Essential Oils from Côa Valley Lamiaceae Species: Cytotoxicity and Antiproliferative Effect on Glioblastoma Cells.

(Mill.) Cav., L. and (L.) L. subsp. are representative species of the Côa Valley's flora, a Portuguese UNESCO World Heritage Site. and are traditionally used to preserve olives and to aromatize bonfires on Saint John's Eve, while is mainly used as a spice for river fish dishes. Despite their traditional uses, these aromatic plants are still undervalued, and literature regarding their bioactivity, especially anticancer, is scarce. In this work, the morphology of secretory structures was assessed by scanning electron microscopy (SEM), and the composition of essential oils (EOs) was characterized by gas chromatography-mass spectrometry (GC-MS). The study proceeded with cytotoxic evaluation of EOs in tumor and non-tumor cells with the cell death mechanism explored in glioblastoma (GB) cells. EO presented the most pronounced cytotoxic/antiproliferative activity against tumor cells, with moderate cytotoxicity against non-tumor cells. Whereas, EO exhibited a slightly lower cytotoxic effect against tumor cells and did not affect the viability of non-tumor cells. Meanwhile, EO did not induce a strong cytotoxic effect against GB cells. and EOs lead to cell death by inducing apoptosis in a dose-dependent manner. The present study suggests that and EOs have a strong cytotoxic and antiproliferative potential to be further studied as efficient antitumor agents.