• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.236-243
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• 2004

Antimicrobial effect of chitosan and its oligosaccharides was examined on Vibrios sp., Edwardsiella tarda and Streptococcus sp., which are major pathogenic bacteria inducing bacterial diseases of acquacultured flounder. Chitosan oligosaccharides (COS ) were produced by enzymatic hydrolysis of chitosan in an ultrafiltration mombrane bioreactor system which was established with three membranes with different molecular weight cut-off (MWCO) 1,000, 5,000 and 10,000, and fractionated into three kinds of COS, based on their molecular weight sizes. The three kinds of COS were as follows : relatively high molecular weight COS [HMW-COS, molecular weight distribution of 7,000 to 24,000 Da〕, medium molecular weight COS 〔MMW-COS, 1,500 to 6,000 Da〕, and low molecular weight COS 〔LMW-COS, 1,000 to 1,500 Da). Chitosan and HMW-COS effectively inhibited the growths of Vibrio sp. and Streptococcus sp. and their antimicrobial activities were superior to the others with smaller molecular weights. This result suggested that antimicrobial effect of chitosan preparations extremely depend on their molecular weight sizes. Antimicrobial effect of chitosan and HMW-COS on E. tarda was improved by longer inoculation times. Scanning electron microscopy in morphological change of E. tarda treated with chitosan preparations showed that chitosan and HMW-COS bound to the cells and suppressed the growth of the cells. This observation appears to prove the fact that positive charged amines of chitosan electrostatically bind to negative charged compounds of cell walls.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.2
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• pp.348-352
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• 2002

This study was carried out to evaluate cytotoxic effects of Atractylodes macrocephala Koidz. (A. macrocephala Koidz.) extract on NIH 3T3 fibloblast. SK-MEL-3 (HBT 69) and KB (ATCC No, OCL 17) cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. 10.2 mg/ml Concentration of A. macrocephala Koidz. extracts in SK-MEL-3 showed that their susceptibility (sensitivity) to these compounds decreased in the following order ; adriamycin > H₂O > ethyl acetate > ethyl alcohol > chloroform > n-hexane in SK-MEL-3 cell lines ; 5-FU > H₂O > n-hexane > ethyl acetate > ethyl alcohol > chloroform in KB cell lines. In order to develop an antimicrobial agent, A. macrocephala Koidz. was extracted with solvents. The minimal inhibitory concentrations (MICs) of each solvent extract of A. macrocephala Koidz. against microogranisms were also examined. Antimicrobial activities of ampicillin and ketoconazole as references were compared to those of each solvent extract of A. macrocephala Koidz. The antimicrobial activity of the ethyl acetate soluble extract of A. macrocephala Koidz. had growth inhibition activity against S. mutans and P. putida (MICs. 500 ㎍/ml). These results suggest that the ethyl acetate soluble extract of A. macrocephala Koidz. possessed antitumorous and antimicrobial agents

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.2
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• pp.171-179
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• 2012

This study is focused on finding new natural materials that have antimicrobial activity. We found that 3 plants extracts, Magnolia sieboldii K. Koch (M. sieboldii K. Koch), Rhus chinensis (R. chinensis) and Metasequioa glyptostroboides (M. glyptostroboides), have antimicrobial activities by disk diffusion method. We determined the Minimum Inhibitory Concentation (MIC) of each and found that 0.3 ~ 0.35 % of M. glyptostroboides essential oil and 0.35 ~ 0.4 % of M. sieboldii K. Koch extracts inhibited fungal growth and 0.45 ~ 0.5 % of R. chinensis extracts inhibited bacterial growth. We isolated compounds from extracts and verified what have antimicrobial activity. As a result we found that caryophyllene oxide and caryophyllene isolated from M. glyptostroboides, costunolide and dehydrocostus lactone from M. sieboldii K. Koch and ethyl gallate, ethyl-3-gallate from R. chinensis have antimicrobial activities. In accordance with antimicrobial activity, O/W cosmetic emulsion containing mixture of 3 plants extracts showed preservative efficacy against both bacteria and fungi. Based on the above data we suggest that extracts from M. siebodii K. Koch, R. chinensis, and M. glyptostroboides, replace chemical synthetic preservatives and be applied as a natural preservative.

• Korean journal of applied entomology
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• v.51 no.3
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• pp.245-253
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• 2012

Benzylinedeneacetone (BZA) is a bacterial metabolite which is synthesized by at least two entomopathogenic bacteria, namely Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata. It has been shown to possess inhibitory effects on insect cellular and humoral immune responses as well as antimicrobial activities against various species of bacteria and fungi. However, its relatively high phytotoxicity, and nonsystematic effect have thus far prevented its development into an optimal pesticide. This study screened five different BZA derivatives in order to select an optimal compound, which would have relatively high solubility and low phytotoxicity while retaining sufficient degrees of the immunosuppressive and antimicrobial activities associated with BZA. Hydroxylation of the benzene ring of BZA was found to significantly suppress its immunosuppressive and antimicrobial activities. Transformation of the ketone of BZA by carboxylation also suppressed the inhibitory activities. However, a shortening of the aliphatic chain of BZA into acetate form (4-hydroxyphenylacetic acid: HPA) did not decrease the inhibitory activity. HPA also showed much less phytotoxicity against the hot pepper plant Capsicum annuum, when compared to BZA. This study identified an optimal BZA derivative, which exhibited relatively little phytotoxicity, but retained a high degree of inhibitory activity to suppress insect immune responses and antimicrobial activities against plant pathogens.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.645-651
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• 2013

The contents of total phenolics and flavonoids, antimicrobial and tyrosinase inhibition activities of five growth stages with four greenhouse-grown cucumber extracts were investigated. Total phenolic content was high in Jangjukcheongjang, Janghyeongnakhap and five growth stage(24~27 cm). The content of total flavonoid did not differ between cultivar or growth stages. Among the four cucumber cultivars, the extract of Janghyeongnakhap showed a relatively strong antimicrobial effect against Staphylococcus aureus. The inhibition zone against Staphylococcus epidermidis of the samples tested in this experiment was 8~12 mm. And the antimicrobial effects against Malassezia furfur was high in Jangjukcheongjang, and showed the highest by the inhibition zone of 14mm in three(17~20 cm) growth stage. The tyrosinase inhibition activity of cucumber extracts showed relatively high activity in Jangjukcheongjang and Sinjoeunbaekdadagi, followed by Janghyeongnakhap. From these results, we confirmed that the extract of cucumber has high antimicrobial and whitening efficacy, and that in the future, the cucumber will be increase the availability in the field of high-value cosmetic materials.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.147-155
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• 2014

This study is conducted to investigate the yield of extract, total phenolic compounds, total flavonoid compound contents, free radical scavenging activities (DPPH assay, ABTS assay), reducing power (Oyaizu's assay, FRAP assay) and antimicrobial activities of spinach according to various cooking methods (non-blanched, blanched, seasoned). The yield of non-blanched spinach is 1.64% and the extract yield of blanched spinach is 1.49%, and on the other hand, the yield of seasoned spinach is 6.01%. Total polyphenol contents of seasoned spinach is recorded as $124.31{\pm}1.37mg$ GAE/100 g FW, non-blanched spinach $51.24{\pm}0.27mg$ GAE/100 g FW, and blanched spinach $42.48{\pm}0.53mg$ GAE/100 g FW. From the total flavonoids, seasoned spinach extracts ($15.60{\pm}0.20mg$ CE/100 g FW) showed higher total flavonoid contents than non-blanched. Total antioxidant activities (DPPH assay, ABTS assay, FRAP assay, reducing power) are shown to be in the order of seasoned spinach > non-blanched spinach > blanched spinach. In the antimicrobial activities, non-blanched spinach (5, 10 mg/disc) showed antimicrobial activity against S. enterica and P. aeruginosa. The inhibition zone diameter from extracts of blanched spinach has not been detected. Seasoned spinach indicated antimicrobial activity only against P. aeruginosa (8.15 mm) at 10 mg/disc. If we are to eat a lot of non-blanched spinach, it would cause calculus. Blanching helps to prevent against calculus, since the blanching process can remove various amounts of oxalic acids. The overall results of this study demonstrate that seasoned cooked spinach would be the most efficient way of ingestion to consume antioxidant compounds.

• KSBB Journal
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• v.18 no.1
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• pp.55-61
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• 2003

To isolate and purify the antimicrobial and antitumor agents in Xanthium strumarium L. hydrothermal extract. The crude extract was extracted in ether or ethylacetate under neutral, acidic, and alkali conditions. The antimicrobial activity of each extract was tested against 16 strains of bacteria, 2 strains of yeast, and 2 strains of fungus. The ether neutral extract (XE-N) exhibited the strongest growth inhibition upon the 8 strains of gram-positive bacteria, 6 strains of gram-negative bacteria and Cryptococcus neoformans. Fluorescein diacetate (FDA) testing of XE-N and XEA-N showed growth inhibition of the 3 strains of E. coli, S. aureus and C. albicans even at 30 ng/mL, with the exception of p. aeruginosa. XE-N-S1 and XE-N-S3 from neutral ether extract (XE-N), XE-N-S3 from the acidic ether extract (XE-A), and XEA-N-S1 from ethylacetate (XEA-N) were purified as antimicrobial and antitumor agents. However all purified compounds decomposed with the exception of XE-N-S1. The results upon the antitumor activities of the crude extract and of its purified compounds, showed that XE-N-S1 had the best antitumor activity against HeLa cells. In terms of antitumor activity against HepG2 cells, XE-N-S1 and XE-N-S3 were superior, and against HT29 cells XE-N and XE-N-Sl were good, against Saos2, NCI H522, NCI H1703, Clone M3 cells XE-N-51 was very good, and against LN CAP cells XE-N-S3 was the best. Comparing of cellular toxicities various extracts and purified compounds with the existing antitumor agents, XE-A, XEA-A and XEA-B had the lowest toxicity, and XE-B had a lower toxicity than etoposide. XE-N-S1 and XE-N-S3 showed higher toxicities than etoposide, and the toxicity of XE-A-S3 was higher than that of etoposide, and lower than that of csplatin.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.517-523
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• 2013

Naphthyridine compounds are important, because they exhibit various biological activities including anticancer, antimicrobial, and anti-inflammatory activity. Some naphthyridines have antimitotic effects or demonstrate anticancer activity by inhibiting topoisomerase II. These compounds have been investigated as potential anticancer agents, and several compounds are now part of clinical trials. A series of naphthyridine derivatives were evaluated for their in vitro cytotoxic activities against human cervical cancer (HeLa), leukemia (HL-60), and prostate cancer (PC-3) cell lines using an MTT assay. Some compounds (14, 15, and 16) were more potent than colchicine against all three human cancer cell lines and compound (16) demonstrated potency with $IC_{50}$ values of 0.7, 0.1, and $5.1{\mu}M$, respectively. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used for quantitative structure-activity relationship (QSAR) molecular modeling of these compounds. We obtained accurate and predictive three-dimensional QSAR (3D-QSAR) models as indicated by the high PLS parameters of the HeLa ($q^2$, 0.857; $r^2$, 0.984; $r^2\;_{pred}$, 0.966), HL-60 ($q^2$, 0.777; $q^2$, 0.937; $r^2\;_{pred}$, 0.913), and PC-3 ($q^2$, 0.702; $q^2$, 0.983; $r^2\;_{pred}$, 0.974) cell lines. The 3D-QSAR contour maps suggested that the C-1 NH and C-4 carbonyl group of the naphthyridine ring and the C-2 naphthyl ring were important for cytotoxicity in all three human cancer cell lines.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.170-177
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• 2010

Bacillus licheniformis N1, previously developed as a biofungicide formulation N1E to control gray mold disease of plants, was investigated to study the bacterial traits that may be involved in its biological control activity. Two N1E based formulations, bacterial cell based formulation PN1E and culture supernatant based formulation SN1E, were evaluated for disease control activity against gray mold disease of tomato and strawberry plants. Neither PN1E nor SN1E was as effective as the original formulation N1E. Fractionation of antifungal compounds from the bacterial culture supernatant of B. licheniformis N1 indicated that two different cyclic lipopeptides were responsible for the antimicrobial activity of the N1 strain. These two purified compounds were identified as iturin A and surfactin by HPLC and LCMS. The purified lipopeptides were evaluated for plant disease control activity against seven plant diseases. Crude extracts and purified compounds applied at 500 ${\mu}g/ml$ concentration controlled tomato gray mold, tomato late blight and pepper anthracnose effectively with over 70% disease control value. While iturin showed broad spectrum activity against all tested plant diseases, the control activity by surfactin was limited to tomato gray mold, tomato late blight, and pepper anthracnose. Although antifungal compounds from B. licheniformis N1 exhibited disease control activity, our results suggested that bacterial cells present in the N1E formulation also contribute to the disease control activity together with the antifungal compounds.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1441-1448
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• 2017

Antibacterial compounds are widely used in the treatment of human and animal diseases. The overuse of antibiotics has led to a rapid rise in the prevalence of drug-resistant bacteria, making the development of new antibacterial compounds essential. This study focused on developing a fast and easy method for identifying marine bacteria that produce antibiotic compounds. Eight randomly selected marine target bacterial species (Agrococcus terreus, Bacillus algicola, Mesoflavibacter zeaxanthinifaciens, Pseudoalteromonas flavipulchra, P. peptidolytica, P. piscicida, P. rubra, and Zunongwangia atlantica) were tested for production of antibacterial compounds against four strains of test bacteria (B. cereus, B. subtilis, Halomonas smyrnensis, and Vibrio alginolyticus). Colony picking was used as the primary screening method. Clear zones were observed around colonies of P. flavipulchra, P. peptidolytica, P. piscicida, and P. rubra tested against B. cereus, B. subtilis, and H. smyrnensis. The efficiency of colony scraping and broth culture methods for antimicrobial compound extraction was also compared using a disk diffusion assay. P. peptidolytica, P. piscicida, and P. rubra showed antagonistic activity against H. smyrnensis, B. cereus, and B. subtilis, respectively, only in the colony scraping method. Our results show that colony picking and colony scraping are effective, quick, and easy methods of screening for antibacterial compound-producing bacteria.