There are more than 100,000 venomous animal species identified in the world. Each of these species is capable of producing venoms that often contain upwards to 100 different molecules. Animal venoms are used effectively for defense and predation. Animal venoms are not composed of single toxins but cocktails of complex chemical mixtures. With the vast number of chemical mixtures in venom this area of science remains virtually unexplored. Investigation on venom composition converges towards the general concept that venoms are composed of about 100 to 500 active compounds. Considering these numbers, there are about 10 to 50 million natural compounds that can be used for drug discovery. Nevertheless, less than 0.01% of these compounds have been identified and characterized. Although several biologically active toxins have been reported from terrestrial and marine organisms, there is a large gap between the initial drug discovery phase, including their validation as drug models, and their use in a clinical study. Drug candidates must pass through an extensive range of tests to establish their pharmacology and biochemistry, and effects on the reproductive system, to assess their safety before moving on to the clinical phases. In other words, drug development includes the discovery of a candidate molecule, preclinical and clinical studies, which are usually costly and takes a significant amount of time to attend the requirements stated by the regulatory agencies throughout the world.
Snake venom
Snake venom has yielded a number of drugs used today, compared to other animal venoms. Firstly, because it is relatively more abundant compared to the minute amounts produced by scorpions and snails.
A little bit of history
Snake venoms have been used in traditional medicine for many thousands of years. Thousands of years ago, animal venoms were the basis of preparations meant to treat smallpox and leprosy and heal wounds. In the first century AD, theriac was developed, a mixture containing snake venom, that continued to be used until the 18th century.
Albert Calmette discovered the method of antivenom preparation from animals injected with tiny doses of venom. First used only for this purpose, venoms have now been found to have multiple important uses.
Venom to medicine
Developing new drugs from snake venom takes a lot of time, effort and money. It starts of by milking the snake that is getting venom from the snake. Next the venom is sent to the lab where the different ingredients inside snake venom are separated. This allows scientists to test and identify those with useful medical applications. Next, scientists try to develop a synthetic (not natural) version of the compound. They then test the compound in small doses on animals. Finally, scientists create a version of the drug for humans. They test it and make sure it’s safe. Once they are sure, they put it on the market.
Current developments
Fast forward to today medicines derived from hemotoxins are used in treatment of heart attacks and blood disorders. The first drug derived from snake venom toxin was developed to treat high blood pressure. This venom was taken from a Brazilian pit viper, consisting of a protein that prevents a compound called angiotensin-converting enzyme from functioning correctly. The human body uses this enzyme to maintain a stable blood pressure. Medical researchers have developed a synthetic version of the snake venom protein that is used in medicines to treat high blood pressure. Other drugs derived from hemotoxins include eptifibatide, which contains a modified rattlesnake venom protein, and tirofiban, which contains a venom protein from the African saw-scaled viper. These medicines are used in treatment of minor heart attacks. They work by helping to dissolve and prevent blood clots. Medical tests indicate that small dosages of the venom from Malayan pit viper help to dissolve stroke-related blood clots and prevent new clots from forming. Medicines derived from neurotoxins are used to treat brain injuries, strokes, and diseases such as Alzheimer’s and Parkinson’s.
Looking at how effective these venoms are in the treatment for circulatory system disorders, researchers are studying the potential of snake venom proteins to be for the treatment against cancer. Researchers have found that a compound in the venom of a certain type of snake which is not yet disclosed has the potential to disrupt the function of endothelial cells that forms the inner surface of blood vessels. This can lead to the cells to separate from one another, which leads to their death. Scientists think that this property of snake’s toxic venom could be used to disrupt the flow of blood to a tumor and thus preventing its growth. Since the venom toxins act on certain types of cells, hence the healthy cells would not be unaffected.
Scientists are also studying and exploring of using snake venom as a potential source of painkilling compounds. Researchers have determined that two molecules isolated from black mamba venom are as effective as morphine in the elimination of pain. But there is yet a lot of research and studies that needs to be made before a black mamba venom–derived drug could be considered for human use. On the positive side to this is that the early tests in the lab have encouraging results to it
The medical breakthroughs that can be provided by venom are endless and scientists are just scratching the surface of it. More research is needed however to better understand the chemical compositions and eventual use of animal venom.
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