Taxanes are a class of . They were originally identified from plants of the genus Taxus (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents.
Taxanes present difficulties in formulation as medicines because they are poorly soluble in water.
Production
As their name suggests, taxanes were first derived from natural sources, but some have been
semisynthesis. Paclitaxel was originally derived from the
Pacific yew tree.
Taxanes are difficult to synthesize because of their numerous
chiral centres—taxol has 11 of these.
Recently, the presence of taxanes in the shells and leaves of Corylus avellana (the common hazel plant) has been reported.
Mechanism of action
The principal mechanism of action of the taxane class of drugs is the disruption of
microtubule function. Microtubules are essential to cell division, and taxanes stabilize GDP-bound
tubulin in the microtubule, thereby inhibiting the process of cell division as
depolymerization is prevented. Thus, in essence, taxanes are mitotic inhibitors. In contrast to the taxanes, the
vinca alkaloids prevent
mitotic spindle formation through inhibition of
tubulin polymerization. Both taxanes and vinca alkaloids are, therefore, named
or mitosis poisons, but they act in different ways. Taxanes are also thought to be
Radiosensitivity.
Substances
Hongdoushans A–C are oxygenated taxane diterpenes, isolated from the wood of
Taxus wallichiana. Hongdoushan A (C
29H
44O
7), hongdoushan B (C
27H
40O
7), and hongdoushan C (C
27H
42O
6) are reported to have anticancer activity
in vitro.
A–D have been isolated from
Taxus.
Names
Taxanes are usually treated as
with
. The name "taxol" began as a common noun (analogous with other terms in which a genus name root was
with
or ), but it was later capitalized as a trade name, and the international nonproprietary name of the compound is paclitaxel.
See also
External links
