Background: Virgin olive oil, the main source of lipids in a mediterranean diet, is broadly
recognised to possess health-beneficial features, namely a protective role against cancer. It comprises
several phenolic compounds, the major ones being tyrosol (p-hydroxyphenylethanol), hydroxytyrosol
(3,4-dihydroxyphenylethanol), lignans and secoiridoids, namely oleuropein (OP) and the oleuropein
aglycones 3,4-(dihydroxyphenyl) ethanol elenolic acid ester and 3,4-(dihydroxyphenyl)ethanol
elenolic acid di-aldehyde.
Objective: The goal of this work is the in vitro evaluation of the anti-proliferative activity against
human amelanotic melanoma (C32 cell line) for hydroxytyrosol and the most important secoiridoids of
olive oil. The effect of hydroxytyrosol on non-neoplastic cells (BJ fibroblass) was also investigated.
Methods: Inhibition of cell proliferation was assessed by the Sulforhodamine colorimetric method, in
both neoplastic and non-tumorigenic cells.
Results: 3,4-(Dihydroxyphenyl)ethanol elenolic acid di-aldehyde and 3,4-(dihydroxyphenyl)ethanol
elenolic acid ester secoiridoid aglycones were found to display growth-inhibiting activity (at ca.
µM), as opposed to oleuropein that elicited a strong protective effect at all concentrations (100 to
1000 μM). 3,4-Dihydroxyphenylethanol evidenced a dual effect (strongly dose-dependent) -
cytoprotective for lower dosages and cytotoxic at high concentrations.
Conclusion: Attending to the recognised structural dependence of the biological activity of phenolic
derivatives, the previously gathered conformational data on the olive oil constituents presently
investigated assisted the interpretation of their biological properties. This type of studies, coupling
structural characterisation to biological assessment, allows the establishment of reliable structure
activity relationships for polyphenolic compounds, ruling their cytoprotective vs cytotoxic activity
and therefore their potential use as natural-based pharmacological agents.