The inhibitory effect of R. acetosa extract on inside-out and outside-in signaling. Platelets were pre-incubated with or without R. acetosa extract (25–200 μg/mL) in the presence of 0.2 mM CaCl2 for 2 min at 37 °C with stirring and stimulated with collagen for 15 min at 37 °C. (A) Representative FACS analysis results of five independent trials [Resting (a), Vehicle (b), R. acetosa extract 25 μg/mL (c), 50 μg/mL (d), 100 μg/mL (e), 200 μg/mL (f) and, EGTA 10 μM (g)]. b Bar graph summarizing the inhibitory effect of R. acetosa extract on fibrinogen binding. c-d Thrombin (1 U/mL) was used to initiate clot retraction in presence or absence of R. acetosa (50–200 μg/mL) or Y-27632 (10 μM). Clot retraction was observed for 90 min and representative images of clot retraction at 1 h (c), while bar graph (d) showing inhibitory effects of R. acetosa extract on clot retraction. *P < 0.05, **P < 0.01 and ***P < 0.001 versus control