In recent years, nutraceuticals have gained great popularity, owing to their physiological and potential health effects, such as anti-inflammatory, anti-cancer, antioxidant, and prebiotic effects, and their regulation of lipid metabolism. Since the Mediterranean diet is a nutritionally recommended dietary pattern including high-level consumption of nutraceuticals, this review aimed to summarize the main results obtained by our in vitro and in vivo studies on the effects of the major constituents of the Mediterranean diet (i.e., extra virgin olive oil compounds, polyunsaturated fatty acids, and fruit components). Based on experimental studies, the therapeutic purpose of nutraceuticals depends on their bioavailability, solubility, toxicity, and delivery system. This review provides more in-depth knowledge on the effects linked to nutraceuticals administration on human health, focusing the gastrointestinal tract and suggesting specific dietary components for personalized adjuvant therapies.

Background: Consumption of flavonoid-rich orange juice has been shown to reduce adiposity and liver steatosis in murine models of diet-induced obesity. However, little is known about the effects of whole orange intake, independent of body weight changes, on liver function and steatosis in individuals with metabolic dysfunction-associated steatotic liver disease (MASLD). The goal is to understand the direct impact of orange consumption on metabolic health. Methods: Sixty-two men and women aged 30–65 with MASLD (Controlled Attenuation Parameter, (CAP) > 275 dB/m) were randomly assigned to consume either 400 g of whole oranges or non-citrus fruits daily for 4 weeks. Baseline evaluations included medical assessments, blood tests, and body composition. Liver health was assessed using transient elastography (FibroScan^®) for steatosis and fibrosis, conducted by blinded personnel. This clinical trial was registered at ClinicalTrials.gov (NCT05558592). Results: After 4 weeks of orange supplementation, liver steatosis decreased in the treatment group, with 70.9% showing steatosis compared to 100% in controls (p < 0.004), indicating a 30% reduction in liver disease prevalence. There were no significant changes in fibrosis or plasma liver enzymes, though plasma gamma glutaril transferase (GGT) levels decreased significantly. Body weight, waist circumference, body composition, lipid profile, fasting glucose, insulin, and C-reactive protein levels remained unchanged. Dietary analysis revealed no change in caloric intake, but vitamins C, A, thiamine, and riboflavin increased in the orange group. Conclusions: Our findings suggest that phytochemical-rich foods, especially whole fruits like oranges, may enhance liver function as an adjunct treatment for MASLD. The notable reduction in liver steatosis prevalence occurred independently of body weight changes. Further studies are needed to investigate the long-term effects of orange supplementation on steatosis and fibrosis progression and to identify the specific bioactive compounds and mechanisms involved.

Grapes represent a significant source of phenolic compounds known for their health-promoting properties, such as antioxidant capacity on normal cells and prooxidant activity on tumor cells. The genotype highly affects the polyphenolic composition in grapes and, consequently, the nutritional quality of berries. This work aimed to characterize the phenolic composition, the antioxidant, and anticancer activity of grape skin extracts (GSEs) of nine new table grape genotypes selected from a breeding program to obtain new cultivars of seedless table grapes, well adapted to the climatic change and with higher nutraceutical properties. The grape polyphenolic profile was characterized by Ultra-High-Performance Liquid Chromatography/Quadrupole-Time of Flight mass spectrometry analysis. GSE antioxidant activity was determined by the ABTS, DPPH, and ORAC assays; GSE cell growth inhibition test was carried out in the Caco2 human cancer cell line. The nine GSEs showed different flavonoid and non-flavonoid profiles, and all possessed antioxidant activity, with the ‘Aika N.’, ‘Turese N.’, and ‘Egnatia N.’ the most active. As anticancer activity against the tested cancer cell line, ‘Daunia N.’ and ‘Apenestae N.’ showed the EC50 after 24 h of 35.60 µg/mL and 150.91 µg/mL, respectively. The relationship between polyphenolic profile and the antioxidant and anticancer activity of GSE was also investigated. Interestingly, among the different classes of polyphenolics, flavan-3-ols e proanthocyanidins showed the highest positive correlation with the anticancer activity of extracts. These findings can be helpful for the preparation of new extracts for the pharmaceutical and nutraceutical industry and geneticists working in vine breeding programs.

The polyphenolic compounds present in grape extracts have chemopreventive and anticancer properties. Here, we studied the ability of two grape skin extracts (GSEs), Autumn Royal and Egnatia, to influence the cell motility and membrane fluidity regulated by the enzyme Stearoyl-CoA desaturase-1 (SCD1) which increases with the cancer aggressiveness. Caco2 and SW480 human colon cancer cell lines were treated with increasing concentrations of GSEs to evaluate cell proliferation and motility. SCD1 levels were evaluated in both treated cell lines, by membrane lipidomic analysis conducted by gas chromatography. The expression levels of SCD1 and other factors involved in the reorganization of the cytoskeleton and focal adhesions were assessed by Real-time PCR, Western Blotting, and Immunofluorescence staining. High-performance liquid chromatography (HPLC) analyses were performed to determine the phenolic composition in the GSEs, finding them more expressed in Autumn Royal than in Egnatia. Both treatments reduced the levels of SCD1, phospho-Rac1/Cdc42/Rac1/Cdc42 ratio, Cofilin, Vimentin, and phospho-Paxillin especially in Caco2 compared to SW480, showing a different behavior of the two cell lines to these natural compounds. Our findings show that GSEs block the cell migration and membrane fluidity through a new mechanism of action involving structural cellular components.