1. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, P. R. China, Graduate University of the Chinese Academy of Sciences, Beijing 100049, P. R. China, and Guangxi Jinxiu Shengtang Yaoye Limited Company, Liuzhou 545700, Guangxi, P. R. China