Oleuropein-Enriched Olive Leaf Extract Affects Calcium Dynamics and Impairs Viability of Malignant Mesothelioma Cells

Figure 1

Time course of level in mesothelioma REN cells loaded with fura-2 and alternatively exposed to the oleuropein-enriched fraction from olive leaf extract (a, b), to standard oleuropein (c, d) or to standard hydroxytyrosol (e, f). The oleuropein fraction and standard oleuropein have been used at nominal concentrations of oleuropein, expressed in μmoles/L. (a) Induction of spikes in REN cells loaded with fura-2 by transient exposure to the oleuropein fraction (ole) at 10 and 30 μM oleuropein. (b) Quantification of dose-dependent induction of spikes by the oleuropein fraction. Data are means ± s.e.m. () of Δ (difference between peak value and basal level of ). (c) Induction of spikes in REN cells by transient exposure to standard oleuropein (ole) at 10 and 100 μM. The inhibitory effect of the T-type Ca²⁺ channel blocker NNC-55-0396 (5 μM) and recovery after washout are shown. (d) Quantification of dose-dependent induction of spikes by standard oleuropein (EC₅₀ = 53 μM), and inhibition by Ca²⁺-free medium (0 Ca) or NNC-55-0396 measured at 100 μM oleuropein. Data as above; , test. (e) Induction of spikes by standard hydroxytyrosol (HT) at 10 and 100 μM, inhibitory effect of NNC-55-0396, and recovery after washout. (f) Quantification of dose-dependent effect of hydroxytyrosol (EC₅₀ = 12 μM) and inhibition by Ca²⁺-free medium (0 Ca) or NNC-55-0396 measured at 10 and 100 μM hydroxytyrosol. Data and statistics as above. (g, h) Induction of spikes by EGCG and statistics of dose-dependent effect (EC₅₀ = 69 μM). Data as above.

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