducted to investigate the responses of various isolates of four Colletotrichum species such as C. gloeosporioides, C acutatum, C. coccodes, and C. dematium isolated from infected tissues of several crops to fungicides such as carbendazim, carbendazim+diethofencarb, four protective fungicides, and three ergosterol biosynthesis-inhibiting (EBI) fungicides. All the isolates of C. acutatum showed $EC_{50}$ values in a range of 0.001-3.040 ${\mu}g/ml$ against carbandazim, a benzimidazole fungicide. As for the response to carbendazim, the isolates of C. gloeosporioides obtained from pepper, apple, and strawberry were clearly divided into two groups, resistant or sensitive isolates. All the resistant isolates showed $EC_{50}$ values above 1000 ${\mu}g/ml$, whereas the sensitive isolates had lower $EC_{50}$ values than 0.550 ${\mu}g/ml$. The isolates of C. gloeosporioides exhibited a negative cross resistance between carbendazim and diethofencarb (a N-phenylcarbamate fungicide), but isolates of C. acutatum did not. Toward carbendazim, C. coccodes and C. dematium isolates showed a similar response to C. acutatum isolates and the sensitive isolates of C. gioeosporioides, respectively. As for response of Protective fungicides, all the isolates of C. acutatum showed a more resistant reaction than all the isolates of C. gloeosporioides. However, there was no difference among 4 species of Colletotrichum against EBI fungicides.

• Journal of The Korean Society of Integrative Medicine
• /
• v.11 no.4
• /
• pp.125-133
• /
• 2023

Purpose : This study aimed to analyze the antibacterial activity of Liriope platyphylla ethanol extract (LPEE) against Streptococcus mutans and Porphyromonas gingivalis and to validate its potential for the prevention and treatment of dental caries, gingivitis, and periodontal disease. Methods : To verify the antibacterial effect of L. pulsatilla ethanolic extract (LPEE) against S. mutans and P. gingivalis, the disk diffusion method was used to determine the inhibition zones at concentrations of 50, 100, 200, and 300 mg/㎖. To determine the minimum inhibition concentration (MIC), the final dose of LPEE was .2, .4, .8, 1.6, 2.5, and 5.0 mg/㎖, and the minimum bactericidal concentration (MBC) was determined based on the MIC results. To confirm the growth inhibitory effect of LPEE on both pathogens, the absorbance was measured at 600 nm after each incubation for 0, 3, 6, 12, and 24 hr at concentrations of .8, 1.6, 2.5, and 5.0 mg/㎖. Results : The cytotoxicity of LPEE was evaluated and the cell viability was more than 70 % at 400 mg/㎖. Therefore, concentrations of 50, 100, 200, and 300 mg/㎖ were used in this study. The antimicrobial effect against S. mutans was seen at 100 mg/㎖ and grew in a concentration-dependent manner, while P. gingivalis was effective at 50 mg/㎖ with the dose dependency. The MIC was .8 mg/㎖ for both strains, and the MBC was 1.6 mg/㎖ with the same results. The growth inhibitory effect of LPEE on S. mutans and P. gingivalis was observed, even at low concentrations. Conclusion : The antibacterial effect of LPEE was evaluated through the analysis of MIC, MBC, and growth inhibition effect on S. mutans and P. gingivalis, which suggests LPEE might have the possibility of utilization as a preventive and therapeutic composition for oral diseases.

• Preventive Nutrition and Food Science
• /
• v.10 no.1
• /
• pp.81-87
• /
• 2005

The objective of this study was to determine the radical scavenging activity, total phenolic content, antimicrobial activity, minimum inhibitory concentration (MIC) of ethanol extracts of 32 medical plant species that have been commonly used in medicinal plants. Total phenolic index of T. chebula exhibited the highest value (498.01㎎/g), followed by R. coreanus miquel (400.33㎎/g), Sanguisorba officinalis (368.25㎎/g), P. thumbergiana (259.74㎎/g) and Eugenia aromaticum (229.38㎎/g). Radical scavenging activity for the DPPH radical was highest in T. chebula (40.91%, p<0.01), followed by C. sappan (36.50%), S. officinalis (32.92%), R. coreanus miquel (26.54%) and P. thumbergiana (24.50%). The extracts from T. chebula, R. coreanus muquel, C. sappan, E. aromaticum, S. officinalis and C. japonica possessed outstanding antimicrobial activity against Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Lactobacillus plantarum. MIC was determined on those extracts that showed high efficacy against the test organisms. The most potent MIC values were seen for T. chebula extract against P. aeruginosa, S. aurusa, E. coli, B. subtilis, L. plantarum and S. Typhimurium at 7.8, 7.8, 15.6, 7.8, 125 and 31.2㎍/mL, respectivley. Furthermore, the total phenolic content and radical scavenging activity were very closely correlated for all samples (r=0.78). The coefficient correlations between total phenolic index and antimicrobial activity were 0.91 (E. coli), 0.91 (B. subtillis), 0.79 (P. aeruginosa), 0.79 (S. Typhimurium) and 0.70 (L. plantarum).

• Journal of Life Science
• /
• v.9 no.4
• /
• pp.358-367
• /
• 1999

Thirty strains of methicillin resistant Staphylococcus aureus were obtained from the clinical isolates. In order to investigate the pursuit of the pathogens of nosocomial infection, these strains were studied for antibiotic sensitivity as well as its resistant pattern. Among the methods of hybridization which directly confirm the specific antibiotic resistant genes by means of the recently developed specific probe DNA, dot blot hybridization and southern blot hybridization were performed and these two methods were compared in their sensitivity and specificity. Strains that is sensitive to cephalothin to the subject of methicillin resistant Staphylococcus aureus were in 43%. Those that are sensitive to cefoperazone and cefuroxime were 26% and 23%, respectively. In case of MIC, MIC50 of cefoperazone was 8 $\mu\textrm{g}$/$m\ell$, and MIC90 was 128 $\mu\textrm{g}$/$m\ell$ to be the lowest. As the results of plasmid DNA electrophoresis, most of methicillin resistant Staphylococcus aureus strains had more than 4 plasmids. These plasmids digested by BamHI, methicillin resistant Staphylococcus aureus is distributed as 10 fragments with the size of 65 kb to 1.5 kb. Dot blot hybridization were performed to examine the existence of mecA gene to show the detection rate of 50%. Southern blot hybridization were done to see if DNA bands which amplify the activity of digoxigenium-labeled probe by PCR were actually PCR products of mecA gene and it showed the detection rate of 53%. It can be concluded that the southern blot hybridization seemed to be better in sensitivity and specificity when it is compared with the results of dot blot hybridization.

• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.10
• /
• pp.1677-1684
• /
• 2018

Objective: To find biological functions such as antibacterial and antioxidant activities in several tropical plants and to investigate the possibility of antibiotic substitute agents to prevent and treat diseases caused by pathogenic bacteria. Methods: Plants such as Poncirus trifoliata fruit (Makrut), Zingiber officinale Rosc (Khing), Areca catechu L. (Mak), Solanum melongena L. I (Makkhuayao), and Solanum melongena L. II (Makhurapro) were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. The free radical scavenging activities were measured using 2-diphenyl-2-picryl hydrazyl photometric assay. Antibacterial activities with a minimum inhibitory concentration (MIC) were observed by agar diffusion assay against pathogenic strains of Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, Clostridium perfringens, and Pantoea agglomerans. Results: Poncirus trifoliata fruit methanol extract showed antibacterial activities against gram-negative and gram-positive pathogens. Additionally, this showed the strongest antibacterial activity against Burkholderia sp. and Haemopilus somnus with MIC $131{\mu}g/mL$, respectively. Areca catechu L. water extract showed antibacterial activities against Burkholderia sp., Haemopilus somnus, and Haemopilus parasuis. The MIC value for Haemopilus parasuis was $105{\mu}g/mL$ in this. Antioxidant activity of Zingiber officinale Rosc n-hexane extract showed 2.23 mg/mL effective concentration 50% ($EC_{50}$) value was the highest activity among tropical plants extracts. Total polyphenol content in Zingiber officinale Rosc methanol extract was $48.4{\mu}g/mL$ and flavonoid content was $22.1{\mu}g/mL$ showed the highest values among tested plants extracts. Conclusion: Taken together, these results suggest that tropical plants used in this study may have a potential benefit as an alternative antibiotics agent through their antibacterial and antioxidant activities.

• Microbiology and Biotechnology Letters
• /
• v.34 no.4
• /
• pp.352-356
• /
• 2006

CW-270031, an injectable carbapenem, is a novel synthesized pyrrolidinyl-thio carbapenems. It was evaluated for its in vitro antibacterial activities in comparison with those of imipenem and meropenem against standard strains and clinical isolated strains, CW-270031 was more active than imipenem against gram-negative (E. coli and Klebsiella oxytoca) clinical isolates, but it was slightly active than meropenem. Against Klebsiella aeruginosa CW-118 MIC were 0.048 $\mu$g/ml for CW-270031, 0.19 $\mu$g/ml for imipenem. Against clinical E. coli MIC range were 0.012$\sim$0.195 $\mu$g/ml for CW-270031, 0.097$\sim$0.39 $\mu$g/ml for imipenem. Against clinical Klebsiella oxytoca MIC$_{50}$ were 0.09 $\mu$g/ml for CW-270031, 0.39 $\mu$g/ml for imipenem. Against gram-positive standard strains and clinical CW-270031 was slightly more activity than meropenem, but CW-270033 was less active than imipenem against these tested isolates. The subcutaneous injection of CW-270031 in mice revealed that the half-life of CW-270031 in serum was about 13 min, long than that of meropenem (10.6 min). CW-270031. was stable to hydrolysis by dog renal dehydropeptidase I (DHP-l) enzyme, to an more stabilities shown by meropenem.