1. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, PRC, Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing 100050, PRC, Graduate School of Chinese Academy of Sciences, Beijing 100039, PRC, and Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education, Research School of Pharmacy, Yunnan University, Kunming, Yunnan 650091, PRC