Ethanolic extract of Tunisian propolis: chemical composition, antioxidant, antimicrobial and antiproliferative properties

Propolis is a byproduct widely used in folk medicine due to its valuable biological and pharmacological properties. In this study, in vitro antioxidant, antimicrobial and antiproliferative capacities of propolis ethanolic extracts (EEPs) collected from four Tunisian regions were evaluated. EEPs showed high total antioxidant and antiradical capacities and were active against all tested microorganisms. These biological capacities were correlated to the amounts of phenolics in the samples. Cytotoxicity of EEPs on human bladder cancer cells RT112 was assessed using both clonogenic and the tetrazolium salt colorimetric (MTT) assays. Clonogenic assay of RT112 cells showed that all EEPs (10 mu g/ml) reduce cell survival, as compared to the control. In addition, MTT assay showed a significant cytotoxic capacity of all samples on RT112 cells with an estimated IC50 ranging between 8 and 11 mu g/ml. Annexin V-FITC staining test was then used to study and quantify the induction of apoptosis. Data showed that propolis induces apoptosis of RT112 cells. These findings show that propolis extracted from different Tunisian regions is an attractive antioxidant/antimicrobial/antiproliferative agent suggesting its potential application in pharmaceutical and nutraceutical products.