• Journal of Microbiology and Biotechnology
• /
• v.22 no.6
• /
• pp.800-805
• /
• 2012

Licochalcone E was firstly isolated from licorice root in 2005, which belongs to the retrochalcone family. Studies on the biological activities of licochalcone E were in the initial stage. In the study, we demonstrated that licochalcone E has potent antimicrobial property against Staphylococcus aureus. Furthermore, via hemolysis, Western blot, and real-time RT-PCR assays, we have shown that subinhibitory concentrations of licochalcone E dose-dependently reduces the production of ${\alpha}$-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The data suggest that licochalcone E may deserve further investigation as a potential therapeutic against S. aureus infections, or the structure of licochalcone E may be used as a basis for chemical synthesis of novel anti-S. aureus compounds.

• Journal of the Korean Chemical Society
• /
• v.57 no.2
• /
• pp.221-226
• /
• 2013

A series of some novel 2-[5-(substituted phenyl)-[1,3,4]oxadiazol-2-yl]-benzoxazoles were synthesized by using benzoxazole-2-carboxylic acid on reaction with thionyl chloride in presence of ethanol solvent at room temperature gave benzoxazole-2-carbonyl chloride, which is turned into benzoxazole-2-carboxylic acid hydrazide on reaction with hydrazine hydrate in ethanol solvent under reflux. The subsequent treatment of benzoxazole-2-carboxylic acid hydrazide with an appropriate aromatic carboxylic acid in presence of polyphosparic acid under reflux afforded the title compounds. The chemical structures of the newly synthesized compounds were elucidated by their IR, $^1H$ NMR and Mass spectral data analysis. Further the compounds are used to find out their ability towards anti microbial and nematicidal activity.

• YAKHAK HOEJI
• /
• v.16 no.2
• /
• pp.97-107
• /
• 1972

Thirty-three Mannich bases of 2,2'-methylene bis(3,4,6-trichlorophenoxyacetic acid) were synthesized as potential antimicrobial agents and tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Trichophyton rubrum, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger and Aspergillus oryzae in vitro. It was found that: 1) Compounds 24 and 22 were active against Staphylococcus aureus and Bacillus subtilis at the concn. of 1 $\mu$g/ml respectively; 2) Compounds 9 and 29 were active against Trichophyton rubrum at the concn. of 2 $\mu$g/ml respectively; 3) Compouns 9 and 30 were active against Microsporum gypseum at the concn. of 2 $\mu$g/ml respectively; 4) Compounds 6,9,13,15,21,28,29,31,33 and 34 were active against Epidermophyton floccosum at the concn. of 1 $\mu$g/ml respectively; 5) Compounds 6,9,18 and 28 were active against Aspergillus niger and Aspergillus oryzae at the concn. of 1 $\mu$g/ml respectively.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.10
• /
• pp.1513-1517
• /
• 2006

One single lactic acid producing bacterium, isolated from kimchi, inhibited the growth and adherence of Helicobacter pylori to the human gastric epithelial cell line MKN-45. This isolate was identified as Lactobacillus plantarum and termed L. plantarum strain PL9011. The adherence of H pylori, in the presence of live or nonviable L. plantarum strain PL9011 (10-fold CFU), decreased to 14-20%. The spent culture supernatant of L. plantarum strain PL9011 resulted in the eradication of H pylori. This activity remained stable following neutralization and heat treatment, but not following pepsin treatment, thereby suggesting small peptides as the inhibitory factor. L. plantarum strain PL9011 did not produce any harmful metabolites or enzymes. The results obtained in this study suggest that the L. plantarum strain PL9011 may be a potential novel probiotic for the stomach.

• Biomedical Science Letters
• /
• v.28 no.1
• /
• pp.50-57
• /
• 2022

In this study, we tried to examine the possibility of developing a dental product such as tooth decay prevention and oral hygiene by manufacturing a natural polymer film for oral use. Natural polymer films were prepared from shark byproduct extract (SBE) and gellan gum (GG). As an antibacterial substance, the antibacterial activity of green tea extract against tooth decay-causing bacteria was measured. An film was prepared by adding green tea extract to the composition of SBE and GG. The mechanical, solubility, moisture content and antibacterial function of the prepared film were investigated in detail. Also, the incorporation of GTE into the SBE/GG film improved the physical performance of the film. Increasing the content of GTE improved the antioxidant and antibacterial properties of the film. Formulation of antimicrobial SBE/GG film containing green tea extract was established and these results evidently showed potential for cavity prevention products application.

• Food Science of Animal Resources
• /
• v.44 no.2
• /
• pp.299-308
• /
• 2024

Proteins in whey have prebiotic and antimicrobial properties. Whey protein comprises numerous bioactive proteins and peptides, including glycomacropeptide (GMP), a hydrophilic casein peptide that separates with the whey fraction during cheese making. GMP has traditionally been used as a protein source for individuals with phenylketonuria and also has prebiotic (supporting the growth of Bifidobacterium and lactic acid bacteria) and antimicrobial activities. GMP supplementation may help positively modulate the gut microbiome, help treat dysbiosis-related gastrointestinal disorders and improve overall health in consumers.

• Journal of Animal Science and Technology
• /
• v.48 no.4
• /
• pp.575-586
• /
• 2006

This study was performed to determine potential antimicrobial activity of lactoferrin, which incorporated into the low-fat/salt sausages during storage either at 30 or 4℃. First, the model study on the antimicrobial activity of lactoferrin was performed. Based on the model study, more than 0.25% of lactoferrin was required to have a distinctive antimicrobial activity for the growth of E. coli O157:H7 in the broth. However, extended shelf-life was not shown in the low-fat/salt sausages manufactured with lactoferrin during refrigerated storage. In addition, no synergistic effects of lactoferrin with sodium lactate were observed in the sausages. These results indicated that the addition of lactoferrin into the low-fat sausages did not have antimicrobial activity of E. coli O157:H7, due to the denaturation of lactoferrin or the complexity of the sausage, even though it had a distinctive antimicrobial effect in the model study.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.4
• /
• pp.1020-1033
• /
• 2020

This study attempted to investigate the usefulness of Rhus javanica L., Cinnamomum verum and Rosmarinus officinalis extracts which have antimicrobial and antioxidant effects without any harm on human health as natural preservatives. In terms of extraction, extraction by 70% ethanol and hot-water extraction were used for Cinnamomum verum and Rhus javanica L. respectively. For Rosmarinus officinalis, a mixed method (70% ethanol and hot-water extraction) was adopted. In terms of experimental methods, antimicrobial effects, antioxidant activity through DPPH and safety and stability of cosmetics were assessed, and a challenge test was performed, and the results found the followings: According to an antimicrobial test, good antimicrobial effects were found in bacteria (Rhus javanica L. extract) and fungi (Cinnamomum verum extract). In contrast, the Rosmarinus officinalis extract was set aside because of poor antimicrobial activity. In the mixed extract (Rhus javanica L. + Cinnamomum verum), antimicrobial effects were observed in 'complex C (mixed in a 1:1 ratio)' while both inhibitory and sterilizing effects were found in 5 different test strains at minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In addition, antioxidant effects were detected in non-mixed extract and mixed extract ('complex C'). Furthermore, a test on cosmetics which adopted '10% complex C' instead of synthetic preservative revealed safety and stability. Therefore, this study has confirmed the potential of the Rhus javanica L., Cinnamomum verum and Rosmarinus officinalis extracts as materials for natural preservatives.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.7
• /
• pp.1026-1034
• /
• 2016

To develop a natural antimicrobial agent, we investigated the antimicrobial activities of 13 species of edible herbal plant extracts against major Gram-positive foodborne bacteria. Among the 13 screened edible herbal plants, Caesalpinia sappan L. showed the highest antimicrobial activity. In the paper disc agar diffusion assay, Caesalpinia sappan L. extracts had strong antibacterial activities against most Gram-positive bacteria but did not have antibacterial activities against most Gram-negative bacteria. Minimum inhibitory concentrations of the ethanol extract were 0.06 mg/mL against Clostridium difficile and Listeria monocytogenes and 0.03 mg/mL against Staphylococcus aureus. Their inhibitory activities were not reduced by heat treatment or pH adjustment against C. difficile, L. monocytogenes, and S. aureus. Antimicrobial activities were higher in ethanol extract than in distilled water extract. These results support the potential use of Caesalpinia sappan L. ethanol extract as an antimicrobial agent or functional food components against Gram-positive bacteria.

• Microbiology and Biotechnology Letters
• /
• v.41 no.3
• /
• pp.335-340
• /
• 2013

The antimicrobial effect of the methanol extract of Inula britannica flowers against methicillin resistant Staphylococcus aureus (MRSA) was investigated. It was confirmed that the methanol extract is mainly composed of quercetin, which has antimicrobial properties. The antimicrobial effect of the methanol extract against 3 MRSA strains was determined by the disc diffusion method. The minimal inhibitory concentrations were ranged from 0.625 mg/ml to 1.25 mg/ml, and the minimum bactericidal concentrations were 2.5 mg/ml. Time kill kinetics revealed bactericidal activities, and the morphological alterations in S. aureus ATCC 33591 treated with the extract were observed using a scanning electron microscope. The methanol extract affected the expression of the resistant genes, mecA, mecI, and mecRI in mRNA. Therefore, the methanol extract of I. britannica flowers clearly demonstrated an antimicrobial effect against MRSA and these results suggest a potential for application as a natural antimicrobial agent.