title: Antioxidant galloylated flavonol glycosides from Calliandra haematocephala.
abstract: Three new acylated quercetin rhamnosides have been isolated from the leaves and stem of Calliandra haematocephala Hassk. (Fabaceae) and their structures were established as quercitrin 2''-O-caffeate (1), quercitrin 3''-O-gallate (2) and quercitrin 2'',3''-di-O-gallate (3). Also, 17 known compounds were identified as gallic acid (4), methyl gallate (5), caffeic acid (6), myricitrin (7), quercitrin (8), myricetin 3-O-beta-D-4C1-glucopyranoside (9), afzelin (10), isoquercitrin (11), myricetin 3-O-(6''-O-galloyl)-beta-D-glucopyranoside (12), myricitrin 2''-O-gallate (13), quercitrin 2''-O-gallate (14), afzelin 2''-O-gallate (15), myricitrin 3''-O-gallate (16), afzelin 3''-O-gallate (17), 1,2,3,4,6-penta-O-galloyl-beta-D-4C1-glucopyranose (18), myricitrin 2'',3''-di-O-gallate (19), quercetin 3-O-methyl ether (20), for the first time from the genus Calliandra except for 6. Compounds 7, 8, 13, 14, 16 and 19 exhibited moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical, superoxide anion generation and DPPH radical in comparison with that of quercetin as a positive control in vitro. Compounds 7 and 8 exhibited lethal effect towards brine shrimp Artemia salina.
authors.affiliation: Pharmacognosy Department, Faculty of Pharmacy, Helwan University, Helwan, Egypt.
authors.forename: F A
authors.initials: FA
authors.lastname: Moharram
authors.forename: M S A
authors.initials: MS
authors.lastname: Marzouk
authors.forename: M T
authors.initials: MT
authors.lastname: Ibrahim
authors.forename: T J
authors.initials: TJ
authors.lastname: Mabry
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001156:Artemia / Q000187:drug effects; D007887:Fabaceae / Q000737:chemistry*; D044948:Flavonols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000975:Antioxidants; D044948:Flavonols; D016166:Free Radical Scavengers; D006027:Glycosides