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Comment by mastazi | Hacker News Reader

Can anyone with a scientific background give an opinion about the first comment to the linked post? They say they are sceptical because "there are a number of Tropane alkaloids which are very close to cocaine and are present in other plants - especially nightshades (e.g., belladonna) - which were known to and used for various purposes by Europeans for a long time."

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As you would expect, this is covered in the actual paper [0]:

> Therefore, the 3rd molecule detected in the brain tissues of our subjects, hygrine (an alkaloid present in the leaves of Erythroxylum spp. only), was essential to determine that the molecules detected in these human remains derived from the chewing of coca leaves or from leaves brewed as a tea, consistent with the historical period.

If I'm reading this right, they checked for a number of markers and one of those is found only in coca leaves.

[0] https://www.sciencedirect.com/science/article/pii/S030544032...

Thank you! I should have thought of checking the paper first

Author here, I had the same question and looked into it. The author of that comment seems to be onto something because hygrine is indeed found in nightshades as well as in coca. Interesting.

Where are you getting that hygrine is found in nightshades? The authors of the paper specifically say it's only found in Erythroxylum and I'm not finding any references in my own research to that specific chemical being present in nightshades.

I'm no chemist, but according to wikipedia, cuscohygrine is found in belladona plants and it metabolizes into hygrine. So that could be what he's referring to?

I read the same wikipedia page and that statement is confusing if not incorrect. Hygrine is a not a metabolite of cuscohygrine, it's in fact the other way round: hygrine is the precursor and cuscohygrine is the metabolite.

The first reference on that page is "The role of hygrine in the biosynthesis of cuscohygrine and hyoscyamine"

No, it does not appear to be true that hygrine is found in nightshades.

Cuscohygrine does occur in those plants yet it's precursor hygrine does not. How it then gets there without us being able to detect hygrine could be because it only occurs in very small concentrations or is produced and then quickly and wholly converted in to its cusco metabolite, or that it's produced through a different biosynthetic pathway.

The research group behind the paper looks reliable, they have a publication record in the area and while it's surprising they can detect metabolites (and surprising that brains were preserved from the 1600s) they seem to have done a lot of detailed work, here's some of their other related work (they also found cannabis residues in some of their material):

"Forensic toxicological analyses reveal the use of cannabis in Milano (Italy) in the 1600's (2023)"

https://www.semanticscholar.org/paper/Forensic-toxicological...

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