Qs people asked me on science and my replies to them - part 203

Krishna's reply: Ricin is a chemical poison present in castor beans. It can be used as a powder, a mist, a pellet, or can be dissolved in water or weak acid and used by some miscreants to create terror. It is a stable substance and does not break down easily in typical indoor or outdoor temperatures.

Castor oil is perfectly safe but ricin is not castor oil. Castor seeds are still poisonous. A lethal dose of castor seeds for adults is about four to eight seeds. But the oil itself does not contain ricin; the ricin protein is left behind in the "castor bean mash" after the oil is extracted from the seed.

Ricin kills the cells in a person's body by preventing the cells from making the proteins they need. It is a ribosome-inactivating protein. Without cells making protein, key functions in the body shut down; even in survivors, permanent organ damage is often the result of ricin poisoning.

Symptoms of ricin poisoning, which can take several hours to show up, vary depending on whether the toxin was inhaled, ingested or — as in the case of Markov — injected. Symptoms may include fever, difficulty breathing, fluid in the lungs, vomiting, diarrhea, dehydration and blood in the urine. Death can result within 72 hours; even survivors may have long-term organ failure and other health problems.

There is no known antidote for ricin poisoning.

How can you use a poison to treat COVID 19 in the first place? Yes, despite its deadly nature — or because of it — ricin has been investigated for medicinal uses, including cancer treatment, . Ricin may have the 'potential' to target and kill cancer cells. Ricin presents great potential as anti-cancer agent and exerts its anti-cancer activity by inducing apoptosis in cancer cells.

Researchers have worked on ricin and combined it with a monoclonal antibody, a chemical that recognizes the receptor on cancer cells and binds only to that specific cell. When that happens, if ricin is attached to the antibody compound, it will be taken into the cell and kill it. The key is to get it so the ricin only enters the cancer cells. But the results are not very encouraging. Out of 150 and 200 patients with lymphoma tested earlier, about 60 percent of patients showed 'some evidence' of tumor shrinkage, and 30 to 40 percent of those get partial or complete reduction (1).

In recent times, challenges associated with its use as therapeutic agent have been studied carefully and recent advances were made to overcome these challenges. Some patients given the experimental treatment developed a symptom called "vascular leak syndrome", which affects blood vessels, particularly in the lungs (3).

Nanotechnology could open the doors for quick development of ricin-based anti-cancer therapeutics. Conceivably, ricin may serve as a chemotherapeutic agent against cancer by utilizing nanocarriers for its targeted delivery to cancer cells (2).

Also, a team from the University of Texas Southwestern Medical Center think they have found a way to genetically modify the toxin so that it is less dangerous to humans - but still as lethal to cancer cells (3).

However, till now nobody tried ricin in COVID 19 treatment. These could be the reasons:

1. Covid 19 is a recently found one and it takes time to study all the possible treatments. Right now we are still trying to understand the mechanisms of SARS-CoV2 virus.

2. Ricin has several severe side effects and these have to be tackled before we think about using it as a treatment.

3. If we can get more safer treatments, there is no point in trying deadly poisons on a severely infected body.

I, therefore, think ricin is not useful in treating COVID 19 in the present circumstances.

Footnotes:

1. Researchers Know Beans About Cancer Treatment

2. https://link.springer.com/article/10.1007/s13277-015-4028-4

3. Ricin cancer therapy tested