Investigation on interactions between bovine thrombin, aptamer and active components in Danshen by capillary zone electrophoresis

Investigation on interactions between bovine thrombin (B-Thr), aptamer29 (Apt29) and three active components (salvianic acid A sodium (SAS), protocatechuic acid (PA), ferulic acid (FA)) in Danshen was carried out by capillary zone electrophoresis (CZE). CZE conditions were as follows: capillary length of 40 cm, voltage of 15 kV, injection volume of 3.45 kPa, injection time of 5 s. By changing concentration of B-Thr or Apt29 with fixed levels of the three active components, binding constants (K_b) were calculated by Scatchard and non-specific binding equations to show interactions between B-Thr, Apt29 and the three active components. The results showed that PA had the strongest affinity to B-Thr with K_b 3.39×10⁴ L / mol. K_b between FA and B-Thr was 1.05×10⁴ L / mol. SAS had no binding with B-Thr. FA showed stronger affinity with Apt29 than PA with K_b of 1.48×10⁴ L / mol and 1.32×10⁴ L / mol, respectively. The present study reported that interactions between the active constituents in Danshen and B-Thr / Apt29. New methods might be supplied for calculation of interactions between Apt (protein) and herbal drug molecules. And it could give insight for target discovery and delivery of herbal drug molecules.