title: Reactive radical scavenging and xanthine oxidase inhibition of proanthocyanidins from Carallia brachiata.
abstract: Antioxidant-guided separation of Carallia brachiata bark led to a new A-type trimeric proanthocyanidin named carallidin (1), along with mahuannin A (2) and p-hydroxy benzoic acid (3). The structure of 1 was fully characterized by interpretation of spectroscopic data and chemical means. Compounds 1 and 2 exhibited radical scavenging against DPPH (IC(50) 102 and 182 microm) and superoxide radical (IC(50) 1.47 and 9.74 microm). In addition, 1 and 2 also inhibited xanthine oxidase with IC(50) values of 12.9 and 16.0 microm.
authors.affiliation: Natural Products Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Preecha
authors.initials: P
authors.lastname: Phuwapraisirisan
authors.forename: Preecha
authors.initials: P
authors.lastname: Sowanthip
authors.forename: D Howard
authors.initials: DH
authors.lastname: Miles
authors.forename: Santi
authors.initials: S
authors.lastname: Tip-pyang
mesh_terms: D016166:Free Radical Scavengers / Q000032:analysis*; D015394:Molecular Structure; D010226:Parabens / Q000302:isolation & purification; D044945:Proanthocyanidins / Q000737:chemistry / Q000302:isolation & purification*; D043982:Rhizophoraceae / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D016166:Free Radical Scavengers; D010226:Parabens; D044945:Proanthocyanidins; C513633:carallidin; C513634:mahuannin A; D014969:Xanthine Oxidase; C038193:4-hydroxybenzoic acid