ABSTRACT
Cephalotaxus harringtonia, known as the Japanese or Chinese plum yew or cowtail pine, in the Taxaceae family, is the source of the anti-cancer alkaloids, harringtonine, homoharringtonine and cephalotaxine. Cephalotaxus fortunei and other species are also sources of homoharringtonine. The potential of extracts of C. harringtonia as a cancer chemotherapy was first recognised in a simple test for activity against experimental leukaemia cells as part of a broad survey of plant extracts by a division of the US National Cancer Institute. Combination therapy of cephalotaxines with other drugs is now practiced in order to overcome the problem of drug resistance. Upon administration, homoharringtonine targets and binds to the 80S ribosome in eukaryotic cells and inhibits protein synthesis by interfering with chain elongation. This reduces levels of certain oncoproteins and anti-apoptotic proteins. The history of the development of harringtonine and its derivatives is complicated and much work was duplicated because independent paths were followed by American and Chinese researchers.
