Study On Extraction Of Protein From Coix And Its Protective Effects On Liver Injury

Coix lachryma-jobi, which is a kind of gramineous plants with rich nutrition, especially protein, is on the list of medicine & food materials that exclaimed by MOH of China. It has no very special formula to enviroment, and grows all over China, so it is very aboundant in natural resources. At present, deep-processing of Chinese Coix in industry is at a low level with less varieties. In addition, there is no systematic study on Coix protein and there is aboundant raw materials for developing new products of Coix protein, which is of extensive practical significance. The purpose of this study is to provide a theoretical envidences for practical application of Coix protein, which is based on research of the physics and chemistry character of Coix protein, extraction methods for Coix protein, and the protective effects of Coix protein on experimental hepatic injure induced in mice.1. Extraction and analysis about the different constituents of Coix protein showed:pI of Coix globulin was pH4.0; the proportion of albumin, globumin and prolamin was 18.3%,8.80%and 64.3%, respectively in the Coix protein. The molecular weight of albumin was between 10 kDa and 90 kDa; globumin was between 15 kDa and 62 kDa; and prolamin was between 19 kDa and 40 kDa. Amino acid analysis in Coix proteins showed:the complete compositions of amino acids existed in Coix proteins, in which content of glutamic acid was the highest. The essential amino acid contained more leucine and less lysine.2. The optimum extraction conditions of extracting Coix proteins with high-temperature a-amylase and fungal amylase, were determined on the basis of Cysteine muriate solution pretreatment by the orthogonal test. The result showed that optimum conditions about extraction of protein from Coix by high-temperature a-amylase were as follows:temperature 80℃a-amylase amount 200U/g starch and time,4 hours. But proteins extracted by fungal amylase contained more starch. 3. In the 30-day feeding test, the Kunming mice were randomly divided into higher, lower dosages groups and fed on food contained Coix proteins 14% and 7%, respectivly.The protective effect of the Coix proteins on carbon tetrachloride (CCI4) induced acute hepatic injury in mice was studied by the measurement of serum ALT, serum AST and MDA in liver, and observation of histopathology. The result showed that Coix protein had obviously protective effects against acute chemical liver induced by CCI4 in mice when a mouse fed 0.28g/d Coix protein extracted by high-temperature a-amylase.The experimental mice models of chronic liver injury were established by gavage of 50% alcohol. At the same time, the normal group were treated with normal saline as the negative control. Serum alamine aminotransferase (ALT) and asparate aminotransferase (AST), liver malondialdehyde (MDA), reduced glutathione (GSH) and triglyceride(TG) content in liver tissue were measured and histopathology was observed after feeding 30 days, in order to evaluate protective effects of Coix protein on chronic alcohol liver injury. The result showed that Coix protein showed protective effects against chronic liver injury induced by alcohol in mice when a mouse fed 0.28～0.56g/d Coix protein.