Yesterday I also received the chemotherapy Vincristine. My nurse mentioned it, too, is plant derived. I thought, "Amazing!"
Vincristine belongs to a class of chemotherapy drugs called plant alkaloids. The active agents are derived from the Periwinkle, Pacific Yew Tree, May Apple Plant, and the Asian Happy Tree. Most amazing to me is the periwinkle plant, which grows wild around most homes in Arnhem Land. I've often used these little flowers in my daily puja, picking five pink ones (to remember the yamas) and five white ones (to remember the niyamas). I'm grateful to have actually handled and cultivated this plant!
For more information on Vincristine, I highly recommend Chemocare.com