Editing Alkaloid (section)

==Extraction==
[[File:Piperine crystals.jpg|thumb|Crystals of [[piperine]] extracted from [[black pepper]].]]

Because of the structural diversity of alkaloids, there is no single method of their extraction from natural raw materials.<ref name="Hesse 116">[[#Hesse|Hesse]], p. 116</ref> Most methods exploit the property of most alkaloids to be soluble in organic solvents<ref name="G. P. Fox et al 2013" /> but not in water, and the opposite tendency of their salts.

Most plants contain several alkaloids. Their mixture is extracted first and then individual alkaloids are separated.<ref name="ref236">[[#Grinkevich|Grinkevich]], p. 132</ref> Plants are thoroughly ground before extraction.<ref name="Hesse 116"/><ref>[[#Grinkevich|Grinkevich]], p. 5</ref> Most alkaloids are present in the raw plants in the form of salts of organic acids.<ref name="Hesse 116"/> The extracted alkaloids may remain salts or change into bases.<ref name="ref236" /> Base extraction is achieved by processing the raw material with alkaline solutions and extracting the alkaloid bases with organic solvents, such as 1,2-dichloroethane, chloroform, diethyl ether or benzene. Then, the impurities are dissolved by weak acids; this converts alkaloid bases into salts that are washed away with water. If necessary, an aqueous solution of alkaloid salts is again made alkaline and treated with an organic solvent. The process is repeated until the desired purity is achieved.

In the acidic extraction, the raw plant material is processed by a weak acidic solution (''e.g.'', [[acetic acid]] in water, ethanol, or methanol). A base is then added to convert alkaloids to basic forms that are extracted with organic solvent (if the extraction was performed with alcohol, it is removed first, and the remainder is dissolved in water). The solution is purified as described above.<ref name="Hesse 116"/><ref>[[#Grinkevich|Grinkevich]], pp. 132–134</ref>

Alkaloids are separated from their mixture using their different solubility in certain solvents and different reactivity with certain reagents or by [[distillation]].<ref>[[#Grinkevich|Grinkevich]], pp. 134–136</ref>

A number of alkaloids are identified from [[insect]]s, among which the [[fire ant]] [[venom]] alkaloids known as [[solenopsin]]s have received greater attention from researchers.<ref>{{Cite book|last=Fox|first=Eduardo Gonçalves Paterson|chapter=Venom Toxins of Fire Ants|date=2016|title=Venom Genomics and Proteomics|pages=149–167|editor-last=Gopalakrishnakone|editor-first=P.|publisher=Springer Netherlands|doi=10.1007/978-94-007-6416-3_38|isbn=978-94-007-6415-6|editor2-last=Calvete|editor2-first=Juan J.}}</ref> These insect alkaloids can be efficiently extracted by solvent immersion of live fire ants<ref name="G. P. Fox et al 2013" /> or by centrifugation of live ants<ref>{{Cite journal|last1=Fox|first1=Eduardo G. P.|last2=Xu|first2=Meng|last3=Wang|first3=Lei|last4=Chen|first4=Li|last5=Lu|first5=Yong-Yue|date=2018-05-01|title=Speedy milking of fresh venom from aculeate hymenopterans|journal=Toxicon|volume=146|pages=120–123|doi=10.1016/j.toxicon.2018.02.050|pmid=29510162|bibcode=2018Txcn..146..120F |issn=0041-0101}}</ref> followed by silica-gel chromatography purification.<ref>{{Cite journal|last1=Chen|first1=Jian|last2=Cantrell|first2=Charles L.|last3=Shang|first3=Han-wu|last4=Rojas|first4=Maria G.|date=2009-04-22|title=Piperideine Alkaloids from the Poison Gland of the Red Imported Fire Ant (Hymenoptera: Formicidae)|journal=Journal of Agricultural and Food Chemistry|volume=57|issue=8|pages=3128–3133|doi=10.1021/jf803561y|pmid=19326861|issn=0021-8561}}</ref> Tracking and dosing the extracted solenopsin ant alkaloids has been described as possible based on their absorbance peak around 232 nanometers.<ref>{{Cite journal|last1=Fox|first1=Eduardo G. P.|last2=Xu|first2=Meng|last3=Wang|first3=Lei|last4=Chen|first4=Li|last5=Lu|first5=Yong-Yue|date=2018-06-01|title=Gas-chromatography and UV-spectroscopy of Hymenoptera venoms obtained by trivial centrifugation|journal=Data in Brief|volume=18|pages=992–998|doi=10.1016/j.dib.2018.03.101|pmid=29900266|pmc=5996826|bibcode=2018DIB....18..992F |issn=2352-3409}}</ref>