Characterization and in vitro antitumor activity of polymeric nanoparticles loaded with Uncaria tomentosa extract

Uncaria tomentosa (UT) extracts have been shown to have promising antitumor activity. We hypothesized that its incorporation into nanostructured systems could improve the anticancer properties. Here, poly-e-caprolactone (PCL) and poly-d,l-lactide-co-glycolide (PLGA) were employed to generate nanoparticles loaded with UT extract in a single emulsion solvent evaporation method. The nanoparticles were characterized by particle size, zeta potential, morphology and entrapment efficiency along with stability and release profiles. The nanoparticles presented entrapment efficiencies above 60% and a mean diameter below 300nm. UT-PCL nanoparticles presented higher entrapment efficiency and mean particle size as well as a slow release rate. The UT-PLGA nanoparticles showed higher drug loading. Two prostate cancer cell-lines, LNCaP and DU145 that were derived from metastatic sites, served as model systems to assess cytotoxicity and anti-cancer activity. In vitro, both formulations reduced the viability of DU145 and LNCaP cells. Yet, the UT-PLGA nanoparticles showed higher cytotoxicity towards DU145 cells while the UTPCL against LNCaP cells. The results confirm that the incorporation of UT into nanoparticles could enhance its anti-cancer activities that can offer a viable alternative for the treatment of prostrate canner and highlights the potential of nanostructured systems to provide a promising methodology to enhance the activity of natural extracts.