The ability of supercritical CO2 carrot and pumpkin extracts to counteract inflammation and oxidative stress in RAW 264.7 macrophages stimulated with LPS or MDA-MB-231 cell-conditioned media†

Supercritical fluid extraction with CO₂ (SFE) is an alternative technology to conventional solvent extraction (CSE), to obtain food-grade bioactives from plants. Here, SFE and CSE extracts from carrot and pumpkin matrices, impregnated with hempseed or flaxseed oil as co-solvents, were characterized by HPLC and GC-MS, and their ability to counteract the inflammatory and oxidative phenomena underlying the onset of several pathologies was assessed in vitro. All extracts showed dose-dependent anti-inflammatory potential and demonstrated an ability to interfere with the pro-inflammatory effects of breast cancer cell-conditioned media, and to inhibit reactive oxygen species (ROS) accumulation and nitrite production (NP) in lipopolysaccharide-stimulated macrophages. Nuclear factor-erythroid-2-related factor 2 (Nrf2) is involved in these response mechanisms, as highlighted by the increased mRNA levels of its target genes revealed by quantitative real-time PCR analyses. NP and ROS concentrations negatively correlated with α-tocopherol and most carotenoids, but positively with the total tocopherol/total carotenoid ratio, suggesting an idiosyncratic effect of these bioactives on cell responses and emphasizing the need to focus on extract constituents’ interactions.