44ª Reunião Anual Virtual da SBQ

Hydrocotyle leucocephala Cham. & Schltdl. (Apiaceae), an aquatic macrophyte native from Brazil, popularly known pennyworth, is worldwide spread due its ornamental use.1 In the present work, leaves of H. leucocephala were submitted to extraction by maceration with MeOH, resuspended in a solution of MeOH:H2O (1:9) and subjected to a liquid-liquid extraction with hexane, EtOAc and n-BuOH, respectively. From HPLC-DAD analysis of n-BuOH phase, it was possible to infer the presence of flavonols based on its characteristic major absorption wavelength number in the UV region from 350 to 385 nm and 270 to 290 nm.2 The same chromatographic conditions were applied to HPLC-ESI-IT-MS2 analysis in the positive and negative mode. Due to observed ions at m/z 465, 597, 611 in the positive ionization mode spectra and fragmentation patterns that afforded ions Y1+ and Y0+, it was possible to affirm that all aglycones were attached to a sugar moiety. The cleavage at glycosidic O-linkages occurred with a concomitant H-rearrangement that resulted an elimination of monosaccharides residues, hexose (162 u), deoxyhexose (146 u) and pentose (132 u) resulting in a fragment with high intensity at m/z 303 and 301 in the positive and negative mode, respectively. In the negative ionization mode MS2 spectra, all quercetin derivatives displayed fragment ions at m/z 179, 255 and 271, which is formed by a specific fragmentation of quercetin aglycone which is in accordance with previous studies.2,3 In this way, it was possible to characterize three chemically related derivatives, quercetin-3-O-hexose-pentoside (1), quercetin-3-O-rutinoside (2), quercetin-3-O-hexoside (3). This is the first occurrence of compounds 1 and 2 in Hydrocotyle leucocephala.