Taxol Paclitaxel and Cancer Chemotherapy

Malignant neoplastic diseases may be treated by various approaches surgery, radiation therapy, immunotherapy, or chemotherapy, or a combination of these. The extent of a malignant disease (staging) should be ascertained in order to plan an effective therapeutic intervention. Plants have antineoplastic activities. 

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Most of the important antitumor compounds used for chemotherapy of tumors are microbially-produced antibiotics. These include actinomycin D, mitomycin, bleomycins and the anthracyclines, daunorubicin and doxorubicin. The recent successful molecule, taxol (=paclitaxel), was discovered in plants but also is a fungal metabolite. It is approved for breast and ovarian cancer and is the only antitumor drug known to act by blocking depolymerization of microtubules. In addition, taxol promotes tubulin polymerization and inhibits rapidly dividing mammalian cancer cells. It also inhibits fungi such as Pythium, Phytopthora and Aphanomyces spp. by the same mechanism. ... 

Clinical use of Taxol included many solid tumours with best results in ovarian and breast cancers. Extraction of Taxol (paclitaxel) from the yew bark is quite difficult three trees were needed for 1 gram of drug (one cycle of chemotherapy). This difficulty has encouraged the pursuit of semisynthetic production. The strategy included immediately increasing the amount of Taxol derived from... 

Paclitaxel is a mitotic inhibitor used in cancer chemotherapy. It was discovered in the US National Cancer Institute program in 1967 when Moiuoe E. WaU and Mansukh C. Wani isolated it from the bark of the Pacific yew tree, Taxus brevifolia, and named it taxol. When it was developed commercially, the generic name was changed to paclitaxel. 

Paclitaxel (Taxol, Bristol-Myers Squibb) is a chemotherapy drug for ovarian cancer, breast cancer, and certain lung cancers. It was discovered by the US National Cancer Institute in the 1960s. Originally, it was extracted from the bark of the North American yew tree (Taxus brevifo-lia). Clinical tests had necessitated the harvesting of the bark, and this method damaged the trees irreversibly. 

Another area in which natural products have had a major impact on longevity and quality of life is in the chemotherapy of cancer. In fact, most major anticancer drugs are derived from plants or microorganisms (see Chapter 62). Examples include bleomycin, doxorubicin, daunorubicin, vincristine, vinblastine, mitomycin, streptozocin, and most recently, additions of paclitaxel (Taxol ), ironotecan (a camptothecin derivative), and etoposide and tenoposide (podophyllo-toxin derivatives). 

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