• Journal of Plant Biotechnology
• /
• v.47 no.1
• /
• pp.100-106
• /
• 2020

Coix lacryma-jobi (Hanjeli) is known to posses anti-microbial properties. Therefore, phytochemical compounds of C. lacryma-jobi have been studied to produce novel antimicrobial agents as treatments against antibiotic-resistant bacteria.The objective of this study was to determine the phytochemical composition and antibacterial activity of the C. lacryma-jobi oil against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The phytochemical composition of the oil was determined via gas chromatography mass spectrophotometry (GC-MS). Moreover, agar disk and agar well diffusion were employed to screen the antibacterial activity of the oil. An agar well diffusion test was implemented to determinate MIC's (minimum inhibitory concentrations). Dodecanoic acid, tetradecanoic acid, 2,3-dihydroxypropylester, 1,3-dioctanoin, N-methoxy-N-methyl-3,4-dihydro-2H-thiopyran6-carboxamide, propanamide, 5-Amino-1-(quinolin-8-yl)-1,2,3-triazole-4-carboxamide, and pyridine were identified in the C. lacryma-jobi oil. The MIC value of the oil was 0.031 g/L and the MBC of the oil was 0.125 g/L effective in all test bacteria. Dodecanoic acid displayed inhibitory activity against gram-positive and gram-negative bacteria. Therefore, our research demonstrated C. lacryma-jobi (Hanjeli) oil exhibited antibacterial activity against E. coli, S. aureus, and B. subtilis. These research suggest that C. lacryma-jobi root oil could be used for medicinal purposes; however clinical and in vivo tests must be performed to evaluate its potential as an antibacterial agent.

• Journal of Microbiology and Biotechnology
• /
• v.34 no.8
• /
• pp.1718-1726
• /
• 2024

Development of novel antibacterial agents is imperative due to the increasing threat of antibiotic-resistant pathogens. This study aimed to develop the enhanced antibacterial activity and in-vivo efficacy of a novel truncated endolysin, CHAP^SAP26-161, derived from the endolysin Lys^SAP26, against multidrug-resistant bacteria. CHAP^SAP26-161 exhibited higher protein purification efficiency in E. coli and antibacterial activity than Lys^SAP26. Moreover, CHAP^SAP26-161 showed the higher lytic activity against A. baumannii with minimal bactericidal concentrations (MBCs) of 5-10 ㎍/ml, followed by Staphylococcus aureus with MBCs of 10-25 ㎍/ml. Interestingly, CHAP^SAP26-161 could lyse anaerobic bacteria, such as Clostridioides difficile, with MBCs of 25-50 ㎍/ml. At pH 4-8 and temperatures of 4℃-45℃, CHAP^SAP26-161 maintained antibacterial activity without remarkable difference. The lytic activity of CHAP^SAP26-161 was increased with Zn²⁺. In vivo tests demonstrated the therapeutic effects of CHAP^SAP26-161 in murine systemic A. baumannii infection model. In conclusion, CHAP^SAP26-161, a truncated endolysin that retains only the CHAP domain from Lys^SAP26, demonstrated enhanced protein purification efficiency and antibacterial activity compared to Lys^SAP26. It further displayed broad-spectrum antibacterial effects against S. aureus, A. baumannii, and C. difficile. Our in vitro and in-vivo results of CHAP^SAP26-161 highlights its promise as an innovative therapeutic option against those bacteria with multiple antibiotic resistance.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1997.04a
• /
• pp.40-47
• /
• 1997

New quinolones generally have a broad antibacterial spectrum against gram-positive, gram-negative, glucose-nonfermenting and anaerobic bacteria. Some of newly developed quinolones have potent activities against S. aureus including MRSA, S.pneumoniae including PRSP, B. fragilis, chlamydiae, mycoplasmas and mycobacteria as well, and show good activities against various strains resistant to antibacterial agents of other classes. Quinolones display postantibiotic effects in vitro and are bactericidal at concentrations similar to or twice that of the minimum inhibitory concentrations (MICs) for susceptible pathogens. In experimental murine infection models including systemic infections with various pathogens such as S. aureus, S. pyogenes, S. pneumoniae, E. coli and P. aeruginosa, quinolones have shown good oral efficacy as well as parenteral efficacy. Good oral absorption and good tissue penetration of quinolones account for good therapeutic effects in clinical settings. The target of quinolones are two structurally related type II topoisomerases, DNA gyrase and DNA topoisomerase IV. Quinolones are shown to stabilize the ternary quinolone-gyrase-DNA complex and inhibit the religation of the cleaved double-stranded DNA. Bacteria can acquire resistance to quinolones by mutations of these target enzymes. Mutation sites and amino acid changes in DNA gyrase and DNA topoisomerase IV are similar in the organisms examined, suggesting that the mechanism of quinolone resistance in the target enzymes is essentially the same among various organisms. Quinolones act on both the target enzymes to different degrees depending on the organisms or agents tested, and bacteria become highly resistant to quinolones in a step-wise fashion. Incomplete cross-resistance among quinolones in some strains of E. coli and S. aureus suggests the possibility of finding quinolones active against quinolone-resistant strains which are prevailing now. To find such quinolones, the potency toward two target enzymes and the membrane permeability including influx and/or efflux systems should be taken into account.

• Applied Chemistry for Engineering
• /
• v.7 no.6
• /
• pp.1096-1104
• /
• 1996

In order to synthesize a new antibacterial and antitumor agents, we have prepared new analogues pteroic acid(13a, 13b), which means C-9 position of pteroic acid has been replaced by norfloxacin(8) or ciprofloxacin(9) and amino group of C-2 position by $CH_3$. These derivatives were synthesized coupling at N-4 piperazine of norfloxacin and ciprofloxacin with 2-amino-3-cyano-5-chloromethylpyrazine(20) provided 1-alkyl(ethyl, cyclopropyl)-6-fluoro-1,4-dihydro-4-oxo-7-[[4-N-(2-amino-3-cyanopyrazin-5-yl)methyl]piperazin-1-yl]-3-quinoline-carboxylic acid(12a, 12b). It was then cyclized with acetamidine. HCI to obtain new analogues of C-2 desaminomethylpteroic acid(13a, 13b) in yield of 76.2% and 82.8 % respectively. These compounds were tested in vitro on antibacterial activity against Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa ATCC9027. In general, these synthesized compounds(13a, 13b) showed less potent activities than those of norfloxacin.

• Membrane Journal
• /
• v.32 no.1
• /
• pp.23-32
• /
• 2022

Bacteria grow biofilm on various surface such as separation membrane, food packaging film and biomedical device. Growth of biofilm is associated with the formation of a complex structure of exopolysaccharides. Effect of antibacterial effect reduce drastically once the biofilm developed due to the difficulties in mass transport of antimicrobial agent. In order to enhance the antibacterial activity, surface of the membrane is modified, coated or immobilized with functional materials with biocidal properties. One of the idea is to introduce positive charge on the membrane surface by the presence of quaternary ammonium group which might displace divalent metal ion such as magnesium or calcium present in the bacteria cell wall. Efficacy of cell membrane disruption depends on the mobility of the agents available directly on the surface environment. In this review, various biocidal agents like quaternary ammonium group, helamine or zwitter ion containing membrane are discussed.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.20 no.3
• /
• pp.512-518
• /
• 1996

Microcapsules containing 2, 4, 4'-trichloro-2-hydroxydiphenyl ether and perfumes were prepared by the coacervation using poly (vinyl alcohol) and crosslinking agents. Effects of dispersing agents, core materials, agitating speed and crosslinking agents on microcapsule size were investigated. The mean and deviation of microcapsule diameters decreased with increasing agitation speed. The diameters of m;crocapsules decreased with increasing dispering agent concentration at 6, 000 rpm of agitation speed, but it was not changed at 10, 000 rpm. The dispering effect of PVA is better than that of gum arabic. The slight increase in the diameter of microcapsule was observed when the amount of core material was increased. As the amount of crosslinking agent was increased, the diameter of microcapsule was decreased.

• Fisheries and Aquatic Sciences
• /
• v.18 no.3
• /
• pp.241-247
• /
• 2015

In an effort to discover alternative phytotherapeutic antimicrobial agents to combat Streptococcus parauberis, a fish pathogenic bacterium, we evaluated the antibacterial activity of seaweed extracts in vitro. A methanolic extract of Ecklonia cava exhibited strong antibacterial activity against S. parauberis isolated from olive flounder Paralichthys olivaceus. Furthermore, the n-hexane soluble (Hexane) fraction of the E. cava methanolic extract exhibited the greatest antibacterial effect on S. parauberis strains with a minimum inhibitory concentration (MIC) ranging from 256 to $1,024{\mu}g/mL$. In addition, the MIC values of oxytetracycline against antibiotic-resistant S. parauberis were markedly reduced up to 64-fold in combination with the Hexane fraction, suggesting that the antibacterial activity of the antibiotic was restored when combined with the Hexane fraction. The interaction between both antibiotics and the Hexane fraction was assessed by the fractional inhibitory concentration (FIC) index. The Hexane fraction and oxytetracycline combination against antibiotic-resistant S. parauberis strains resulted in a median ${\sum}FIC$ range of 0.502 to 0.516. Thus, the synergistic ranges of median ${\sum}FIC$ < 1 were observed for all combinations of the Hexane fraction and oxytetracycline against S. parauberis. To the best of our knowledge, this is the first report indicating the efficacy of an E. cava extract against fish pathogenic bacterium S. parauberis.

• The Korea Journal of Herbology
• /
• v.30 no.5
• /
• pp.15-21
• /
• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• Journal of Life Science
• /
• v.16 no.2 s.75
• /
• pp.297-301
• /
• 2006

For developing natural antibacterial agents from Houttuynia cordata Thunb., antibacterial effects of volatile flavor component using various bacterial sp. were tested. Extraction from Houttuynia cordata Thunb. by using SDE (Simultaneous steam Distillation-Extraction) showed strong antibacterial activities against Vibrio and Bacillus genus, such as Vibrio. cholerae, V. parahaemolyticus, V. vulnificus, Bacillus. cereus, and B. subtilis. Then chemical compositions of leaf and stem were analyzed. The contents of crude protein, lipid, and ash in stem were less than those of leaf, but fiber contents were higher than those of leaf. Among the amino acids, aspartic acid, glutamic acid, glycine, and arginine were higher than those of other amino acids. Linolenic acid, linoleic acid, oleic acid, and palmitic acid were major fatty acids. Major minerals of Houttuynia cordata Thunb. were potassium, calcium, phosphorus, magnesium, iron, zinc, and copper. Especially, in the case of potassium, it was highest.

• KSBB Journal
• /
• v.15 no.3
• /
• pp.226-231
• /
• 2000

Antibacterial activities of edible plant extracts were investigated to develop natural antimicrobial agents protecting horticultural products from spoiling-microorganisms during their storage. Crude extracts of Artemisa capillaris Allium tuberosum Ailanthus altissima Zanthoxylum pieperitum Pinus densiflora Morus alba lxeris dentata and Allium sativum showed remarkable antibacterial activities against Escherichia coli K 12 and Bacillus subtilis KCTC 1028 After solvent extraction of the crude extracts with n-hexane ethyl acetate chloroform and water in sequence each fractions was re-examined for the antbacterial activities. As results the ethyl acetate fractions of A. capillaris Aaltissima, P. densiflora and I. dentata and all fractions of Z. piperitum and A. sativium showed relatively strong antibacterial activities against E. coli and B. subtilis and the ethyl acetate fraction of A. altissima was the strongest(6mm and 7mm respectively) against two strawberry-spoiling bacteria isolated and identified at our laboratory as Staphylococcus sp. TG-101 and Staphylococcus sp. TG-102.