Structure-activity relationship of natural flavonoids in hydroxyl radical-scavenging effects
CHEN Ji-Wu, ZHU Zhen-Qin, HU Tian-Xi, ZHU Da-Yuan (School of Life Science, East China Normal University, Shanghai 200062; State Key Laboratory for New Drug Research, Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China)
AIM: To study the relationship between the structure and hydroxyl radical (OH)-scavenging activity of twelve natural flavonoids. METHODS: The hydroxyl radical-generating chemiluminescence system with ascorbate-CuSO4-yeast-H2O2 was used to determine the hydroxyl radical-scavenging activity of twelve natural flavonoids. RESULTS: Guercetin, heliosin, hyperoside, kaemp-ferol, baicalin, corylifolin, lysionotin, matteucinol, corylifolinin, and genistein could effectively scavenge OH and inhibit the chemiluminescence of the system. The IC50 values (95 % confidence limits) of the flavonoids were 12.1 (9.9-14.5) g/L, 15.8 (14.0-19.2) g/L, 19.5 (16.8-27.4) g/L, 20.1 (13.6-29.0) g/L, 34.6 (28.4-43.4) g/L, 66.8 (63.2-74.4) g/L, 187 (147-235) g/L, 211 (165-284) g/ L, 262 (190-346) g/L, and 708 (498-994) g/L, respectively; whereas nobilelin and corylifolin-Ac could not scavenge OH. CONCLUSION: (l) Phenolic hydroxyls in flavonoids were the main active groups capable of scavenging OH; (2) Hydroxyl groups in ring B and A were important OH-scavenging active groups; (3) The ortho-dihydroxyl groups in ring A and/or B could greatly enhance the OH-scavenging activity of the rings; (4) Comparing the IC50 values of guercetin, heliosin, hyperoside, baicalin, lysionotin, and matteucinol, it was suggested that the hydroxyl groups on 3',4' position of ring B possessed high OH-scavenging activity and the scavenging activity of hydroxyl groups in ring B was higher than that of hydroxyl groups in ring A.The hydroxyl group or glucoside on 3 position of ring C of the above mentioned 6 flavonoids was also related to the OH-scavenging ability. (5) The structural types of flavonoids themselves could influence their OH-scavenging activity.
【CateGory Index】： R914