Study On The Method Of Enriching Baicalin In Scutellaria Baicalensis Georgi With MOFs

Metal organic frameworks?MOFs?are a kind of porous crystalline materials formed by self-assembly of metal or metal oxides with organic ligands.MOFs has the functions of large specific surface area,high porosity and adjustable pore volume and pore diameter,which makes it have the potential unmatched by traditional porous materials in the field of adsorption.Scutellaria baicalensis is the dried root of Scutellaria baicalensis Georgi,a Labiatae plant.It is a large traditional Chinese medicine with a long economic and medical value.Bai-calin(molecular formula:C₂₁H₁₈O₁₁;molecular weight:446.32)is a flavonoid monomer extracted from Scutellaria baicalensis.Due to its multi potency,such as anti-tumor,antioxidant,anti anxiety,anti-inflammatory and antiviral pharmacological prope-rties,it has attracted considerable attention.The purpose of this work is to ex-plore a new method for the enrichment of Baicalin in Scutellaria baicalensis by MOFs,and to expand the application of MOFs in the adsorption field.In this paper,the method of baicalin detection by high performance liquid chromatography has been verified.It is proved that this method has good linear correlation,high accuracy and high practical value.The linear equation of ba-icalin is Y=29814500X+156000?R²=0.9999?,and the linear range is 0.05?0.50mg?m L^-1.Then seven kinds of MOFs were synthesized by solvothermal method.Their structures were characterized by XRD,TG,SEM and N₂ adsorption desorption experiments.The results showed that the materials were synthesized accurately and their crystal forms are good.In this paper,we studied the adsorption properties of baicalin in Scutellaria baicalensis by seven kinds of MOFs materials.Two kinds of MOFs materials,ZIF-8 and mer-[Cu??-Nic??H₂O??2-meim?₂]_n,with high adsorption and desorption rates,were selected.At last,two kinds of MOFs were further studied,and the following concl-usions were obtained:In this paper,the best adsorption parameters of ZIF-8 and mer-[Cu??-Ni-c??H₂O??2-meim?₂]_n for baicalin were obtained by response surface analysis?RSM?.Under these conditions,the optimal adsorption rates were 97.31%and 84.08%respectively,and the adsorption effect of these two materials on other compo-nents of Scutellaria baicalensis was not significant.The desorption rates of ZIF-8and mer-[Cu??-Nic??H₂O??2-meim?₂]_n were 62.46%and 41.27%respectively,using Phosphate Buffered Saline?PBS?at p H 6.8 as the desorption solution.The purity of baicalin increased from 21.55%before adsorption to 64.27%and 75.77%after desorption.The two materials have good stability before and after adsorption,and the recovery rates can reach 83.50%and 78.64%,respectively.This paper also studied the adsorption regular pattern and mechanism of baicalin in Scut-ellaria baicalensis by two materials:ZIF-8,mer-[Cu??-Nic??H₂O??2-meim?₂]_n The adsorption process fit pseudo second order kinetics equation and Langmuir is-otherm equation with adsorption capacity.The mechanism of ZIF-8 adsorption process may be?-?conjugation,and the mechanism of mer-[Cu??-Nic??H₂O??2-meim?₂]_n adsorption process is hydrogen bonding.Therefore,the two MOFs synthesized in this paper,ZIF-8 and mer-[Cu??-Nic??H₂O??2-meim?₂]_n,have potential applications in enriching and purifying ba-icalin in baicale value.A HPLC method for the determination of baicalin was established.Through the verification of precision,stability,repeatability and recovery,it was proved that the method has good linear correlation,high accuracy and high practical value.