Porophyllum sp. pl. (Asteraceae): chemical compounds obtained by hydrodistillation and supercritical CO2 extraction procedures

Species of Porophyllum are characterized by the presence of essential oils, with reports of the occurrence of thiophenes. Essential oils have most often been obtained by hydrodistillation while thiophenes are isolated from nonpolar extracts and also by supercritical fluid extraction (SFE). In this study, essential oils from P. ruderale, P. lanceolatum, P. angustissimum and P. curticeps were obtained by hydrodistillation. Porophyllum lanceolatum, collected in greater quantity, was subjected to SFE under different pressures (90-250 bar). Except for P. lanceolatum, which showed high levels of aldehydes such as decanal (60.24%) and dodecadienal (12.14%), all species were rich in hydrocarbon monoterpenes. The fraction obtained by SFE at 90 bar, when analyzed by GC/MS, presented monoterpenes, with limonene as the main component (22.58%) while decanal constituted only 3% of the sample. All the fractions obtained by supercritical extraction contained compounds with chromatographic profile of thiophenes. The compounds, distinguished by intense fluorescence, were isolated by planar circular chromatography and subjected to H-1 NMR analyses. The spectra exhibited the characteristic signals of thiophenes. The mass spectra also presented the fragments expected for these compounds. The present data confirm this genus as a producer of potentially active molecules that deserve deeper studies.