Correlation between toxicity and changes of alkaloids in combinationof Yeratrum ni}grum and ginseng Chemical constituents in stems and leaves of Veratrum nigrum var. ussuriense Neuroprotection of Veratrum nigrum var. ussurience alkaloids on focal cerebral ischemia-reperfusion injury in rats Effects of Veratrum nigrum var.ussuriense alkaloids on platelet aggregation and time of coagulation and bleeding Correlation between toxicity and changes of alkaloids in combination of Veratrum nigrum and ginseng Antithrombotic effect of verussurinine from Veratrum nigrum var.ussuriense alkaloids