1 plant tissue culture
Plant tissue culture uses the totipotency of plant cells, and can use tender stems, needles, bark, cambium, aril and embryo of Taxus plants as explants for culture, thus forming a large number of extraction raw materials. At present, there are many reports at home and abroad, and remarkable results have been achieved.
2 Microbial production
A parasitic fungus (Taxomyces andreanae) isolated from the phloem of Taxus brevifolia by Stierle et al. can produce paclitaxel and its related economic products in a specific medium, but it has not been applied to production at present because of its extremely low yield. By changing culture conditions and applying recombinant DNA technology, it is expected to improve the yield of paclitaxel.
Because roots are organs with high taxol content except bark, people use Agrobacterium rhizogenes to infect explants of Taxus plants to induce roots, and try to produce taxol through this culture system, because this culture system does not need exogenous hormones, and it has attracted much attention because of its fast hairy roots and stable genetic traits.
It will be more meaningful than plant research to actively search for microorganisms that can synthesize paclitaxel or its analogues, locate key enzymes and clone related genes from microbial synthesis routes.
3. Synthesis by bioengineering method
Large-scale production of taxol by bioengineering is to cultivate and screen strains that can produce taxol in large quantities, and to produce taxol in culture medium through continuous expansion of culture without cutting down the few remaining Taxus trees in nature.
Example At present, a taxol-producing strain named HQD33 has been isolated and screened from the bark of a hundred-year-old Taxus chinensis, and then its gene structure was mutated and optimized by many chemical and physical methods, and then it was bioengineered, and finally a high-yield strain containing 448.52 micrograms of taxol per liter of culture medium was cultivated and constructed.
4 artificial semi-synthesis
In order to protect the precious Taxus resources and avoid the destruction of resources caused by collecting a large number of Taxus bark, the goal should be to produce taxol from renewable resources. Bristol-Myers Squibb Company successfully extracted primary raw materials from renewable materials such as branches and leaves of Taxus chinensis in 1994 on the premise of fully ensuring the quality of taxol products, and then produced taxol by artificial semi-synthesis. Its semi-synthetic production method has been approved by FDA. Since then, Taxus Pacific is no longer destructively collected, and the sustainable production and supply of paclitaxel has also been guaranteed.
The molecular structure of organic taxol is complex, with special tricyclic [6+8+6] carbon skeleton, bridgehead double bonds and many oxygen-containing substituents. Its total synthesis has attracted the interest of many organic chemists at home and abroad. It is rare that more than 30 research groups have participated in the research. After more than 20 years' efforts, two research groups, R.A.Holton and K.C.Nicolaou in the United States, completed the total synthesis of paclitaxel in 1994.
Later, there were S.T. Danishevski (1996), P.A. Wen-De (1997), T. Mukai Mountain (1998) and I. Kuwaji-Ma (1998). Although the six synthetic routes are different, they all have excellent synthetic strategies to raise the chemistry of natural organic synthesis to a new level.