Seseli bocconei Guss. and S. tortuosum subsp. maritimum Guss. essential oils inhibit colon cancer cell viability

In this study, the chemical compositions of two essential oils (EOs) obtained from different parts (flowers, leaves, stems, and roots) of Seseli bocconei Guss. and of Seseli tortuosum subsp. maritimum Guss., wild endemic species of Sicily, were investigated. The main classes of metabolites for the essential oils of S. bocconei were, respectively, monoterpenes hydrocarbons for flowers, sesquiterpenes hydrocarbons for leaves, and a breakdown between the two previously mentioned classes for stems. In the case of S. tortuosum subsp. maritimum, on the other hand, the main metabolite class for all the vegetative parts analyzed (flowers, stems, and roots) was monoterpene hydrocarbons, with a slight percentage in other non-terpenoid compounds. Furthermore, the EOs' antitumor effects against HCT116, human colon cancer cells were evaluated. Cell viability assays evidenced that stems' EOs of both plants exhibit strong cytotoxic effects at low concentrations, while the EOs from other vegetative parts do not show a relevant effect. In fact, EO of stems of S. tortuosum subsp. maritimum reduced the cell viability of 82% at the concentration of 125 mu g/mL, while at the concentration of 250 mu g/mL of stems EO of S. bocconei the 97% of cells resulted dead. The analysis of the effects exerted by the main phytocostituents (S-(-)-limonene, R(+)-limonene, sabinene, (1S)-(- )-alpha-pinene, (1R)-(+)-alpha-pinene, and (-)-fl-pinene, and germacrene D) of these EOs on colon cancer cells revealed germacrene D as a new promising molecule with anticancer properties that deserve to be explored in future directions.