Introduction Page 6

Many plants have been the source of vital drugs for many conditions, - cancer, high blood pressure, antipsychotic drugs to name but a few. Some of the anti cancer drugs come from the most amazing sources.

E.g. The Yew tree ( Taxus baccata Linnaeus) produces two specific drugs for treating cancer, Paclitaxel (Pacific Yew {26}) and Docetaxel (European Yew {27}). We can see there is a difference between the two compounds, substitution of a benzene group in Paclitaxel for i-Butyl in Docetaxel. These drugs are used as mitotic inhibitors used in cancer chemotherapy and have been used for lung, ovarian, breast cancer, head and neck cancer, and advanced forms of Kaposi's sarcoma.

 

Madagascan Periwinkle (Catharanthus roseus)

Another interesting source of chemotherapy drugs comes from the Madagascan periwinkle plant. These two substances are also mitotic inhibitors; Vinblastin {28} and Vincristane {29}. The Madagascar periwinkle (Catharanthus roseus), is the source of the Vinblastin and Vincristane, these alkaloids are used respectively in the treatment of Hodgkin's disease and pediatric leukaemia. As an anti-mitotic drug - it stops mitosis of the cancer cells in metaphase.

 

Page 7 of Introduction