Ulcerative colitis is a type of inflammatory bowel disease which in long run can lead to colorectal cancer (CRC). Chronic inflammation can be a key factor for the occurrence of CRC thus mitigating an inflammation can be a preventive strategy for the occurrence of CRC. In this study we have explored the anti-inflammatory potential of phloretin, in in vitro gut inflammation model, developed by co-culture of Caco2 (intestinal epithelial) cells and RAW264.7 macrophages (immune cells). Phloretin is a dihydrochalcone present in apple, pear and strawberries. An anti-inflammatory effect of phloretin in reducing LPS induced inflammation and maintenance of transepithelial electric resistance (TEER) in Caco2 cells was examined. Paracellular permeability assay was performed using Lucifer yellow dye to evaluate the effect of phloretin in inhibiting gut leakiness caused by inflammatory mediators secreted by activated macrophages. Phloretin attenuated LPS induced nitric oxide levels, oxidative stress, depolarization of mitochondrial membrane potential in Caco2 cells as evidenced by reduction in reactive oxygen species (ROS), and enhancement of MMP, and decrease in inflammatory cytokines IL8, TNFα, IL1β and IL6. It exhibited anti-inflammatory activity by inhibiting the expression of NFκB, iNOS and Cox2. Phloretin maintained the epithelial integrity by regulating the expression of tight junction proteins ZO1, occludin, Claudin1 and JAM. Phloretin reduced LPS induced levels of Cox2 along with the reduction in Src expression which further regulated an expression of tight junction protein occludin. Phloretin in combination to sodium pyruvate exhibited potential anti-inflammatory activity via targeting NFkB signaling. Our findings paved a way to position phloretin as nutraceutical in preventing the occurrence of colitis and culmination of disease into colitis associated colorectal cancer.

溃疡性结肠炎是一种炎症性肠病，从长远来看可导致结直肠癌（CRC）。慢性炎症可能是结直肠癌发生的关键因素，因此减轻炎症可能是结直肠癌发生的预防策略。在这项研究中，我们在体外肠道炎症模型中探索了根皮素的抗炎潜力，该模型是通过 Caco2（肠上皮）细胞和 RAW264.7 巨噬细胞（免疫细胞）共培养而开发的。根皮素是一种二氢查尔酮，存在于苹果、梨和草莓中。研究了根皮素在减少 LPS 诱导的炎症和维持 Caco2 细胞中跨上皮电阻 (TEER) 方面的抗炎作用。使用荧光黄染料进行细胞旁通透性测定，以评估根皮素抑制活化巨噬细胞分泌的炎症介质引起的肠漏的作用。根皮素可减弱 LPS 诱导的一氧化氮水平、氧化应激、Caco2 细胞中线粒体膜电位的去极化，具体表现为活性氧 (ROS) 的减少、MMP 的增强以及炎症细胞因子 IL8、TNFα、IL1β 和 IL6 的减少。它通过抑制 NFκB、iNOS 和 Cox2 的表达发挥抗炎活性。根皮素通过调节紧密连接蛋白 ZO1、occludin、Claudin1 和 JAM 的表达来维持上皮完整性。根皮素降低了 LPS 诱导的 Cox2 水平，同时降低了 Src 表达，进一步调节了紧密连接蛋白 occludin 的表达。根皮素与丙酮酸钠组合通过靶向 NFkB 信号传导表现出潜在的抗炎活性。我们的研究结果为将根皮素定位为预防结肠炎发生和疾病最终发展为结肠炎相关结直肠癌的营养保健品铺平了道路。