Vinca alkaloids are a family of anticancer alkaloids
, and vinorelbine
. The first two
chemicals occur naturally and are found in the Madagascar
, Catharanthus roseus
(the plant was formerly classified as Vinca rosea
led to these compounds becoming called Vinca alkaloids).
These alkaloids all work against cancer by inhibiting mitosis (cell division) in metaphase.
These alkaloids bind to tubulin, thus preventing the cell from making the
spindles it needs to be able to move its chromosomes around as it divides
(this is similar to the action of colchicine, but is different from the
action of paclitaxel, which interferes with cell division by keeping the
spindles from being broken down).
These alkaloids also seem to interfere
with cells' ability to synthesize DNA and RNA. They are all administered
intravenously in their sulfate form once a week; these solutions are fatal
if they're administered any other way, and can cause a lot of tissue
irritation if they leak out of the vein.