Phloretin, a dihydrogen chalcone flavonoid, is mainly isolated from apples and strawberries. Phloretin has been proven to have many biological activities such as anti-inflammatory and anti-oxidative. Herein, we investigated the protective efficacy and potential mechanism of phloretin in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. The results showed that phloretin resulted in a reduced DSS-induced disease activity index (DAI), colon length shortening and colonic pathological damage. The levels of pro-inflammatory cytokines in the colon were also decreased by the administration of phloretin. Exploration of the potential mechanism demonstrated that phloretin suppressed the inflammatory response by regulating the nuclear factor-κB (NF-κB), toll-like receptor 4 (TLR4) and peroxisome proliferator-activated receptor γ (PPARγ) pathways. Phloretin also inhibited the DSS-induced (NOD)-like receptor family and pyrin domain containing 3 (NLRP3) inflammasome activations. Further studies found that phloretin reduced key markers of oxidative stress as well as regulated the expression of zonula occludens-1 (ZO-1) and occludin. Interestingly, the concentration of serum lipopolysaccharide (LPS) was significantly decreased. Escherichia coli (E. coli) and Lactobacillus levels were also re-balanced after phloretin treatment. These results indicate that phloretin might be a new dietary strategy for the treatment of UC.

中文翻译：

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伞菌素对硫酸葡聚糖钠诱导的小鼠溃疡性结肠炎的保护作用

蝶呤是一种二氢查尔酮类黄酮，主要从苹果和草莓中分离出来。磷脂已被证明具有许多生物活性，例如抗炎和抗氧化。在这里，我们调查了佛瑞丁在硫酸右旋糖酐钠（DSS）诱导的小鼠溃疡性结肠炎（UC）中的保护作用和潜在机制。结果表明，促肾上腺皮质激素导致DSS诱导的疾病活动指数（DAI）降低，结肠长度缩短和结肠病理损害。施用促胰泌素后，结肠中促炎性细胞因子的水平也降低了。探索潜在的机制表明，伞菌素通过调节核因子-κB（NF-κB）抑制炎症反应，Toll样受体4（TLR4）和过氧化物酶体增殖物激活的受体γ（PPARγ）途径。荧光素还抑制DSS诱导的（NOD）样受体家族和含有3（NLRP3）炎性小体活化的吡喃结构域。进一步的研究发现，phloretin减少了氧化应激的关键标志物，并调节了小带闭合蛋白1（ZO-1）和闭合蛋白的表达。有趣的是，血清脂多糖（LPS）的浓度明显降低。毛菌素治疗后大肠杆菌（E. coli）和乳酸杆菌水平也重新达到平衡。这些结果表明，促肾上腺皮质激素可能是治疗UC的新饮食策略。