Ce(Ⅵ)与6种天然黄酮化合物的氧化还原体系及其应用  

Redox System of Cerium(Ⅳ)-Flavonoids and Applications

作　　者：龚双梅[1] 李晓波[1] 张荣荣[1] 赵良容[1] 杨昌英[1] 

机构地区：[1]天然产物研究与利用湖北省重点实验室三峡大学,宜昌443002

出　　处：《应用化学》2011年第11期1286-1291,共6页Chinese Journal of Applied Chemistry

基　　金：湖北省自然科学基金(2010CDB10704);宜昌市科学技术研究(A09302)资助项目

摘　　要：选取结构相近的6种天然黄酮化合物:槲皮素(Quercetin)、山奈酚(Kaempferol)、木犀草素(Luteolin)、柚皮素(Naringenin)、黄芩素(Baicalein)和芹菜素(Apigenin),利用紫外可见分光光度法,结合微量滴定手段,追踪并记录了6种黄酮化合物与Ce(Ⅳ)形成的氧化还原体系的紫外吸收信号,根据化合物对Ce(Ⅳ)响应差异,探讨了不同位置酚羟基对化合物抗氧化活性的贡献及作用机制。结果表明,色原酮C环上3-OH首先与Ce(Ⅳ)作用,发生质子解离而氧化,其氧化产物在294 nm产生较强的吸收峰,3',4'邻位—OH有利于在氧化剂Ce(Ⅳ)存在时4'羟基解离形成分子内氢键,紫外吸收光谱带Ⅱ的双峰会明显分离。其它位置的酚羟基也会对Ce(Ⅳ)产生响应,且C环上的羟基比A环上的更灵敏。同时,低浓度的黄酮会引起Ce(Ⅳ)的吸光度明显降低,由此得出6种化合物抗氧化能力顺序为Quercetin>Kaempferol>Luteolin>Apigenin>Baicalein>Naringenin,与化合物的紫外吸收光谱响应灵敏度一致。Six different natural flavonoids with similar structures,quercetin,kaempferol,luteolin,naringenin,baicalein,and apigenin were selected to examine the redox system between flavonoids and Ce（Ⅳ） using ultraviolet spectrophotometry and microtitration methods.According to their responding difference to Ce（Ⅳ）,the mechanism of the reaction and the contribution of phenolic hydroxyls on different sites of the chromone to the antioxidation activity were investigated.The result indicates that the 3-OH of the pyrone ring is a sensitive site to react with Ce（Ⅳ） involving the proton dissociation,and the obtained product has a strong absorbance at 294 nm.The 3′-OH and 4′-OH on the B ring of the 2-phenyl-chromone are also the sensitive sites to oxidants since 4′-OH dissociates and forms intramolecular hydrogen bonding.The hydroxyl on ring C is more sensitive to Ce（Ⅳ） than that on ring A.The antioxidant capacity order of the six compounds is：QuercetinKaempferolLuteoinApigeninBaicaleinNaringenin,which is consistent with the sensitivity of spectral response of the six compounds to Ce（Ⅳ）.

关 键 词：Ce(Ⅵ) 黄酮化合物 抗氧化活性 紫外可见吸收光谱 

分 类 号：O657.3[理学—分析化学]