All about Vincristine and Vinblastine

Vinca alkaloids are a class of therapeutically important drugs obtained from the Madagascar periwinkle plant. This plant has diversity of medicinal properties though the alkaloids are found in very little quantities. They are obtained naturally from the pink periwinkle plant, Catharanthus roseus G. Don and have a hypoglycemic as well as chemotherapeutic activity. They have been used earlier to treat diabetes, hypertension moreover they are known for their disinfectant properties. There are four major vinca alkaloids in clinical use: Vinblastine (VBL), vinorelbine (VRL), vincristine (VCR) and vindesine (VDS). VCR, VBL and VRL have been approved for use in the United States. Vinca alkaloids are considered the second most used class of anti-cancer drugs. Other synthetic derivatives have also been found. Many researchers didn’t found it appropriate to allow the use of some other alkaloidal constituents of periwinkle plant because of their reported toxic effects. Vindesine and vinorelbine are in clinical use today, however the third synthetic alkaloid mainly vinflunine is still under clinical trials.
What are Vinca Alkaloids?
Vinca Alkaloids are basically a class of organic compounds called alkaloids that are mainly obtained from a plant source. They are known for their beneficial physiological mainly antineoplastic effects. They are called vinca alkaloids because they belong to the vinca genus of plant Vinca roesa.The drugs belonging to the Vinca family are known for their cytotoxic effects. They elicit cytotoxic responses by inhibiting the activity of crucial elements (e.g. Microtubules) that are important for cellular activities. Due to which they are also known as Microtubule inhibitors. Although the vinca alkaloids i.e. Vincristine and vinblastine are structurally very similar to each other, their therapeutic indications are different. They are generally administered in combination with other drugs. Their Anti-diabetic effects are not of much importance as compared to anti-cancer activity. Synthetic derivatives have been in use in Europe today, however the naturally occurring have been approved By US and are in therapeutic use for more than 30 years.
There are four major vinca alkaloids in clinical use:
Vinblastine (VBL), vinorelbine (VRL), vincristine and vindesine (VDS).
HISTORICAL REVIEW OF VINCA ALKALOIDS
The indigenous inhabitants of Madagascar were the first to discover the periwinkle's medical virtues, originally treating diabetes with extracts from the plant. But the plants have been used all over the world for ailments ranging from eye infections and eczema to malaria, high blood pressure and wasp stings.
 JAMES COLLIP-CANADIAN RESEARCHER
The narrative of their usage in traditional medicine begins in the 1950s, in the Toronto laboratory of James Collip, one of the first Canadian researchers to purify insulin for clinical testing in the 1920s.
 ROBERT NOBLE
Collip's team, which included a postdoc named Robert Noble, was looking into the qualities of ancient herbal treatments in the hopes of discovering new oral diabetic drugs. CD Johnston, a black Jamaican surgeon who received his training in Canada, told them about a tea produced from periwinkle leaves that was traditionally used to manage diabetes and sent them a sample of the plant to examine. Unfortunately, rats' blood sugar and hormone levels were unaffected by the tea.
 HALINA CZAJKOWSKI-ROBINSON
Halina Czajkowski-Robinson, a Polish-born scientist and Holocaust survivor, enters the plot at this point. She worked as a laboratory technician in Collip's lab after her family relocated to Canada
She was a chemical engineer by training and worked in a cancer research lab at the famed Karoliska Institute in Sweden after WWII. It was her job, under Noble's supervision, to test the rats' blood glucose levels after they'd had the periwinkle tea. She was also interested in putting a technique she'd learnt in Sweden  counting the number of infection-fighting white blood cells  into practice.
When the trials went on to injections, Czajkowski-Robinson discovered that the animals' white blood cell counts had dropped, implying that the animals were being killed by the injections.
This grabbed Noble's interest as a prospective treatment for leukemia and lymphoma, malignancies of the blood and bone marrow caused by excessive white blood cell growth
ISOLATION OF ACTIVE INGREDIENTS FROM PLANT
The next stage was to extract the plant's active component. Czajkowski-Robinson had suggested that the researchers use chromatography to purify the molecule, but it wasn't until 1954, when a scientist named Charles Beer joined the lab, that it was finally done. Beer and his team identified a molecule named vincaleukoblastine, which was immediately shortened to vinblastine, and began testing it on malignancies in animals.