Which of the following chemicals are found in eggplant seeds?

The story behind the answer

Nicotine is correct because eggplant (aubergine) is a member of the nightshade family (Solanaceae), the same plant family as tobacco. Many nightshades produce trace amounts of nicotine as a defensive alkaloid, and in eggplant it’s most concentrated in the seeds and skin. The amounts are tiny—roughly 0.01 mg per 100 g—so you’d need about 10 kg of eggplant to match the nicotine in one cigarette.

The other options don’t fit: psilocybin occurs in certain mushrooms, mescaline in peyote and other cacti, and cyanide (as cyanogenic glycosides) in plants like bitter almonds and apricot kernels. Memory tip: eggplant is a “tobacco cousin,” so think “nightshade → nicotine.”