血竭及其成分的活血化瘀活性研究

Studies on the Vasoactive-Antithrombotic Effect of Draconis Resina and Its Components

血竭(Draconis Resina)為棕櫚科(Palmae)植物麒麟竭果實及樹幹滲出的睛紅色樹脂，記載中具有活血化瘀及止血功效。由活體動物(in Vivo)實驗結果穎示：(1)血渴以腹腔給藥對鼯鼠的一半致死劑量及其95%可信限分別為3.98及3.53~4.48g/kg。(2)血竭以腹腔給藥(0.6~3.0k/kg)，是可以縮短ICR鼯鼠的出血時間。(3)血竭以腹腔給藥（1.0和1.5g/kg），可以有意義地減少醋酸誘導鼯鼠腹部產生的抽搐作用，但對熱引致鼯鼠的疼痛並沒有抑制作用（1.5和2.5g/kg）。另外，由離體(in vitro)實驗結果顯示：(1)血竭在兔子血小板懸浮液中，能夠抑制花生四烯酸、膠原蛋白或血小板活化因子所引起的凝集，其IC50分別為11.0、11.0和37.0μg/ml；但血竭在25.0μg/ml時，反而會促進凝血酵素引起的血小板凝集作用。血竭的存在對血漿凝因時間並無影響。(2)血竭成分之(2S)-5-甲氧基－6-甲基黃烷－7-醇((2S)-5-methoxy-6-methylnavan-7-ol)在血小板懸浮液中，對花生四烯酸、膠原蛋白、血小板活化因子、U46619或ADP所引發之凝集具抑制作用，且呈現劑量－效應對應關係，其IC50分別為12.5、4.3、47.3、27.4、45.0μg/kg。但(2S)-5-methoxy-6-methslnavan-7-ol對血漿凝固時間及纖維溶解並無影響。(3)血竭成分之血竭紅素(dracorubin)與去甲法血竭紅素(nordracorubin)可以促進血小板凝集作用，但對血漿凝因時間並無影響。綜合上述結果，血竭是具活血化瘀之效，亦有部份止痛之效。其活性成分之(2S)-5-methoxy-6-methylflavan-7-ol具抗血小板活性，但dracorubin與nordracorubin卻具促進血小板活化之效。其成分在活血化瘀之作用機轉仍在進一步探討。

Draconis Resina, a red resin secreted from the fruits of Daemonorops draco Blume, has been used as a vasoactive-antithrombotic agent for treat thrombotic stroke and as a hemostatic agent by Chinese physicians. In vivo studies yielded the following results: (1) The median lethal dose and 95% confidence limits of Draconis Resina by intraperitoneal injection to ICR mice were 3.98 and 3.53-4.48g/kg, respectively; (2) Draconis Resina (0.6-3.0 g/kg, i. p.) shortened the tail bleeding time in conscious mice; (3) Draconis Resina (1.0 and 1.5 g/kg, i. p.) significantly decreased the writhing response induced by acetic acid in mice. However, Draconis Resina (1.5 and 2.5 g/kg, i. p.) had no analgesic effect as evaluated by the hot-plate method. On the other hand, in vitro studies indicated that (1) Draconis Resina inhibited the aggregation of washed rabbit platelets induced by arachidonic acid (AA), collagen and platelet-activating factor (PAF) (IC50: 11.0, 11.0 and 37.0μg/ml, respectively) and enhanced thrombin-induced aggregation even though Draconis Resina had no effect on coagulation as evaluated by the prothrombin time (PT) and activated partial thromboplastin time (APTT); (2) (2S)-5-methoxy-6-methylflavan-7-ol, one of the bioactive components in Draconis Resina, dose-dependently inhibited rabbit platelet aggregation induced by AA, collagen, PAF, U46619 or ADP (IC50: 12.5, 4.3, 47.3, 27.4, and 45.0μg/ml, respectively) in platelet suspension although (2S)-5-methoxy-6-methylflavan-7-ol had no effect on the PT and APTT, the fibrinolytic system; (3) Dracorubin and nordracorubin, other bioactive principles in Draconis Resina, enhanced platelet aggregation but did not affect PT and APTT. The present studies demonstrated that Draconis Resina possessed vasoactive-antithrombotic activity and some analgesic effect. The activities of Draconis Resina components include the antiplatelet activity by (2S)-5-methoxy-6-methylflavan-7-ol and enhancement of platelet activation by dracorubin and nordracorubin. Further studies are needed to elucidate the action mechanism of Draconis Resina and its components.