Antitumor, Antioxidant, and Hepatoprotective Effects of Grape Seed Oil Nanoemulsion as a Dietary Phytochemical Intervention in Ehrlich Solid Tumors

<b>Background/Objectives:</b> Grape seed oil (GSO) is a potent source of dietary phytochemicals, particularly polyphenols and flavonoids, known for their health-promoting properties. This study aims to investigate the anticancer and hepatoprotective effects of a nanoemulsion formulation of grape seed oil (GSONE), to enhance the efficacy and bioavailability of its phytochemical constituents against solid tumors. <b>Methods:</b> Ninety female Swiss albino mice were divided into six groups: control, alone, GSONE alone, Ehrlich solid tumor (EST), EST treated with GSO, and EST treated with GSONE. Tumor development, growth performance, serum biochemistry, antioxidant status, hepatic histopathology, apoptotic gene expression, and flow cytometry analyses were assessed following 30 days of daily oral treatment. <b>Results:</b> GSONE significantly reduced tumor weight and volume (52.9%) and more effectively counteracted tumor-induced body weight loss than crude GSO. Treatment with GSONE normalized serum protein levels and improved liver function markers (AST, ALT, ALP, total bilirubin) to near-control values. Tumor markers (AFP, CEA) and oxidative stress indices (MDA, 8-OHdG) were markedly decreased, while activities of hepatic antioxidants (SOD, CAT, GPx, GSH) were restored. GSONE enhanced gene expression of pro-apoptotic markers (Bax, TP53, caspase-3, caspase-9), suppressed anti-apoptotic Bcl-2, and significantly increased the proportion of p53- and cleaved caspase-3-positive tumor cells. Liver histopathology and ultrastructure demonstrated normalized morphology and reduced damage in GSONE-treated mice. Multivariate analyses confirmed GSONE's restorative effect compared to raw GSO. <b>Conclusions:</b> The delivery of dietary phytochemicals via nanoemulsion significantly enhances antitumor and hepatoprotective actions in a preclinical solid tumor model. These findings support the potential of phytochemical-rich edible oils, enhanced by nanotechnology, for dietary prevention and adjunctive management of cancer.