What is Alkaloid?
[[File:Ephedrine.png|thumb|Chemical structure of [[ephedrine]], a phenethylamine alkaloid]] [[File:Caffeine.svg|180px|thumb|[[Caffeine]]]] An '''alkaloid''' is a [[chemical compound]] that can be made naturally. They contain [[base (chemistry)|basic]] [[nitrogen]] atoms.<ref>{{GoldBookRef|title=alkaloids|file=A00220|year=1995}}</ref> The name comes from the word [[alkaline]] and was used to describe any alkaline containing nitrogen. Alkaloids are made by a large variety of organisms, such as [[bacteria]], [[fungus|fungi]], [[plant]]s, and [[animal]]s and are part of the group of [[natural products]] (also called [[secondary metabolite]]s). Many alkaloids can be [[wiktionary:purification|purified]] from basic substances by [[acid-base extraction]]. Many alkaloids are [[poison|toxic]] to other organisms. Some alkaloids have a [[bitter]] [[taste]]. == Well-known alkaloids == All of the following alkaloids are produced by [[flowering plants]]. They are one of the main ways plants reduce or [[Defence against herbivory|avoid being eaten by herbivores]]. * [[Cocaine]], used as an [[anesthetic]] and a [[stimulant]], is an [[illegal drug]] when it is not used [[medicine|medically]]. * [[Caffeine]], used as a stimulant, is used as something [[addiction|addictive]] in [[coffee]] or [[tea]]. In this case and the following, herbivores can eat the leaves but they get heart palpitations if they eat too many. * [[Nicotine]], used as a stimulant in [[cigarette]]s, can also be used to treat certain forms of [[epilepsy]]. * [[Morphine]] is widely used to subdue [[analgesic|severe pain]]. In a special slow-release form, it is sometimes used to help people get away from drug addiction. * [[Quinine]], used to treat certain forms of [[malaria]], is sometimes used to give food a bitter taste. * [[Curare]], the poison dart substance, is originally a plant product from ''Strychnos toxifera'', which is later concentrated in [[poison dart frog]]s. * [[Strychnine]] and [[brucine]] are [[toxic]] alkaloids produced by ''Strychnos nux-vomica