Gambogic Acid and Epigambogic Acid, C-2 Epimers with Novel Anticancer Effects from Garcinia hanburyi - Han, Quanbin; Yang, Ling; Liu, Yong; Wang, Yulin; Qiao, Chunfeng; Song, Jingzheng; Xu, Lijia; Yang, Dajian; Chen, Shilin; Xu, Hongxi (Planta Medica, 2006)