title: Isolation and characterization of (15Z)-lycopene thermally generated from a natural source.
abstract: (15Z)-Lycopene was prepared by thermal isomerization of (all-E)-lycopene derived from tomatoes, and isolated by using a series of chromatographies. The fine red crystalline powder of (15Z)-lycopene was obtained from 556 mg of (all-E)-lycopene with a yield of 0.6 mg (purity: reversed-phase HPLC, 97.2%; normal-phase HPLC, ≥99.9%), and (1)H and (13)C NMR spectra of the isomer were fully assigned. More refined computational analyses that considered differences in the energy levels of the conformers involved in isomerization have also determined the stabilities of (15Z)-lycopene and other geometric isomers, along with the activation energies during isomerization from the all-E form. The fine control of conditions for HPLC separation and an advanced theoretical insight into geometric isomerization have led to the discovery of the 15Z-isomer generated from a natural source.
authors.affiliation: Department of Materials Science, The University of Shiga Prefecture, Hassaka, Hikone 522-8533, Japan. Electronic address: takehara@mat.usp.ac.jp.
authors.forename: Munenori
authors.initials: M
authors.lastname: Takehara
authors.affiliation: Department of Materials Science, The University of Shiga Prefecture, Hassaka, Hikone 522-8533, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kuwa
authors.affiliation: Department of Materials Science, The University of Shiga Prefecture, Hassaka, Hikone 522-8533, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Materials Science, The University of Shiga Prefecture, Hassaka, Hikone 522-8533, Japan.
authors.forename: Chitoshi
authors.initials: C
authors.lastname: Kitamura
authors.affiliation: Research & Development Division, Kagome Co., Ltd., Nishitomiyama, Nasushiobara 329-2762, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Honda
mesh_terms: D002338:Carotenoids / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D000077276:Lycopene; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D002338:Carotenoids; D000077276:Lycopene
keywords: Density-functional theory; Geometric isomerization; Lycopene; Purification; Spectral analysis; Tomatoes