Chen Ji-Wu, Zhu Zhen-Qin, Hu Tian-Xi, Zhu Da-Yuan
School of Life Science, East China Normal University, Shanghai 200062, China.
Acta Pharmacol Sin. 2002 Jul;23(7):667-72.
To study the relationship between the structure and hydroxyl radical (*OH)-scavenging activity of twelve natural flavonoids.
The hydroxyl radical-generating chemiluminescence system with ascorbate-CuSO4-yeast-H2O2 was used to determine the hydroxyl radical-scavenging activity of twelve natural flavonoids.
Guercetin, heliosin, hyperoside, kaempferol, 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.
(1) 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.
研究12种天然黄酮类化合物的结构与羟自由基（·OH）清除活性之间的关系。
采用抗坏血酸 - 硫酸铜 - 酵母 - 过氧化氢产生羟自由基的化学发光体系，测定12种天然黄酮类化合物的羟自由基清除活性。
槲皮素、向日葵素、金丝桃苷、山柰酚、黄芩苷、紫铆亭、石蒜碱、毛蕊异黄酮、紫铆因和染料木黄酮能够有效清除·OH并抑制体系的化学发光。这些黄酮类化合物的IC50值（95%置信限）分别为12.1（9.9 - 14.5）μg/L、15.8（14.0 - 19.2）μg/L、19.5（16.8 - 27.4）μg/L、20.1（13.6 - 29.0）μg/L、34.6（28.4 - 43.4）μg/L、66.8（63.2 - 74.4）μg/L、187（147 - 235）μg/L、211（165 - 284）μg/L、262（190 - 346）μg/L和708（498 - 994）μg/L；而川陈皮素和紫铆亭乙酸酯不能清除·OH。
（1）黄酮类化合物中的酚羟基是能够清除·OH的主要活性基团；（2）B环和A环上的羟基是重要的·OH清除活性基团；（3）A环和/或B环上的邻二羟基可大大增强环的·OH清除活性；（4）比较槲皮素、向日葵素、金丝桃苷、黄芩苷、石蒜碱和毛蕊异黄酮的IC50值，表明B环3'，4'位上的羟基具有较高的·OH清除活性，且B环上羟基的清除活性高于A环上的羟基。上述6种黄酮类化合物C环3位上的羟基或葡萄糖苷也与·OH清除能力有关。（5）黄酮类化合物自身的结构类型可影响其·OH清除活性。
