In this 4-part series, renowned toxicologist and organic chemist dr. Gerhard Verdoorn takes us on a journey to illustrate some of the fundamentals of chemistry. In doing so, the widely misunderstood subject of what makes a product toxic as well as organic versus synthetic chemistry will be explored and explained with the help of practical examples and within the context of the particular environment.
Part 2 – Is natural safer and better than man-made?
The idea of all-natural chemicals being better than man-made chemicals is not valid. The penicillin anti-microbials are natural products while some of the other antibiotics are man-made synthetic chemicals and collectively, they serve a great purpose, namely fighting diseases that would otherwise have wiped out humankind.
Imagine a bubonic plague outbreak without antibiotics to fight the Yersinia pestis bacterium; we could have a repeat of the Black Plague that killed about 20 million people in Europe early in the 14th Century. Natural soaps contain a load of chemicals while man-made soaps also contain a load of chemicals.
Some of the natural pesticides like nicotine had better be left alone (you know why) while man-made molecules like the pyrethroids are more efficient than most natural pesticides. It does not mean that natural molecules are not efficient; take for example azadirachtin, abamectin and matrine: these are natural compounds with excellent insecticidal properties.
We do, however, have man-made molecules that are equally efficient like the diamides and the old organophosphates, but the latter are rapidly falling out of favour due their acute toxicity. We can easily dump the man-made synthetic chemistry for natural synthetic compounds, but are we prepared for the sacrifices? Loss of life to dreadful diseases due to loss of synthetic drugs. Loss of crops due to insect pests, rodents, plant pathogens and weeds. Or would you perhaps enjoy food produced with mercury and arsenic as pesticides? And would one cope without detergents to clean laundry, cutlery and crockery? Would the women of the world sacrifice all their perfumes and beauty care products, most of which are serious concoctions of natural and man-made chemicals?
Chemistry is part of our lives. Chemistry is life. Without man-made and natural chemicals there is no life for humankind, at least not as we enjoy it today. Natural and man-made chemicals are all chemicals; our mission is to find those ones that serve our purposes, and it may very well be that Mother Nature is the synthesiser of such molecules.
Organic, natural and synthetic pesticides
If there was ever a misunderstood topic, this one reaches the finishing line ahead of everything else. Various copper compounds are certified for “organic” agriculture, yet the very same chemicals are used in conventional agriculture. Pyrethrum is used in organic agriculture and similarly in conventional agriculture. So is neem oil, of which the active ingredient is azadirachtin. The list goes on and on.
A pesticide is a pesticide, irrespective of whether it was synthesised in a laboratory by the hands of an organic chemist or whether nature synthesised it in some living organism. The molecules are all organic in the chemical sense of being built on carbon frameworks.
Synthetic chemicals are harmful to people and the environment: Really?
The fact that Mother Nature synthesised a molecule does not necessarily mean it is safe. On the contrary, the fact is that we have never been able to synthesise a molecule in the laboratory that beats the toxicity of some of the natural organic compounds.
Try and snack on poorly prepared Japanese puffer fish and feel the effects of tetrodotoxin, a deadly alkaloid that is much more potent than Sarin, one of the feared nerve gases used in chemical warfare. Or touch the vividly coloured poison arrow frogs of the Amazon and collapse in seconds to the incredible power of curare toxins and batrachotoxin that can paralyse a victim in seconds.
Go a few steps forward to one of the world’s most powerful toxins namely botulinum toxin that is produced and stored in decaying food matter, evaporating water bodies and bones of skeletons. It can be deadly, and it is Mother Nature’s ultimate weapon. Wild animals like birds die by the thousands if this naturally made protein poisons open water bodies during high temperatures that cause wilting and rapid evaporation. Ungulates that chew on bones of their fallen mates drop dead due to flaccid paralysis caused by this toxin and people who get food poisoning sometimes wish they could die! Same goes for some natural metabolites of plants. Monofluoroacetic acid of the poison leaf plant is a terrible livestock killer and as little as 4 mg can kill an adult person within four hours.
Yes, some of our man-made synthetic chemicals are very toxic to people and the environment but Mother Nature’s chemical arsenal is nothing to play with. A toxin or toxicon or poison or venom is an organic compound (mostly) that need not be man-made to be incredibly toxic.
In the next part of this series we will put the concept of toxicology into context by applying the father of toxicology, Paracelsus’s founding principle.