The Protective Effects Of Baicalin And Quercetin On Iron Overload Induced Tissue Oxidative Injury

Iron is an essential component of numerous proteins and enzymes. The number and diversity of enzymes contain or depend on the presence of iron for activity is extensive in human body. In recent years, the deleteriousness of iron has been given more and more attention, and many studies have focused on the reactive oxygen species induced by excess iron, which can induce the oxidative injury. Liver, heart and kidney are the main organ to be injured when iron overload occurs. Flavonoids are a group of natural antioxidants, which have been researched in antioxidative and pharmacological effects for many years. In this thesis, the protective effects of baicalin and quercetin on iron induced mouse tissue oxidative injury were studied,and the result shows that these two flavonoids have good effects of anti-toxicity on iron overload. The main results are as follows:The model with i.p.injection with iron-dextran was used to induce acute iron overload,and supplementation with baicalin or quercetin containing diet (1% w/w) at the same time, to study the protective effects of the two flavonoids on iron induced liver,kidney and heart injury. The results showed that supplementation with baicalin and quercetin could protect tissues oxidative injuries caused by iron overload, decreased the hepatic iron content and renal iron content significantly. It was also confirmed that baicalin and quercetin could form flavonoid-iron complex and excrete it from body.The high performance liquid chromatography and inductively coupled plasma mass spectrometry, isoelectric focusing and X-ray fluorescence were used to analyze the iron content and distribution in mouse liver. The results showed that iron overload could increase the iron content in cytosol, mitochondria and microsome, the iron content order in subcellular fractions was microsome > cytosol > mitochondria. After supplemented with baicalin and quercetin, the iron content in subcellular fraction are decreased, the decreasing order was cytosol >microsome >mitochondria. Meanwhile, the results also showed that these two flavonoids have different affinity to iron ions in mouse liver. The distribution of iron-containing proteins in cytosol and microsome were three major forms. In cytosol, the iron-containing proteins mainly existed in the form of a negative charge of a complex compound, but in mitochondria and microsome mainly existed in the form of ferritin.