Determination of propolis volatile compounds by GC-MS method

Propolis is hard, yellow brown substance collected by Apis millifera bees from plants around the hives. Because of its antioxidant, antibacterial, antiviral and etc. properties, propolis was used in folk medicine as a remedy from the ancient times. In this assay we search for volatile compounds in Lithuanian propolis raw material. Volatile compounds were extracted using solid phase micro extraction (SPME) and identified with gas chromatography – mass spectrometry (GC-MS). Benzyl alcohol, nonanal, benzoic acid, decanal, α-copaene, β-bourbonene, Bicyclo [7.2.0] 11,11-dimethyl-, 4,8-bis(methylene)-undecan-3-ol, γ-muurolene, , α-farnesene and β-farnesene was identified as volatile propolis compounds. Sesquiterpenes α-copaene, γ-muurolene, β-bourbonene, zonarene can be found in other plants essential oils. This shows that propolis chemical composition differs according to plants around the hives. We also identified 2-ethyl-hexanol, which are recognized as irritant substance. Three volatile compounds showed the biggest concentration: benzoic acid 24.56 %, benzyl alcohol 22.37 % and Bicyclo [7.2.0] 11,11-dimethyl-, 4,8-bis(methylene)-undecan-3-ol 13.26 %. Benzoic acid and benzyl alcohol are known as antibacterial substances, so we can relate them to be responsible for Lithuanian propolis antibacterial activity.