Screening the potential chemopreventive agents from traditional medicines using biochemical markers of carcinogenesis

• Main Authors: UanTeng Tsai, 蔡萬騰
• Other Authors: EricIC Li
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/09813897526191968921

碩士 === 國立成功大學 === 藥理學研究所 === 88 === Chemoprevention can be defined as the use of chemicals to prevent the occurrence of cancer. It is often heard from folklore that someone get cured by the use of traditional medicines. Hence the traditional or herbal medicines may contain some chemopreventive substances without our knowledge. The present research was undertaken to see if the traditional herbal medicines do contain such substances. We chose the herbs based on their frequent appearance in the traditional regimens: Oldenlandia diffusa (Willd.) Roxb, Trichosanthes kirilowii Maxim, Agrimonia pilosa Ledeb, Lobelia chinensis Lour, Curcuma zedoaria Rosc, Andrographis paniculata (Burm.f.) Nees, and Allium fistulosum L as our research materials. The chemoprevention efficacy is tested by the following 2 criteria: 1. Induction of quinone reductase in liver cell. Quinone reductase reduces quinone to hydroquinone which is then glucuronidated and secreted out of the body. The enzyme is one of the phaseⅡ biotransformed enzymes of the liver to metabolize xenobiotics. The enzyme functions to prevent the cell from getting attacked by carcinogens or mutagens on it’s DNA. 2. Induction of reduced glutathione (GSH) in liver cells. Glutathione can conjugate with electrophilic substances and reduce their chance to bind to DNA. Increasing the amount of reduced glutathione can therefore reduce the chance of cancer initiation. Our preliminary results indicate all of the test herbs have the capacity to increase quinone reductase activity and the level of reduced glutathione. So these test herbs may have chemopreventive ability. But none of the herbs have the capacity to increase quinone reductase and glutathione better than the chemical sudanⅠ. We think it is necessary to purify the substances of traditional medicines, because traditional medicines are mixtures of many unknown chemicals that may better than sudanⅠ and has no mutagenicity. If we still not take emphasis on it, we may delay the time of these unknown chemicals to contribution toward human beings.