Alkaloids

 Alkaloids are a diverse group of naturally occurring organic compounds that often contain nitrogen atoms in a heterocyclic ring structure. They are found in various plants and some animals, and many of them have significant pharmacological effects. Examples of alkaloids include caffeine, nicotine, morphine, and quinine. They can have both stimulant and sedative effects on the human body, depending on their chemical structure and dosage. Alkaloids have been used for medicinal, recreational, and cultural purposes throughout history.