Everywhere in the media and popular press we hear stories praising natural ingredients and how ‘natural’ products feature superior benefits and are much safer than their ‘unnatural’ counterparts. Whether it comes to food, personal care or cosmetics the popular consensus seems to be that natural ingredients are better for our health than scary unnatural or ‘synthetic’ alternatives.
When it comes to drugs this distinction between natural and synthetic is curious because half of the pharmacopeia derives from molecules initially discovered from nature. The corollary is that the other half comes from synthetic molecules designed and developed by pharmaceutical companies.
The power of natural products as a source of drugs could be explained by millions of years of evolution alongside biological systems which make them well suited to interact with biomolecules. In some cases natural products can cure diseases but their high level of bioactivity can also lead to toxicity or even death. Common examples of harmful natural products include snake venoms which like human proteins are mostly polypeptides made of amino acids. Admirers of Japanese food certainly know about the puffer fish or fugu which has to be properly cooked to avoid lethal intoxication because of the marine natural product tetrodotoxin. Fans of the American TV show Breaking Bad will certainly remember that ricin, a protein produced in the castor oil plant, is a traceless and highly toxic substance that can kill humans even at a low dose.
Similarly to natural products, synthetic molecules can be useful drugs or feature toxic and unpleasant side effects. Designed synthetic drugs such as Gleevec and Paracetamol have contributed as much to medicine as gifts from nature like Penicillin or Artemisinin.
For a chemist or a pharmacologist the source of the molecule does not really matter because molecules are made of the same atoms whether they come from a natural source or spring from the imagination of a chemist. The difference in the way atoms are assembled provides molecules with functions as varied as medicinal agent, fragrance, agrochemical or lubricant to name just a few. The only important factor for our health is whether these molecules interact with the human body in a beneficial or harmful manner. These interactions depend on the structure of the molecule, the dose and the individual taking it.
So what drugs are best to use — natural or synthetic? The answer to that question is not black or white because the only answer we can provide is that it depends on what molecule is used, how much is the dose, and who is taking it.