• Microbiology and Biotechnology Letters
• /
• v.40 no.1
• /
• pp.23-29
• /
• 2012

To isolate a novel antifungal compound, we obtained 100 kinds of endolichenic fungi from Korean Lichen & Allied Bioresources Center and examined their antifungal capability. Three fungi Usnea rigidula (2326), Parmotrema pseudotinctorum (2202) and Myelochroa sp. (2292) showed high antifungal activity against Candida albicans when they grew in both liquid and solid media. We extracted the culture supernatants of these three fungi with chloroform and then with ethyl acetate. Chloroform fraction exhibited the highest antifungal activities when those fractions were examined for the growth inhibition of Candida albicans with disc diffusion method. The chloroform faction was on further analysis with $C_{18}$ column chromatography to see whether the inhibitors are already known or not. Two peak fractions were collected from 4-day culture extract for Usnea rigidula and from 6-day culture extract for Parmotrema pseudotinctorum on the HPLC. A peak fraction from chloroform extracts of 4-day culture filtrate of Parmotrema pseudotinctorum showed higher antifungal activities against C. albicans and C. glabrata than another peak fraction. It appears that the antifungal materials are relatively nonpolar as usnic acid often found in lichenic fungi.

• Journal of Food Hygiene and Safety
• /
• v.27 no.4
• /
• pp.449-455
• /
• 2012

The purpose of this study is to evaluate antimicrobial effects of organic acid and some natural occurring antimicrobials against Staphylococcus aureus isolated from various origins (vegetables, peanut, pea leaf, kim-bab, person, perilla leaf, and animal) and to calculate their MIC and MBC values. Five organic acids (acetic, lactic, citric, malic, and propionic acid), three essential oils (carvacrol, thymol, and eugenol), and two other natural antimicrobials (nisin and cinnamic acid) were evaluated for their antimicrobial effects against 113 strains of S. aureus using combination treatments. Propionic acid (7%), nisin (1%), thymol (1%), carvacrol (1%) showed antimicrobial activities against S. aureus strains in agar disc diffusion test. And, carvacrol, thymol, and nisin were found to be the most effective with the lowest MIC values of 0.0313%, 0.0625%, and 0.0625% against S.aureus, respectively. Propionic acid (0.2313%) and citric acid (0.6000%) were the most effective among organic acids tested. Therefore, these five antimicrobials were selected for next combination treatments. Combination of propionic acid and citric acid were showed the strongest inhibitory effectiveness against S. aureus among combination treatments. These results suggest that organic acid such as propionic and citric acid, and natural occurring antimicrobial such as nisin, carvacrol, and thymol might be possibly used as preservatives for inhibiting S. aureus in foods.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.102-108
• /
• 2019

Melaleuca alternifolia contains terpineol-4, cineol, sesquiterpenes etc., and has a germicidal effect and skin moisturizing effect. It also has the characteristics of relieving acne inflammation, treating dandruff, relieving pain, and relieving depression. In this study, an antimicrobial substance extracted from tea tree using an organic solvent (methanol, dichloromethane, ethyl acetate) and hydrothermal extraction method. And confirmed the antimicrobial activity of each extract. In order to verify the antimicrobial activity, nine pathogenic bacteria (Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa and Vibrio parahaemolyticus) were used. The antimicrobial activity of each extracts were confirmed by the commonly used disc diffusion method. The results showed that the fraction extracts of ethyl acetate and methanol had antimicrobial effects against V. parahaemolyticus and S. aureus. Using these results, we confirmed the antimicrobial activity of each fraction extracts and hot water extracts against V. parahaemolyticus. After the treat of samples, we confirmed at over 99.9 % of antimicrobial activity. In case of antifungal activities, we confirmed of preservation effect during over 45 hours. Based on the results of this research, further studies will be conducted to confirm the possibility of development as a new antimicrobial agent.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.2
• /
• pp.214-220
• /
• 2019

Hwangryunhaedok-tang (HT) is prescribed in oriental medicine to treat inflammation-related diseases. This study examined the anti-bacterial effect to select the index components of Traditional Chinese Medicine (TCM) HT. The disc diffusion method and minimum inhibition concentrations (MIC) tests were conducted to measure the antibacterial activity of HT. The strains were Staphylococcus aureus ATCC 25923 and Escherichia coli 23724. Berberine and geniposide were selected as the index components of HT and were analyzed quantitatively by high-performance liquid chromatography (HPLC). As a result, the inhibition ring was formed at $11.7{\pm}1.3mm$ and $8.7{\pm}0.7mm$ at HT 20 mg and 10 mg on S.aureus ATCC 25923, respectively; and $8.0{\pm}0.0mm$ at HT 20 mg on E.coli ATCC 23724. The MIC were 31.25 mg/mL in S.aureus ATCC 25923 and 125.0 mg/mL in E.coli ATCC 23724. In quantitative analysis for standardization, HT contained 16.55 mg/g of berberine and 81.85 mg/g of geniposide. Overall, when antibiotics are developed using natural products, they may reduce the side effects and inhibit resistant bacteria. If research on HT continuously proceeds, positive developments are expected to be made in oriental medicine as well as in various other industries.

• Journal of Food Hygiene and Safety
• /
• v.37 no.4
• /
• pp.285-295
• /
• 2022

The ability of volatile components of essential oils (EO) from cinnamon, clove, and lemongrass to inhibit biofilms formed on polyethylene and stainless steel by six types of food poisoning bacteria was investigated. The main components of cinnamon EO were identified as cinnamaldehyde (38.30%), linalool (9.61%), β-caryophyllene (8.90%), and 1,3,4-eugenol (8.19%). 1,3,4-Eugenol (61.84%) was the dominant component of clove EO. The major component of lemongrass EO was citral. Citral is a natural mixture of two isomeric acyclic monoterpene aldehydes: geranial (trans-citral, 19.11%) and neral (cis-citral, 19.23%). Among these major compounds, cinnamaldehyde, linalool, eugenol, and citral exhibited comparatively strong antimicrobial activity in the disc diffusion assay. Treatments with 0.1% eugenol and citral were highly effective on biofilm inhibition on both tested surfaces. Cinnamaldehyde (0.1%) was effective against biofilm formation by Listeria monocytogenes ATCC 19112 and Staphylococcus aureus KCCM 11812. These results suggested the potential of cinnamaldehyde, eugenol, and citral treatments in inhibiting the formation of biofilms by food poisoning bacteria.

• Korean Journal of Pharmacognosy
• /
• v.54 no.2
• /
• pp.72-79
• /
• 2023

MRSA is Staphylococcus aureus resistant to β-lactam antibiotics, and is a worldwide infectious disease. Even with the discovery of new antibiotics, resistance develops rapidly, so new alternatives are needed. Jakyakgamcho-tang (JGT) is a combination of Jakyak and Gamcho, and has been mainly used as an antispasmodic and analgesic in oriental medicine. This study was conducted to find out whether there is an effect on MRSA in relation to the anti-inflammatory effect of JGT and the antibacterial effect of Jakyak and Gamcho found in previous studies. In this study, in order to investigate the antibacterial activity of JGT and the combined effect of existing antibiotics, after extracting JGT with 70% EtoH, the disc diffusion method, minimum inhibitory concentration (MIC), drug combination effect (FICI), and time-kill analysis (Time-kill assay), metabolic inhibition, Western blot and qRT-PCR analysis were used to confirm the antibacterial activity mechanism of MRSA of JGT. As a result of the experiment, all of MRSA showed antibacterial activity in JGT's disc diffusion method, and the MIC was 250-1000 ㎍/mL. When existing antibiotics and JGT were combined with drugs, most had synergy or partial synergy. In addition, it was confirmed that the degree of bacterial growth was suppressed over time when simultaneous administration for 24 hours. JGT showed a synergistic effect when administered together with the ATPase-inhibitor DCCD, suggesting that it affected the inhibition of ATPase. As a result of observing the expression of PBP2a, and hla protein in the JGT-treated group and the untreated control group through wstern blot, it was confirmed that the protein expression of the JGT-treated group was significantly suppressed, and the expression levels of mecA, mecR1 and hla genes were also suppressed during JGT treatment. was observed by qRT-PCR. Combining the results of the experiment, it can be seen that JGT has antibacterial activity in MRSA, and when combined with existing antibiotics, the effect was increased compared to treatment with the drug alone. This suggests that JGT can be an alternative to treatment for antibiotic resistance of MRSA.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.10
• /
• pp.1353-1360
• /
• 2011

This study was performed to investigate the antimicrobial effects against food-borne pathogens and antioxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The $IC_{50}$ of the extract for DPPH radical scavenging activity was about half that of ${\alpha}$-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.3
• /
• pp.975-979
• /
• 2012

Structure and Dynamics of dilute two-dimensional (2D) ring polymer solutions are investigated by using discontinuous molecular dynamics simulations. A ring polymer and solvent molecules are modeled as a tangent-hard disc chain and hard discs, respectively. Some of solvent molecules are confined inside the 2D ring polymer unlike in 2D linear polymer solutions or three-dimensional polymer solutions. The structure and the dynamics of the 2D ring polymers change significantly with the number ($N_{in}$) of such solvent molecules inside the 2D ring polymers. The mean-squared radius of gyration ($R^2$) increases with $N_{in}$ and scales as $R{\sim}N^{\nu}$ with the scaling exponent $\nu$ that depends on $N_{in}$. When $N_{in}$ is large enough, ${\nu}{\approx}1$, which is consistent with experiments. Meanwhile, for a small $N_{in}{\approx}0.66$ and the 2D ring polymers show unexpected structure. The diffusion coefficient (D) and the rotational relaxation time ($\tau_{rot}$) are also sensitive to $N_{in}$: D decreases and $\tau$ increases sharply with $N_{in}$. D of 2D ring polymers shows a strong size-dependency, i.e., D ~ ln(L), where L is the simulation cell dimension. But the rotational diffusion and its relaxation time ($\tau_{rot}$) are not-size dependent. More interestingly, the scaling behavior of $\tau_{rot}$ also changes with $N_{in}$; for a large $N_{in}$ $\tau_{rot}{\sim}N^{2.46}$ but for a small $N_{in}$ $\tau_{rot}{\sim}N^{1.43}$.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.6
• /
• pp.1343-1349
• /
• 2004

A native strain of Pasteurella multocida was isolated from pigs suffering from severe atrophic rhinitis at domestic farms in Gyeonggi Province, Korea, and was identified as capsular serogroup 'D' and somatic serotype '4' by disc diffusion decapsulation and gel diffusion precipitation tests, respectively. The P. multocida (D:4) induced atrophic rhinitis in healthy pigs by the secondary infection. The gene for outer membrane protein H (ompH) of P. multocida (D:4) was cloned in Escherichia coli DH5$\alpha$ by PCR. The open reading frame of the ompH was composed of 1,023 bp, possibly encoding a protein with 341 amino acid residues containing a signal peptide of 20 amino acids at N-terminus, and the gene product with molecular mass of ca. 38 kDa was identified by SDS-PAGE. Hydropathy profiles indicated that there are two variable domains in the OmpH. To express the ompH in E. coli, the gene was manipulated in various ways. Expression of the truncated as well as full-length forms of the recombinant OmpH was fatal to the host E. coli BL21 (DE3). However, the truncated OmpH fused with GST was consecutively expressed in E. coli DH5$\alpha$. A large quantity of the fused polypeptide was purified through GST-affinity chromatography.

• Journal of dental hygiene science
• /
• v.21 no.2
• /
• pp.119-126
• /
• 2021

Background: Dental caries is mainly composed of various cellular components and is deposited around the tooth surface and gums, causing a number of periodontal diseases. Streptococcus mutans is commonly found in the human oral cavity and is a significant contributor to tooth decay. The use of antibacterial ingredients in oral hygiene products has demonstrated usefulness in the management of dental caries. This study investigated the anticaries effect of the ethanol extract of Terminalia chebula (EETC) against S. mutans and their cytotoxicity to gingival epithelial cells. Methods: The EETC was prepared from T. chebula fruit using ethanol extraction. Disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and colony forming unit (CFU) were analyzed to investigate the antimicrobial activity of the EETC. Glucan formation was measured using the filtrate of the bacterial culture medium and sucrose. Gene expression was analyzed using reverse transcription-polymerase chain reaction (RT-PCR). Cytotoxicity was analyzed via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Results: The antibacterial activity of the EETC was explored using disc diffusion and CFU measurements. The MIC and MBC of the EETC were 10 and 20 ㎍/ml, respectively. EETC treatment decreased insoluble glucan formation by S. mutans enzymes and also resulted in reduced glycosyltransferase B (gtf B), gtf C, gtf D, and fructosyltransferase (ftf), expressions on RT-PCR. In addition, at effective antibacterial concentrations, EETC treatment was not cytotoxic to gingival epithelial cells. Conclusion: These results demonstrate that the EETC is an effective anticaries ingredient with low cytotoxicity to gingival epithelial cells. The EETC may be useful in antibacterial oral hygiene products for the management of dental caries.