Malaria kills around 400 thousand individuals annually. It’s the result of a bodily infection by single-celled parasitic organisms from the Plasmodium genus and causes fever, vomiting, chills and body aches. There is some good news though. Malaria can be treated with quinine, the main component of tonic water!

Quinine is isolated from the bark of the cinchona tree, which has been used for hundreds of years by groups like the Quechua people to treat maladies like shivers and diarrhea.

In the 1700s a Scottish doctor, George Cleghorn, discovered that quinine could be used to treat malaria. This quickly led to tonic water being drunk by British soldiers stationed in India to fight malaria. But as you may know, tonic water is quite bitter. So, in the 1800s, soldiers took to adding first gin, and eventually lemon and lime to their tonic water, to hide the bitter flavour, thus inventing the classic (and my favourite!) gin and tonic.

Nowadays the quinine content of tonic water is minimal, and more effective antimalarial drugs have been developed, but a close relative of quinine, quinidine, is still commonly used as an antiarrhythmic drug to treat irregular heart rhythms. The two compounds only differ in the position of one of their chemical groups: quinine features an OH group that points in one direction, while in quinidine it points in the opposite direction. This small switch is enough to change the function of the drug from antimalarial to antiarrhythmic.

@AdaMcVean

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