A Comparative Study of Brassica Sprout Extracts on Intestinal Inflammation and Epithelial Barrier Integrity

The consumption of Brassica spp. vegetables has been associated with antioxidant, anti-inflammatory, and prebiotic effects, mainly attributed to glucosinolates and polyphenols which are abundant in sprouts. Although broccoli sprouts are a recognized source of these bioactive compounds, other Brassicaceae sprouts remain comparatively understudied, particularly in relation to gastrointestinal disorders. In this in vitro study, hydroalcoholic extracts from red cabbage (CR) and pak-choi (PC) sprouts were compared with broccoli (BR) for their phytochemical composition, anti-inflammatory and intestinal barrier-protective activities. Caco-2 cells were stimulated with IL-1β, IFN-γ, and digested gliadin, while a Caco-2/THP-1 co-culture stimulated with LPS and IFN-γ was used to mimic intestinal permeability. CR contained the highest amounts of glucoraphanin (GFN, 22.133 ± 0.212 mg/g of extract) and sulforaphane (SFN, 9.517 ± 0.661 mg/g of extract), whereas BR showed the lowest levels. Polyphenol contents were comparable among the three extracts (3.5-4.5%). At 50 µg/mL, CR and PC extracts inhibited MCP-1 release (-37% and -48%, respectively), followed by BR (-31%), and this inhibitory effect was maintained after simulated gastrointestinal digestion. None of the extracts impaired the NF-κB-driven transcription, whereas only PC significantly enhanced the activity of Nrf-2. In the co-culture model, CR preserved epithelial barrier integrity measured by TEER and Lucifer Yellow assays (25-100 µg/mL). A PCR array showed that PC and CR (50 µg/mL) modulated genes involved in inflammation and barrier function, with a partial overlap with GFN. At the nominal p-value level, CR reduced CLDN1 and STAT3 transcript levels; however, these changes did not remain significant after FDR correction. These findings identify CR as a promising source of bioactive compounds associated with the preservation of epithelial barrier integrity, possibly through the modulation of selected inflammatory and barrier-related pathways. The lack of a direct relationship between glucosinolate abundance and biological activity suggests that the observed effects may depend on the overall phytochemical complexity of the extracts, including both sulfur-containing compounds and polyphenols.