Molecular mechanisms underlie the biological activities of phytochemicals: searching the gap

The health benefit of plant-derived foods is established and new researches are identifying active plant derived molecules among the thousands phytochemicals. Throughout life, the exposure to specific phytochemicals can affect gene expression via reversible epigenetic mechanisms. This has recently launched re-exploration of nutritional, botanical or phytopharmaceutical compounds for their epigenetic effects in order to identify promising nutraceuticals or cosmeceuticals [1]. Polyphenols from grape seed extracts (GSE) possess a broad spectrum of chemo-protective properties, and lycopene, found in tomatoes and other vegetables, have been proposed to modulate hormonal and immune systems, metabolic pathways, and gap junction intercellular communication (GJIC). In animal cells, GJIC has been implicated in the cell growth control via adaptive responses: differentiation, proliferation and apoptosis. GJIC is deficient in many human tumors and its restoration or upregulation is associated with decreased cell proliferation. In the carcinogenesis process, the reversible inhibition of GJIC has been hypothesized to be involved in the tumor promotion phase. Some innovative, safe and environmentally friendly processes such as supercritical carbon dioxide (S-CO2) extraction are developing for the antioxidant production from plant matrices. GSE and new S-CO2-extracted oleoresins obtained from tomato and tomato added with grape seeds were analyzed for antioxidant activities and biological properties on human keratinocytes [2] and human breast cancer cell (MCF-7) cultures. Plant extracts showed the ability to enhance the GJIC and connexin 43 expression in human cell cultures, and were able to completely overcome the GJIC inhibition induced by the tumor promoter HgCl2. The knowledge of molecular mechanisms underlies the phytochemical effects and the availability of environmentally friendly methods to produce plant-derived molecules with potentially healthy properties, from natural sources (e.g., tomato and waste winery by-products), could lay new bases for preventive nutrition. [1] vel Szic KS., Ndlovu MN., Haegeman G., Berghe WV. (2010) Nature or nurture: Let food be your epigenetic medicine in chronic inflammatory disorders. Biochemical Pharmacology, 80: 1816-183. [2] Leone A., Zefferino R., Longo C., Leo L., Zacheo G. (2010) Supercritical CO2-extracted tomato oleoresins enhance gap junction intercellular communications and recover from mercury chloride inhibition in keratinocytes. Journal of Agricultural Food Chemistry, 58: 4769-4778.