title: Photosensitizing anthraquinones from Heterophyllaea lycioides (Rubiaceae).
abstract: Seven anthraquinones were isolated from aerial parts of Heterophyllaea lycioides (Rusby) Sandwith (Rubiaceae), including three derivatives that have not been described before: a hetero-bianthraquinone identified as (R)-2-hydroxymethyl-2'methyl-1,1',6,6'-tetrahydroxy-5,5' bianthraquinone (lycionine), and two mono-chlorinated derivatives related to soranjidiol. One of them is a homo-bianthraquinone: (R)-7-chloro-2,2'-dimethyl-1,1',6,6'-tetrahydroxy-5,5' bianthraquinone (7-chlorobisoranjidiol), whereas the second halogenated derivative corresponds to a monomeric structure: 5-chloro-1,6-dihydroxy-2-methyl anthraquinone (5-chlorosoranjidiol). The four known compounds were already isolated from another species of this genus, H. pustulata, and they were identified as 5,5'-bisoranjidiol, soranjidiol, pustuline and heterophylline. Structural elucidation was performed by means of an extensive spectroscopic analysis, including 1D and 2D NMR data as well as by HRMS analysis. Chemical structures of 7-chlorobisoranjidiol and 5-chlorosoranjidiol were confirmed by their synthesis from 5,5'-bisoranjidiol and soranjidiol, respectively. Type I photosensitizing properties (superoxide anion radical generation, O2-) were assessed by using the nitroblue tetrazolium assay. When lycionine and chlorinated derivatives were irradiated, they enhanced the O2-production with respect to the control; 7-chlorobisoranjidiol stood out by generating an increase of 20%, whereas the other anthraquinones only produced a slight increase of 7%.
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET and Farmacognosia, Dpto. de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina.
authors.forename: Jesica A
authors.initials: JA
authors.lastname: Dimmer
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET and Farmacognosia, Dpto. de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina.
authors.forename: Susana C
authors.initials: SC
authors.lastname: Núñez Montoya
authors.affiliation: Dpto. de Farmacia, Facultad de Ciencias Químico Farmacéuticas y Bioquímicas, Universidad de San Francisco Xavier de Chuquisaca, Dalence 51, Sucre, Bolivia.
authors.forename: Caterine S
authors.initials: CS
authors.lastname: Mendoza
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET and Farmacognosia, Dpto. de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina. Electronic address: jcabrera@fcq.unc.edu.ar.
authors.forename: José L
authors.initials: JL
authors.lastname: Cabrera
mesh_terms: D000880:Anthraquinones / Q000737:chemistry* / Q000302:isolation & purification; D015394:Molecular Structure; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000302:isolation & purification; D035261:Plant Components, Aerial / Q000737:chemistry; D019666:Rubiaceae / Q000737:chemistry*
chemical_list: C000616895:7-chlorobisoranjidiol; D000880:Anthraquinones; D017319:Photosensitizing Agents
keywords: 5-Chlorosoranjidiol; 7-Chlorobisoranjidiol; Chlorinated anthraquinones; Heterophyllaea lycioides; Lycionine; Rubiaceae; Structural elucidation; Type I photosensitizers