{{Short description|Alkaloid found in Peyote}} {{Chembox | ImageFile = Anhalotine.svg | ImageClass = skin-invert-image | ImageSize = 180px | ImageAlt = | IUPACName = 6,7-dimethoxy-2,2-dimethyl-8-hydroxy-1,2,3,4-tetrahydroisoquinolin-2-ium iodide | OtherNames = Anhalidine methiodide; anhalotine iodide | Section1 = {{Chembox Identifiers | ChemSpiderID = | PubChem = | InChI = 1S/C13H20NO3.I/c1-14(2)6-5-10-8(13(14)7-11(10)15-3)9(16-4)12(17)10;/h7,9,12,17H,5-6H2,1-4H3;/q+1;-1 | InChIKey = | SMILES = [I-].COc1c(OC)c(O)c2c(c1)CC[N+](C)(C)C2 }} | Section2 = {{Chembox Properties | C=13 | H=20 | I=1 | N=1 | O=3 | MolarMass = 365.21 | Appearance = Colorless crystals | MeltingPt = 219 | MeltingPt_notes = –220 °C | Solubility = Soluble in water and ethanol }} }}
'''Anhalotine''' is a tetrahydroisoquinoline alkaloid found in the cactus ''Lophophora williamsii'' (peyote).<ref name="Kapadia1968">{{Cite journal |last1=Kapadia |first1=G. J. |last2=Shah |first2=N. J. |last3=Zalucky |first3=T. B. |title=Peyote alkaloids. II. Anhalotine, lophotine, and peyotine, the quaternary alkaloids of ''Lophophora williamsii'' |journal=Journal of Pharmaceutical Sciences |year=1968 |volume=57 |issue=2 |pages=254–262 |pmid=5641668}}</ref> It is a quaternary ammonium compound, specifically the methiodide of the secondary alkaloid anhalidine.<ref name="Kapadia1968" /> Anhalotine occurs in trace amounts alongside other peyote alkaloids such as mescaline, anhalonidine, pellotine, and anhalonine. As a quaternary salt, it is not psychoactive.<ref name="Trout2013">{{Cite book |last1=Trout |first1=Keeper |title=Trout's Notes on the Cactus Alkaloids: Nomenclature, Physical Properties, Pharmacology, and Occurrences |edition=4th |publisher=Mydriatic Productions/Better Days Publishing |year=2013 |url=https://troutsnotes.com/pdf/C13_CactusAlkaloids.pdf |pages=188}}</ref>
== History == Anhalotine was first isolated from peyote in 1968 by Govind J. Kapadia, Narendra J. Shah, and Theodore B. Zalucky at the University of Michigan.<ref name="Kapadia1968" /> Using thin-layer chromatography, ultraviolet spectroscopy, and infrared spectroscopy, they identified it as the methiodide of anhalidine, yielding 7 mg from 2.3 kg of dried peyote buttons (0.0003% dry weight).<ref name="Kapadia1968" />
== Natural occurrence == Anhalotine is a minor alkaloid in ''Lophophora williamsii'', present at concentrations of approximately 0.0003% by dry weight.<ref name="Kapadia1968" /> It has also been reported in trace amounts in other ''Lophophora'' species, such as ''L. diffusa'', and potentially in related cacti like ''Aztekium ritteri'' and ''Pelecyphora aselliformis'' via its parent compound anhalidine.<ref name="Trout2013" /> Concentrations vary depending on factors such as plant age, habitat, and analytical methods.
== Chemistry == === Structure === Anhalotine is a quaternary tetrahydroisoquinoline alkaloid with the chemical formula C<sub>13</sub>H<sub>20</sub>NO<sub>3</sub><sup>+</sup> (cation) and C<sub>13</sub>H<sub>20</sub>INO<sub>3</sub> (iodide salt). It consists of a 1,2,3,4-tetrahydroisoquinoline core substituted with methoxy groups at positions 6 and 7, a hydroxy group at position 8, and a 2,2-dimethyl-2-ium iodide at the nitrogen (position 2).<ref name="Kapadia1968"/><ref name="Southon1989">{{Cite book |last1=Southon |first1=I. W. |last2=Buckingham |first2=J. |title=Dictionary of Alkaloids |publisher=Chapman and Hall |year=1989 |volume=2 |isbn=0-412-24910-3 |pages=T-00108}}</ref><ref name="Trout2013" /> It is structurally related to anhalidine, from which it differs only by the additional methyl group on the nitrogen, forming the quaternary salt.<ref name="Kapadia1968" />
=== Biosynthesis === Anhalotine shares the biosynthetic pathway common to peyote's tetrahydroisoquinoline alkaloids, beginning with the amino acid L-tyrosine. Tyrosine undergoes decarboxylation to tyramine, followed by meta-hydroxylation, para-O-methylation, and cyclization via a Pictet-Spengler reaction with formaldehyde (derived from S-adenosylmethionine). This yields anhalidine, which is then N,N-dimethylated to form the quaternary anhalotine.<ref name="Lundström1971">{{Cite journal |last1=Lundström |first1=J. |title=Biosynthesis of mescaline and tetrahydroisoquinoline alkaloids in ''Lophophora williamsii'' (Lem.) Coult. |journal=Acta Pharmaceutica Suecica |volume=8 |issue=3 |pages=261–274 |year=1971 |pmid=5560271}}</ref>
== Pharmacology == As a quaternary ammonium compound, anhalotine is highly polar and poorly crosses the blood-brain barrier, suggesting minimal central nervous system activity.<ref name="Trout2013" /> No dedicated pharmacological studies or human/animal bioassays have been conducted on anhalotine, likely due to its trace occurrence and the challenges of isolating sufficient quantities.<ref name="Trout2013" /> It is not considered to contribute significantly to the psychoactive effects of peyote, which are primarily attributed to mescaline.
== Legal status == Anhalotine is not specifically scheduled under international conventions such as the Convention on Psychotropic Substances or in major national drug laws, including the U.S. Controlled Substances Act. However, it is a constituent of ''Lophophora williamsii'', which is classified as a Schedule I controlled substance in the United States owing to its mescaline content. Exemptions exist for traditional religious use by members of the Native American Church.<ref name="DEA">{{Cite web |title=Drug Scheduling |url=https://www.dea.gov/drug-information/drug-scheduling |website=U.S. Drug Enforcement Administration |access-date=2025-11-05}}</ref>
== See also == {{columns-list|colwidth=22em| * Anhalidine * Anhalonidine * Peyotine * Pellotine * Mescaline * Tetrahydroisoquinoline }}
== References == {{Reflist}}
Category:Tetrahydroisoquinoline alkaloids Category:Quaternary ammonium compounds Category:Cacti of North America