The Synthesis Of Pyroglutamic Acid And The Functional Evaluation Of Its Calcium Salt

In this paper,pyroglutamic acid is prepared from cheap and easily available glutamic acid,and the preparation process and conversion rate detection methods are optimized.Then,the prepared pyroglutamic acid was chelated with calcium in the shell to prepare calcium pyroglutamate,and the animals experiment and osteogenic mechanism are studied.First of all,this paper studies two simple methods to determine the conversion rate of glutamic acid for the preparation of pyroglutamic acid: ninhydrin method and polarimetry.After the reaction of glutamic acid and ninhydrin,according to the spectrophotometric method,there is an absorption peak at pH 6.0,568 nm,while the absorbance of pyroglutamic acid is zero.After reaction,the glutamic acid has a good linear relationship in the range of 20 ?g/m L to 100 ?g/mL.Thus,the glutamic acid content in the after-reacting solution can be calculated by the standard curve.In the production of pyroglutamic acid,the rotation versus conversion rate curves,by which the remaining glutamic acid of the after-reacting solution can be calculated,were established on the basis of glutamic acid and pyroglutamic acid optical rotation.In addition,the ninhydrin method and the polarimetry are compared with the widely used high performance liquid chromatography.Secondly,in this paper,the process of producing pyroglutamic acid from glutamic acid was optimized.This article uses a miniature high-pressure reaction vessel with mass transfer,high heat transfer efficiency,uniform temperature concentration distribution,and high operational flexibility to facilitate control and change of reaction conditions.In the reaction vessel,the temperature was controlled at 140° C.,the reaction time was 4.6 h,and the solute solvent ratio was 21:100(w/w)to prepare pyroglutamic acid.Finally,calcium pyroglutamate was prepared by chelating the prepared pyroglutamic acid and calcium in shells.The prepared calcium pyroglutamicate and the commercially available calcium supplementation product were fed to mice for growth and metabolism tests.After the end of the experiment,the effects of various calcium supplements on bone strengthening were determined by measuring mouse serum markers,metabolic indices,femur bone mineral density,and performing femur electron microscope scans.The results show that calcium pyroglutamate has a stronger calcium and bone strengthening effect than commercially available calcium supplements.This paper also explored the osteogenic mechanism of calcium glutamate,and determined the expression of the key genes BMP2,Smad5 and Smad6 in the osteogenic BMP-Smad pathway by Western-blot.The results showed that calcium pyroglutamate promoted osteoblast formation by up-regulating BMP2 and down-regulating Smad6 expression.