Cytotoxic effect of Cuban propolis extracts against tumor cells lines

Propolis is a resin formed by a complex mixture of chemical substances that bees collect from plants. Since ancient times, propolis has been used in folk medicine due to its biological properties that include antimicrobial, antioxidant, anti-inflammatory, and antitumoral activities. The aim of this study was to compare the in-vitro cytotoxic activities of 16 Cuban propolis extracts of different chemical types: brown (1, 4, 5, 16, and 17 BCP), red (9, 29, 35, 37, 45 and 72 RCP) and yellow (18, 39, 41, 50 and 60 YCP) against murine breast carcinoma F3II, human breast adenocarcinoma MDAMB-231, human lung adenocarcinoma A549, and human fibroblast MRC-5. These cells were incubated with different concentrations of propolis and 72 hours after, the IC50 was calculated for each cell. The results showed the antiproliferative effect of Cuban propolis against all cell lines tested. RCP was the most interesting group because they did not affect normal cells. RCP-45 extract showed the highest selectivity index (SI>2) toward A549 compared with MRC-5.In addition, this extract induced necrosis and caused an increase in mRNA levels of Xiap in A549 cell after 8 h of treatment. These results could be related tothe classification of Cuban propolis, which is highly dependent onchemical composition. Our results indicate that Cuban propolis represents an interesting natural source for anticancer treatment.