1. School of Pharmacy; Guangdong Medical University; Dongguan 523808 China
2. Guangdong Key Laboratory for Research and Development of Natural Drugs; Guangdong Medical University; China
3. Guangxi Key Laboratory of Chemistry and Engineering of Forest Products; Guangxi University for Nationalities; College of Chemistry and Chemical Engineering; Nanning Guangxi 530006 China
4. Department of Chemistry; Faculty of Science; University of Lucknow; Lucknow 226 007 India
5. School of Chemistry; Monash University; Victoria 3800 Australia
6. Department of Chemistry; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia