title: Phenolic constituents and antioxidant properties of Xanthosoma violaceum leaves.
abstract: An extract of Xanthosoma violaceum leaves was subjected to a polyphenol profile determination, including total polyphenols, and antioxidant activity evaluation. Analysis of the extract resulted in the isolation of a new flavone C-glycoside, apigenin 6-C-beta-D-glucopyranosyl-8-C-beta-D-apiofuranoside (1), as well as known flavone C-glycosides, including vitexin (2), isovitexin (3), isovitexin 4'-O-rhamnopyranoside (4), apigenin 6-C-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside] (5), and apigenin 6,8-diC-beta-D-glucopyranoside (6). The antioxidant activity of the extract was assessed by means of two different in vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and peroxidation induced by the water-soluble radical initiator 2,2'-azobis(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles (LP-LUV test). In both tests used, the extract and a fraction II showed a significant antioxidant/free-radical scavenging effect (fraction II, EC(50) = 11.6 microg/mL) in comparison to alpha-tocopherol (EC(50) = 10.1 microg/mL).
authors.affiliation: Dipartimento di Scienze Farmaceutiche and Scuola di Specializzazione in Scienza e Tecnologia Cosmetiche, University of Salerno, Invariante 11/C, 84084 Fisciano, Salerno, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Picerno
authors.forename: Teresa
authors.initials: T
authors.lastname: Mencherini
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Lauro
authors.forename: Francesco
authors.initials: F
authors.lastname: Barbato
authors.forename: Rita
authors.initials: R
authors.lastname: Aquino
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D047310:Apigenin; D001713:Biphenyl Compounds; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006027:Glycosides; D009005:Monosaccharides / Q000032:analysis / Q000494:pharmacology; D010545:Peroxides / Q000737:chemistry; D010636:Phenols / Q000032:analysis* / Q000494:pharmacology*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*; D031063:Xanthosoma / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; C438934:C-glycoside; D005419:Flavonoids; D016166:Free Radical Scavengers; D006027:Glycosides; D009005:Monosaccharides; D010545:Peroxides; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D047310:Apigenin; C032731:vitexin; C004931:1,1-diphenyl-2-picrylhydrazyl; C049772:isovitexin