Propolis was extracted following the protocol developed by
Boeru and Derevici (1978), with slight modifications. A small
piece of propolis (approximately 50 g) was sliced and squashed
with a mortar and pestle, and the extract was cultured for ten
days in the dark at 45 C with continuous shaking (100 rpm) in
a flask containing ethyl alcohol (95%) at a ratio of 1:5. It was
then filtered through Whatman paper, and the crude extract of
propolis (66.6% concentration) was dried at 60 C. Following
the same technique, aqueous propolis extract was obtained
(36.9 mg/ml) using distilled water in a separate flask; it was
stored at 4 C for further studies.