Characterization of OMWW A009 Extracts

The OMWW A009 extracts were provided by the “Azienda Agricola-Fattoria La Vialla”, following purification as described below. Four batches from different preparations were characterized for molecular contents [10 (link),15 (link),16 (link)], revealing similar molecules (Supplementary Table S1, Figure 1). The two most recent batches produced, termed L3 and L4 respectively, were used in this study. Hydroxytyrosol (HyT), purity ≥ 98%, was purchased from Sigma Aldrich (Sigma-Aldrich, Saint Luis, MO, USA) and used as a reference oil polyphenol. For treatments, HyT was dissolved in 100% ethanol (EtOH) and diluted to the same concentration present in A009 in RPMI 1640 medium. Medium with EtOH alone at the same dilution was used as control vehicle for HyT. Crystal violet staining solution and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide were purchased from Sigma Aldrich (Milan, Italy).