林业工程学报2016，Vol.1Issue(6)：58-63,6.DOI:10.13360/j.issn.2096-1359.2016.06.010
荧光猝灭法测定高粱原花青素－金属离子络合反应
The determining of complexation reaction between Sorghum bicolor Moench proanthocyanidin and metal ions by method of fluorescence quenching
摘要
Abstract
Proanthocyanidins (epicatechin16(4➝8) catechin, PC) from Sorghum bicolor Moench are a class of polyphe⁃nol compounds widely distributed in higher plants with good physiological and pharmacological effects. It is well known that both procyanidin monomers and oligomers have the capacity to chelate with metal ions. However the studies on the metal⁃chelating capacity of proanthocyanidins with high molecular weight have been little reported hitherto due to the dif⁃ficulty in obtaining these proanthocyanidins from the natural products. The fluorescence quenching effects of polyphenolic compounds epicatechin16(4➝8) catechin by metal cations Al3+, Cu2+, Sn2+and Zn2+were studied at pH 6 by measuring fluorescence quenching spectra. To measure fluorescence, 1μL of 0�5 mmol/L metal ions solution were titrated into 100μL of 0�5 mmol/L polyphenolic compounds solution in 2 900μL pH 6 acetate buffer solution. The volume of metal ions solution was varied from 0μL to 10μL with the final concentration of 1�67μmol/L. The results indicated that an obvi⁃ous quenching effect on PC fluorescence intensity by Al3+, Cu2+, Sn2+and Zn2+ was observed, indicating the interaction between metal ions and PC. Continue adding more Sn2+, Al3+, Cu2+ and Zn2+ ions into solution caused a gradual de⁃crease in the PC fluorescence intensity without changes of the maximum emission wavelength and shape of the peaks, which was interpreted that Al3+, Cu2+, Sn2+ and Zn2+ could quench the intrinsic fluorescence of PC. The Stern⁃Volmer equation was used to assessment of the Stern⁃Volmer constants ( Ksv ) between metal ions and PC. The results shown the metal Stern⁃Volmer constants of metal ions Al3+, Cu2+, Sn2+, Zn2+ for PC were 1�35, 0�32, 1�44, and 0�29 ( × 106 L/mol) , respectively. The stoichiometry of the metal ions binding to PC was determined using the method of continuous variations. Fluorescence quenching titration with metal ions have revealed that the stoichiometry of Al3+, Cu2+, Sn2+, Zn2+⁃bound PC were 1∶2, 1∶2, 1∶1 and 1∶2, respectively. These quantitative models of PC⁃metal interaction will im⁃prove the understanding of the likely physiological function of PC.关键词
荧光猝灭法/原花青素/金属离子/化学计量比/络合常数Key words
Fluorescence quenching/proanthocyanidin/metal ions/stoichiometry/Stern-Volmer constants分类
农业科技引用本文复制引用
张亮亮,徐曼,汪咏梅,胡新宇..荧光猝灭法测定高粱原花青素－金属离子络合反应[J].林业工程学报,2016,1(6):58-63,6.基金项目
国家重点研发计划（2016YFD0600806）。 （）
