certain species of the family Solanaceae, which includes nightshades, tomato, potato, aubergine and chilli peppers, may contain very low levels of nicotine-like substances, but I have found no scientific reference stating it is so. Several substances are present, like solanine (potatoes) and solanidine (chillies) which are about the closest, but they have no resemblance to the structure of nicotine.

The well documented substances, the capsaicinoids, are found in chillies. Hot peppers are rich in capsaicin, which creates a burning sensation that affects pain receptor cells and causes them to release endorphins, the body?s natural opiate-like painkillers, that create a temporary feeling of euphoria.

Just because one plant species in a botanical family produces a chemical is no reason to think others in that family will do the same. Nightshades produce atropine, a powerful drug and heart stimulant. I don't think it occurs in solanum vegetables, although old aubergine varieties might come close.

Also to be considered is the way nicotine gets into the body, to have an effect. It is either inhaled or passes across the skin barrier when used as patches. If eaten, it would not have much effect for the same reason why cocaine is either inhaled or injected.

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Steve