Synthesis,method,paclitaxel,Pa health Synthesis method of paclitaxel
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Paclitaxel is one of the more complex naturalproducts, belonging to diterpene, the skeleton has four rings, from left toright are A, B, C, D, of which A, B, C are carbon ring, another D ring isoxetane. Paclitaxel was originally extracted from the bark of Taxus Brevifoliawhich growing in the U.S., but its content is very low, about 10-50kg of bark can be extracted fromone gram of paclitaxel. Do a group of clinical trials need 25000 adult yewtrees, and this kind of trees in the world distribution is very small,slow-growing, high-volume logging will make it has endangered risk, which wasmade paclitaxel become a thorny issue. Accordingto pharmaceuticalraw materials suppliers, paclitaxel has become theworld's first selling anticancer drugs currently. At the same time, researchersare doing other clinical trials about the effect of paclitaxel on Alzheimer'sdisease and other cancers. Currently, methods of human obtaining paclitaxelhave: A. natural extract, B. artificially synthesized, C. semi- synthetic, D.biological fermentation. Of which the latter three methods are mostly remainedin the laboratory stage. Paclitaxel biosynthesis Themolecular formula of paclitaxel is C47H51NO14, terpene ring structure naturalsecondary metabolites. It mainly made by the taxane ring and side chains. Studythe biosynthesis for the efficiency of artificially direction and the cloningcombinations, gene which forming critical enzyme, improve the yield of paclitaxelhas significant meaning. Currently, whether can find one or two key enzymes andmake its gene purified and gene cloning is the key of researching. Whethertaxus gene cloning can be breakthrough remains to be seen, it stills in thestage of imaginary ways which people have found, at present these technologiesare still in the laboratory stage. Chemical synthesis of paclitaxel Accordingto the study and reported: 10-deacetylbaccatin b (baccatin b) which isolated from Taxus plants,its activity is obviously lower than paclitaxel, but can be extracted fromyew needles. This substance through a four-step chemical process can besynthesized paclitaxel, bring significant progress for solving the new sourcesway of paclitaxel. However, chemical synthesis from the substantive sense hasnot yet achieved a complete breakthrough, without application value at present. Microbial synthesis of paclitaxel Researchersisolated a kind of parasitic fungus from taxus brevifolia phloem, which canproduce paclitaxel and related hydrocarbon compounds in a particular medium,but due to the current low yield, it cannot be applied in production.Recombinant DNA technology is expected to improve the yield of paclitaxel. Bythe studies also found that: the yew root is the organ that has the highest paclitaxelcontent except for bark. People use agrobacterium rhizogenes dipping the yewplant explants to induce rooting. This approach does not need foreign aidhormones, the roots growing rapidly, genetic traits are stable and get moreattention. If can combined the synthesis paclitaxel or their similarderivatives, the key enzymes which obtained in microbial biosynthesis with therelated genes of cloned yew, this method would get a breakthrough. ArticleSource:http://www.cospcn.com
Synthesis,method,paclitaxel,Pa