1. State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, P. R. China
2. College of Chemistry and Environmental Engineering, Baise University, Baise, Guangxi 533000, P. R. China
3. School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning, 530008, P. R. China