Background: Propolis is a complex resinous sticky substance that honeybees collect from buds and exudates of various plants. Owing to its versatile biological and pharmacological activities, propolis is widely used in medicines, cosmetics and foods. The aim of this study was to evaluate the cytotoxic and antioxidative effects of various ethanolic extracts of propolis (EEPs) on human colon cancer cell line HCT-116 and compare them with their composition determined by HPLC-DAD.
Results: The most abundant flavonoids in all samples were chrysin, pinocembrin and galangin (12.697-40.811 µg mg⁻¹), while the main phenolic acids were caffeic acid, ferulic acid and isoferulic acid. Dose- and time-dependent inhibition of growth of HCT-116 cells was observed for all propolis samples, with IC₅₀ values ranging from 26.33 to 143.09 µg mL⁻¹. Differences in cytotoxic activity of propolis samples were associated with differences in their composition. All EEP samples reduced both superoxide anion radical and nitrite levels and also had strong DPPH-scavenging activity.
Conclusion: All tested propolis samples had pronounced cytotoxic and antioxidative activities.
Keywords: HCT-116 cell line; antioxidants; cytotoxicity; polyphenols; propolis.
© 2013 Society of Chemical Industry.