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Allicin
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<h2 id="structure-and-occurrence">Structure and occurrence</h2> <p>Allicin features the <a href="/facts/Thiosulfinate/394kgygA">thiosulfinate</a> functional group, R-S-(O)-S-R. The compound is not present in garlic unless tissue damage occurs,<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> and is formed by the action of the enzyme <a href="/facts/Alliinase/ILJgSy3m">alliinase</a> on <a href="/facts/Alliin/yFkD3NNm">alliin</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> Allicin is <a href="/facts/Chirality_(chemistry)/p5a9pftB">chiral</a> but occurs naturally only as a <a href="/facts/Racemate/STEagtrD">racemate</a>.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> The <a href="/facts/Racemic/STEagtrD">racemic</a> form can also be generated by oxidation of <a href="/facts/Diallyl_disulfide/f3JAd8b9">diallyl disulfide</a>:<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a><a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p> (SCH2CH=CH2)2 + 2 RCO3H + H2O → 2 CH2=CHCH2SOH + 2 RCO2H 2 CH2=CHCH2SOH → CH2=CHCH2S(O)SCH2CH=CH2 + H2O <p>Alliinase is irreversibly deactivated below pH 3; as such, allicin is generally not produced in the body from the consumption of fresh or powdered garlic.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a><a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> Furthermore, allicin can be unstable, breaking down within 16 hours at 23 °C.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> </p> <h3>Biosynthesis</h3> <p>The biosynthesis of allicin commences with the conversion of cysteine into <a href="/facts/S-allyl-L-cysteine/YLxTVUjs"><i>S</i>-allyl-L-cysteine</a>. Oxidation of this thioether gives the sulfoxide (<a href="/facts/Alliin/yFkD3NNm">alliin</a>). The enzyme <a href="/facts/Alliinase/ILJgSy3m">alliinase</a>, which contains <a href="/facts/Pyridoxal_phosphate/GTGIzISg">pyridoxal phosphate</a> (PLP), cleaves alliin, generating allylsulfenic acid (CH2=CHCH2SOH), pyruvate, and ammonium ions.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> At room temperature, two molecules of allylsulfenic acid condense to form allicin.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> </p> <h2 id="research">Research</h2> <p>Allicin has been studied for its potential to treat various kinds of <a href="/facts/Multiple_drug_resistance/TPbHtAvz">multiple drug resistance</a> bacterial infections, as well as viral and fungal infections <a href="/facts/In_vitro/evp3hAX6">in vitro</a>, but as of 2016, the safety and efficacy of allicin to treat infections in people was unclear.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p><p>A Cochrane review found there to be insufficient clinical evidence regarding the effects of allicin in preventing or treating <a href="/facts/Common_cold/fP9A03U9">common cold</a>.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> </p> <h2 id="history">History</h2> <p>It was first isolated and studied in the laboratory by <a href="/facts/Chester_J._Cavallito/CMfgjkXM">Chester J. Cavallito</a> and John Hays Bailey in 1944.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a><a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> Allicin was discovered as part of efforts to create <a href="/facts/Thiamine/37RC4MCS">thiamine</a> derivatives in the 1940s, mainly in Japan. Allicin became a model for <a href="/facts/Medicinal_chemistry/SLNHz1hb">medicinal chemistry</a> efforts to create other thiamine disulfides. The results included <a href="/facts/Sulbutiamine/3uMvt68b">sulbutiamine</a>, <a href="/facts/Fursultiamine/2g7XDnDU">fursultiamine</a> (thiamine tetrahydrofurfuryl disulfide) and <a href="/facts/Benfothiamine/tRb2xyC4">benfothiamine</a>. These compounds are hydrophobic, easily pass from the intestines to the bloodstream, and are reduced to thiamine by cysteine or <a href="/facts/Glutathione/5bSxjusL">glutathione</a>.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a>: 302 </p> <h2 id="see-also">See also</h2> Wikimedia Commons has media related to Allicin. <ul><li><a href="/facts/Allyl_isothiocyanate/5b0SaJHF">Allyl isothiocyanate</a>, the active piquant chemical in <a href="/facts/Mustard_plant/wCTpahzP">mustard</a>, <a href="/facts/Radish/NvNvoIdU">radishes</a>, <a href="/facts/Horseradish/DotKB3yz">horseradish</a> and <a href="/facts/Wasabi/RbTcqDxD">wasabi</a></li> <li><a href="/facts/Syn-Propanethial-S-oxide/k39N17wc"><i>syn</i>-Propanethial-<i>S</i>-oxide</a>, the <a href="/facts/Lachrymatory_agent/SLJoBYEN">lachrymatory</a> chemical found in <a href="/facts/Onion/2ajXf00d">onions</a></li> <li><a href="/facts/List_of_phytochemicals_in_food/mkUEqWmm">List of phytochemicals in food</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Block E (March 1985). "The Chemistry of Garlic and Onions". Scientific American. 252 (3): 114–9. Bibcode:1985SciAm.252c.114B. doi:10.1038/scientificamerican0385-114. PMID 3975593. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Kourounakis PN, Rekka EA (November 1991). "Effect on active oxygen species of alliin and Allium sativum (garlic) powder". Research Communications in Chemical Pathology and Pharmacology. 74 (2): 249–52. PMID 1667340. <a href="/wiki/PMID_(identifier)" target="_blank">/wiki/PMID_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Ilic D, Nikolic V, Nikolic L, Stankovic M, Stanojevic L, Cakic M (2011). "Allicin and related compounds: Biosynthesis, synthesis and pharmacological activity" (PDF). Facta Universitatis. 9 (1): 9–20. doi:10.2298/FUPCT1101009I. <a href="http://facta.junis.ni.ac.rs/phat/pcat2011/pcat2011-02.pdf" target="_blank">http://facta.junis.ni.ac.rs/phat/pcat2011/pcat2011-02.pdf</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Borlinghaus J, Albrecht F, Gruhlke MC, Nwachukwu ID, Slusarenko AJ (August 2014). "Allicin: chemistry and biological properties". Molecules. 19 (8): 12591–618. doi:10.3390/molecules190812591. PMC 6271412. PMID 25153873. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Nikolic V, Stankovic M, Nikolic L, Cvetkovic D (January 2004). "Mechanism and kinetics of synthesis of allicin". Die Pharmazie. 59 (1): 10–4. PMID 14964414. <a href="/wiki/PMID_(identifier)" target="_blank">/wiki/PMID_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Rabinkov A, Miron T, Konstantinovski L, Wilchek M, Mirelman D, Weiner L (February 1998). "The mode of action of allicin: trapping of radicals and interaction with thiol containing proteins". Biochimica et Biophysica Acta (BBA) - General Subjects. 1379 (2): 233–44. doi:10.1016/s0304-4165(97)00104-9. PMID 9528659. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Block E (March 1985). "The Chemistry of Garlic and Onions". Scientific American. 252 (3): 114–9. Bibcode:1985SciAm.252c.114B. doi:10.1038/scientificamerican0385-114. PMID 3975593. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Block E (March 1985). "The Chemistry of Garlic and Onions". Scientific American. 252 (3): 114–9. Bibcode:1985SciAm.252c.114B. doi:10.1038/scientificamerican0385-114. PMID 3975593. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Block E (2010). Garlic and Other Alliums: The Lore and the Science. Cambridge: Royal Society of Chemistry. ISBN 978-0854041909. <a href="978-0854041909" target="_blank">978-0854041909</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Cremlyn RJ (1996). An introduction to organosulfur chemistry. Wiley. ISBN 0-471-95512-4. <a href="0-471-95512-4" target="_blank">0-471-95512-4</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Borlinghaus J, Albrecht F, Gruhlke MC, Nwachukwu ID, Slusarenko AJ (August 2014). "Allicin: chemistry and biological properties". Molecules. 19 (8): 12591–618. doi:10.3390/molecules190812591. PMC 6271412. PMID 25153873. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Brodnitz MH, Pascale JV, Derslice LV (1971). "Flavor components of garlic extract". Journal of Agricultural and Food Chemistry. 19 (2): 273–5. Bibcode:1971JAFC...19..273B. doi:10.1021/jf60174a007. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Yu TH, Wu CM (1989). "Stability of Allicin in Garlic Juice". Journal of Food Science. 54 (4): 977. doi:10.1111/j.1365-2621.1989.tb07926.x. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Hahn G (1996). Koch HP, Lawson LD (eds.). Garlic: the science and therapeutic application of Allium sativum L and related species (2nd ed.). Baltimore: Williams and Wilkins. pp. 1–24. ISBN 978-0-683-18147-0. <a href="978-0-683-18147-0" target="_blank">978-0-683-18147-0</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Rabinkov A, Miron T, Konstantinovski L, Wilchek M, Mirelman D, Weiner L (February 1998). "The mode of action of allicin: trapping of radicals and interaction with thiol containing proteins". Biochimica et Biophysica Acta (BBA) - General Subjects. 1379 (2): 233–44. doi:10.1016/s0304-4165(97)00104-9. PMID 9528659. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Nikolic V, Stankovic M, Nikolic L, Cvetkovic D (January 2004). "Mechanism and kinetics of synthesis of allicin". Die Pharmazie. 59 (1): 10–4. PMID 14964414. <a href="/wiki/PMID_(identifier)" target="_blank">/wiki/PMID_(identifier)</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Borlinghaus J, Albrecht F, Gruhlke MC, Nwachukwu ID, Slusarenko AJ (August 2014). "Allicin: chemistry and biological properties". Molecules. 19 (8): 12591–618. doi:10.3390/molecules190812591. PMC 6271412. PMID 25153873. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271412</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Marchese A, Barbieri R, Sanches-Silva A, Daglia M, Nabavi SF, Jafari NJ, Izadi M, Ajami M, Nabavi SM (2016). "Antifungal and antibacterial activities of allicin: A review". Trends in Food Science and Technology. 52: 49–56. doi:10.1016/j.tifs.2016.03.010. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Lissiman E, Bhasale AL, Cohen M (November 2014). "Garlic for the common cold". The Cochrane Database of Systematic Reviews. 2020 (11): CD006206. doi:10.1002/14651858.CD006206.pub4. PMC 6465033. PMID 25386977. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465033" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465033</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Cavallito CJ, Bailey JH (1944). "Allicin, the Antibacterial Principle of Allium sativum. I. Isolation, Physical Properties and Antibacterial Action". Journal of the American Chemical Society. 66 (11): 1950. Bibcode:1944JAChS..66.1950C. doi:10.1021/ja01239a048. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Block E (2010). Garlic and Other Alliums: The Lore and the Science. Cambridge: Royal Society of Chemistry. ISBN 978-0854041909. <a href="978-0854041909" target="_blank">978-0854041909</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Bettendorff L (2014). "Chapter 7 - Thiamine". In Zempleni J, Suttie JW, Gregory JF, Stover PJ (eds.). Handbook of vitamins (Fifth ed.). Hoboken: CRC Press. pp. 267–324. ISBN 978-1-4665-1557-4. <a href="978-1-4665-1557-4" target="_blank">978-1-4665-1557-4</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> </ol>