Protective role of Egyptian propolis against tumor in mice.

BACKGROUND: Propolis has numerous biologic activities including antibiotic, antifungal, antiviral and anti-inflammatory properties. The present work is aimed to study the effect of crude Egyptian propolis on tumor in mice induced by Ehrlich ascitis carcinoma (EAC) cell line. RESULTS: The administration of propolis (160 mg/kg body weight), by gastric intubation 2 h before the intraperitoneal injection of EAC, effectively inhibited tumor growth and the proliferation of EAC. The tumor volume was markedly reduced from 7+/-0.9 ml in EAC-infected mice to 1.6+/-0.95 ml in propolis-treated mice. Also, the lipid peroxide level which was 13.3+/-1.24 nmol malodialdehyde (MDA)/mg protein in EAC infected mice was significantly decreased to 3.3+/-2.1 nmol MDA/mg protein. Reduced glutathione (GSH) and glutathione S-transferase (GST) concentrations were markedly increased in propolis-treated mice. This effect was associated with inhibition of cell cycle progression and induction of apoptosis. Administration of propolis 2 h before injection of EAC arrested cells in G0/G1 phase and resulted in a decrease in the viability, DNA, total RNA and protein level of tumor cells. CONCLUSIONS: Crude Egyptian propolis has a strong inhibitory activity against tumors. The anti-tumor mechanism may be mediated by preventing oxidative damage and induction of apoptosis.