Triterpenoid Saponins from Androsace umbellata and their Anti-proliferative Activities in Human Hepatoma Cells - Wang, Ying; Zhang, Dongmei; Ye, Wencai; Yin, Zhiqi; Fung, Kwok-Pui; Zhao, Shouxue; Yao, Xinsheng (Planta Medica, 2008)