Impairment of Vascular Function of Rat Thoracic Aorta in an Endothelium-Dependent Manner by Shikonin/Alkannin and Derivatives Isolated from Roots of Macrotomia euchroma - Hu, Chien-Ming; Cheng, Yu-Wen; Cheng, Hui-Wen; Kang, Jaw-Jou (Planta Medica, 2004)