Higher Plant Sources of Cancer Chemotherapeutic Agents and the Potential Role of Biotechnological Approaches for Their Supply

There are five major structural groups of cancer chemotherapeutic agents derived from higher plants approved clinically in the USA. These are used either in their unmodified naturally occurring form, as semi-synthetic derivatives, or as a conjugate as part of a larger drug molecule. In this chapter, those compounds used currently as approved oncolytic drugs will be described, following by a brief mention of selected plant-derived compounds in current clinical trials as potential cancer chemotherapeutic agents. Next, details on the methods proposed for the production for the oncology drug market of three examples of different structural groups of plant-derived anticancer agents will be given [viz., bisindole (Vinca) alkaloids, podophyllotoxin lignan analogs, and taxane diterpenoid derivatives]. The plant natural products surveyed represent sustainable sources of specialized pure chemicals that are valuable in treating cancer.