Sub-therapeutic antibiotics are widely used as growth promoters in the poultry industry; however, the resulting antibiotic resistance threatens public health. A plant-derived growth promoter, Macleaya cordata extract (MCE), with effective ingredients of benzylisoquinoline alkaloids, is a potential alternative to antibiotic growth promoters. Altered intestinal microbiota play important roles in growth promotion, but the underlying mechanism remains unknown. We generated 1.64 terabases of metagenomic data from 495 chicken intestinal digesta samples and constructed a comprehensive chicken gut microbial gene catalog (9.04 million genes), which is also the first gene catalog of an animal’s gut microbiome that covers all intestinal compartments. Then, we identified the distinctive characteristics and temporal changes in the foregut and hindgut microbiota. Next, we assessed the impact of MCE on chickens and gut microbiota. Chickens fed with MCE had improved growth performance, and major microbial changes were confined to the foregut, with the predominant role of Lactobacillus being enhanced, and the amino acids, vitamins, and secondary bile acids biosynthesis pathways being upregulated, but lacked the accumulation of antibiotic-resistance genes. In comparison, treatment with chlortetracycline similarly enriched some biosynthesis pathways of nutrients in the foregut microbiota, but elicited an increase in antibiotic-producing bacteria and antibiotic-resistance genes. The reference gene catalog of the chicken gut microbiome is an important supplement to animal gut metagenomes. Metagenomic analysis provides insights into the growth-promoting mechanism of MCE, and underscored the importance of utilizing safe and effective growth promoters.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD), and its pathogenesis is related to intestinal mucosal barrier damage and gut microbiota imbalance. Protopine (PRO), an isoquinoline alkaloid, is one of the main anti-inflammatory ingredients of traditional Chinese medicine Macleaya cordata (Willd.) R. Br. This study investigated the effects of PRO on the intestinal mucosal barrier and gut microbiota in dextran sodium sulfate (DSS)-induced colitis mice. C57BL/6J mice were treated with 3% DSS in drinking water to induce acute colitis, while PRO was administered orally once daily for 7 days. The results showed that PRO administration significantly alleviated the symptoms of DSS-induced colitis in mice and inhibited the expression of inflammation-related genes. In addition, PRO restored the integrity of the intestinal barrier in colitis mice by restoring colonic mucin secretion and promoting the expression of tight junction proteins. Furthermore, PRO alleviated the DSS-induced gut microbiota dysbiosis by decreasing the abundance of Proteobacteria, Escherichia-Shigella and Enterococcus, as well as enhancing the abundance of beneficial bacteria, such as Firmicutes and Akkermansia. These findings suggested that PRO effectively alleviated DSS-induced ulcerative colitis by suppressing the expression of inflammation-related genes, maintaining the intestinal mucosal barrier and regulating the intestinal microbiota.

Allocryptopine (ALL) is an isoquinoline alkaloid extracted from Macleaya cordata(Willd). R. Br., which has been claimed to have anti-inflammatory and neuroprotection properties. However, the mechanism by which ALL ameliorates inflammatory bowel disease (IBD) remains unclear. Here, we used network pharmacology and quantitative proteomic approaches to investigate the effect of ALL on IBD pathogenesis. Network pharmacology predicted potential targets and signaling pathways of ALL’s anti-IBD effects. As predicted by network pharmacology, gene ontology (GO) analysis, in terms of the proteomic results, showed that the immune response in mucosa and antimicrobial humoral response were enriched. Further study revealed that the ALL-related pathways were the chemokine signaling pathway and apoptosis in the Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, we identified AKT1 as a hub for the critical pathways through protein–protein interaction (PPI) network analysis. Similar to mesalazine (MES), Western blot verified that ALL downregulated upstream chemokine CX3CL1 and GNB5 content to reduce phosphorylation of AKT and NF-κB, as well as the degree of apoptosis, to improve inflammatory response in the colon. Our research may shed light on the mechanism by which ALL inhibits the CX3CL1/GNB5/AKT2/NF-κB/apoptosis pathway and improves the intestinal barrier to reduce colitis response and act on the CX3CL1–CX3CR1 axis to achieve neuroprotection.

In this study, we assessed the therapeutic effects of Macleaya cordata (Willd). R. Br.-derived protopine-type alkaloids (MPTAs) in a mouse model of lipopolysaccharide (LPS)-induced intestinal inflammation. The experimental design involved the allocation of mice into distinct groups, including a control group, a model group treated with 6 mg/kg LPS, a berberine group treated with 50 mg/kg berberine hydrochloride and low-, medium- and high-dose MPTA groups treated with 6, 12 and 24 mg/kg MPTAs, respectively. Histological analysis of the ileum, jejunum and duodenum was performed using Hematoxylin and Eosin (H&E) staining. Moreover, the quantification of intestinal goblet cells (GCs) was performed based on PAS staining. The serum levels of IL-1β, IL-6, IL-8 and TNF-α were quantified using an enzyme-linked immunosorbent assay (ELISA), while the mRNA levels of TLR4, NF-κB p65, NLRP3, IL-6 and IL-1β were assessed using quantitative PCR (qPCR). The protein levels of TLR4, Md-2, MyD88, NF-κB p65 and NLRP3 were determined using Western blotting. Furthermore, the 16S rDNA sequences of bacterial taxa were amplified and analysed to determine alterations in the gut microbiota of the mice following MPTA treatment. Different doses of MPTAs were found to elicit distinct therapeutic effects, leading to enhanced intestinal morphology and an increased abundance of intestinal GCs. A significant decrease was noted in the levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α). Additionally, the protein levels of TLR4, MyD88, NLRP3 and p-p65/p65 were markedly reduced by MPTA treatment. Furthermore, 16S rDNA sequencing analysis revealed that the administration of 24 mg/kg MPTAs facilitated the restoration of microbial composition.