Fig. 2

Inhibition of meningococcal pili binding to bovine thyroglobulin by salvianolic acid B (98 and 70 % purity). Tested concentrations ranged from 0.313 mg/mL to 0.6 µg/mL for both SA-Bs. Each point on the curves represents the mean ± SD, n = 9. The binding of pili to reference glycoprotein was significantly inhibited by both SA-B of 70 % purity (P < 0.001) and SA-B of 98 % purity (P < 0.001) when compared to control (no inhibitor). The difference between the inhibition activity caused by SA-B of 70 % purity compared to SA-B of 98 % purity was significant (*P = 0.03, except for the concentration of 0.002 mg/mL *P = 0.01)