• 제목/요약/키워드: natural chemicals

검색결과 328건 처리시간 0.026초

Antiplatelet Action of Ilexoside D, a Triterpenoid Saponin from Ilex pubescens

  • Lee, Dug-Keun;Lee, Hye-Sun;Huh, Min-Do;Lee, Chul-Hoon;Lee, Young-Su;Kim, Hyun-Su;Han, Yong-Nam
    • Archives of Pharmacal Research
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    • 제14권4호
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    • pp.352-356
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    • 1991
  • The anti-platelet activity of ilexoside D isolated from the roots of Ilex pubescens Hook. et Arn. was investigated in in vitro and ex vivo models of platelet aggregation induced by ADP, thrombin or collagen in rats. In vitro ilexoside D inhibited more effectively platelet aggregation induced by ADP and thrombin than by collagen as compared with aspirin. Ex vivo ilexoside D also inhibited platelet aggregation induced by ADP and collagen, but not by thrombin, and the inhibitory action of ilexoside D was more effective than that of aspirin. However, in vitro ilexoside D inhibited very poorly the generation of malonyldialdehyde, which is known to be concomitantly released with thromboxane $A_2$ during platelet aggregation. These results suggest that the anti-platelet activity of ilexoside D may not be responsible for prostaglandin synthesis in platelets.

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Occupational Cancers with Chemical Exposure and their Prevention in Korea: A Literature Review

  • Rim, Kyung-Taek
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권6호
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    • pp.3379-3391
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    • 2013
  • The usage and types of chemicals being developed, with diversified new exposure of workers, are of natural concern to occupational disease. In Korea, with industrialization, application of many chemicals has increased. A large proportion of mortality and disease is due to cancer, and the causal hazardous agents include chemical agents, like heavy metals and so on. Due to the long latency period with malignancies and the fact they are usually found after workers' retirement, it is suggested that management policies must be established to prevent occupational cancers occurring among workers in Korea. To give a general description about the efforts to prevent the occupational cancer with exposure to chemicals, articles on the trends of occupational cancers were reviewed and summarized with related research and efforts for prevention in Korea. It is important to improve the understanding of occupational cancer and help to maintain sustainable and appropriate measures to guarantee workers safety and health.

Estrogenic Activity Assessment of Alkylphenolic chemicals using in vitro assays : III. Rcombinant Yeast Transcriptional Assay

  • Park, Hyo-Joung;Lee, Ho-Ja;Park, Kyunghee;Ryu, Jae-Chun
    • 한국환경독성학회:학술대회논문집
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    • 한국환경독성학회 2001년도 춘계심포지움 및 학술발표회
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    • pp.127-127
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    • 2001
  • There is a concern that chemicals in our environment are affecting human health by disrupting a normal endocrine function. Much of the concern has focused on chemicals that can interact directly with steroid hormone receptors. The ability of certain man-made chemicals to mimic the effects of natural steroid hormones and their potential to disrupt the delicate balance of the endocrine system in animals are of increasing concern. (omitted)

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Binary Mixture Toxicity of AROCLOR 1248, Oleic Acid, and Elemental Sulfur to Vibrio fischeri Luminescence

  • Kalciene, Virginija;Dabkeviciene, Daiva;Cetkauskaite, Anolda
    • 한국환경과학회지
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    • 제24권11호
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    • pp.1541-1546
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    • 2015
  • The objective of this research was to evaluate the toxicity of the industial xenobiotic Aroclor 1248 (A) and natural origin substances~elemental sulfur (S80) and oleic acid (OA) and their binary mixtures to V. fischeri bioluminescence during the prolonged exposure time (up to 60 min). The bioluminescence quenching test was used to determine the toxic effects. Full factorial experiment design and multiple regression analysis and the comparison of binary mixture effect with the sum of effects of individual chemicals were used for the evaluation of combined effects of toxicants. The analysis of general trend of mixture toxicity to bioluminescence showed that mixture toxic effects were reversible up to 60 min. Data analysis revealed different joint effects, which were depended on mixture composition. S80 enhanced toxic effect of A and acted additively with synergistic interaction. Hydrophobic OA in mixture with A acted antagonistically and in mixture with sulfur caused an additive effect with antagonistic component of interaction. It was concluded that low concentrations of natural toxic substances present in environmental samples as mixtures of chemicals can define the toxicodynamic character of industrial xenobiotics.

The development of hair styling products with new “ Aspartate polymer (Poly amino acid derivative) ”

  • Yonetani, Akio;Hono, Masaya;Miyata, Minori;Katoh, Toshio;Nagatomo, Akinori
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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    • pp.245-252
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    • 2003
  • There have been many kinds of hair styling sprays with various setting effects. Consumers have used strong setting effect hair sprays to get a long lasting hold. In recent years, however, more and more consumers have come to prefer a "soft & natural" touch feeling, keeping the same long lasting hold. Nonetheless, the existing approaches to this feature could not respond to the consumers′ needs, since products lose the hold strength if the soft feeling is pursued, and vice versa. We have researched and developed a new products to attain a compatible feature with both long lasting hold and natural feeling. Then, we have developed a new multifunctional hair styling material "Poly Amino Acid Derivative (PAAD)." We have focused on the PAAD′s feature that highly diffuses onto a hair and makes thin and even layer on a hair, and have made trials and errors to improve holding strength. "P AAD" excellently makes hair memorize its curl shape which is as the same effect as existing ordinary acrylic resin. Further more, it leaves a soft and natural touch feeling on the hair. We have accomplished a new Poly Amino Acid Derivative with ambivalent features, "soft & natural finish" and "long lasting hold ", and now we report about it.

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스마트폰의 센서를 이용한 가상 실험 콘텐츠의 개발 및 설계 (Design and Development of Sensor-based Virtual Experiment Contents for Smart Phone)

  • 정광식;권수열;웬하오 후앙
    • 디지털콘텐츠학회 논문지
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    • 제14권2호
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    • pp.161-169
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    • 2013
  • 자연과학에 있어서 실험실습은 중요한 과정이다. 그러나 실험 과정에 대한 선행학습을 통해 자연과학 전공자들은 위험한 실험을 인지할 수 있고, 이를 통해 실제 실험에서의 위험을 피할 수 있다. 모바일 어플리케이션인 가상 실험 콘텐츠는 학습자에게 안드로이드 스마트폰이 가지고 있는 다양한 센서를 통해 상호작용을 제공한다. 그리고 본 논문에서 개발한 가상 실험 콘텐츠를 통해 학습자들은 화학 실험실습 도구를 다룰 수 있는 선행 학습을 수행하게 된다. 본 논문은 학습자들의 실험 능력을 향상시키기 위한 가상 실험 콘텐츠를 설계하고 개발하였다.

Protective Effects of Antoxidant Enzymes of Candida albicans against Oxidative Killing by Macrophages

  • Kim, Hye-Jin;Na, Byoung-Kuk;Kim, Moon-Bo;Park, Duk-Young;Song, Chul-Yong
    • Journal of Microbiology
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    • 제37권2호
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    • pp.117-122
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    • 1999
  • Protective roles of antioxidant enzymes, copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), and catalase of Candida albicans against exogenous reactive oxygens and oxidative killing by macrophages were investigated. The initial growth of C. albicans was inhibited by reactive, oxygen-producing chemicals such as hydrogen peroxide, pyrogallol, and paraquat, but it was restored as the production of antioxidant enzymes were increased. The growth inhibition of C. albicans by reactive, oxygen-producing chemicals was reduced by treating the purified candidal SOD and catalase. Also, in the presence of SOD and catalase, the oxidative killing of C. albicans by macrophages was significantly inhibited. These results suggest that antioxidant enzymes, CuZnSOD, MnSOD, and catalase of C. albicans may play important roles in the protection of C. albicans not only from exogenous oxidative stress but also from oxidative killing by macrophages.

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Plant cell culture strategies for the production of natural products

  • Ochoa-Villarreal, Marisol;Howat, Susan;Hong, SunMi;Jang, Mi Ok;Jin, Young-Woo;Lee, Eun-Kyong;Loake, Gary J.
    • BMB Reports
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    • 제49권3호
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    • pp.149-158
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    • 2016
  • Plants have evolved a vast chemical cornucopia to support their sessile lifestyles. Man has exploited this natural resource since Neolithic times and currently plant-derived chemicals are exploited for a myriad of applications. However, plant sources of most high-value natural products (NPs) are not domesticated and therefore their production cannot be undertaken on an agricultural scale. Further, these plant species are often slow growing, their populations limiting, the concentration of the target molecule highly variable and routinely present at extremely low concentrations. Plant cell and organ culture constitutes a sustainable, controllable and environmentally friendly tool for the industrial production of plant NPs. Further, advances in cell line selection, biotransformation, product secretion, cell permeabilisation, extraction and scale-up, among others, are driving increases in plant NP yields. However, there remain significant obstacles to the commercial synthesis of high-value chemicals from these sources. The relatively recent isolation, culturing and characterisation of cambial meristematic cells (CMCs), provides an emerging platform to circumvent many of these potential difficulties.