Phenolic compounds from Hypericum calycinum and their antioxidant activity.
From the MeOH extract of Hypericum calycinum, two caffeoylquinic acid derivatives, butyl chlorogenate (1), and chlorogenic acid (2), seven flavonoids, quercetin (3), quercitrin (4), hyperoside (5), isoquercitrin (6), miquelianin (7), rutin (8) and I3,II8-biapigenin (9) and two flavanols, (+)-catechin (10) and (-)-epicatechin (11) were isolated. Identification of the isolates was carried out by spectroscopic analysis including 1D and 2D NMR experiments as well as mass spectrometry. Free radical scavenging activities of the isolated compounds were determined in in-vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging models. The compounds showed strong DPPH and moderate NO scavenging activities in a concentration dependent manner. (+)-Catechin and (-)-epicatechin were found to be the most active compounds with IC50 values of 4.16 and 4.67 microM for DPPH and 190 and 170 microM for NO scavenging activities, respectively.
Kirmizibekmez
Hasan
H
Department of Pharmacognosy, Faculty of Pharmacy, Yeditepe University, TR-34755, Kayişdaği, Istanbul, Turkey. hasankbekmez@yahoo.com
Bassarello
Carla
C
Piacente
Sonia
S
Celep
Engin
E
Atay
Irem
I
Mercanoğlu
Güldem
G
Yeşilada
Erdem
E
D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000737:chemistry; D020902:Hypericum / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry
D000975:Antioxidants; D001713:Biphenyl Compounds; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D009569:Nitric Oxide; C004931:1,1-diphenyl-2-picrylhydrazyl