Southern Brazilian autumnal propolis shows anti-angiogenic activity: an in vitro and in vivo study.

The present study focuses on the effects of a hydro-alcoholic propolis extract collected in autumn (2010) in Santa Catarina State (Southern Brazil), on the angiogenesis, using in vitro and in vivo models. Cultures of human umbilical vein endothelial cells were used to assess the effects of propolis on viability, proliferation, and cell migration, as well as capillary tube formation. The propolis autumnal extracts significantly decreased the cell viability, based on CC50 values, which decreased (56%) from 297 to 130 μg/ml in 24 h and 72 h of treatment, respectively (cytotoxicity assay). The process of cell proliferation was decreased by 81.7 to 48.4% due to exposure (72 h) to 130-180 μg/ml of propolis extract, as compared with control (vehicle). In these same concentrations, the cell migration was also reduced by 39.6 to 12.6%, respectively (versus control). Furthermore, autumnal propolis extract (100-200 μg/ml) inhibited the tube-like structure formation (tubulogenesis) of endothelial cells on Matrigel™ (16.2-69.9% inhibition). The treatments performed in vivo with administration of 450 mg propolis.kg(-1) inhibited both angiogenesis and vasculogenesis by 82.3 and 66.5% in the chorioallantoic and yolk-sac membranes of chick embryos. Furthermore, by means of UV-vis-spectrophotometry, reverse phase-high performance liquid chromatography analysis and 1D and 2D-nuclear magnetic resonance experiments reveal higher contents of flavonoids and total phenolic compounds with predominance of the flavonol quercetin and the phenolic acids, e.g., gallic acid, protocatechuic acid and chlorogenic acid in the propolis hydro-alcoholic extract. Our findings related to the anti-proliferative, anti-migration, and anti-tubulogenic actions on human umbilical vein endothelial cell line agree with the inhibitory effects in the in vivo vessel formation exerted by propolis extract under study. The results also suggest that autumnal propolis extract might be potentially instrumental in providing alternative tools for angiogenic disease therapeutics.