Radical scavenging and xanthine oxidase inhibitory activity of phenolic compounds from Bridelia ferruginea stem bark.
Bridelia ferruginea Benth. (Euphorbiaceae) is a subtropical medicinal plant widely used in traditional African medicine against various diseases, including rheumatic pains. Seven of its constituents (3-O-methylquercetin (1), 3,7,3',4'-tetra-O-methylquercetin (rutisin, 2), myricetin (3), 3',4',5'-tri-O-methylmyricetin (ferrugin, 4), 3,3',4',5'-tetra-O-methylmyricetin (5), quercetin 3-O-glucoside (6), and a biflavanol gallocatechin-[4'-O-7]-epigallocatechin (7)) have been evaluated in-vitro in the xanthine-xanthine oxidase enzymatic system for inhibition of xanthine oxidase and radical scavenging activity. Results indicated that compounds 1, 3, 4 and 6 exhibited, at different levels, xanthine oxidase inhibiting and superoxide scavenging activity at micromolar concentrations, whereas compound 7 showed scavenging activity only. Compounds 2 and 5 were inactive in both cases. Study of the structure-activity relationship demonstrated that for flavonoids the xanthine oxidase inhibitory activity was reduced by methylation of the hydroxyl functionality at C-3 and in rings A and B. These results may partly explain and support the use of B. ferruginea stem bark for the treatment of rheumatic pains in traditional medicine.
Cimanga
K
K
Department of Pharmaceutical Sciences, University of Antwerp (UIA), Belgium.
Ying
L
L
De Bruyne
T
T
Apers
S
S
Cos
P
P
Hermans
N
N
Bakana
P
P
Tona
L
L
Kambu
K
K
Kalenda
D T
DT
Pieters
L
L
Vanden Berghe
D
D
Vlietinck
A J
AJ
D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D016488:Medicine, African Traditional; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts; D010946:Plants, Medicinal; D014969:Xanthine Oxidase / Q000187:drug effects / Q000378:metabolism*
D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D014969:Xanthine Oxidase