Inflammation related responses of intestinal cells to plum and cabbage digesta with differential carotenoid and polyphenol profiles following simulated gastrointestinal digestion

Scope: Plums/cabbages represent fruits/vegetables rich in carotenoids and polyphenols, and have been associated with anti-inflammatory properties. Methods and results: We tested four plum (Italian Plum, Plum 620, Ersinger, and Cherry Plum) and cabbage varieties (Duchy, Kalorama, Kale, Scots Kale) with contrasting carotenoid/polyphenol content for their capability to alter inflammation/oxidative stress following simulated gastrointestinal digestion. Digesta were exposed to Caco-2(TC-7) and to a triple-culture(Caco-2/HT-29-MTX (90:10 v/v) including THP-1 like macrophages), stimulated to induce inflammation (10 μg/mL LPS, 100 ng/mL TNF-α, 25 ng/mL IL-1-β for 24 h, the last 18 h with digesta). Endpoints investigated included IL-6, IL-8, PGE-2, NO (all ELISA), NF-κB, MAPK, IL-6, IL-8, iNOS, Nrf2, COX-2 (real-time-PCR) and Nrf2 (immunostaining). IL-6 secretion was reduced in THP-1 cells by Scots Kale and Kalorama (up to 22%, p<0.05), and IL-8 secretion in the coculture (up to 35% in plums, p<0.05). This was accompanied by decreased NF-kB expressions in THP-1 cells (up to 30%, p<0.05). Nrf2 translocation to the nucleus was partly reduced by plums and cabbages (up to 40% (p<0.05). Conclusions: Some varieties, especially in the triple-culture, reduced inflammation, though this was unrelated to concentrations of carotenoids/polyphenols. The potential of phytochemical-rich fruits and vegetables to ameliorate gastrointestinal inflammation should be further investigated.