Assessment in vitro of cytogenetic and genotoxic effects of propolis on human lymphocytes

► Propolis is used in folk medicine, to exhibit a broad spectrum of biological activities. ► A good tool to evaluate this product is the study of cytogenetic and genotoxic effects. ► Human peripheral lymphocytes has useful to detect exposures to genotoxic compounds. We evaluated the genetic damage by ethanolic extract of propolis (EEP) induced to human lymphocytes which were exposed to increasing concentrations (0–2000μgml−1). The results indicated that EEP reduced significantly the mitotic index (MI) and proliferation index (PI) when high concentrations of EEP were used. Sister chromatid exchange (SCE) rates indicated that EEP could have genotoxic effects at high concentrations. Exposure of the cells to the amount of ethanol used as solvent did not alter either the MI and cell proliferation kinetics (CPK), or the rate of SCE. The results showed: (a) statistical increase in the percentage the cells with CAs and in the frequency of SCE at the highest concentrations, (b) a decrease in MI and in the CPK values was observed, (c) no effect was noticed in negative controls. In conclusion, it can be assumed that high concentrations of EEP have a cyto and genotoxic effect, in vitro, for human peripheral lymphocytes.