title: Inhibitory effects of Acanthopanax gracilistylus saponins on human platelet aggregation and platelet factor 4 liberation in vitro.
abstract: OBJECTIVE
  To study the effects of Acanthopanax gracilistylus var pubescens Li saponins (AGVPS) on human platelet aggregation and platelet factor 4 (PF4) liberation in vitro.
  
  
  METHODS
  Human platelet aggregations induced by ADP, adrenaline, and collagen were measured turbidimetrically. The aggregation curve was recorded on a platelet aggregometer and the maximal aggregation rate (ARmax), effective deaggregation rate in 5 min (DR5 min) and lag time (LT) were autocalculated by the built-in microcomputer; PF4 liberation from human platelets stimulated by ADP and collagen was determined by recording the heparin thrombin clotting time (HTCT). Thrombosis was tested by weighing the wet and dry thrombi formed in a siliconized revolving ring.
  
  
  RESULTS
  AGVPS inhibited in vitro the ARmax with IC50 of 1.33 (95% confidence limits: 1.09-1.63, ADP-induced), 1.66 (1.54-1.79, adrenaline-induced), and 4.2 g.L-1 (0.6-29, collagen-induced). The DR5 min (on ADP-induced aggregation) and LT (collagen-induced) were also increased as well. Meanwhile, AGVPS 0.63-2.50 g.L-1 prolonged HTCT on ADP- and collagen-stimulated PF4 liberation. At 0.34-1.39 g.L-1, AGVPS reduced the wet and dry weight of thrombi formed in vitro.
  
  
  CONCLUSIONS
  AGVPS inhibits human platelet aggregation, liberation, and thrombosis in vitro, suggesting its possible antithrombotic action in man.
authors.affiliation: Department of Pharmacology, Hainan Medical College, Haikou, China.
authors.forename: X C
authors.initials: XC
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Xia
authors.forename: S
authors.initials: S
authors.lastname: Hu
authors.forename: G
authors.initials: G
authors.lastname: Huang
mesh_terms: D000328:Adult; D005260:Female; D005343:Fibrinolytic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D019684:Magnoliopsida / Q000737:chemistry; D008297:Male; D010946:Plants, Medicinal / Q000737:chemistry*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D010978:Platelet Factor 4 / Q000096:biosynthesis*; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D012503:Saponins; D010978:Platelet Factor 4