Poppy seeds lack alkaloids which are compounds responsible for the pharmaceutical effect in plants. In Opium, there are more than 30 different alkaloids present. The most important of these are morphine which exists to the extent of 4 to 21%; codeine, 0.8 to 2.5%; noscapine, 4 to 8%; papaverine 0.5 to 2.5 %; and thebaine, 0.5 to 2%.
Other opium alkaloids include narceine, protopine, laudanine, codamine, cryptopine, lanthopine and meconidine. Each of these alkaloids acts chiefly on the central nervous system- their action first stimulates then depresses the nerve impulse. They serve as analgesic, hypnotic and narcotic.
