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I recall a story from one of my Botany professors where he encountered a woman picking Solanum dulcamara (nightshade) berries. When he asked her what she was doing with them, she responded that her husband had her make a pie from them every year.

As her husband was presumably still alive, and since I regard this particular professor as reliable, what would have removed enough solanine from the berries to avoid ill effects? Does the concentration decrease upon ripening, or would cooking destroy the toxin? Would that also be why we fry green tomatoes?

(As a disclaimer, no-one should eat plants that are known to be poisonous. Even though some people don't react to poison ivy, it is still a bad idea to rub it all over your body.)

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Did you mean Solanum viride or Solanum viridifolium? –  mgkrebbs Oct 11 '12 at 5:35
    
The common name is green nightshade. I am guessing viridi, but I will check in Flora of the Pacific Northwest. –  S. Albano Oct 11 '12 at 5:41
    
Actually, it doesn't show either of those in my area. I don't have one to key out, but the illustration for S. dulcamara looks like the correct one. –  S. Albano Oct 11 '12 at 5:45
    
Do you have a reference for the diminishing of the alkaloids during ripening? –  John Mar 10 at 16:26
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1 Answer

up vote 4 down vote accepted

If you ask Dr. Duke's phytochemical database, by far the most solanine is found in green potatoe fruits (their skin), with much less in leaves and tissues. Similar values are seen in green tomatoes, with dozens of mg per 100g fruit. There is no value for Solanum dulcamara (doesn't mean there is nothing in it) but it appears to have small quantities of atropine. Furthermore, Wikipedia gives for solanine a minimum toxically effective dose for humans of 200 mg---that's where dizzyness and dispnoe starts---, and gives for children a lethal amount of S. dulcamara of 30-40 unripe berries or less. The amount of solanine increases (in potato) when temperature goes up, because it is produced by plants as an antifungal against rot. Ripening in S. dulcamara and, as we know all ourselves, potato and tomato, destroys solanine, so fully ripe berries seem to be okay. Solanine does not degrade when cooked but is lost with the cooking water. For an account of solanine poisoning from potatoes see e.g. this free paper. Newer potato varieties have much less solanine than those from former times.

http://www.ars-grin.gov/duke/

http://de.wikipedia.org/wiki/Solanin

Know your databases!

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The database link is good. My background is in taxonomy and phylogenetics, so I am at a loss for knowing where to look up things that are not gene/protein sequences or species identification. It is unfortunate that the evidence in the answer for reduced levels in nightshade after ripening is all implicit. I would have thought there would be some information about levels, or lack thereof in the ripe berries. –  S. Albano Oct 14 '12 at 6:07
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