Taxol is a compound originally obtained from the bark of the Pacific Yew tree Taxus brevifolia
, an "environmentally protected species". It was discovered following a screening programme, in which it was found to have the ability to slow down or prevent growth of cancerous tumours.
It was then produced by complex chemical manipulation of a similar compound from a related species Taxus baccata
- "the English Yew" - which is much more widely available. It is well known in churchyards.
It is now produced by a plant cell culture process which is said to be sustainable.
It has a complex molecular structure in 3D, and a number of alarmingly long chemical names. The 4-membered oxetane ring
seems to be the main active part but the central section is a 17-carbon
Its therapeutic action appears to be due to its effect on microtubules making up the spindle, which is involved in mitosis which precedes cell division. Taxol binds to the beta-tubulin subunits of microtubules and stabilises their structure so that spindle does not form and re-form as required in the mitotic cycle, and it may even suppress microtubule detachment from centrosomes at the start of the process.
By preventing mitosis, it will affect rapidly dividing cells such as cancer cells more than other ordinary cells which are not dividing.
Under the trade name of Paclitaxel
it is being used to treat ovarian, breast and certain lung cancers.