Poisonous alkaloid is a term used to describe a type of chemical compound that is toxic and can be found in certain plants. NICOTINE, conin, and propine are all examples of poisonous alkaloids. NICOTINE is an alkaloid found in tobacco plants and is the main component of cigarettes. Conin is an alkaloid found in coca plants and is the main component of cocaine. Propine is an alkaloid found in opium poppy plants and is the main component of opiates.