Research On Component Basis Of Salvianolic Acid Extracts And Their In Vitro Antioxidant Activity

In order to study relationship between water soluble components in Danshen and their antioxidant activity, sixteen different salvianolic acid (SA) samples were prepared by hydrolysis under different conditions making use of the property that salvianolic acids easily hydrolyze in water. Then nine SA samples being significantly different both in components and compositions were selected by multi-statistic test and principal component analysis based on their UV spectra.HPLC fingerprint of the nine screened SA samples were detected and the peaks of the HPLC graphs were matched through Matlab procedure. Euclidean distance and similarity coefficient were applied to evaluate the variability of SA sample based on their HPLC fingerprints. The threshold values of the two evaluation indices were defined based on HPLC data of method validation and repeatly preparing total salvianolic acid extract and sample pH12h3, respectively. The result showed that all of the nine SA samples could not been clusterd under the thresholds defined by the method validation and repeatly preparing TSAE.Two models of anti-hemolysis of mice red cell caused by auto-oxidation and mice liver homogenate lipid peroxidation were used to study antioxidant activity of the nine SA samples. The results indicated that the SA samples prepared under violent hydrolysis conditions, which contain larger amount of salvianolic acids with small molecular weights, have stronger effect on inhibiting hemolysis of mice red cell caused by auto-oxidation; while those SA samples prepared under mild hydrolysis conditions, in which contents of salvianolic acid B (SalB) and small molecule salvianolic acids are moderate, have better activity to inhibit liver homogenate lipid peroxidation in mice. The activity of pure SalB is weaker in both models than the mixtures containing some small molecule salvianolic acids.Partial least square (PLS) multivariate regression model was applied to model the antioxidant activity of the selected SA samples from the HPLC fingerprints to indicate peaks possibly responsible for this activity. The result indicated that SalB's hydrolysis decomposition produces products with stronger anti-oxidant activity but also produces substances advancing oxidation and the anti-oxidant composition (such as danshensu) are highly positive correlative to the advancing oxidation composition (such as ferulic acid). It indicates that the antioxidant activity of SA extracts is contributed by cooperative and antagonistic effect of many components. It is suggested defining the minimum and maximum content of key components such as Sal B and Danshensu and their mutual proportion on the basis of analyzing HPLC fingerprints with their activity data to guarantee safety, effectiveness and stability of Danshen preparations.