Osteogenic Activity and Bone Matrix Mineralization Induced by <scp> <i>Vitis vinifera</i> </scp> Leaves Extract in Human Osteoblastic Cells

The agricultural production of <i>Vitis vinifera</i> leaves represents the majority of agricultural remains among the least studied and valorized in the wine industry. <i>Vitis vinifera</i> contains a variety of bioactive compounds, for example, polyphenols with positive effects on human health. Grape polyphenols can modulate the expression of specific bone matrix proteins, promoting osteoblast differentiation and bone mineralization. In this study, we investigated the effect of <i>Vitis vinifera</i> leaves extracts (VVLE) on bone matrix formation in the human fetal osteoblast cell line (hFOB 1.19). Specifically, we assessed: (i) <i>cytotoxicity</i> of VVLE using the MTT assay; (ii) mineralization quantification by staining calcium deposits with Alizarin Red S (ARS) and the enzyme activity by using the alkaline phosphatase (ALP) assay; and (iii) the osteogenic expression levels of specific markers in the processes of bone mineralization (BMP-2, ERK, ALP, β-GLAP, SPP1, and BSP) by quantitative real-time PCR (qRT-PCR) and Western blot. The results showed that the addition of VVLE in the medium stimulated the calcium deposits and the expression of genes involved in bone formation through the induction of <i>ERK</i>-mediated <i>BMP2</i> expression. These data suggest that <i>VVLE</i> may positively influence physiological responses underlying bone tissue regeneration.