• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.538-546
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• 2024

Cinnamaldehyde is a natural compound extracted from cinnamon bark essential oil, acclaimed for its versatile properties in both pharmaceutical and agricultural fields, including antimicrobial, antioxidant, and anticancer activities. Although potential of cinnamaldehyde against plant pathogenic bacteria like Agrobacterium tumefaciens and Pseudomonas syringae pv. actinidiae causative agents of crown gall and bacterial canker diseases, respectively has been documented, in-depth studies into cinnamaldehyde's broader influence on plant pathogenic bacteria are relatively unexplored. Particularly, Pectobacterium spp., gram-negative soil-borne pathogens, notoriously cause soft rot damage across a spectrum of plant families, emphasizing the urgency for effective treatments. Our investigation established that the Minimum Inhibitory Concentrations (MICs) of cinnamaldehyde against strains P. odoriferum JK2, P. carotovorum BP201601, and P. versatile MYP201603 were 250 ㎍/ml, 125 ㎍/ml, and 125 ㎍/ml, respectively. Concurrently, their Minimum Bactericidal Concentrations (MBCs) were found to be 500 ㎍/ml, 250 ㎍/ml, and 500 ㎍/ml, respectively. Using RNA-sequencing analysis, we identified 1,907 differentially expressed genes in P. carotovorum BP201601 treated with 500 ㎍/ml cinnamaldehyde. Notably, our results indicate that cinnamaldehyde upregulated nitrate reductase pathways while downregulating the citrate cycle, suggesting a potential disruption in the aerobic respiration system of P. carotovorum during cinnamaldehyde exposure. This study serves as a pioneering exploration of the transcriptional response of P. carotovorum to cinnamaldehyde, providing insights into the bactericidal mechanisms employed by cinnamaldehyde against this bacterium.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.19-29
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• 2010

Phytoncide, essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Candida albicans, which is a commensal colonizer of the mucous membranes but has become an opportunistic pathogen. C. albicans was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its optical density, cell viability and morphology. As concentrations of phytoncide added to the culture medium increased, optical density and cell viability of C. albicans decreased. Minimum inhibitory concentration of phytoncide for C. albicans was observed to be 0.25%, and minimum fungicidal concentration was 0.5%. Numbers of morphologically atypical cells with electron-dense cytoplasm and granules and increased with increasing concentration of the phytoncide. At higher concentrations of phytoncide, compartments and organelles in the cytoplasm became indistinguishable. The overall results indicate that the phytoncide used for this study has a strong antimicrobial activity against C. albicans. Therefore, the phytoncide may be used as a candidate for prevention and therapeutic agent against oral candidiasis.

• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.111-122
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• 2017

Objectives: Coriolus versicolor is an edible mushroom with physiological activities that has been used in traditional medicine. The aim of this study was to investigate the antimicrobial activity of extracts obtained from Coriolus versicolor against oral pathogens. Methods: The antimicrobial activities of various extracts of Coriolus versicolor were examined by disc diffusion assay, and minimum inhibitory concentration (MIC) of these extracts were also was determined by broth dilution method. The growth inhibition effect of extracts was measured at 600 nm for 12 hrs against Streptococcus ratti, Streptococcus criceti, Aggregati--bacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israelii. Results: Coriolus versicolor extracts showed antimicrobial activities against all nine oral pathogens through disc diffusion assay. The ethanol extract and ethyl acetate extract differed significantly compared with acetone extract against Streptococcus ratti, Streptococcus criceti, Actinomyces viscosus, Actinomyces israelii and Aggregatibacter actinomycetemcomitans (p<0.05). These extracts exhibited MIC ranges of 2.63 to >10.50 mg/ml against the tested bacteria. The ethanol extract from Coriolus versicolor showed lower MIC values of 2.63 to 5.25 mg/ml. According to the obtained growth curve, the extracts of Coriolus versicolor were more effective against Actinomyces viscosus. Conclusions: The acetone, ethanol, and ethyl acetate extracts from Coriolus versicolor showed antimicrobial activities against Streptococcus mutans, Staphylococcus aureus, Streptococcus sanguinis, Streptococcus sobrinus, Streptococcus ratti, Streptococcus criceti, Aggregatibacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israeli.i Therefore, they could be considered as natural oral antimicrobial agents against oral pathogens.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.552-557
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• 1992

To study antibacterial activities of Ganoderma lucidum, its extract was fractionated by various organic solvents with different polarities and the fractions were purified by thin layer chromatography and silica gel column chromatography. The results of antibacterial test of the extracts showed that antimicrobial activities were detected in fractions B and E of the ethylacetate extract. The minimum inhibitory concentration (MIC) of fraction B to Staphylococcus aureus and to Salmonella typtimurium were 0.8% (8,000 ppm). MIC of fraction E to Staphylococcus aureus was 0.185% (1,875 ppm).

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.159-165
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• 1980

A total of 98 strains of Bordetella bronckiseptica isolated from pigs affected the infectious atrophic rhinitis(AR) during 1978 were surveyed for drug sensitivity to 26 chemotherapeutic agents, and minimum inhibitory concentration(MIC), incidence rate of resistant strain and resistant patern from the strains which were obtained from the different pig farm in Jeonnam province were examined. The results obtained are summarized as follows. 1. Most of the strains tested were resistant to Ampicillin (AB, PC), spiramycin(SPO, sulfa drugs (SD) (MIC:$400.0{{\mu}g/ml}$) and streptomycin(SM) (MIC:$200.0{{\mu}g/ml}$). Of the 75.0% of strains were also resistant to penicillin(PC) (MIC:$200.0{{\mu}g/ml}$) and of the 14.3 of strains were inhibited to grow to tetracycline(TC), chlortetracycline(CTC), oxytetracyc-line(OTC), erythromycin(EM), tylosin(TS), leucomycin (LM) and chloramphenicol (CP) (MIC:$6.25{{\mu}g/ml}$). On the other hand, most of the strains tested were inhibited to grow to kanamycin(KM), gentamycin(GM) neomycin(NM) (MIC:$25.0{{\mu}g/ml}$) and to colistin(CL) (MIC:$12.5{{\mu}g/ml}$). 2. Incidence rate of resistant strains to main chemotherapeutic agents was 100.0% of sulfa drugs, 96.4% of streptomycin, 85.7% of penicillin, tetracycline, chloramphenicol and erythromycin, 46.4% of gentamycin, 17.9% of colistin and 0.0% of kanamycin and nalidixic acid.

• The Korean Journal of Mycology
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• v.23 no.2 s.73
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• pp.176-189
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• 1995

For the development of antibiotics from Korean mushrooms, the biological activities of extracts from 98 species of mushrooms and from 25 mushrooms were tested against 9 different Gram-negative bacteria and 8 fungi, respectively. Fruiting bodies of each mushrooms were extracted with petroleum ether (P), 80% ethanol (E), and distilled water (H) in that order. P, E, or H extracts from 20 mushroom samples exhibited the antibacterial activity against 8 different Gram-negative bacteria containing Klebsiella pneumoniae, selectively. Among the mushroom extracts with antibiotic activity, E extracts of Boletus umbriniporus, Armillariella tabescens, Rhodophyllus sinuatus, and Suillus luteus showed various antibiotic activities against several bacteria. E extracts of Abortiporus biennis, Phellinus gilvus, and Polyporus dispansus are highly active against Salmonella typhi and their minimum inhibitory concentration (MIC) was all $10\;{\mu}g/ml$. E extract of Armillariella tabescens showed the antifungal activity against Trichopyton mentagrophytes, and its MIC was $300\;{\mu}g/ml$.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1301-1304
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• 2009

Macelignan is a bioactive compound isolated from nutmeg (Myristica fragrans Houtt.) which has been traditionally used for the food and pharmaceutical purposes. In this study, the activities of macelignan against vegetative cells and spores of Bacillus cereus were evaluated in vitro. Our results showed that the vegetative cells of B. cereus were significantly inhibited in growth by macelignan with minimum inhibitory concentration (MIC) of $4{\mu}g/mL$. The vegetative cells of B. cereus were completely killed with minimum bactericidal concentration (MBC) of $8{\mu}g/mL$ of macelignan. Killing time of macelignan against vegetative cells of B. cereus was very fast; endpoint of macelignan was reached after 4 hr of incubation at $4{\times}MIC$. Macelignan inactivated more than 3-log (99.9%) of spores/mL of B. cereus at the concentration of $100{\mu}g/mL$. Macelignan was found to be effective against vegetative cells and spores of B. cereus. These results suggest that macelignan might be good to be developed as a food preservative.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.301-304
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• 2019

The objective of this study was to determine the in vitro intracellular and extracellular minimum inhibitory concentrations (MICs) of 13 antimicrobials against one recently isolate Lawsonia intracellularis, the etiological agent of proliferative enteropathy (PE). The final MICs were assessed by counting the number of heavily infected cells (HICs;>30 bacteria per cell) using an immunoperoxidase monolayer assay. Enrofloxacin (InMIC; 1~2 ㎍/mL and ExMIC; 16 ㎍/mL) still presented the most notable antimicrobial susceptibility, and marbofloxacin (2 ㎍/mL and 8 ㎍/mL) was followed. Colistin (0.25 ㎍/mL and 2 ㎍/mL) presented a susceptibility followed by tylvalosin (1 ㎍/mL and 2 ㎍/mL). Florfenicol and lincomycin had the weakest susceptibility and amoxicillin, penicillin G, chlortetracycline, oxytetracycline, tiamulin, tilmicosin, and tylosin displayed weak susceptibility. Although some antibiotics showed decreased susceptibility patterns, they showed similar patterns to recent antibiotic susceptibility patterns in Korea. In addition, these results could be one of contributions in clinical fields.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.967-973
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• 2020

The fungal cell wall is a major target of antifungals. In this study, we report the antifungal activity of an ethanol extract from Aucklandia lappa against Candida albicans. We found that the extract caused cell wall injury by decreasing chitin synthesis or assembly and (1,3)-β-D-glucan synthesis. A sorbitol protection assay demonstrated that the minimum inhibitory concentration (MIC) of the A. lappa extract against C. albicans cells increased eight-fold from 0.78 to 6.24 mg/ml in 72 h. Cell aggregates, which indicate damage to the cell wall or membrane, were commonly observed in the A. lappatreated C. albicans cells through microscopic analysis. In addition, the relative fluorescence intensities of the C. albicans cells incubated with the A. lappa extract for 3, 5, and 6 h were 92.1, 84.6, and 79.8%, respectively, compared to the controls, estimated by Calcofluor White binding assay. This result indicates that chitin content was reduced by the A. lappa treatment. Furthermore, synthesis of (1,3)-β-D-glucan polymers was inhibited to 84.3, 79.7, and 70.2% of that of the control treatment following incubation of C. albicans microsomes with the A. lappa extract at a final concentration equal to its MIC, 2× MIC, and 4× MIC, respectively. These findings suggest that the A. lappa ethanol extract may aid the development of a new antifungal to successfully control Candidaassociated disease.

• Journal of Life Science
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• v.30 no.3
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• pp.278-284
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• 2020

Magnolia kobus is known to exert various biological effects, such as antioxidant and hypnotic activity. In this study, we investigated the antimicrobial and anti-inflammatory activity of M. kobus essential oil extracted using steam distillation. Its antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa by the paper disk diffusion and minimum inhibitory concentration (MIC) methods. Its anti-inflammatory activity was evaluated by measuring its inhibition ratio on the production of nitric oxide (NO) and PGE₂ in lipopolysaccharide (LPS)-induced RAW264.7 cells. Its composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that M. kobus essential oil exhibited excellent antibacterial activity against S. aureus, with a clear zone of 18 mm and an MIC value of 0.25 mg/ml. Its clear zones against P. aeruginosa and E. coli were 14 mm and 17 mm, respectively, while its MIC values were 1 mg/ml and 0.5 mg/ml, respectively. The essential oil exhibited no cytotoxicity to the RAW264.7 cells at a concentration of 500 ㎍/ml while showing NO (37.7%) and PGE₂ inhibition (24.0%). Its three main fragrance ingredients identified were 3-carene (77.07%), β-elemene (6.92%), and caryphyllene (2.86%). The results suggest that M. kobus essential oil has potential as a cosmetic functional material with antimicrobial and anti-inflammatory effects.