John Hopton for redOrbit.com – @Johnfinitum
People often talk about natural cures, but none are quite like these. There are currently six FDA-approved drugs on the market containing animal-derived ingredients like venoms extracted from snakes, lizards, spiders, and sea creatures.
Professor Glenn King from the University of Queensland, Australia, is an expert in the field. RedOrbit spoke to him and began by asking why elements generally thought of as being dangerous can in some cases have a positive effect on human health.
“It’s possible because the toxins have evolved to work on ion channels and receptors in the nervous system of prey that are slightly different and typically more complex in humans, and often located in different parts of the body,” Professor King explained. “So a toxin that kills an insect or other type of prey can be beneficial in a human.”
For example, the analgesic (painkilling) drug Prialt, made from the venom of a marine cone snail, is toxic to fish (which the cone snail hunts), and yet a useful painkiller in humans (find out why in the videos below).
Also from the ocean, sea anemone venom has been used for treatment of multiple sclerosis (MS) and other autoimmune diseases.
Drugs from bugs
Professor King particularly focusses on “getting drugs from bugs.” He utilizes spiders, centipedes, and even scorpions, hoping they will be useful for treatment of things like chronic pain, epilepsy, and stroke.
Venomous animals have a long history as a source of medical treatments. For example, snake venom has been used since the 7th century BCE to treat arthritis and gastrointestinal ailments. Tarantulas are used by indigenous populations of Central and South America to treat ailments ranging from asthma to cancer, while cobra venom has long been used to treat conditions as diverse as polio and rheumatism.
However, modern medicine’s relationship with venom-based drugs began in the 1970s with the development of the blockbuster antihypertensive drug captopril based on the venom of the Brazilian viper, Bothrops jaracaca.
Now, many of the major pharmaceutical companies have venom-based drug discovery programs, including AstraZeneca, Eli Lilly, Johnson & Johnson, and Merck.
At the heart of the processes are the naturally occurring biological molecules, peptides. Professor King explains that: “Venom proteins and peptides are usually endowed with a disulphide-rich architecture that provides them with a high degree of chemical and thermal stability as well as resistance to proteases. It is this feature, along with their selectivity and potency, that has made venoms a valuable source of lead molecules for the development of novel therapeutics.”
According to Professor King, along with the six current FDA-approved drugs derived from venom peptides or proteins, several more are in clinical trials. The majority of approved venom-derived drugs come from snakes or lizards and they mostly target the cardiovascular system. Chronic pain, auto-immune diseases, and stroke are targets, too.
The most recent venom-derived drug to be approved by the FDA is exenatide, which helps insulin to be secreted in order to treat type 2 diabetes. It is isolated from the saliva of the Gila monster, a venomous lizard.
“Despite recent progress, only a tiny fraction of the chemical diversity encoded in animal venoms has been explored. Fortunately, a much wider range of animal venoms can now be studied in detail due to recent advances in analytical techniques,” Professor King said.
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