Modification of resveratrol via coupling six-armed PCL

Resveratrol which is a natural polyphenol with good biological activity is mainly used in medicine, but it has poor photostability in vitro and short plasma half-life in vivo. Multi-armed poly( ε -caprolactone) (PCL) has attracted great attention because the increased number of terminal group broadens the polymeric flexibility in biomedical application. In the work, six-armed PCL was coupled with resveratrol through the hydrolysable ester bond to solve its disadvantage and realize protection for more resveratrol. The synthesized product was characterized with 1 H NMR, GPC and DSC. The molecular weight of the designed polymer was less than the experimental, and the polymeric distribution of molecular weight was narrow. In addition, resveratrol changed the physical form of six-armed PCL. The resveratrol coupling with six-armed PCL presented better photostability compared to original resveratrol. The concentration curve of the coupled resveratrol extended to the plain terrain after 80 min of irradiation, while the original resveratrol continued to decline. They were 72.10% and 52.35% at 2 h, respectively. Moreover, six-armed PCL could effectively protect resveratrol in vivo, and buy time for reaching the target site. The in vitro released amount of the original resveratrol was 52.89% within 3 h, while the coupled resveratrol was only 6.28%. Then this study provides a promising strategy for efficient usage of resveratrol.