Dietary 5-demethylnobiletin attenuated dextran sulfate sodium-induced colitis in mice by inhibiting immune response and regulating gut microbiota.

This study investigated the preventive effect of 5-demethylnobiletin (5DN), a natural polymethoxyflavone found mainly in citrus fruits, on dextran sulfate sodium (DSS)-induced colitis in mice and explored its potential mechanisms. Our results indicated that dietary 5DN (0.05% w/w in diet) could alleviate colitis symptoms in DSS-treated mice by preventing body weight loss, reducing the disease activity index, decreasing the colon weight to colon length ratio, and lessening colon tissue damage. Additionally, 5DN inhibited the inflammatory response in colitis mice through decreasing the production of inflammatory cytokines. Immunohistochemical analysis revealed that 5DN could reverse the DSS-induced decrease in the expression of claudin-1 and ZO-1 to improve the intestinal barrier function. Furthermore, 5DN altered gut microbiota dysbiosis in DSS-treated mice via up-regulating the level of probiotics (Roseburia) and down-regulating the level of pathogenic bacteria (Clostridium, Parabacteroides, and Sutterella). Taken together, these data provided a solid scientific basis for utilizing 5DN as a therapeutic candidate in colitis and related diseases.

Overexpression of CpADC from Chinese Cherry (Cerasus pseudocerasus Lindl. 'Manaohong') Promotes the Ability of Response to Drought in Arabidopsis thaliana.

Polyamines (PA) play an important role in the growth, development and stress resistance of plants, and arginine decarboxylase (ADC) is one of the key enzymes in the biosynthetic pathway of polyamines. Previously, the transcriptional regulation of the 'Manaohong' cherry under the shelter covering was carried out, and the PA synthase-related genes, particularly the ADC gene, were differentially expressed as exposure to drought stress. However, the mechanisms of how ADC is involved in the response of cherry to abiotic stress (especially drought stress) are still unknown. In the present work, the full-length coding sequence of this gene was isolated and named CpADC. Bioinformatics analysis indicated that the coding sequence of CpADC was 2529 bp in length. Cluster analysis showed that CpADC had the highest homologies with those of sweet cherry (Prunus avium, XP_021806331) and peach (Prunus persica, XP_007200307). Subcellular localization detected that the CpADC was localized in the plant nucleus. The qPCR quantification showed that CpADC was differentially expressed in roots, stems, leaves, flower buds, flowers, and fruits at different periods. Drought stress treatments were applied to both wild-type (WT) and transgenic Arabidopsis lines, and relevant physiological indicators were measured, and the results showed that the putrescine content of transgenic Arabidopsis was higher than that of WT under high-temperature treatment. The results showed that the MDA content of WT was consistently higher than that of transgenic plants and that the degree of stress in WT was more severe than in transgenic Arabidopsis, indicating that transgenic CpADC was able to enhance the stress resistance of the plants. Both the transgenic and WT plants had significantly higher levels of proline in their leaves after the stress treatment than before, but the WT plant had lower levels of proline than that of transgenic Arabidopsis in both cases. This shows that the accumulation of proline in the transgenic plants was higher than that in the wild type under drought and high and low-temperature stress, suggesting that the transgenic plants are more stress tolerant than the WT. Taken together, our results reveal that, under drought stress, the increase in both expressions of CpADC gene and Put (putrescine) accumulation regulates the activity of ADC, the content of MDA and Pro to enhance the drought resistance of Arabidopsis thaliana.