title: Activity-guided isolation and identification of free radical-scavenging components from various leaf extracts of Sorbus aria (L.) Crantz.
abstract: Nine phenolics were obtained from the leaves of Sorbus aria (L.) Crantz by activity-directed isolation: isorhamnetin 3-O-β-glucopyranoside (1), astragalin (2), isoquercitrin (3), hyperoside (4), kaempferol 3-O-β-glucopyranoside-7-O-α-rhamnopyranoside (5), quercetin 3-O-β-glucopyranoside-7-O-α-rhamnopyranoside (6), rutin (7), chlorogenic acid (8) and neochlorogenic acid (9). The isolates were identified by spectral methods (UV, (1)H- and (13)C-NMR, COSY, HMQC and HMBC), and their free radical-scavenging activity was tested using the l,l-diphenyl-2-picrylhydrazyl (DPPH) method. The antioxidant potential of the different extracts obtained in the fractionation process was evaluated using the DPPH test in relation to the HPLC contents of the isolates 1-9, total phenolics and total proanthocyanidins. Among the analytes tested, superior activity was expressed by isoquercitrin (3, EC(50) = 2.76 mg L(-1)) and the ethyl acetate extract (EC(50) = 2.99 mg L(-1)). Five strongly active isolates 3, 6, 7, 8 and 9 were found to be major components and to be principally responsible for the radical-scavenging activity of S. aria extracts.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Medical University of Łódź, 1 Muszyński St., 90-151 Łódź, Poland. monika.olszewska@umed.lodz.pl
authors.forename: Monika A
authors.initials: MA
authors.lastname: Olszewska
authors.forename: Piotr
authors.initials: P
authors.lastname: Michel
mesh_terms: D002855:Chromatography, Thin Layer; D016166:Free Radical Scavengers / Q000302:isolation & purification* / Q000494:pharmacology; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*; D031994:Sorbus / Q000737:chemistry*
chemical_list: D016166:Free Radical Scavengers; D010936:Plant Extracts