• Advances in Traditional Medicine
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• v.10 no.3
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• pp.208-213
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• 2010

The aerial parts of methanol extract of Oxystelma esculentum (MEOE) (Asclepiadaceae) was evaluated for in vitro lipid peroxidation and antimicrobial activity. Lipid peroxidation was assayed by the change in optical density of the various concentrations (20 - 320 ${\mu}g$/ml) and the percentage inhibition was estimated. Ascorbate/FeSO4-induced peroxidation was inhibited by MEOE and standard antioxidants such as BHA, BHT and the percentage inhibition of the methanol extract was increased with dose dependent manner. The $IC_{50}$ value of the MEOE, BHA and BHT for lipid peroxidation was found to be 135.24 ${\mu}g$/ml, 25.62 ${\mu}g$/ml and 17.13 ${\mu}g$/ml, respectively. The antimicrobial activity of MEOE was determined by disc diffusion method with three grampositive, five gram-negative and two fungal microorganisms. MEOE exhibited the antimicrobial activity against the tested microorganisms except Salmonella typhimurium (MTCC 98). In present study, it is concluded that MEOE has significant effect in the inhibition of lipid peroxidation and possesses good antimicrobial activity.

• Food Science and Biotechnology
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• v.15 no.4
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• pp.582-588
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• 2006

The antioxidant and antimicrobial activity of the fermentation extract (PFE) and the 50 and 80% ethanol extracts (PE 50, PE 80) of Pinus densiflora pine needles were evaluated. Electron donating ability, superoxide dismutase (SOD) ability, and antimicrobial activity were observed in PFE; those abilities differed in PE 80 and PE 50, depending on the ethanol concentration used for the extraction. PFE had the highest electron donating ability with a value of 92.20%, while PE 80 and PE 50 had values of 74.66 and 53.47%, respectively. For SOD activity, PE 80 exhibited a slightly higher value of 31.11% compared to that of PFE and PE 50, which were 29.65 and 25.43%, respectively. PFE, PE 50, and PE 80 were all found to inhibit bacteria, and the effectiveness of this inhibition was strongly related to the type of extracts used. PFE showed good antimicrobial effects for all of the tested Gram-positive strains and for most of the tested Gram-negative strains. These results suggest that PFE has superior functionality compared to the ethanol extracts (PE 80, PE 50), in terms of antioxidant and antimicrobial activity. On the basis of these results, pine needle fermentation extracts can be used for industrial applications as a functional material.

• The Journal of Internal Korean Medicine
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• v.31 no.2
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• pp.290-297
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• 2010

Objectives : This study evaluated the effect of Dioscoreae Rhizoma on antioxidant and antimicrobial activity in vitro. Methods : In vitro experiments were made on antioxidant by DPPH radical scavenging activity, enzyme activity of SOD, protective effect about $H_2O_2$ and DNA fragmentation in RAW264.7 cells, as well as antimicrobial by Cox-2 expression in LPS-induced RAW264.7 cells. Results : 1. Dioscoreae Rhizoma's antioxidant ability was improved by DPPH radical scavenging activity. 2. Antioxidant ability of Dioscoreae Rhizoma produced good results at more than 0.025 mg/$m{\ell}$. 3. On protective effect of Dioscoreae Rhizoma about $H_2O_2$ on RAW264.7 cells, with addition of Dioscoreae Rhizoma extract the cells' survival increased compared to adding $H_2O_2$ only. 4. About revelation-control of Cox-2 at RAW264.7 cells which induce by LPS, when Dioscoreae Rhizoma's concentration was higher from 0.0125 mg/$m{\ell}$ to 1 mg/$m{\ell}$, its control activity was stronger. Thus we found Dioscoreae Rhizoma has antimicrobial activity. 5. The power of DNA fragmentation control of Dioscoreae Rhizoma was time-independent. Conclusions : From this study we conclude that Dioscoreae Rhizoma has effects on antioxidant and antimicrobial activity. However, considerable work still needs to be done studying antioxidants by concentration, as well as a variety of experiments about antimicrobial activity.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.1052-1061
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• 2019

Objective: This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens. Methods: Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity. Results: The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope. Conclusion: Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4227-4232
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• 2011

A number of new 2,5-disubstituted 1,3,4-thiadiazole and their S- or N-substituted derivatives as well as the corresponding sugar hydrazone derivatives were synthesized and tested for their antimicrobial activity against Bacillus subtilis (Gram-positive), Pseudomonas aeruginosa (Gram-negative), and Streptomyces species (Actinomycetes). The synthesized compounds displayed different degrees of antimicrobial activities or inhibitory actions.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.95-102
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• 2009

Purpose: The purpose of this study is to investigate antimicrobial activity of ally derivative of garlic against eye diseases, and to get basic data for an application development of the derivative, as a natural preservative, to multi-purpose solution (MPS). Methods: Antimicrobial activity of allyl derivative of garlic, diallyl sulfide (DAS), against Pseudomonas aeruginosa (P. aeruginosa) and Staphyloccus aereus (S. aereus) was determined. After DAS treatment in MPS of no microbial activity, its growth inhibition effect to bacteria was also determined. Results: DAS concentrations of $IC_{50}$ against P. aeruginosa and S. aereus were found when both bacteria were treated with DAS concentration of 0.25% and 0.64%, respectively. At MPS test, a product from Company A did not show any effects against both bacteria, but one from Company B showed antimicrobial activity against both bacteria. Antimicrobial activity test of the product from Company B in MPS did not showed any significant difference on both gram-negative and gram-positive bacteria. For a trial application of antimicrobial activity of DAS as a natural preservative, DAS was added to MPS of Company A which did not show any antimicrobial activity at treated concentration. Addition of DAS into MPS of Company A resulted in antimicrobial activity of DAS, which suggested a possible application of DAS as a germicide for contact lenses. Conclusions: This study showed allyl derivative of garlic has antimicrobial activity against both P. aeruginosa and against S. aereus, but more effects on P. aeruginosa. The result suggests that allyl derivative derived from garlic can be developed to a preservative of MPS as a natural substance.

• International Journal of Oral Biology
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• v.39 no.4
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• pp.169-176
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• 2014

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format $O_{(1-6)}XXXXX-NH_2$, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-$NH_2$ (pep-1) and WXXXXN-$NH_2$ (pep-2), and one positioned peptide, RRRWRN-$NH_2$ (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic ${\alpha}$-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.47-53
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• 2008

In a previous study, we showed that Cecropin A (1-8)-Magainin 2 (1-12) hybrid peptide (CA-MA)'s analogue, Anal P5, exhibit broad-spectrum antimicrobial activity. Anal P5, designed by flexible region (positions 9, 10)-substitution, Lys- (positions 4, 8, 14, 15) and Leu- (positions 5, 6, 12, 13, 16, 17, 20) substitutions, showed an enhanced antimicrobial and antitumor activity without hemolysis. The primary objective of the present study was to gain insight into the relevant mechanisms of antimicrobial activities of Anal P5 by using flow cytometric analysis. Anal P5 exhibits strong antifungal activity in a salt concentration independent manner. In addition, Anal P5 causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy, supporting its antibacterial activity. Its potent antibiotic activity suggests that Anal P5 is an excellent candidate as a lead compound for the development of novel antibiotic agents.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.109-116
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• 2012

The study indicated that antimicrobial activity about gram positive and gram negative bacteria of ginger-oleoresin(GO) extract with the condition of ethanol and supercritical fluid extractions. As the concentration of extraction increases, the clear zone of GO ethanol extract also increased dependently. This led the antimicrobial activity of gram positive bacteria to take bigger place than gram negative bacteria especially in Listeria monocytogenes. There was a high antimicrobial activity in E-III treatment where the ratio of the ginger powder extract to ethanol extraction was 1:6. It was quite effective to treat the antimicrobial activity of GO ethanol extract under $80^{\circ}C$ and there was not big difference in the intervals which were the extraction time - 1 to 7 hours. The antimicrobial activity of supercritical fluid extract seemed to take the biggest place in Listeria monocytogenes. From the supercritical fluid extract, it was shown the strong ability of antimicrobial activity in the condition with 100 bar $35^{\circ}C$, 250 bar $35^{\circ}C$ and 250 bar $65^{\circ}C$. Furthermore, according to the case of solvent extract, there was not any significant difference in the antimicrobial activity with condition of extraction. However, there was significant antimicrobial activity in E-III treatment of 100 bar and 500 bar of extraction pressure, and $35^{\circ}C$ and $65^{\circ}C$ of extraction temperature.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.353-361
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• 2018

RFW and RFE of castor fruit selected as part of the development of natural antimicrobials and antioxidants yielded 15.8% and 18.4% respectively. In the results of measuring the antimicrobial activity through paper disc method, the antimicrobial activity of castor fruits in ethanol extracts appeared. Especially, the activity was excellent in P. aeruginosa and S. aureus, and antimicrobial activity of C. was 1.5mm up to 16 hours. However, the proliferation of C. was observed again after 24 hours. In the MIC experiment results of RFE, S. aureus and P. aeruginosa showed 96% and 93% of antimicrobial activity, respectively. The DPPH radical scavenging activity of RLW and castor leaf ethanol extract showed $1.8{\pm}0.6%$ and $2.1{\pm}0.7%$ free radical scavenging activity at $1000({\mu}g/m{\ell})$. This study is expected to provide basic data for the development of antimicrobial agents and antioxidants using natural products.