• Natural Product Sciences
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• v.26 no.4
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• pp.317-325
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• 2020

A new dimer stilbene [Monalittorin (1)] and ten known compounds [engeletin (2), aurantiamide acetate (3), lupeol (4), friedelin (5), quercetin (6), tiliroside (7), rutoside (8), astragalin (9), isoquercitrin (10) and quercimeritroside (11)] have been isolated from the leaves of Monanthotaxis littoralis (Annonaceae). The structures of these compounds were established by interpretation of their data, mainly, HR-TOFESIMS, 1-D NMR (1H and 13C) and 2-D NMR (1H-1H COSY, HSQC, HMBC and NOESY) and by comparison with the literature. The evaluation of their antimicrobial activities against three bacteria (Staphylococcus aureus ATCC 25923, Escherichia coli S2 (1) and Pseudomonas aeruginosa PA01) and three fungal strains (Candida albicans ATCC10231, Candida tropicalis PK233 and Cryptococcus neoformans H99) using broth micro dilution method, showed the largest antimicrobial activities of EtOAc fraction and compounds 1, 5, 6, 8 and 11 (MIC = 8 - 64 ㎍/mL). In addition, EtOAc fraction presented synergistic effect with Vancomycin and fluconazole against the tested microorganisms.

• YAKHAK HOEJI
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• v.18 no.4
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• pp.243-248
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• 1974

Nine benzoxazolin-2-thione derivatives were sunthesized as the potential antimicrobial substances. These compounds were tested for the antimicrobial activities using Staphylococcus aureus and Escherichia coli by way of tube dilution method. The three compounds of I, II and VII omjoboted the growth of S.aureus at the concentration of 1${\mu}$g/ml, and III,VI,VIII and IX exhibited considerable antimicrobial activities against S. aureus at the concentration of 10.m.u.g/ml. As to the growth of E. Coli, VII VII and VIII inhibited at the concentration of 1${\mu}$g/,l. II,III and IV exhibited considerable antimicrobial activities against E. coli at the concentration of 10${\mu}$g/ml.

• Mycobiology
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• v.36 no.2
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• pp.110-113
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• 2008

During a continuing search for antimicrobial substances from Korean native wild mushroom extracts, we found that the methanolic extract of the fruiting body of Clitocybe nebularis exhibited mild antifungal activity against pathogenic fungi. Therefore we evaluated the antifungal substances and other chemical components of the fruiting body of Clitocybe nebularis, which led to the isolation of nebularine, phenylacetic acid, purine, uridine, adenine, uracil, benzoic acid, and mannitol. Nebularine showed mild antifungal activity against Magnaphorthe grisea and Trichophyton mentagrophytes, and phenylacetic acid potently inhibited the growth of Pythium ultium and displayed moderate antifungal activity against Magnaphorthe grisea, Botrytis cinerea, and Trichophyton mentagrophytes. The other isolated compounds showed no antimicrobial activity.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.154-161
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• 2017

An antimicrobial peptides-producing Bacillus strain CBS73 was isolated from fermented food (kimchi) that produces low-molecular-weight proteins with broad-spectrum antimicrobial activity. Our goal was to explore the therapeutic potential of antimicrobial substances produced by Bacillus species. Peptide CBS73 was purified from Bacillus subtilis subsp. subtilis with identity of 99.79%. It was found to be stable at pH 4.0-10.0 and temp $20-60^{\circ}C$. A protein band around 5.2 kDa was detected in tricine-SDS-PAGE and band was confirmed by MALDI-TOF test. Peptide CBS73 showed antimicrobial activity against MDR bacteria. The minimal inhibitory concentration (MIC) of peptide CBS73 for vancomycin-resistant S. aureus (VRSA), vancomycin resistant Enterococci (VRE) and Salmonella typhimurium ranged from $10-40{\mu}g/mL$. The antioxidant activity of peptide CBS73 was measured by DPPH scavenging, reducing power activity and total phenolic content. Cell viability and NO production result showed less cytotoxic effect upto $12{\mu}g/mL$. Peptide CBS73 could be a promising antimicrobial agent for clinical application.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.1-7
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• 2007

Garlic (Allium sativum L.) contains a specific sulfur compound, the S-allyl derivative of L-cysteine sulfoxide, and has long been known for its antimicrobial activity against various microorganisms, including bacteria, fungi, and protozoa. The principal antimicrobial compound of garlic is S-allyl-L-propenethiosulfinate (allicin) which is generated by an enzyme, alliinase (L-cysteine sulfoxide lyase), from S-allyl-L-cysteine sulfoxide (alliin). This compound exists exclusively in Allium as a major non-protein sulfur-containing amino acid. S-Allyl-L-propenethiosulfinate belongs to the chemical group of thiosulfinates and is a highly potent antimicrobial. The potency of garlic extract is reduced during storage since thiosulfinates are unstable and are degraded to other compounds some of which do not have antimicrobial activity. Diallyl polysulfides and ajoene are sulfur compounds derived from allicin that do possess antimicrobial activity. It was recently found that garlic becomes antimicrobial on heating at cooking temperatures, and that the compound responsible for this is allyl alcohol, which is generated from alliin by thermal degradation.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.6
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• pp.700-707
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• 2010

Effects of protease-resistant antimicrobial substances (PRA) produced by Lactobacillus plantarum and Leuconostoc citreum on rumen methanogenesis were examined using the in vitro continuous methane quantification system. Four different strains of lactic acid bacteria, i) Lactococcus lactis ATCC19435 (Control, non-antibacterial substances), ii) Lactococcus lactis NCIMB702054 (Nisin-Z), iii) Lactobacillus plantarum TUA1490L (PRA-1), and iv) Leuconostoc citreum JCM9698 (PRA-2) were individually cultured in GYEKP medium. An 80 ml aliquot of each supernatant was inoculated into phosphate-buffered rumen fluid. PRA-1 remarkably decreased cumulative methane production, though propionate, butyrate and ammonia N decreased. For PRA-2, there were no effects on $CH_4$ and $CO_2$ production and fermentation characteristics in mixed rumen cultures. The results suggested that PRA-1 reduced the number of methanogens or inhibited utilization of hydrogen in rumen fermentation.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.352-355
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• 2004

The extracts from 70 different plant natural products were used to investigate the antimicrobial activities against Brachyspira hyodrsenteriae, the causative agent of swine dysentery. Among them, the extracts from Terminalia chehula exhibited the highest antimicrobial activities against B. hyodysenteriae. It showed the antimicrobial activity against B. hyodysensteriae mostly in parts of its shell. Minimum inhibitory concentration (MIC) of the water extracts of T chehula was 12.5 mg/ml. After organic solvent extractions, the ethylacetate extracts exhibited higher antimicrobial activities against B. hyodysenteriae, and their antimicroactivities were similar to that of the tannin. In conclusion, these findings suggest that the extracts from T chebula may be used as animal feed additives for their antimicrobial activities against B. hyodysenteriae.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.149-155
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• 2019

The antimicrobial activity of acetone, hexane, dichloromethane, and methanol extracts from leaves, stems, immature green fruits, and red fruits of tomato plants was examined against six phytopathogens. The minimum inhibitory concentration (MIC) of the acetonic extracts from these four plant parts was lower than that of the other solvents. Among the acetonic extracts, tomato leaves had a lower MIC than the other tomato parts. The acetonic extract from tomato leaves was therefore selected as a source of antimicrobial substances. The acetonic extract from tomato leaves inhibited mycelial growth of Fusarium oxysporum f. sp. lycopersici, Glomerella cingulata, and Rhizoctonia solani. Mycelial growth of R. solani treated with acetone extract from leaves showed more susceptibility than the other phytopathogens. Using 0.31 mg/ml of the acetonic extract from leaves, mycelial growth of R. solani on days 1, 2, and 3 decreased by 50.0, 52.1, and 64.0%, respectively, compared with acetone solvent treatment. The antimicrobial compounds effective against R. solani were identified as linolenic acid and caffeic acid by bioautography and GC-MS. These two compounds were used to treat six phytopathogens to confirm their antimicrobial activities. Linolenic acid inhibited mycelial growth of R. solani, while caffeic acid showed only slight antimicrobial activity. Results indicated that we propose extracts from tomato leaves which included antimicrobial compounds may provide a new lead in the pursuit of new biological sources of agrochemical candidates.

• Food Science and Preservation
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• v.10 no.1
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• pp.37-40
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• 2003

Coptis chinensis extract and grapefruit seed extract, natural antimicrobial substances, were applied to the dipping treatment of strawberry and incorporated in the packaging films. Strawberry was steeped in the extract solutions of 50 ppm concentration and packed with the low density polyethylene(LDPE) films incorporated with 1% extracts. During the storage at 5$^{\circ}C$, the qualities of microbial counts, awぶy ratio, texture and chemical attributes were measured for the pretreated strawberry. The LDPE films incorporated with the extracts retarded the growth of aerobic bacteria, lactic acid bacteria and yeast that had been contaminated before the pretreatment, significantly lowed the decay ratio, and gave better retention of textural firmness. The chemical and physical qualities of strawberry were not affected by the packaging films. When strawberry was steeped in the extract solutions, the effects of the packaging film incorporated with the extracts on the qualities of strawberry were accelerated.

• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1793-1800
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• 2020

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or anti-inflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.