1. College of ChemistryBejjing Normal University Xinjiekouwai Street 19 Beijing China
2. State Key laboratory of bioactive substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical College Xiannongtan Street 1 Beijing China
3. National Institute for Food and Drug ControlInstitute of Chemical Drug Control TianTan XiLi 2 Beijing 100050 China