title: Carotenoid analysis of several dark-green leafy vegetables associated with a lower risk of cancers.
abstract: We have examined the carotenoid contents of several dark green vegetables found to be associated with a lower risk of various epithelial cancers in our epidemiological study and animal study. Samples of these vegetables were quantitatively examined by high-performance liquid chromatography (HPLC) on a C-18 reversed-phase column for individual carotenoid content. Pure reference compounds (alpha-carotene, beta-carotent, lycopene, canthaxanthin, and lutein) and internal standard (beta-Apo-8'-carotenal) were employed to quantify xanthophylls and carotenes in these vegetables. The results indicated that fresh, dark-green, leafy vegetables were high in beta-carotene (0.94-9.36 mg/100 g) and oxygenated carotenoids or xanthophylls, primarily lutein (0.94-7.39 mg/100 g), whereas lycopene and alpha-carotene were not prominent and canthaxanthin was non existent in these vegetables. These analyses suggest that consumption of carotenoids such as lutein in addition to beta-carotene may be associated with a lower risk of cancers.
authors.affiliation: Department of Clinical Oncology, Kyushu University, Beppu, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: C Y
authors.initials: CY
authors.lastname: Huang
authors.forename: S S
authors.initials: SS
authors.lastname: Peng
authors.forename: J
authors.initials: J
authors.lastname: Li
mesh_terms: D002338:Carotenoids / Q000032:analysis*; D004032:Diet; D006801:Humans; D009369:Neoplasms / Q000517:prevention & control*; D014675:Vegetables / Q000737:chemistry*
chemical_list: D002338:Carotenoids