1. School of Life Sciences, Yunnan University, Kunming, Yunnan 650500, P.R. China
2. School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650500, P.R. China
3. School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650500, P.R. China
4. Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA