1. State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources
2. School of Chemistry and Pharmaceutical Sciences
3. Guangxi Normal University
4. Guilin 541004
5. P. R. China
6. College of Chemistry and Environmental Engineering
7. Baise University
8. Baise
9. College of Chemistry and Pharmaceutical Engineering
10. Nanyang Normal University
11. Nanyang 473061