Antibacterial activity and phytochemical evidence for the plant origin of Turkish propolis from different regions

Honeybees collect propolis from practically any abundant plant source in the neighborhood of the hive, be it populus, eucalyptus, pine, sugarcane, cashew nut or orange trees. We have described that the origin plants of Turkish propolis are Populus sp., Eucalyptus sp. and Castanea sativa. In our previous study, propolis samples from Middle Anatolia displayed the typical pattern of "poplar" propolis: they contained pinobanksin, caffeic and ferulic acids and their esters. The propolis samples examined in this study were shown not to contain polar phenolics. The main components of Eucalyptus propolis were aromatic acids, mainly cinnamic acid and its esters, that are usually found in Eucalyptus species resins. The second distinct sample originated from West Anatolia. Although it contained low amounts of phenolic substances and aromatic acids, its main components were sugars and glycosides. The study revealed that there was no significant difference between propolis samples in antibacterial activity, however the yeasts were shown to be more sensitive to eucalyptus-propolis. Gram negative bacteria were susceptible to none of the samples tested.