ABSTRACT
Objective To investigate the effects of saponins from Allium Macrostemon Bunge Bulbs (SMBB) on platelet aggregation and platelet-neutrophil-interactions. Methods The effects of SMBB on platelet aggregation in SD rats were observed in vivo and in vitro. The adhesion of platelets to neutrophils was measured by rosette test. The effect of SMBB on activated platelet calcium levels was detected. Results Platelet aggregation induced by platelet activating factor (PAF), adenosine diphosphate (ADP) and arachidonic acid (AA) was significantly inhibited by SMBB in vitro concentration-dependent. Platelet aggregation induced by PAF, AA and ADP was significantly inhibited by 5 mg/kg of SMBB. SMBB could reduce the intracellular calcium concentration in the wash platelets. SMBB significantly reduced the adhesion between neutrophils and thrombin-activated platelets and inhibited neutrophil supernatant-induced platelet aggregation, with IC50of 2.7 μmol/L and 9.6 μmol/L, respectively. Conclusion SMBB can inhibit platelet aggregation in vitro and ex vivo, and inhibit the interactions between platelets and neutrophils.
ABSTRACT
Objective To investigate the effects of geraniin on platelet aggregation and platelet-neutrophil interactions.Methods Platelet aggregation,in vitro and ex vivo,was determined by use of Born's method,and the binding of thrombin-stimulated platelets to neutrophils was observed based on the rosette assay.Intracellular calcium concentration of platelets was measured by using Fura-2-AM.Results Geraniin in vitro significantly inhibited arachidonic acid (AA)-,adenosine diphosphate (ADP)-,or platelet activating factor (PAF)-induced platelet aggregation,in a concentration-dependent manner.The medium inhibitory concentrations (IC50) were 2.4,0.4 and 1.1 μmol/L,respectively.Intragastric geraniin at 5 mg/kg markedly suppressed platelet aggregation induced by AA,ADP,or PAF.Geraniin decreased the total rise of [Ca2+]i,Ca2+ release,and Ca2+ influx,in a concentration-dependant manner.The IC50 values were 71.9,84.9,and 62.9 μmol/L,respectively.Geraniin decreased the binding of thrombin-stimulated platelets to neutrophils,and significantly inhibited washed platelet aggregation stimulated by fMLP-activated neutrophils.The IC50 values were 3.2 and 10.2 μmol/L,respectively.Conclusion It is suggested that geraniin inhibited platelet aggregation in vitro and ex vivo,decreased the calcium mobilization of platelets,and suppressed the interactions between platelets and neutrophils.