Kim H S, Zhang Y H, Fang L H, Yun Y P, Lee H K
Department of Pharmacology, College of Pharmacy, Chungbuk National University, Cheongju, South Korea.
J Ethnopharmacol. 1999 Aug;66(2):241-6. doi: 10.1016/s0378-8741(98)00237-2.
Tetrandrine (TET) and fangchinoline (FAN) are two major components of the radix of Stephania tetrandra. The effects of TET and FAN on human platelet aggregation and formation of thromboxane (TX) B2, a stable metabolite of TXA2, were examined in the aspect of platelet aggregation. TET and FAN inhibited platelet-activating factor (PAF)-induced human platelet aggregation. IC50 values for TET and FAN were 28.6+/-3.24 microM and 21.7+/-2.61 microM, respectively. In the PAF-receptor binding assay, neither TET nor FAN showed any inhibitory effects on the specific bindings of PAF to its receptor. TET and FAN also inhibited PAF-, thrombin- and arachidonic acid-induced thromboxane B2 formation in human washed platelet. These results indicate that TET and FAN inhibit the platelet aggregation by interfering with the intracellular messengers system, but not by inhibiting the binding of PAF to PAF-receptor on the platelet membrane directly, and the suppression of TXA2 formation by TET and FAN may be responsible for their inhibitory activities on the platelet aggregation and further on the thrombosis.
粉防己碱（TET）和防己诺林碱（FAN）是粉防己根中的两种主要成分。从血小板聚集方面研究了TET和FAN对人血小板聚集及血栓素（TX）B2（TXA2的稳定代谢产物）形成的影响。TET和FAN抑制血小板活化因子（PAF）诱导的人血小板聚集。TET和FAN的IC50值分别为28.6±3.24微摩尔和21.7±2.61微摩尔。在PAF受体结合试验中，TET和FAN对PAF与其受体的特异性结合均未显示出任何抑制作用。TET和FAN还抑制人洗涤血小板中PAF、凝血酶和花生四烯酸诱导的血栓素B2形成。这些结果表明，TET和FAN通过干扰细胞内信使系统抑制血小板聚集，而不是直接抑制PAF与血小板膜上PAF受体的结合，并且TET和FAN对TXA2形成的抑制作用可能是其对血小板聚集进而对血栓形成具有抑制活性的原因。
