THE POISON GARDEN website       

Saturday 4th August 2012

Sometimes you can determine how myths and misinformation begin. To take one example, the notion that the fruit of Atropa Belladonna, deadly nightshade, is ‘insanely sweet’ when, in fact, it has an insipid, slightly sweet taste can be traced directly to Mrs Grieve’s frequently flawed ‘A Modern Herbal’. Most of the time, however, it proves impossible to get back to the root of a story.

I can’t help thinking that a new myth is in creation so I thought I’d document its start so that, in the future, it will be easier to debunk.

It starts with the simultaneous publication of two papers in ‘Proceedings of the National Academy of Sciences of the United States of America (PNAS)’ on 29th July. The first¹ is concerned with finds in a cave in South Africa and the second², that interests me, is about the analysis of substances found in the cave and what they say about technological development.

Amongst the items discovered and investigated were pieces of a stick identified as a poison applicator. The abstract says ‘A wooden poison applicator, dated to ~24,000 BP, retains residues with ricinoleic acid, derived from poisonous castor beans.’

The paper itself says;

‘Ricinoleic acid is found in mature castor beans (Ricinus communis L., Euphorbiaceae), a species common in this part of Africa. The protein ricin in castor beans is known to be among the most dangerous natural poisons.’

Let’s look at ricinoleic acid. It systematic name is 12-hydroxy-9-cis-octadecenoic acid. (See this blog entry about the naming of chemical found in plants) It is a fatty acid found in Ricinus communis, castor oil plant, and Claviceps purpurea, ergot fungus. It is present in castor oil. Castor oil is, of course, non-toxic at normal levels. Rats fed castor oil as 10% of their total diet showed no signs of poisoning.³

Ricinus communis, castor oil plant

The discovery of ricinoleic acid does not confirm that the stick found was used to apply poison to arrow tips. The ricinoleic acid may be all that remains from crushed castor beans used as toxins but the present work cannot confirm this. It may be that it was ergot fungus that was used for the arrow tips.

So, the paper says ricinoleic acid was found, points out that this is a component of castor beans and says that there is evidence that these cave-dwellers used poison on arrow heads to help them hunt. The next thing to do is see how it was reported.

In the early hours of 30th July Live Science said the researchers had found ‘traces of ricinoleic acid, a natural poison found in castor beans’⁴. So, immediately, we have a supposed scientific site calling ricinoleic acid a poison when it isn’t. A couple of hours later, another science site, Science 2.0, also called ricinoleic acid a poison.⁵

In the evening, the New Scientist reported the story by concentrating on what it tells us about evolution. There is no mention of poison or ricinoleic acid⁶.

Ricinus communis, castor oil plant

It wasn’t just scientific media that reported the work. ABC News headlined a key part of the findings; ‘Researchers: Modern Culture May Have Earlier Start’ and, though it made no mention of ricinoleic acid, it couldn’t resist starting its report with ‘Poisoned-tipped arrows’⁷. The Los Angeles Times is also interested in the earlier emergence of ‘modern culture’ but still calls ricinoleic acid a poison.⁸ The New York Times manages to mangle the science more than any other report, so far, by saying the scientists studied ‘bone arrowheads tipped with poison from toxic castor bean oil’.⁹

On 31st July, iol (‘Independent Online, a premium South African online news brand.’) carried the story in its scitech section and described the finding of ‘a poison containing ricinoleic acid found in castor beans’.¹⁰ In some ways that is not so bad since you can have a poison containing ricinoleic acid where the toxin comes from other substances. If, these primitive people did use castor beans to make arrow poison that is what you would have. But the ‘if’ is important because the researchers only found ricinoleic acid and could not draw firm conclusions about what it was doing there.

Huffington Post relied on re-reporting both Science 2.0 and Live Science so its story also called ricinoleic acid a natural poison.¹¹

Ricinus communis, castor oil plant

But it was Medical Daily that upped the ante by headlining its piece ‘World's Oldest Poison Reveals Modern Civilization Began in Africa 20,000 Years Earlier Than We Thought’¹² even though its report simply repeats the ‘traces of ricinoleic acid, a natural poison found in castor beans’ claim that appears in a number of the other reports.

So, here is the first part of the myth, established within 48 hours of the papers being published. Henceforward ricinoleic acid will be described as a poison in spite of the easily accessible fact that it is found in castor oil and castor oil is most definitely not poisonous.

The second, and more serious, part of the myth has started and will, in time, I have no doubt spread itself. The start has come from Twitter where people have posted links to one or other of the stories referred to above but have said things like;

‘People Were Poisoning Each Other w Ricin 20,000 Years Ago’

‘Ricin in a preparation from the castor bean (Ricinus communis) may be oldest known human use of poison - 20K years ago’

And

‘People Were Poisoning Each Other With Ricin 20,000 Years Ago’

I fully expect that all those stories that would have begun ‘ricin a bioterror weapon known since the First World War’ will begin ‘ricin a poison with a 20,000 year history’.

I’m not so optimistic as to think that this piece can stop the development of that myth in its tracks but it will make it easier to debunk it each time it appears.

References

1. Border Cave and the beginning of the Later Stone Age in South Africa PNAS July 30, 2012    
2. Early evidence of San material culture represented by organic artifacts from Border Cave, South Africa  PNAS July 30, 2012     
3. Final Report on the Safety Assessment of Ricinus Communis (Castor) Seed Oil, Hydrogenated Castor Oil, Glyceryl Ricinoleate, Glyceryl Ricinoleate SE, Ricinoleic Acid, Potassium Ricinoleate, Sodium Ricinoleate, Zinc Ricinoleate, Cetyl Ricinoleate, Ethyl Ricinoleate, Glycol Ricinoleate, Isopropyl Ricinoleate, Methyl Ricinoleate, and Octyldodecyl Ricinoleate International Journal of Toxicology May 2007 vol. 26 no. 3 suppl 31-77
4. Oldest Poison Pushes Back Ancient Civilization 20,000 Years Live Science 30th July 2012
5. Ancient Nature: Using Poison To Kill 44,000 Years Ago Science 2.0  30th July 2012
6. Modern culture began in South Africa 44,000 years ago New Scientist 30th July 2012
7. Researchers: Modern Culture May Have Earlier Start ABC News Tech 30th July 2012
8. Modern culture emerged in Africa 20,000 years earlier than thought Los Angeles Times 30th July 2012
9. Artifacts Revive Debate on Transformation of Human Behavior The New York Times 30th July 2012 
10. Startling find in SA cave IOL scitech 31st July 2012
11. Stone Age Poison Pushes Back Dawn Of Ancient Civilization 20,000 Years Huffington Post 31st July 2012
12. World's Oldest Poison Reveals Modern Civilization Began in Africa 20,000 Years Earlier Than We Thought Medical Daily 31st July 2012

'Is That Cat Dead? - and other questions about poison plants' is now also available in Kindle form from Amazon.