Study On Large Scale Production Process For Salvianolic Acid A

Salvianolic acid A (SAA) has the highest antioxidant activity in Salvia miltiorrhiza, with broad pharmacological function, which plays a significant role in cardiovascular and cerebrovascular diseases. It was found that the preparation process for SAA had lots of problems, such as expensive preparation cost due to a low natural content of SAA, the purity of extracted substances not up to the standard, also, poor repeatability in the preparation process together with the difficult to achieve large-scale preparation, above all, the preparation process still belonging to laboratory level by summarizing literature. In this paper, it was researched that the process which transformed salvianolic acid extracts into SAA based on the transformation mechanism, and optimized that the process which prepared highly purified SAA by combining fractional extraction with industrial chromatograph.Based on the yield of SAA as examining indexes and determined by single-factor experiment and orthogonal experiment, the optimized transforming conditions were as follows:material concentration was 10 mg·mL-1, pH value was adjusted into 6 with disodium hydrogen phosphate, reaction temperature and time 120℃,4 h.This process condition and its repeatability were stable and good.Based on the extraction rate and purity of SAA as examining indexes, fractional extraction conditions were determined as follows:transformation solution/dichloromethane was 1:2, for one time; ethyl acetate/extract liquor was 1:1, for three times; the purity of SAA reached above 49%(Area normalization method), by which the solvent extraction could be used repeatedly.Based on the yield and purity of SAA as examining indexes, (1) enrichment process conditions were as follows:AB-8 macroporous resin was selected. Adsorption condition was as follows:ratio of diameter to height of resin column 1:7, flow rate 1.5 mL·min-1, pH value 2-3, max adsorption capacity 38.67 mg·g-1, concentration of sample was 3.5 mg·mL-1. Elution conditions were as follows:flow rate 2.5 mL-min"1, volume of 30% MeOH was 10 BV, volume of 50% MeOH was 15 BV. Purity of SAA reached above 79%(Area normalization method). (2) Fine separation process conditions were as follows:SG64 resin was selected. Adsorption condition was as follows:ratio of diameter to height of resin column 1:6, flow rate 1.0 mL·min-1, pH value 2-3, max adsorption capacity 39.83 mg·g-1, concentration of sample was 7.25 mg·mL-1. Elution conditions were as follows:flow rate 2.0 mL·min-1, volume of 20% MeOH was 8 BV, volume of 40% MeOH was 15 BV. Purity of SAA reached above 92%(Area normalization method). (3) Purification process conditions were as follows: UniTMPS resin was selected. It utilized high pressure on-line preparation method, measurement wavelength 288 nm, ratio of diameter to height of resin column 1:7.5, loading quantity of sample 8.85 mg·g-1, the elution program was as follows:from 0 to 30 min, the concentration of MeOH-water was changed from 40% to 50%; then the 50% MeOH-water continued eluting to 150min; purity of SAA reached above 98%(Area normalization method).Pilot-scale experiment indicated that the process was stable and conformed to requirements of large-scale production.SAA was identified by the detection of UV,1H-NMR and 13C-NMR. And it was identified that the purity of salvianolic acid A reached above 98% through detection of TLC and HPLC (3D).