ESI(−) is a soft ionisation technique and mass spectra mainly detected components as their intact deprotonated molecules. ESI(−)–MS provides therefore fingerprinting characterisation of propolis extracts via characteristic

profiles of their chemical composition in terms of the most polar and acidic or basic http://www.selleckchem.com/products/Erlotinib-Hydrochloride.html components (Sawaya et al., 2004 and Sawaya et al., 2007). Fig. 1 shows the ESI(−)–MS fingerprints of ODEP fractions and indicates great differences in the chemical composition between the fractions. OLSx1 and OLSx2 were complex fractions with several high to medium abundant ions, such as m/z 387, 311, 341 and 275 (OLSx1). For OLSx2, the highest abundant ions were those of m/z 315, 339, with medium abundant ions of m/z 265, 325, 293 and 377. Fractions OLSx 3–6 were simpler and showed mostly a single major ion. OLSx3 showed mostly the ions of m/z 247, 231, 301 and 393 whereas OLSx4 showed those of m/z 301, 245, 393 and 287 as most abundant. Fractions OLSx5 and OLSx6 showed check details a major common ion of m/z 299 and other less abundant ions of m/z 329 and 387 (OLSx5) and m/z 249, 285, 311 and 387 (OLSx6). To characterise the fractions constituents, LC–MS and LC–MS/MS were performed. Via comparisons with the fragmentation pattern of previously identified compounds

(Marcucci, Sawaya, Custodio, Paulino, & Eberlin, 2008), several components have been identified: 3,4-dihydroxi-5-prenyl-cinnamic acid (m/z 247, OLSx3); dihydrokaempferide (m/z 301, OLSx3 and OLSx4); 3-prenyl-4-hydroxicinnamic acid (m/z 231, OLSx3); (E)-3–4-hydroxy-3-[(E)-4-(2,3-dihydrocinnamoyl oxy)-3-methyl-2-butenyl]-5-prenylphenyl-2-propenoic

GBA3 acid (m/z 447, OLSx2). Isosakuranetin (m/z 285, OLSx4 and OLSx6) was identified by comparison of its MS/MS fragmentation with a standard kindly provided by Vassya S. Bankova, (Bulgarian Academy of Science). We have identified some of those compounds previously in the oil extracts of propolis ( Buriol et al., 2009). In addition, LC–MS identified two compounds with the same m/z 299 but different retention time. Compound in OLSx2 with [M–H]− of m/z 299 and tR 24 min showed in its ESI(−)–MS/MS a fragmentation to the ion of m/z 255 via initial loss of 45 Da and of m/z 244, 200 and 145. It was identified as 3,5-diprenyl-4-hydroxicinnamic acid also known by artepellin C. ESI(−)–MS/MS of the other compound with [M–H]− of m/z 299 but tR 14 min in OLSx5 and OLSx6 underwent fragmentation to the ion of m/z 284 via initial loss of a methyl radical and was identified as kaempferide. Other fragment ions of m/z 164, 151, and 107 are typical of the cleavage of the flavonoids central C-ring ( Cuyckens & Claeys, 2004) ( Table 1).