• 폴리머
• /
• 제30권5호
• /
• pp.402-406
• /
• 2006

천연 옻 나무에서 추출되는 항균물질 우르시올을 폴리우레탄 발포체 성형 시스템에 도입하여 항균 폴리우레탄 발포체를 제조하였다. 항균물질 우르시올 첨가량을 증가시키는 경우 발포체 성형 반응성이 약간 저하되는 것이 관찰되었으나 기계적 물성 측면에서는 항균물질 미처리 발포체와 비교하여 큰 물성저하는 관찰되지 않았다. 반면 항균성 측면에서는 항균물질 미처리 발포체에 비하여 초기 균수 대비 균수의 성장성이 감소되는 것을 확인할 수 있었다.

• 약학회지
• /
• 제43권3호
• /
• pp.342-350
• /
• 1999

The antibacterial activity against Propionibacterium acnes (P. acnes), $5{\alpha}-reductase$ inhibition and comedolytic effects are the important pharmacological target sites of antiacne drughs. We previously reported on the antibacterial activities against P. acnes by natural products. In the present study the screening of $5{\alpha}-reductase$ inhibition and comedolytic effects from natural products were performed. Seven natural products such as Angelica koreana, Sophora flavescens, Prunus persica, Bombyx mori, Areca catechu, Galla rhois and Gleditschia koraiensis perfectly inhibited the activity of $5{\alpha}-reductase$ at the concentration of 0.01% (w/v). Sixteen natural products which were shown to have the potent antibacterial activities against P.acnes or $5{\alpha}-reductase$ inhibition activities were assayed for the comedolytic test. In the results of comedolytic effects on experimentally-induced comedones (EIC), Sophora flavescens showed the strongest comedolytic effect on EIC, and Polygonum cuspidatum and Angelica koreana showed stronger comedolytic effects on EIC than azelaic acid used for a positive control at the concentration of 3% (w/v). These results suggest that several natural products including Sophora flavescens can be developed as noble antiacne agents.

• Journal of Microbiology and Biotechnology
• /
• 제23권7호
• /
• pp.953-958
• /
• 2013

Selaginella tamariscina is a traditional herb used in medicine. Phytochemical amentoflavone, a biflavonoid class of flavonoids, was isolated from the plant of Selaginella tamariscina. In this study, the antibacterial effects and combination effects of amentoflavone and conventional antibiotics such as ampicillin, cefotaxime, and chloramphenicol were investigated. These results showed that amentoflavone had a considerable antibacterial effect and synergistic interaction with antibiotics against various bacterial strains (fractional inhibitory concentration index ${\leq}$ 0.5), except for Streptococcus mutans. To study the mechanism(s) involved in the synergistic activities between amentoflavone and antibiotics, we detected hydroxyl radical formation using 3'-(p-hydroxyphenyl) fluorescein and measured the $NAD^+/NADH$ ratio by $NAD^+$ cycling assay. The results indicated that the formation of hydroxyl radical would be a cause of the synergistic effect and that this oxidative stress originated from a transient NADH depletion. This study suggests that amentoflavone synergizes with antibiotics and has potential as a therapeutic agent for antimicrobial chemotherapy.

• Environmental Engineering Research
• /
• 제24권4호
• /
• pp.566-571
• /
• 2019

One-pot hydrothermal route was adopted to synthesize Al:BiVO₄, at 4 h and 8 h reaction durations, by adding 1% aluminiumoxide powder (w/v) to the precursors. The products were investigated using several characterization techniques that conform a significant morphological change and a decrease in bandgap energy of the materials upon Al modification of scheelite monoclinic bismuth vanadate matrix at both hydrothermal durations. Antibacterial experiments were performed against methicillin-resistant Staphylococcus aureus in visible light condition to harness the photoxidation property of Al-doped BiVO₄ and compare to that of unaltered BiVO₄. Minimum inhibitory concentration of the synthesized materials was identified. The results indicate that Al-doping on BiVO₄ has a significant effect on its photocatalytic antibacterial performance. Al:BiVO₄ synthesized at 8 h hydrothermal treatment parades excellent sunlight-driven photocatalysis compared to the one synthesized at 4 h.

• Journal of Microbiology and Biotechnology
• /
• 제32권12호
• /
• pp.1547-1552
• /
• 2022

β-Amyrin is a pentacyclic triterpene widely distributed in leaves and stems worldwide. The ability of β-amyrin to induce the production of reactive oxygen species (ROS) in microorganisms suggests its potential as an antimicrobial agent. Thus, this study aimed to elucidate the antibacterial mode of action of β-amyrin. We treated Escherichia coli cells with β-amyrin and found that it triggered ROS accumulation. Excessive stress caused by ROS, particularly hydroxyl radicals, induces glutathione (GSH) dysfunction. GSH protects cells from oxidative and osmotic stresses; thus, its dysfunction leads to membrane depolarization. The resultant change in membrane potential leads to the release of apoptotic proteins, such as caspases. The activated caspases-like protein promotes the cleavage of DNA into single strands, which is a hallmark of apoptosis-like death in bacteria. Apoptotic cells usually undergo events such as DNA fragmentation and phosphatidylserine exposure, differentiating them from necrotic cells, and the cells treated with β-amyrin in this study were positive for annexin V and negative for propidium iodide, indicating apoptosis-like death. In conclusion, our findings suggest that the antibacterial mode of action of β-amyrin involves the induction of ROS, which resulted in apoptosis-like death in E. coli.

• 한국식품위생안전성학회지
• /
• 제10권1호
• /
• pp.33-39
• /
• 1995

The antibacterial and antifungal effect of grapefruit seed extract(GFSE) was investigated for its purpose of application to a diverse spectrum of field as sanitizers, disinfectants and preservatives. GFSE showed coparatively high content of such flavoniods as naringin and hesperidin and ascorbic acid. GFSE containing a low level of organic acids is a heavy viscous and water-soluble liquid. As a result of the antimicrobial test of GFSE, Bacillus subtilis and Aspergillus oryzae did not survive at detectable levels when treated with more than 100 ppm of GFSE. The minimum inhibitory concentrations of GFSE for a wide variety of pathogenic and putrefactive bacteria, fungi and yeasts were 100 ppm and 250 ppm, respectively. In the comparable electron micrograph of microbial cells treated with GFSE or not, we could conclude that GFSE destroy microorganisms by disrupting the functions of the cell wall membrane and microbial spores.

• 한국지역사회생활과학회지
• /
• 제21권1호
• /
• pp.13-18
• /
• 2010

This study was performed to investigate the antimicrobial effects of Euphorbia humifusa ethanol-extract against food-borne pathogens. The growth inhibitory effects of the extract at a concentration of 250, 500, 1,000 or 2,000 mg/L on food poisoning microorganism were determined against Salmonella typhimurium, Listeria monocytogenes, Yersinia enterocolitica, Escherichia coli O157:H7 and Staphylococcus aureus. The microorganisms growth was not affected by the extract at the concentration up to 250 mg/L, but was significantly (p<0.05) inhibited by the extract at a concentration higher than 1,000 mg/L. The extract of Euphorbia humifusa had strong antimicrobial activity against all test strains at a concentration of 2,000 mg/L. The results in the present study demonstrate antimicrobial effects of Euphorbia humifusa ethanol-extract against food-borne pathogens, suggesting that Euphorbia humifusa could be an effective natural antibacterial agent in food.

• 한국세라믹학회지
• /
• 제54권3호
• /
• pp.167-183
• /
• 2017

Zinc oxide (ZnO) is one of the most versatile semiconductors, and one-dimensional (1D) ZnO nanostructures have attracted significant interest for use in ultraviolet (UV) lasers, photochemical sensors, and photocatalysts, among other applications. It is known that 1D ZnO nanowires can be fabricated readily owing to the anisotropic growth of ZnO along the [0001] direction. However, this type of growth results in a decrease in the surface area of the (0001) plane, which plays a vital role not only in UV lasing but also in the photocatalytic process. Thus, we attempted to synthesize ZnO crystals with an increased polar surface area by controlling the crystal growth process. The purpose of this review is to propose a simple route for the synthesis of plate-like ZnO crystals with highly enhanced polar surfaces and to explore their feasibility for use in UV lasers as well as as a photocatalyst and antibacterial agent. In addition, we highlight the recent progress made in the pilot-scale synthesis of plate-like ZnO crystals for industrial applications.

• 한국식품저장유통학회지
• /
• 제8권2호
• /
• pp.206-212
• /
• 2001

Water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activity. The sensitivity of Staphylococcus aureus and Salmonella typhimurium to the green tea extracts in various pH of culture broth was tested. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts was adjusted to pH 5.0∼7.0 and inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacteria. The plate counting method and clear zone test were used to determine inhibitory effect of green tea extracts. Green tea extracts completely inhibited the growth of S. aureus at 0.5% level and bactercidal at 0.5∼1.0% level of GTW and GTE at pH 5.0∼7.0. Green tea extracts were bactercidal to S. typhimurium at 1.5∼2.0% level of GTW and 1.0∼2.0% level of GTE at pH 7.0. Sal. typhimurium was more resistant than S. aureus. in same concentration of green tea extracts at same pH. The resistance of S. aureus and Sal. typhimurium was increased with decreasing pH of culture broth. The morphology of S. aureus cells treated with green tea extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. Green tea extracts stimulated autolysis and cell death of S. aureus. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Toxicological Research
• /
• 제21권1호
• /
• pp.39-43
• /
• 2005

The present study was carried out to investigate the antibacterial activity against Staphylococcus aureus with antibiotic-resistance in vitro and the skin irritation in rabbits with surfactin produced by Bacillus subtilus Complex BC1212. The antibacterial activities of selected antimicrobial agents (surfactin, amoxacillin, colistin, norfloxacin and streptomycin) were evaluated by using the broth microdilution method. As the results, the minimum inhibitory concentration (MIC) of the surfactin was less than 15.6 ㎍/ml. In the skin irritation test, two out of 4 rabbits showed very slight edema at 24 h after the administration of surfactin, and then recovered at 72 h. The change of body weight was normal during the skin irritation test. The primary irritation index in accordance with the Draize evaluation of topical reaction was calculated to be '0.125', which meant not irritating. Based on these results, it could be concluded that the test agent, surfactin, was a non-irritant. We could also think that the surfactin may be useful for the treatment of S. aureus infections such as bovine mastitis.