Preparation method of tannin-histidine metal complex

The invention discloses a preparation method of a tannin-histidine metal complex. The preparation method comprises the following steps: firstly, histidine reacts with tannin to prepare a tannin-histidine salt; secondly, benzyl bromide react with the tannin-histidine salt to protect a part of phenolic hydroxyl groups of tannic acid; complex reactions are separately carried out with metal ions Fe, Mn, Cu and Zn; and then benzyl bromide is hydrolyzed by adopting boron trifluoride-diethyl ether to prepare a tannin-histidine metal complex. The structure of the tannin-histidine metalcomplex prepared by the method contains imidazolyl, metal ions and polyphenol hydroxyl, and the three groups synergistically play a role in resisting oxidation, so that excessive free radicals in a living body can be efficiently removed, and the tannin-histidine metal complex has catalytic activity of pseudo-superoxide dismutase. 一种单宁-组氨酸金属络合物的制备方法是首先利用组氨酸和单宁酸进行反应制备成单宁-组氨酸盐，其次利用苄基溴和单宁-组氨酸盐进行反应保护单宁酸的部分酚羟基，再分别与金属离子Fe、Mn、Cu