1. Department of Plant Sciences; Quaid-I-Azam University; Islamabad Pakistan
2. Center of Natural Product Lab, Chengdu Institute of Biology; Chengdu 610041 China
3. Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University; Chengdu Sichuan 610064 China