A Promising Anticancer Drug
It was back in 1966 when Dr. Monroe E. Wall and Dr. Mansukh C. Wani discovered camptothecin, which is an alkaloid found in the stem wood of the Camptotheca acuminata Decne or Chinese happy tree. The C. acuminata is also known as the cancer tree and the tree of life, which makes sense since camptothecin extracted from the C. acuminate bark possesses anticancer properties. Traditional Chinese Medicine practitioners have been using Camptotheca acuminate stem wood for thousands of years. Modern research supports camptothecin’s anticancer properties, and an analogue of camptothecin is even in use as an anticancer drug by the branded name of Camptosar.
Originally, Dr. Monroe E. Wall and Dr. Mansukh C. Wani had Camptotheca acuminata tree’s stem wood in order to isolate camptothecin. The discovery they made has also been elaborated in the article “Camptothecins and topoisomerase I.” Basically, camptothecin possesses antileukemic or antitumour activity. It also tends to bind to and stabilize the topoisomerase-DNA covalent complex, inhibiting Mitochondrial Topo I.
Studies like “Camptothecin suppresses nitric oxide biosynthesis” also reveal that the fact that camptothecin inhibits NOS2 or inducible nitric oxide synthase (iNOS) could be responsible for its antitumor activity. NOS2 or iNOS generates nitric oxide, which plays a crucial role in regulating biochemical pathways, including angiogenesis.
In simpler words, camptothecin is a plant alkaloid and many of its analogues happen to be an active ingredient in several well-known chemotherapy drugs, such as Camptosar (Irinotecan). Since it is a plant alkaloid, camptothecin happens to be cell-cycle specific, which means that it attacks cancer cells during their various phases of division. As mentioned, camptothecin also interferes with the action of topoisomerase enzymes. These enzymes play a crucial role in the manipulation of the DNA structure that is essential for replication, without which cancer cells cannot replicate.
Several derivatives of camptothecin are also being developed to not only further boost its antileukemic or antitumour activity but also reduce its potential side effects. Even the FDA has approved camptothecin as an orphan drug, and it is regarded as a promising anticancer drug today.
Camptothecin is currently not available in the form of a capsule, pill or tablet. The only way to take camptothecin is intravenously, i.e. through a vein. According to Shanghai Natural Bio-engineering Co., exceeding the recommended dosage of 10 milligrams once per day, dissolved in normal 20 milligrams of saline, should be avoided. However, at the same time the dosage of camptothecin that a person may receive can also depend on various factors, such as their height and weight, the condition or type of cancer being treated, and any other health problems the patient may be suffering from. The dosage and schedule is general determined by the doctor.
Camptothecin Side Effects
If dosage is exceeded above 100 milligrams, which is a relatively high dose, there are chances of experiencing emesis, gastroenteritis, lack of appetite and nausea.
Camptothecin may inhibit and may also lead to hemorrhagic cystitis. It is also advised that a trained doctor or nurse should inject camptothecin to prevent it from escaping the vein, as this may cause inflammation.
- Curr Med Chem Anticancer Agents: Camptothecins and topoisomerase I: a foot in the door. Targeting the genome beyond topoisomerase I with camptothecins and novel anticancer drugs: importance of DNA replication, repair and cell cycle checkpoints.
- Life Sci: Camptothecin suppresses nitric oxide biosynthesis in RAW 264.7 macrophages.
- Shanghai Natural Bio-engineering Co: Camptothecin.