Alkaloids are big class of natural products with different skeletons as indole, isoquinoline, tropane, phenyl-alkyl amine alkaloids and so on. For this reason, they have a lot of pharmacological effects. Some affect the eye as atropine (mydriatic) and pilocarpine (miotic). Some are used to prevent precipitation of uric acid in the joints (gout) as colchicine. Some used as anticancer agents as vincristine and vinblastine....etc