Propolis samples were collected as fresh from Dinaran area (Iran) and kept at -20°C. Ethanolic extract of propolis
(EEP) was prepared according to Kalogeropoulos and Konteles method (12). Briefly, the collected propolis samples were frozen for 24 h. Then, they were grounded by moulinex vivacio grinder, and 50 g of the obtained powder was dissolved in 500 cc ethanol solution (V/V) in a dark glass container and incubated at 37°C for 14 days