Propolis, a natural resinous substance collected by honeybees from buds and exudates of plants, is known for its use in the beehive as a protective barrier against intruders. It is widely used as a popular remedy in folk medicine and as a constituent of bio-cosmetics. Recently, it is extensively used in food and beverages to improve health and prevent diseases. Depending on the season, bee species, vegetation and the area of collection, the chemical composition of propolis are qualitatively and quantitatively variable, resulting in diverse biological properties. In this project, the antimicrobial activity of several propolis samples obtained from various parts of the world (Europe, Australia, USA and the Philippines) was determined. The propolis samples were extracted with ethanol and the extracts were assayed with Gram-positive and Gram-negative microorganisms. Results demonstrate that propolis is effective against a range of opportunistic pathogens, with the samples from Russia and Washington showing the most potent antibacterial activity, inhibiting seven microorganisms each. The propolis from the Philippines (Bicol and Laguna) also exhibited notable antimicrobial effects, although to a slightly lesser extent.
