Oligo-polyethene glycol (PEG)-modified 14-deoxy-11,12-didehydroandrographolide derivatives: synthesis, solubility and anti-bacterial activity

Abstract A class of 14-deoxy-11,12-didehydroandrographolide ( DA ) derivatives with oligo-polyethylene glycol (PEG) substituents has been synthesized. It is found that small degree of polymerization of PEG favors the synthesis of dual-PEGylated DA derivatives, whereas large degree of polymerization is good for the preparation of mono-PEGylated DA derivatives. As compared to the prototype compound DA , the PEGylated DA derivatives show enhanced water solubility which is beneficial to drug's bioavailability. Preliminary study finds that the PEGylated DA derivatives exhibit better anti-bacterial activity than that of DA .