title: Looking for the physiological role of anthocyanins in the leaves of Coffea arabica.
abstract: The aim of this study was to determine which anthocyanins are related to the purple coloration of young leaves in Coffea arabica var. Purpurascens and assess their impact on photosynthesis as compared to C. arabica var. Catuaí, with green leaves. Two delphinidin glicosides were identified and histological cross-sections showed they were located throughout the adaxial epidermis in young leaves, disappearing as the leaves mature. Regardless the irradiance level, the photosynthetic performance of Purpurascens leaves did not differ from that observed in leaves of the Catuaí variety, providing no evidence that anthocyanins improve photosynthetic performance in coffee plants. To analyze the photoprotective action of anthocyanins, we evaluated the isomerization process for chlorogenic acids (CGAs) in coffee leaves exposed to UV-B radiation. No differences were observed in the total concentration of phenolic compounds in either variety before or after the UV treatment; however, we observed less degradation of CGA isomers in the Purpurascens leaves and a relative increase of cis-5-caffeoylquinic acid, a positional isomer of one of the most abundant form of CQA in coffee leaves, trans-5-caffeoylquinic acid, suggesting a possible protective role for anthocyanins in this purple coffee variety.
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Adilson Pereira
authors.initials: AP
authors.lastname: Domingues Júnior
authors.forename: Milton Massao
authors.initials: MM
authors.lastname: Shimizu
authors.forename: Jullyana Cristina Magalhães Silva
authors.initials: JC
authors.lastname: Moura
authors.forename: Rodrigo Ramos
authors.initials: RR
authors.lastname: Catharino
authors.forename: Rômulo Augusto
authors.initials: RA
authors.lastname: Ramos
authors.forename: Rafael Vasconcelos
authors.initials: RV
authors.lastname: Ribeiro
authors.forename: Paulo
authors.initials: P
authors.lastname: Mazzafera
mesh_terms: D000872:Anthocyanins / Q000032:analysis*; D002726:Chlorogenic Acid / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D040503:Coffea / Q000033:anatomy & histology / Q000737:chemistry* / Q000502:physiology; D003116:Color; D006027:Glycosides / Q000032:analysis; D007536:Isomerism; D010636:Phenols / Q000032:analysis*; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000033:anatomy & histology / Q000737:chemistry* / Q000502:physiology; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D000872:Anthocyanins; D006027:Glycosides; D010636:Phenols; C472707:caffeoylquinic acid; D011801:Quinic Acid; D002734:Chlorophyll; D002726:Chlorogenic Acid; C017185:delphinidin