PEG-scutellarin prodrugs: synthesis, water solubility and protective effect on cerebral ischemia/reperfusion injury

Fifteen PEG-scutellarin prodrugs were synthesized by modifying carboxyl and phenolic hydroxyl groups of scutellarin with mPEG of different molecular weight (400-3000). The water solubility of prodrugs increased remarkably and reached the maximum value of 783.88 mg/mL (scutellarin, 0.02 mg/mL). The anti-infarct effects of four PEG prodrugs with high water solubility were evaluated by Cerebral Ischemia/Reperfusion in the Middle Cerebral Artery Occlusion (MCAO) model. The results showed that the prodrug 7e could significantly reduce the infarct area from 27.2% to 12.2% (33.3% for the control) and decrease the neurological deficit score from 2.77 to 1.32 (2.85 for the control). The half-life (18.62 min) of the prodrug 7e was significantly longer than that of scutellarin (3.03 min).