Preparation Method Of Rotundic Acid And Its Solid Dispersion And Study On Their Inhibitory Activities To Alpha-glucosidase

Purpose:The total triterpenic acid was extracted from the dry bark of llex rotunda Thunb,and rotundic acid which is a main component of the total triterpene acid was extracted and purified.To increase the solubility and bioavailability of rotundic acid a solid dispersion was prepared.The in vitro inhibitory effects to the alpha-glycosidase of total triterpenic acid,rotundic acid and its solid disperstion were studied.Methods:The content of total triterpenic acid in the extract was determined by ultraviolet spectrophotometry,and the method of box-behnken response surface was used to optimize the extraction process.The main components of total triterpene acid,rotundic acid was isolated and purified by ODS atmospheric pressure column,and the structural identification was carried out.Using solvent method to produce rotundic acid solid dispersed preparation,using X-ray diffraction,SEM analysis and determination of dissolution rate methods to evaluate the decentralized state and quality of the solid dispersed preparation.The determination of the content of rotundic acid in the extraction was established by using high performance liquid chromatography?HPLC?.The PNPG method was used to study the inhibitory activity of triterpenoid acid,rotundic acid content and its solid dispersion.Results:The final prepation technology was determined through the extraction and purification process of total triterpenoid acid.The preparation technology contains the following procedures:The raw llex rotunda Thunb.was extracted by using 45%ethanol which containing 8%NaOH solution,material liquid ratio is 1:8,for 2 times,each time lasted for 2h,filtrating,merge the filtrate,use hydrochloric acid to adjust pH value to 5-6,place,filtrating,abandon the filtrate,the filtrated residue was washed with water to neutral,dry the residule,the total triterpenoid acid crude product were botained;Dissolve the crude product with 95%ethanol solution on water bath,and the ratio of crude product to liquid was 1:25,add 1%of the medicinal activated carbon,filtrate,recover the solvent and dry the filtrate,total triterpenoid acid product was obtained.The content of total triterpenic acid in the total triterpenoid acid product was about 90%,and rotundic acid content was more than 80%.Using atmospheric ODS column to separate rotundic acid from total triterpene acid,and through the thin layer chromatography?TLC?,high performance liquid chromatography?HPLC?,the physical and chemical properties,nuclear magnetic resonance?NMR?spectroscopy to identify the structure of rotundic acid.Take the dissolution rate and dissolubility of rotundic acid as index to investigate different kinds of drug carrier and different drug load ratio of rotundic acid solid dispersions,ultimately PVPK30 was dermined as the carrier and the drug loading ratio was 1:5,the solid dispersions was prepared by solvent method.Through X-ray diffraction and SEM electron microscopy,the formation of solid dispersion is confirmed and the new form is different from that of raw materials.The dissolution rate of the solid dispersion in 60 minutes reaches98%,which improves the solubility and bioavailability of the rotundic acid.Take PNPG as substrate to study the inhibitory activities of total triterpenoid acid,rotundic acid and solid dispersed preparation of rotundic aci on alpha glycosidase,the experimental results show that all the samples under test have certain inhibition of alpha glycosidase.The IC₅₀ value of solid dispersed preparation,rotundic acid and total triterpenoid acid was 1.06mg·mL^-1,1.98 mg·mL^-1 and 2.53 mg·mL^-1 respectively.The results showed that the solubility of the rotundic acid formed solid dispersion was increased,and the activity was significantly enhanced,which showed that the preparation of solid dispersion was of practical significance.Conclusion:Through the study on the inhibitory activities of total triterpenoid acid,rotundic acid and its solid dispersions to alpha glycosidase,a foundation for the development of a new hypoglycemic drug from total triterpenoid acid llex rotunda Thunb.has been laid.