• Food Science and Preservation
• /
• v.10 no.1
• /
• pp.41-46
• /
• 2003

To prove the extension of shelflife of soybean curd(Tofu) steeped in the diluted solution of botanical antimicrobial agent and stored at 20$^{\circ}C$, such chemical ＆ microbial properties as the contents of moisture, crude protein and crude fat, colony count and surface color of Tofu were investigated in comparison with the control. Tofu treated with botanical antimicrobial agents showed higher contents of moisture, crude protein and crude fat compared to those of the control Tofu through all the storage period. After 7 days of the storage period, cell count of coliform bacteria reach 75 x 103CFU/m1 in the control Tofu, whereas 13∼39 CFU/ml in Tofu treated with botanical antimicrobial agent Treatment of Tofu with botanical antimicrobial agent seemed to be a potential method to prolong the shelflife of processed Tofu.

• Advances in Traditional Medicine
• /
• v.4 no.3
• /
• pp.197-209
• /
• 2004

The study was aimed at evaluating the antioxidant and antimicrobial activities of methanol extract of Caesalpinia bonducella leaves (MECB) (Family: Caesalpiniaceae). The effect of MECB on antioxidant activity, reducing power, free radical scavenging (DPPH radical, nitric oxide radical, superoxide anion radical, hydroxyl radical and hydrogen peroxide radical scavenging), total phenolic content and antimicrobial activities were studied. The antioxidant activity of MECB increased in a dose dependent manner. About 50, 100, 250 and 500 g of MECB showed 53.4, 61.2, 69.1 and 76.2 % inhibition respectively on peroxidation of linoleic acid emulsion. Like antioxidant activity, the effect of MECB on reducing power increased in a dose dependent manner. The free radical scavenging activity of MECB was determined by DPPH radical scavenging method. The potency of this activity was increased with increased amount of extract. MECB was found to inhibit the nitric oxide radicals generated from sodium nitroprusside $(IC_{50}\;=\;102.8\;g/ml)$ whereas the $IC_{50}$ value of curcumin was 20.4 g/ml. Moreover, the MECB was found to scavenge the superoxide generated by photoreduction of Riboflavin. MECB was also found to inhibit the hydroxyl radical generated by Fenton reaction, where the $IC_{50}$ value is 104.17 g/ml compared with catechin 5 g/ml, which indicates the antioxidant activity of MECB. The MECB capable of scavenging hydrogen peroxide in a concentration-dependent manner. The amounts of total phenolic compounds were also determined. Antimicrobial activities of MECB were carried out using disc diffusion methods with five Gram positive, four Gram negative and four fungal species. The results obtained in the present study indicate that MECB leaves are potential source of natural antioxidant and antimicrobial agents.

• Korean Journal of Pharmacognosy
• /
• v.49 no.2
• /
• pp.155-164
• /
• 2018

Nypa fruticans Wurmb is a species of palm, which is widely distributed in the mangrove forest of Southeast Asia. Various parts of N. fruticans has been used as a traditional medicinal plant. However, the physiological activities of N. fruticans has not yet been clarified well. Therefore, in this study, the 50% ethanol extract and its aqueous and ethyl acetate fractions of young shoots of N. fruticans were investigated for their antioxidant, cytoprotective effect, and antimicrobial activities. Every sample possessed very high free radical and various ROS scavenging capacities assessed by employing different in vitro assays such as $DPPH^{\cdot}$, $O_2^{{\cdot}-}$, ${\cdot}OH$, and $^1O_2$ scavenging activities. Based on these results, the cytoprotective effect was investigated using the oxidative hemolysis of erythrocyte. We found that the extract and fractions provide a greater protective effect compared with (+)-${\alpha}$-tocopherol. Furthermore, antimicrobial activities were confirmed against skin pathogens by broth microdilution assay. The ethyl acetate fraction had much higher antimicrobial activities than methyl paraben against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans. Taken together, our results indicated that the young shoots of N. fruticans may have the potential role as a natural active ingredient through their antioxidant, cytoprotective effect, and antimicrobial activities.

• KSBB Journal
• /
• v.26 no.2
• /
• pp.100-106
• /
• 2011

Strain BCNU 5011 was isolated from forest soil samples collected in the Taebaek mountain in the Gangwon province, Korea. The biochemical, physiological and 16S rRNA sequence analysis strongly indicated that this isolate was most closely related to Paenibacillus polymyxa. A maximum production level of antimicrobial substances of Paenibacillus sp. BCNU 5011 was achieved under aerobic incubation at $30^{\circ}C$ for 3 days in SST broth.Paenibacillus sp. BCNU 5011 showed a broad spectrum of activity against Gram positive and Gram negative bacteria, including methicllinresistant Staphylococcus aureus (MRSA). Paenibacillus sp. BCNU 5011 was also shown to inhibit the growth of different potential human pathogenic bacteria and fungi in vitro. Peptide extract showed better antimicrobial activity than solvent extracts. But active antimicrobial compounds might be included in both peptide extract and solvent extracts. Further separation, purification and identification of active principles leads project to develop antimicrobial agents and anti-MRSA agents.

• CELLMED
• /
• v.4 no.1
• /
• pp.5.1-5.8
• /
• 2014

Healthcare-associated infection represents a frequent cause of mortality that increases hospital costs. Due to increasing microbial resistance to antibiotics, it is necessary to search for alternative therapies. Consequently, novel alternatives for the control of resistant microorganisms have been studied. Among them, plant antimicrobial protein presents enormous potential, with flowers being a new source of antimicrobial molecules. In this work, the antimicrobial activity of protein-rich fractions from flower tissues from 18 different species was evaluated against several human pathogenic bacteria. The results showed that protein-rich fractions of 12 species were able to control bacterial development. Due its broad inhibition spectrum and high antibacterial activity, the protein-rich fraction of Hibiscus rosa-sinensis was subjected to DEAE-Sepharose chromatography, yielding a retained fraction and a non-retained fraction. The retained fraction inhibits 29.5% of Klebsiella pneumoniae growth, and the non-retained fraction showed 31.5% of growth inhibition against the same bacteria. The protein profile of the chromatography fractions was analyzed by using SDS-PAGE, revealing the presence of two major protein bands in the retained fraction, of 20 and 15 kDa. The results indicate that medicinal plants have the biotechnological potential to increase knowledge about antimicrobial protein structure and action mechanisms, assisting in the rational design of antimicrobial compounds for the development of new antibiotic drugs.

• Microbiology and Biotechnology Letters
• /
• v.35 no.4
• /
• pp.278-284
• /
• 2007

A novel screening strategy for salt-resistant antimicrobial peptides from a M13 peptide library was developed. Fusion of MSI-344, a magainin derivative and indolicidin to pIII coat proteins did not significantly affect viability of the recombinant phages, which indicated that the pIII could neutralize toxicity of the antimicrobial peptides and therefore it is possible to construct antimicrobial peptide library in Escherichia coli. On the basis of the conserved sequence of ${\alpha}$-helical antimicrobial peptides, a semi-combinatorial peptide library was constructed in which the peptides were displayed by pIII. To remove hemolytic activity from the library, the phages bound to red blood cells were removed, and the subtracted phage library was screened for binding to target bacteria Pseudomonas aeruginosa and Staphylococcus aureus under high salt concentrations. The screened peptides showed relatively low antimicrobial activity against the target bacteria. However, antimicrobial activities of the screened peptides P06 and S18 were not affected by the cation concentrations of 150 mM $Na^+$, 2 mM $Mg^{2+}$ and 2 mM $Ca^{2+}$ without significant hemolytic activity. This screening strategy that is based on binding capacity to target cells provides new potential to develop salt-tolerant antimicrobial peptides.

• Korean Journal of Microbiology
• /
• v.54 no.4
• /
• pp.428-435
• /
• 2018

In this study, we isolated and identified bacteria from freshwater and soil collected from Osang reservoir, to screen antimicrobial bacteria against various pathogenic bacteria. 38 strains were isolated and assigned to the class Proteobacteria (22 strains), Actinobacteria (7 strains), Bacteroidets (6 strains), and Firmicutes (3 strains) based on 16S rRNA gene sequence analysis. Among them, strain OS17 showed a good growth inhibition against 5 methicillin-resistant Staphylococcus aureus subsp. aureus strains and Bacillus cereus, Bacillus subtilis, Filobasidium neoformans. As a result of the 16S rRNA gene sequence analysis, strain OS17 show the high similarity with Burkholderia ambifaria $AMMD^T$, B. diffusa $AM747629^T$, B. tettitorii $LK023503^T$ 99.8%, 99.7%, 99.6%, respectively. We investigated cell growth and antimicrobial activity according to commercial culture medium, temperature, pH for culture optimization of strain OS17. Optimal conditions for growth and antimicrobial activity in strain OS17 were found to be: YPD medium, $35^{\circ}C$ and pH 6.5. When the strain was cultured in LB, NB, TSB, R2A media at $20^{\circ}C$ and $25^{\circ}C$, the antimicrobial activity did not show. Culture filtrate of strain OS17 showed antimicrobial activity against 5 MRSA strains, Bacillus cereus, Bacillus subtilis, and Filobasidium neoformans with inhibition zones from 2 to 8 mm. Optimal reaction time was 48 h in YPD medium, 100 rpm and 0.3 vvm in 2 L-scale fed-batch fermentation process for antimicrobial activity. Culture optimization of strain OS17 can be improved on antimicrobial activity. Therefore, the antimicrobial activity of Burkholderia sp. OS17 had potential as antibiotics for pathogens including MRSA.

• Food Science and Preservation
• /
• v.21 no.3
• /
• pp.427-433
• /
• 2014

Ethanol and hot water extracts were prepared from Lindera obtusiloba Blume (LO) and Zanthoxylum piperitum DC (ZP) and used to evaluate their antimicrobial activities and thermal stability against six foodborne pathogens (3 gram-positive and 3 gram-negative bacteria). The antimicrobial activities were assessed using the agar diffusion method, and the thermal stabilities of extracts were examined after heat treatment at 60, 70, 80, and $100^{\circ}C$ for 10 min. The zones of inhibition by the LO extract or the ZP extract of the tested microorganisms were in the range of 21-30 mm and 19-25 mm, respectively, at 100 mg/mL concentrations. The 60% ethanol extract and the hot water extracts from LO showed the strongest antimicrobial effects against MRSA and Staphylococcus aurues, respectively. For the extract from ZP, the strongest antimicrobial effect was shown against S. aurues by 60% ethanol, and the weakest antimicrobial effect was shown against E. coli by the hot water extracts. The ZP extracts showed that the gram-positive bacteria were more sensitive than gram-negative bacteria. For the thermal stability of the extracts, the antimicrobial effects stabilized after heat treatment. Overall, the data suggest that the extracts have a potential for application in various food products for which a natural antimicrobial additive is desired.

• Applied Chemistry for Engineering
• /
• v.27 no.5
• /
• pp.502-507
• /
• 2016

This study was conducted to develop novel antimicrobial nano-composites, with the aim of fully utilizing antimicrobial properties of multi-walled carbon nanotubes (MWCNTs), nickel (Ni) and zinc oxide (ZnO). Ni coated-MWCNTs (Ni-CNT) were prepared and evaluated for their potential application as an antimicrobial material for inactivating bacteria. Field emission scanning electron microscopy (FE-SEM), and X-ray energy dispersive spectroscopy (EDS) were used to characterize the Ni coating and morphology of Ni-CNT. Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil) were employed as the target bacterium on antimicrobial activities. Comparing with the nitric acid treated MWCNTs and Ni-CNT which have been previously reported to possess antimicrobial activity towards S. aureus and E. coil, Ni-CNT/ZnO exhibited a stronger antimicrobial ability. The nickel coating was confirmed to play an important role in the bactericidal action of Ni-CNTs/ZnO composites. Also, the addition of ZnO to the developed nanocomposite is suggested to improve the antimicrobial property.

• Archives of Pharmacal Research
• /
• v.14 no.3
• /
• pp.199-203
• /
• 1991

7H-thiazolo-[3,2-a]-pyridines as potential antimicrobial agents were prepared by reaction of $\alpha,\beta$-unsaturated nitriles and thioglycolic acid.