title: Antioxidative flavonoids from Cleistocalyx operculatus buds.
abstract: Four new flavonoids, 3'-formyl-4',6',4-trihydroxy-2'-methoxy-5'-methylchalcone (1), 3'-formyl-6',4-dihydroxy-2'-methoxy-5'-methylchalcone 4'-O-beta-D-glucopyranoside (2), (2S)-8-formyl-6-methylnaringenin (3), and (2S)-8-formyl-6-methylnaringenin 7-O-beta-D-glucopyranoside (4) were isolated from the buds of Cleistocalyx operculatus (Myrtaceae). The structures of the new metabolites (1-4) were determined on the basic of spectroscopic analyses including 2 dimensional NMR. Compounds 1 and 3 exhibited 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with IC(50) values of 22.8 and 27.1 microM, respectively.
authors.affiliation: College of Pharmacy, Catholic University of Daegu, Gyeongsan, Korea. bsmin@cu.ac.kr
authors.forename: Byung-Sun
authors.initials: BS
authors.lastname: Min
authors.forename: Cao Van
authors.initials: CV
authors.lastname: Thu
authors.forename: Nguyen Tien
authors.initials: NT
authors.lastname: Dat
authors.forename: Nguyen Hai
authors.initials: NH
authors.lastname: Dang
authors.forename: Han-Su
authors.initials: HS
authors.lastname: Jang
authors.forename: Tran Manh
authors.initials: TM
authors.lastname: Hung
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D001713:Biphenyl Compounds; D002942:Circular Dichroism; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D035264:Flowers / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D009097:Multienzyme Complexes / Q000737:chemistry; D027822:Myrtaceae / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D001617:beta-Glucosidase / Q000737:chemistry
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D005419:Flavonoids; D009097:Multienzyme Complexes; D010851:Picrates; D010936:Plant Extracts; C004931:1,1-diphenyl-2-picrylhydrazyl; C039827:naringinase; D001617:beta-Glucosidase