Cytotoxic Effect of Turkish Propolis on Liver, Colon, Breast, Cervix and Prostate Cancer Cell Lines

Purpose: To investigate the total polyphenolic and flavonoid contents, antioxidant power and cytotoxic activity of ethanol extracts of Turkish propolis (EEP). Methods: The total polyphenolic and flavonoid contents of EEP were determined by spectrometric methods. Antioxidant power and cytotoxic activity of EEP were evaluated using ferric reducing antioxidant power (FRAP) and MTT assays, respectively. Results: The total polyphenolic and flavonoid contents, and FRAP value of EEP were 124.6 +/- 1.5 mg gallic acid/g sample dry weight, 42.0 +/- 0.8 mg quercetin/g sample dry weight and 311.0 +/- 2.5 mg trolox/g sample dry weight, respectively. EEP exhibited powerful cytotoxic effects against the five human cancer cell lines. The highest cytotoxic activity of Turkish EEP was demonstrated on PC-3 cell line (IC50 = 20.7 +/- 3.4 mu g/mL). Conclusion: The results demonstrate that EEP is a good source of antioxidant and a natural antitumor agent capable of reducing cancer cell proliferation.