Effects Of Cyanidin-3-O-glucoside On Cardiac Protection

Anthocyanins, a group of water-soluble flavonoids subgroup, are widely distributed in fruits and vegetables.It also has lots of physiological functions, such as free radical scavenging activity, anti atherosclerosis andsuppresses inflammation. This research employed fluorescence spectroscopy, UV-vis absorbance, circular dichroism and molecular modeling techniques to investigate the mutual interactions between cyanidin-3-O-glucoside(C3G) and three proteins(bovine serum albumin(BSA), hemoglobin(Hb) and myoglobin(Mb)), and calculated the concentration of free C3 G after the combination of C3 G and proteins. The research provided the theory basis for the transport, storage, distribution and producing physiological effect of C3 G. Based on this research, we also used Langendorff technique to investigate the protective effect of C3 G against myocardial ischemia-reperfusion injury(MIRI). This research revealed the mechanism of C3 G against MIRI, which may be attributed to the inhibition of autophagy.It was of great significance for the development of anthocyanin healthy food and medicine.The study offered theoreticalbasis for the development of C3 G.This thesis mainly consists of the following two parts:In the chapter one, fluorescence spectroscopy, UV-vis absorbance, circular dichroism and molecular modeling techniques were used to investigate the mutual interactions between cyanidin-3-O-glucoside and three proteins(BSA, Hb and Mb) under physiological conditions. Fluorescence and time-resolved fluorescence studies suggested that C3 G quenched BSA, Hb or Mb fluorescence in a static mode. Based on the value of binding constant, the order of the binding strength among the three proteins was BSA > Mb > Hb. The thermodynamic parameters and molecular modeling results represented hydrogen bonds and van der Waals forces dominated the binding. The distances between C3 G and BSA, Hb and Mb were obtained as 2.52 nm, 2.53 nm and 2.62 nm, respectively. Synchronous fluorescence, three-dimensional fluorescence and CD spectra results indicated the secondary structures of BSA, Hb and Mb were partially destroyed by C3 G with the a-helix percentage of C3G-Hb and C3G-Mb decreased while that of C3G-BSA was increased. UV–vis spectral results showed these binding interactions partially affected the heme bands of Hb and Mb. After the combination with BSA and Hb, free concentrations of C3 G were fu> 92% and fu> 93%, respectively.In the chapter two, the protective effect of C3 G against MIRI was investigated by the Langendorff technique. The results of heart rate suggested that C3 G could significantly improvedrat myocardial functions, after the pretreatment of C3 G. The results of the physical and chemical testing showed that C3 G could reduce the release of LDH, the content of CK-MB in coronary effluent and reduce the injury of myocardial cells, and improve the function of the heart after myocardial ischemia-reperfusion injury. The results of western bloting showed that treatment with C3 G inhibited the expression levels of Beclin-1, ratio of LC3-II/LC3-I, which meant that C3 G could control autophagy induced by myocardial ischemia-reperfusion injury. The results indicated that C3 G could protect the isolated rat heart from MIRI through the mechanism of autophagy.