plant alkaloids


3. PLANT ALKALOIDS


These are anti-tumor agents derives from plants. The drugs in this class are identified basing on where they were first identified

a)      Vinca alkaloids


These were isolated from periwinkle plant. Examples of drugs in this class are;
  •                  Vincristin
  •           vinblastine and
  •           Vindesine.


They act by binding to tubulin (globular proteins that polymerize into microtubules during cell division) and inhibiting microtubule formation. This results in hindered cell division and therefore prevents progression of cancer. They are mostly used in the treatment of hematologic and sometimes non-hematologic cancers.

These drugs however are known for their potential to cause neurotoxicity

See (General principles of care in oncology)


b)      Epipodophyllotoxins


It is a synthetic derivative of podophyllotoxin an extract of mandrake plant.  It works by binding and forming a ternary complex with DNA and the topoisomerase II enzyme (which aids in DNA unwinding), preventing re-ligation of the DNA strands, and by doing so causes DNA strands to break. Cancer cells rely on this enzyme more than healthy cells, since they divide more rapidly.

The only drug in this class is - Etoposide


c)       Texans   

Are derived from taxus (yews) plants. They work by binding to tubulin (globular proteins that polymerize into microtubules during cell division).
Taxanes cause hypersensitivity reactions and patients should be premedicated with steroids, H1 and H2 antagonists prior to treatment.



4. CYTOTOXIC ANTIBIOTICS



cytotoxic drugs, leukemia



Comments