| As a kind of natural polyphenols,ellagic acid usually exists in the form of condensation(such as tannin,glycoside,etc.),and a small part of it exists in the form of free.Ellagic acid has a variety of biological activities,such as anti-inflammatory,antibacterial,anti-oxidation,anti-cancer and so on.However,because of its low purity,poor water solubility,low bioavailability and other reasons,the activities of ellagic acid have not been fully utilized.Therefore,the following research has been done to solve these problems:1.Tannic acid was extracted from pomegranate peel and then hydrolyzed to 45%ellagic acid.2.High purity ellagic acid was prepared by anti-solvent precipitation method.The purity of tannic acid was up to 98%by high performance liquid chromatography.The morphology of tannic acid and high purity ellagic acid was observed by SEM.The chemical structure of crude ellagic acid and high purity ellagic acid was analyzed by FTIR and LC-MS.The results showed that the morphology of crude ellagic acid was irregular and the particle size was between 24.8?m and 92.3 p.m,while the morphology of high-purity ellagic acid showed a regular block shape.The average particle size was about 438.0± 11.8 nm as measured by a laser particle size analyzer.The results of FTIR and LC-MS showed that the chemical structure and molecular weight of the obtained ellagic acid were consistent with those of the standard ellagic acid.The results of in vitro transdermal experiments showed that the maximum osmotic capacity of high purity tannic acid was about 16.53 ?g/cm-2 at the same time,and the maximum osmotic capacity of crude ellagic acid was about 13.94?g/cm2.In addition,the osmotic coefficients of tannin powder and high purity tannic acid on rat skin were 4.65 and 5.51 ?g/cm/h,respectively.3.The inclusion compound of hydroxypropyl-?-cyclodextrin of ellagic acid was prepared by antisolvent precipitation method.The optimal conditions for the preparation of Inclusion compound of hydroxy propyl-?-cyclodextrin of ellagic acid by single factor were as follows:the concentration of hydroxypropyl-?-cyclodextrin was 300mg/mL,the inclusion temperature was 60?,the inclusion time was 10 min,and the volume ratio of antisolvent to solvent was detennined by 15:1.The results of SEM shows that high purity ellagic acid is regular blocks with a particle size of about 8-10 ?m.The appearance of the inclusion compound of hydroxypropyl-?-cyclodextrin of ellagic acid is almost spherical,and the particle size is between 300-600nm.FTIR,XRDX,DSCTG and 1HNMR results show that the size of the inclusion compound is about the same as that of HP-?-cyclodextrin.Ellagic acid was successfully encapsulated in hydroxypropyl-?-cyclodextrin,and the inclusion compound of hydroxy propyl-?-cyclodextrin of ellagic acid existed in an amorphous form.Gas chromatography detection shows that the residues of N-methylpyrrolidone and acetone in the inclusion complex are 28 ppm and 93 ppm.The dissolution rate of tannic acid in the inclusion compound of hydroxypropyl-?-cyclodextrin ellagic acid was much higher than that of high purity ellagic acid.Bioavailability test showed that the highest concentration of ellagic acid in the inclusion compound of hydroxypropyl-?-cyclodextrin of ellagic acid in blood was 5438.8 ng/mL and the highest concentration of high pirity ellagic acid in blood was 275.6 ng/mL.The area under the curve of the inclusion compound of hydroxy propyl-?-cyclodextrin of ellagic acid and high purityellagic were 1873.703p?g/L·h and 13890.49 ?g/L·h,respectively. |
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