Introduction

Venenum Bufonis (VB), also called ChanSu or toad venom, is an important Traditional Chinese Medicine derived from the parotid gland secretion of giant toads (Bufo bufo gargarizans or Bufo melanostictus).(1−3) It is applied in various preparations, such as Liu-Shen-Wan, She-Xiang-Bao-Xin pill, and ChanSu injection, for the treatment of heart failure, pains, and various cancers in clinics.(4,5) The total bufadienolides are known to be the major active constituents of VB in these preparations and more than 50 bufadienolides have been isolated.(6) However, the high toxicity, low bioavailability, and poor water solubility of total bufadienolides limit the clinic applications.(7,8) Glycosylation is a universal approach to increase the water solubility, which would also improve their pharmacodynamic and pharmacokinetic properties.(9−11) Therefore, it is of great significance to develop an efficient strategy for the glycosylation of total bufadienolides in VB, which would possibly alleviate its toxicity and facilitate the clinical application.