Phenolic Compounds in Extra Virgin Olive Oil Stimulate Human Osteoblastic Cell Proliferation

Abstract

In this study, we aimed to clarify the effects of phenolic compounds and extracts from different extra virgin olive oil (EVOO) varieties obtained from fruits of different ripening stages on osteoblast cells (MG-63) proliferation. Cell proliferation was increased by hydroxytyrosol, luteolin, apigenin, p-coumaric, caffeic, and ferulic acids by approximately 11-16%, as compared with controls that were treated with one vehicle alone, while (+)-pinoresinol, oleuropein, sinapic, vanillic acid and derivative (vanillin) did not affect cell proliferation. All phenolic extracts stimulated MG-63 cell growth, and they induced higher cell proliferation rates than individual compounds. The most effective EVOO phenolic extracts were those obtained from the Picual variety, as they significantly increased cell proliferation by 18-22%. Conversely, Arbequina phenolic extracts increased cell proliferation by 9-13%. A decline in osteoblast proliferation was observed in oils obtained from olive fruits collected at the end of the harvest period, as their total phenolic content decreases at this late stage. Further research on the signaling pathways of olive oil phenolic compounds involved in the processes and their metabolism should be carried out to develop new interventions and adjuvant therapies using EVOO for bone health (i.e.osteoporosis) in adulthood and the elderly.

Fig 1. Effect of EVOO phenolic extracts on the growth of MG-63 cells as determined by MTT.

Cells were treated with various concentrations of EVOO phenolic extract or vehicle alone (control) for 24 h. Data are means, with standard error of the mean shown by vertical bars of three separate experiments and at least every experiment was performed in triplicate. Mean values were significantly different as compared with control groups: *p<0.05, **p<0.01.

Fig 2. Bi-plot (A. Scores and B. Loadings) for the PCA model.

Samples are plotted by selected letters and numbers: Picual RI 0.37 (P1); Picual RI 2.75 (P2); Picual RI 4.67 (P3); Hojiblanca RI 0.51 (H1); Hojiblanca RI 1.78 (H2); Hojiblanca RI 4.44; Arbequina RI 0.48 (A1); Arbequina RI 2.92 (A2); Arbequina RI 3.67 (A3); Picudo RI 0.88 (Pi1); Picudo RI 1.74 (Pi2); Picudo RI 3.84 (Pi3). The capital letters A, B and C correspond with 0.001, 0.0001 and 0.0001% extract concentration in osteoblast culture medium.