• Journal of Korean society of Dental Hygiene
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• v.18 no.1
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• pp.9-18
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• 2018

Objectives: Pleurotus eryngii is used both for edible and medicinal purposes, and has a physiological activity. The purpose of this study is to investigate the antibacterial effect of Pleurotus eryngii against six oral pathogens (Staphylococcus aureus, Streptococcus criceti, Streptococcus mutans, Streptococcus ratti, Streptococcus sobrinus, and Actinomyces viscosus). Methods: The antibacterial activities of various extracts of Pleurotus eryngii were examined by disc diffusion assay and minimum inhibitory concentration (MIC). The disc diffusion assay was performed by putting a paper disc soaked in extracts on plates inoculated bacterial cultures. The MIC of these extracts was determined by using a broth microdilution assay at a concentration ranging between 0.03 mg/ml to 15.00 mg/ml. The growth inhibition effect of extracts was measured at 600 nm for 24 hrs. Results: The antibacterial activity was confirmed against all six tested bacteria at Pleurotus eryngii ethyl acetate extract by the disc diffusion method. Acetone extract showed the antibacterial activity only against 4 strains containing Streptococcus criceti, Streptococcus mutans, Streptococcus ratti, and Actinomyces viscosus. In ethanol extract, no activity was observed against other strains except Staphylococcus aureus. MIC values of ethyl acetate extract were the same, 7.50 mg/ml in all tested bacteria. Conclusions: Pleurotus eryngii exhibited the antibacterial activity against oral pathogens (Staphylococcus aureus, Streptococcus criceti, Streptococcus mutans, Streptococcus ratti, Streptococcus sobrinus, and Actinomyces viscosus). Thus, Pleurotus eryngii may be considered as a natural antibacterial agent for treatment of dental diseases.

• KSBB Journal
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• v.30 no.5
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• pp.253-256
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• 2015

The antibacterial activity from Tricholoma matsutake extracts were confirmed by minimum inhibitory concentration (MIC) test against various bacteria. Tricholoma matsutake extracts was applied for manufacturing low salted Jeot-gal with sodium DL-malate and sodium nitrite as food preservatives. Due to antibacterial activity from Tricholoma matsutake extracts, MIC of sodium DL-malate and sodium nitrite were significantly reduced to 0.025 g/L and 0.25 g/L, respectively. As a result of this study, a premium low salted Jeot-gal can be developed with low concentration of food preservatives by adding Tricholoma matsutake extracts.

• Advances in nano research
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• v.7 no.4
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• pp.241-248
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• 2019

Recent researches demonstrated well promising anticancer activities for antibiotics. Such effects would be significantly increased while nanoparticle based delivery systems were applied. In this study, the goal was aim to improve anticancer and antitoxic effects of Streptomycin by loading on special kind of dendrimer (anionic-linear-globular second generation). In the current study, Size and zeta potential as well as AFM techniques have been used to prove the fact that the loading was performed correctly. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the drug loaded on dendrimer nanoparticle were determined and compared with both of dendrimer alone and free drug with respect to staphylococcus aureus as the test microorganism. The anticancer activity among three groups including Streptomycin, Streptomycin -G2 dendrimer, and control was measured in vitro. In vitro studies showed that G2 anionic linear-globular polyethylene-glycol-based dendrimer, which loaded on Streptomycin was able to significantly improve the treatment efficacy over clinical Streptomycin alone with respect to proliferation assay. Maximal inhibitory concentration (IC50) was calculated to be $257{\mu}g/mL$ for streptomycin alone and $55{\mu}g/mL$ for Streptomycin -G2 dendrimer. In addition, Streptomycin -G2 dendrimer conjugate prevented the growth of MCF-7 cancerous cells in addition to enhance the number of apoptotic and necrotic cells as demonstrated by an annexin V-fluorescein isothiocyanate assay. Streptomycin -G2 dendrimer conjugate was able to increase Bcl-2/Bax ratio in a large scale compared with the control group and Streptomycin alone. Based on results a new drug formulation based nano-particulate was improved against S. aureus with sustained release and enhanced antibacterial activity as well as anticancer activity shown for functional cancer treatment with low side effects.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.418-429
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• 2019

This study was conducted to evaluate the antioxidant and antimicrobial activities of lyophilized extracts of scallions (Allium fistulosum L., SLE), garlic (Allium sativum, GLE), and gold kiwi (Actinidia chinensis, GKE) and their effects on the quality of chicken breast meat inoculated with L. monocytogenes during storage for 9 days at $4^{\circ}C$. The lowest minimum inhibitory concentration and minimum bactericidal concentration (25 and 100 mg/mL, respectively) against L. monocytogenes were observed for SLE and GLE, respectively. GKE had the lowest half-maximal inhibitory concentration ($IC_{50}$) for 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity (5.06 mg/mL). The pH values of meat inoculated with L. monocytogenes and dipped in 1% SLE (LSLE), 1% GLE (LGLE), or 1% GKE (LGKE) were lower than that of the control on day 3 of storage (p<0.05). The initial population of L. monocytogenes in meat was 4.95-5.01 Log CFU/g. However, the population in the LSLE (5.73 Log CFU/g) was lower than that in the control (6.23 Log CFU/g) on day 5 (p<0.05). The volatile basic nitrogen value of the LSLE (19.90 mg/100 g) was lower than that of the control (24.38 mg/100 g) on day 7 (p<0.05). Moreover, treatment with SLE resulted in the maintenance of meat quality and reduced the population of L. monocytogenes on the meat. Thus, SLE may be used as an alternative natural and environmentally friendly sanitizer for reducing L. monocytogenes contamination in the chicken meat industry.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1656-1666
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• 2021

Dental pathogens lead to chronic diseases like periodontitis, which causes loss of teeth. Here, we examined the plausible antibacterial efficacy of copper nanoparticles (CuNPs) synthesized using Cupressus macrocarpa extract (CME) against periodontitis-causing bacteria. The antimicrobial properties of CME-CuNPs were then assessed against oral microbes (M. luteus. B. subtilis, P. aerioginosa) that cause periodontal disease and were identified using morphological/ biochemical analysis, and 16S-rRNA techniques. The CME-CuNPs were characterized, and accordingly, the peak found at 577 nm using UV-Vis spectrometer showed the formation of stable CME-CuNPs. Also, the results revealed the formation of spherical and oblong monodispersed CME-CuNPs with sizes ranged from 11.3 to 22.4 nm. The FTIR analysis suggested that the CME contains reducing agents that consequently had a role in Cu reduction and CME-CuNP formation. Furthermore, the CME-CuNPs exhibited potent antimicrobial efficacy against different isolates which was superior to the reported values in literature. The antibacterial efficacy of CME-CuNPs on oral bacteria was compared to the synergistic solution of clindamycin with CME-CuNPs. The solution exhibited a superior capacity to prevent bacterial growth. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and fractional inhibitory concentration (FIC) of CME-CuNPs with clindamycin recorded against the selected periodontal disease-causing microorganisms were observed between the range of 2.6-3.6 ㎍/ml, 4-5 ㎍/ml and 0.312-0.5, respectively. Finally, the synergistic antimicrobial efficacy exhibited by CME-CuNPs with clindamycin against the tested strains could be useful for the future development of more effective treatments to control dental diseases.

• The Korea Journal of Herbology
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• v.35 no.3
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• pp.47-54
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• 2020

Objective : Infectious diseases are a growing problem worldwide by Methicillin-resistant Staphylococcus aureus (MRSA). Daehwangmokdan-tang is one of the oriental medicine prescriptions contained in Principles and Practice of Eastern Medicine. This study investigated the antibacterial activity of EtOH 70% extracts of Daehwangmokdan-tang (DMT) which prescription is composed of oriental medicine against MRSA. Methods : The antimicrobial activity and active concentration of MRSA were verified by measuring the minimum inhibitory concentration (MIC) of DMT. In addition, the effects of the disease were checked by treating the existing antibiotics and large ethanol extract in parallel, and the extent of growth suppression was checked over time. In addition, cell membrane permeability experiment confirmed the effect of large DMT on the immunity mechanism of MRSA. Results : TThe minimum inhibitory concentration of DMT against MRSA is 500 ~ 2000 ㎍/㎖ by broth dilution method. In the checkerboard method, the combinations of DMT with antibiotics has partial synergistic effect or synergy effect and DMT markedly reduced the MICs of the antibiotics oxacillin (OX), gentamicin (GEN) against MRSA. In the inhibition of resistance mechanism of DMT against MRSA, the expression of resistance gene and protein about β-lactam antibiotic was reduced. Also, we observed the effect of DMT about cell membrane permeability against MRSA, and confirmed that DMT suppressed growth of strains by increasing cell membrane permeability and energy metabolism. Conclusion : Basis on the result, we speculate that DMT may be useful for the treatment of MRSA infections when used in combination with β-lactam antibiotic.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1179-1188
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• 2023

Escherichia coli, particularly multidrug-resistant (MDR) strains, is a serious cause of healthcare-associated infections. Development of novel antimicrobial agents or restoration of drug efficiency is required to treat MDR bacteria, and the use of natural products to solve this problem is promising. We investigated the antimicrobial activity of dried green coffee (DGC) beans, coffee pulp (CP), and arabica leaf (AL) crude extracts against 28 isolated MDR E. coli strains and restoration of ampicillin (AMP) efficiency with a combination test. DGC, CP, and AL extracts were effective against all 28 strains, with a minimum inhibitory concentration (MIC) of 12.5-50 mg/ml and minimum bactericidal concentration of 25-100 mg/ml. The CP-AMP combination was more effective than CP or AMP alone, with a fractional inhibitory concentration index value of 0.01. In the combination, the MIC of CP was 0.2 mg/ml (compared to 25 mg/ml of CP alone) and that of AMP was 0.1 mg/ml (compared to 50 mg/ml of AMP alone), or a 125-fold and 500-fold reduction, respectively, against 13-drug resistant MDR E. coli strains. Time-kill kinetics showed that the bactericidal effect of the CP-AMP combination occurred within 3 h through disruption of membrane permeability and biofilm eradication, as verified by scanning electron microscopy. This is the first report indicating that CP-AMP combination therapy could be employed to treat MDR E. coli by repurposing AMP.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.283-291
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• 2024

This study compared and evaluated the antibacterial activities and MIC of snowberry extract and fermented extract. For antibacterial activity, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida Albicans were used. Antimicrobial activity and MIC were measured at concentrations of 10, 50, 100, and 200 mg/mL. Antibacterial activity was measured using the 8mm paper disc method. In the case of snowberry extract, it was confirmed that the root extract showed antimicrobial activity at concentrations of 100 mg/mL and 200 mg/mL, and in the case of fermented extract, it showed antimicrobial activity at 200 mg/mL. As a result of the MIC, for fermentation in snowberry leaf and root extracts, the minimum inhibitory concentration for each bacterium was confirmed in stem extracts. The above results indicate that the antibacterial properties of snow berries are improved by fermentation.

• 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.

• YAKHAK HOEJI
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• v.50 no.1
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• pp.15-20
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• 2006

Puerarin and daidzin have been isolated from Puerariae thunbergiana Benth. Structures were determined by spectroscopic methods. Compounds showed weak antimicrobial activity against S. mutans, S. epidermidis, S. aureus, and C. albicans (MIC, $800{\mu}g/ml$). However, these compounds were not antioxidative. Puerariae thunbergiana Benth. extracts against microorganisms were evaluated in terms of the minimum inhibitory concentrations (MIC). In general, C. albicans was stronger antimicrobial activity than the other microorganisms. The antioxidative activity of was observed in the etyl acetate extract ($IC_{50},\;119.87{\pm}0.16\;{\mu}g/ml$). The DPPH radical scavenging effect ($IC_{50},\;1,673.3{\pm}0.54\;{\mu}M$) of the puerarin was comparable with that of synthetic antioxidant, BHA $(IC_{50},\;88.39{\pm}1.1){\times}10^{3}{\mu}M$. These results suggest that puerarin and daidzin have a potential antimicrobial activity.