title: Preparation of (+)-trans-isoalliin and its isomers by chemical synthesis and RP-HPLC resolution.
abstract: Naturally occurring (+)-trans-isoalliin, (R(C)R(S))-(+)-trans-S-1-propenyl-L-cysteine sulfoxide, is a major cysteine sulfoxide in onion. The importance of producing it synthetically to support further research is very well recognized. The (+)-trans-isoalliin is prepared by chemical synthesis and reversed-phase (RP)-HPLC. First, S-2-propenyl-L-cysteine (deoxyalliin) is formed from L-cysteine and allyl bromide, which is then isomerized to S-1-propenyl-L-cysteine (deoxyisoalliin) by a base-catalyzed reaction. A mixture of cis and trans forms of deoxyisoalliin is formed and separated by RP-HPLC. Oxidation of the trans form of deoxyisoalliin by H2O2 produces a mixture of (-)- and (+)-trans-isoalliin. Finally, RP-HPLC is used successfully in separating (-)- and (+)-trans-isoalliin, and hence, (+)-trans-isoalliin is synthesized for the first time in this study. In addition, the (±) diastereomers of cis-isoalliin are also separated and purified by RP-HPLC.
authors.affiliation: Protein Research Laboratory, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60612, USA; and.
authors.forename: Lasanthi
authors.initials: L
authors.lastname: Jayathilaka
authors.affiliation: Protein Research Laboratory, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60612, USA; and.
authors.forename: Shalini
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Protein Research Laboratory, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60612, USA; and.
authors.forename: Jin-Sheng
authors.initials: JS
authors.lastname: Huang
authors.affiliation: Department of Chemical Engineering, Columbia University, New York, New York 10027, USA.
authors.forename: Jenny
authors.initials: J
authors.lastname: Lee
authors.affiliation: Protein Research Laboratory, Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60612, USA; and.
authors.forename: Bao-Shiang
authors.initials: BS
authors.lastname: Lee
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007536:Isomerism; D019697:Onions / Q000737:chemistry*; D012451:Safrole / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000498:Allyl Compounds; C006453:alliin; C065299:S-allylcysteine; D006861:Hydrogen Peroxide; C050431:allyl bromide; D003545:Cysteine; D012451:Safrole; C005746:sulfoxide
keywords: 1-propenyl-L-cysteine sulfoxide; Allium cepa; organosulfur compounds