Application of nanoLC-ESI-TOF-MS for the metabolomic analysis of phenolic compounds from extra-virgin olive oil in treated colon-cancer cells.

Crude phenolic extracts (PE) have been obtained from naturally bearing Spanish extra-virgin olive oil (EVOO) showing different polyphenol families such as secoiridoids, phenolic alcohols, lignans, and flavones. EVOO-derived complex phenols (especially from the Arbequina variety olive) have been shown to suppress cell growth of SW480 and HT29 human colon adenocarcinoma cell lines. Inhibition of proliferation by EVOO-PE Arbequina variety extract was accompanied by apoptosis in both colon-cancer-cell lines and a limited G₂M cell-cycle arrest in the case of SW480 cells. The metabolized compounds from EVOO-PE in culture medium and cytoplasm of both cell lines were analyzed using nano-liquid chromatography (nanoLC) coupled with electrospray ionization-time-of-flight-mass spectrometry (ESI-TOF-MS). The results showed many phenolic compounds and their metabolites both in the culture medium as well as in the cytoplasm. The main compounds identified from EVOO-PE were hydroxylated luteolin and decarboxymethyl oleuropein aglycone.