Studies On Transformation And Preparation Of Salvianolic Acid A And The Reaction Mechanism

Salvianolic acid A, which is well known for the prominent antioxidant activity in Salvia miltiorrhiza, has far-ranging pharmacological effects. The content of salvianolic acid A in Salvia miltiorrhiza is particularly low. It is differicult to achieve the large-scale preparation of salvianolic acid A with the conventional method of extraction and separation from the root of Salvia miltiorrhiza Bunge. In this work, salvianolic acid A was gotten with the method of separation from transformation products of salvianolic acids extracts under high temperature and high pressure. The optimal transformation and prepatation process was put forward, which solved the difficulty of large-scale preparation of salvianolic acid A. The transformation mechanism was researched and reaction process of salvianolic acids extracts to salvianolic acid A under high temperature and high pressure was explained, and it is signicant for the research of active constituent and dose-respinse relationship of salvia miltiorrhiza preparation.On the basis of the results of single factor experiment and orthogonal experiment, the optimal reaction conditions of salvianolic acids extracts to salvianolic acid A under high temperature and high pressure were as follows:with pH value 5, the concentration of salvianolic acids extracts was 5 mg·mL-1, and the reaction was performed at 120℃ for 4 h.The transformation products of salvianolic acids extracts under high temperature and high pressure were isolated with extraction and several column chromatographies, and salvianolic acid A which is purity of 98% was gotten. Through the detection of IR, ESI-MS, ’H-NMR and 13C-NMR, and contrast with literature data, salvianolic acid A was identified.The analysis of component changes during the reactions of salvianolic acids extracts, salvianolic acid B and lithospermic acid under high temperature and high pressure was performed by HPLC. The result was as follows:Salvianolic acid A was the primary product in salvianolic acid B and lithospermic acid’s transformation process, and lithospermic acid was an intermediate in the transformation process of salvianolic acid B. Compared with salvianolic acid B, lithospermic acid could convert into more salvianolic acid A and fewer other products in the same conditions. Salvianolic acid A was not stable under high temperature and high pressure, and could sequentially convert into other small molecules.UPLC/Q-TOF MS was applied to the characterization of the transformation products of salvianolic acids extracts under high temperature and high pressure. A total of twenty-seven salvianolic acids were detected. The reaction process of salvianolic acids was deduced on the basis on the structions of salvianolic acids and the detection result of UPLC/Q-TOF MS, and the transformation mechanism of salvianolic acids to salvianolic acid A under high temperature and high pressure was explained.