Propolis produced in Bulgaria and Mongolia: phenolic compounds and plant origin

Phenolic composition of Bulgarian and Mongolian propolis and their possible plant sources (the resinous secretions of different tree buds) were investigated by gas chromatography-mass spectrometry (GC/MS). The results obtained demonstrate that in both countries propolis is collected mainly from poplars: from Populus nigra and to some extent from P italica in Bulgaria, and from P suaveolens in Mongolia