• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.355-364
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• 2016

This study was initiated to evaluate the antioxidant and antimicrobial activities of methanol extract (ME) and hot water extract (HWE) obtained from the fruiting bodies of medicinal mushroom, Phellinus gilvus. The free radical scavenging activity of ME from P. gilvus on 1,1-diphenyl-2-picrylhydrazyl (DPPH) were 93.65% at 2 mg/mL, which was comparable with the positive control, butylated hydroxytoluene (BHT, 96.97%) at the same concentration. The ferrous ion-chelating ability of ME and HWE was significantly higher than that of BHT at all concentration levels. The antimicrobial assay of ME was performed against six bacteria and one species of fungus. ME exhibited antibacterial activity against 5 out of 6 bacteria: Staphylococcus aureus, Streptococcus mutans, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa; whereas, ME did not show antimicrobial activity against gram-negative bacterium Vibrio vulnificus and fungal species Candida albicans. The minimum inhibitory concentration (MIC) of ME against 5 strains of bacteria, such as S. aureus, S. mutans, B. subtilis, E. coli, and P. aeruginosa, was 100, 100, 50, 100, 200 mg/mL, respectively. The results suggest that good antioxidant and microbial activities of P. gilvus fruiting bodies might be used for natural antioxidant and antimicrobial agents.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.311-318
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• 2023

This study was performed to determine the contents of propionic, benzoic, and sorbic acids in dried seasoned seafood products (n=27) sold in Korea. Propionic acid was determined using a gas chromatogramphy-flame ionization detector. Benzoic and sorbic acid were analyzed by using a high-performance liquid chromatography-diode array detector. Benzoic acid was not detected in the dried seasoned seafood products; however, propionic and sorbic acid were detected in some samples. The concentrations of propionic acid and sorbic acid were up to 125.10 mg/kg and 658.18 mg/kg in dried seasoned seafood products, respectively. Of eight samples labeled with potassium sorbate, sorbic acid was detected in seven of them. The detected sorbic acid levels in these samples met the regulations for sorbic acid usage in Korea. The propionic, benzoic, and sorbic acid contents of dried seasoned seafood products determined in this study can provide basic data for safety management of dried seasoned seafood products in future.

• Food Science and Preservation
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• v.18 no.1
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• pp.87-90
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• 2011

The methanol extracts of 19 commercial herb medicines was analyzed to antibacterial activities against Edwardsiella tarda, causing several fish diseases. Rhus javanica showed most strong antibacterial activity against E. tarda and Escherichia coli. Methanol extract of R. javanica was further extracted using several organic solvents having different polarity. Extract from ethyl acetate fraction showed strong activity against E. tarda as well as E. coli. Minimal inhibitory concentration, MIC of R. javanica extract was measured and resulted showing $64\;{\mu}g/m{\ell}$ for E. tarda and $256\;{\mu}g/m{\ell}$ for E. coli. It is needed that, from these results, further purification and isolation of reposible compound of these activities and further study on the synergy effect using combination with antibiotics against pathogenic bacteria.

• Journal of Life Science
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• v.34 no.3
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• pp.153-159
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• 2024

Dioscorea alata L, commonly known as "tropical yam" is the most widely consumed yam species among the 650 yam species belonging to the Dioscoreacea family. It is extensively cultivated in tropical and subtropical regions and is a major food source in Africa and India. Also, it is used for medicinal purposes, particularly in China and Taiwan, for its anti-inflammatory properties. In comparison to other yam varieties such as D. batatas or D. opposita, the tropical yam has gained popularity in Korea due to its higher yield per unit area. In this study, the nutritional characteristics and anti-thrombosis activity of the aerial bulbils of D. alata L. tropical yam were compared to those of D. opposita. The results showed that the aerial bulbils of tropical yam exhibited nutritional characteristics and potent anticoagulant activity compared to those of domestic yam varieties. The bulbils extract of tropical yam showed superior anticoagulant activities against thrombin, prothrombin and blood coagulation factors. Furthermore, the bulbils extract of tropical yam exhibited strong platelet aggregation inhibition at 0.25 mg/ml and showed no hemolytic activity up to a concentration of 2.5 mg/ml. These findings suggest the potential development of high-value anti-thrombosis agents utilizing the aerial bulbils of tropical yam.

• Food Science and Preservation
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• v.10 no.1
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• pp.89-93
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• 2003

To develope natural food preservatives, ethanol and water extracts were prepared from the Lentinus edodes and antimicrobial activities were examined against 10 microorganisms which were food borne pathogens and / or food poisoning microorganisms and food-related bacteria and yeasts. Ethanol extract exhibited antimicrobial activities for the microorganisms tested, but not on lactic acid bacteria and yeast Especially, minimum inhibitory concentration(MIC) for Escherichia coli were as low as 0.5 mg/mL. Antimicrobial activity of the ethanol extract was stable by the heating at 121$^{\circ}C$ for 15 min and not affected by pH. The ethanol extract of Lentinus edodes exhibiting high antimicrobial activity. The highest antimicrobial activity adjust bacteria tested was found in the ethylacetate fraction.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.470-476
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• 2003

Daehwang (Rheum tanguticum) was extracted by methanol, and the antimicrobial activities of the extract, against some food hazardous microorganisms, were investigated by the paper disc method. The minimum inhibitory concentration (MIC) of the extract against the microorganisms was determined, and the extract components were analyzed by GC/MS. The Daehwang extract showed the strongest antimicrobial effect against P. aeruginosa. The MICs on S. aureus, P. aeruginosa and S. typhimurium were 250, 300 and 300mg/$m\ell$, respectively. In the methanol extracts from Daehwang, 120 different compounds were separated, with the extraction yield of the phenolic compounds being relatively high (29.85%). Substances with antimicrobial activity, such as 2-methoxy-phenol and 4-vinyl-2-methoxy-phenol were detected in the study.

• The Korean Journal of Food And Nutrition
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• v.16 no.1
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• pp.7-14
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• 2003

This study mainly focused on to investigate the effects of Schizandra chinensis on the growth of a bacterium, CS6 which was isolated from kimchi. CS6 was final]y identified to lactobacillus plantarum that caused acidification of kimchi. The ethanolic extract of Schizandra chinensis(EES) inhibited the growth of L. plantarum. Minimum inhibition concentration of crude EES on L. plantarum was 62.5mg/$m\ell$. In broth culture, 5$\mu\textrm{g}$/$m\ell$ of EES completely inhibited the growth of L. plantarum during fermentation. The addition of 0.4% of EES has no apparent effect on quality including the taste and color on kimchi. It was expected that EES-containing kimchi could extend the period of preservation. Analysis of organic acids in water fractions of EES was carried out by HPLC. It is apparent that antimicrobial active fractions contained the highest concentration of succinic acid, a little tartaric acid and malic acid. Among these organic acids, succinic acid showed the strong inhibitory effect against L. plantarum CS6 in vitro. Succinic acid-containing kimchi with a concentration of 0.4 and 0.5% had the inhibitory effect on growth of L. plantarum. Inhibitory effect of EES on amylase, cellulase and pectinase was also tested. In conclusion, the present experiment demonstrated that EES inhibited the growth of L. plantarum, and various enzyme activity. EES-containing kimchi was sustained the hardness, and initial acidity during fermentation. EES was considered as the possible additive of kimchi process and EES added in kimchi increase the quality, and storage period of kimchi.

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

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.306-310
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• 2006

For screening of the compounds exhibiting antimicrobial activities against the D-alanyl-D-alanine of Gram positive bacteria, approximately 2,500 actinomycetes isolated from soil were examined far antimicrobial activity. In consequence, we recently isolated the Streptomyces sp. G91353 strain produced an active compound, A91353, that inhibits the growth of Gram positive bacteria. A91353 was identified as N-acetyl-phenylalanine by various spectroscopic methods. The minimum inhibitory concentration (MIC) values of N-acetyl-phenylalanine on Gram positive bacteria such as Streptococcus pyogenes 308A, Streptococcus pyogenes 77A were determined as $50{\mu}g/ml$, respectively, but did not effect on Gram negative strains. These results indicate that N-acetyl-phenylalanine have an antimicrobial activity, which may be caused by the disturbance of D-alanyl-D-alanine synthesis.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.255-258
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• 2018

The objective of this study was to investigate the inhibitory effect of natural antimicrobials on Listeria monocytogenes isolated from Korean slaughterhouses. A mixture of 15 strains of L. monocytogenes at low (3 Log CFU/mL) or high (7 Log CFU/mL) concentration was exposed to various extracts (grapefruit seed extract, citrus fruit extract, ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, and omija extract) at $0.001-4.0{\mu}g/mL$. Ginger extract, pear extract, Japanese apricot concentrate, balloon flower extract, jujube extract, or omija extract showed no antimicrobial effects on high-concentration of L. monocytogenes (7 Log CFU/mL). However, grapefruit seed extract and citrus fruit extract showed antibacterial effects against L. monocytogenes at 3 and 7 Log CFU/mL with MBCs of 0.001 and $0.002{\mu}g/mL$, respectively. These results indicate that grapefruit seed extract and citrus fruits extract can be used to control L. monocytogenes as natural antimicrobials.