title: Phytochemistry: structure of the blue cornflower pigment.
abstract: The same anthocyanin pigment makes roses red but cornflowers blue, a phenomenon that has so far not been entirely explained. Here we describe the X-ray crystal structure of the cornflower pigment, which reveals that its blue colour arises from a complex of six molecules each of anthocyanin and flavone, with one ferric iron, one magnesium and two calcium ions. We believe that this tetrametal complex may represent a previously undiscovered type of supermolecular pigment.
authors.affiliation: Department of Physics, Graduate School of Science, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shiono
authors.forename: Naohiro
authors.initials: N
authors.lastname: Matsugaki
authors.forename: Kosaku
authors.initials: K
authors.lastname: Takeda
mesh_terms: D000872:Anthocyanins / Q000737:chemistry* / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D031179:Centaurea / Q000737:chemistry*; D003116:Color; D018360:Crystallography, X-Ray; D035264:Flowers / Q000737:chemistry*; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D010858:Pigmentation; D027826:Rosa / Q000737:chemistry
chemical_list: D000872:Anthocyanins; D002412:Cations; D008670:Metals