1. a School of Pharmacy Guangdong Pharmaceutical University Guangzhou 510006 P. R. China
2. b State Administration of Traditional Chinese Medicine Key Laboratory for Production and Development of Lingnan Medicinal Material School of Chinese Medicine Guangdong Pharmaceutical University Guangzhou 510006 P. R. China
3. School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 P. R. China
4. d Guangdong Provincial Cosmetics Engineering and Technology Research Center School of Chemistry and Chemical Engineering Guangdong Pharmaceutical University Zhongshan 528458 P. R. China