Lonicera rupicola Hook.f.et Thoms flavonoids ameliorated dysregulated inflammatory responses, intestinal barrier, and gut microbiome in ulcerative colitis via PI3K/AKT pathway.

Background: Lonicera rupicola Hook.f.et Thoms (LRH) is used as a customary medicinal herb in Tibetans. And LRH flavonoids have excellent anti-inflammatory and antioxidant pharmacological activities. However, the specific effects of LRH and its mechanism remain unknown, and there is a deficiency of systematic research, leading to the waste of LRH as a medicinal resource.

Purpose: In this study, in an attempt to rationalize the development and utilization of Tibetan herbal resources, the therapeutic efficacy and the underlying molecular mechanisms of LRH flavonoids on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) were investigated, establishing the favorable basis for the pharmacodynamic material basis of LRH and providing a scientific basis for the discovery of new drugs for the treatment of UC.

Methods: Firstly, ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was used for identification and detection of the flavonoid components of LRH. Meanwhile, their potential targets, biological functions and signaling pathways were predicted with the assistance of network pharmacology analysis. Subsequently, pharmacological efficacy of LRH were evaluated by body weight loss, colon length, disease activity index (DAI), histology observation and the expression levels of inflammatory mediators, messenger RNA (mRNA) and tight junction proteins. Moreover, in the present investigation, we also profiled the gut microbiome via high-throughput sequencing of the V3-V4 region of 16S ribosomal DNA (rDNA) for bacterial community composition and diversity by Illumina MiSeq platforms. Finally, the key regulatory proteins in the PI3K/AKT pathways were measured to investigate their underlying molecular mechanisms.

Results: A total of 37 LRH flavonoid components were identified and detected by UPLC-MS/MS, and 12 potential active components were obtained after screening. 137 of their common targets with UC were further predicted. GO and KEGG pathway enrichment analysis and molecular docking experiments demonstrated that LRH flavonoids could interfere with UC through "multi-component-multi-target-multi-pathway". In the animal experiments, LRH flavonoids could significantly attenuate UC as demonstrated by reducing the body weight loss and DAI, restoring colon length, decreasing oxidative stress, and improving the intestinal epithelial cell barrier. The mRNA and proteins expression levels of inflammatory mediators were returned to dynamic balance following LRH flavonoids treatment. 16S rDNA sequence analysis indicated that LRH flavonoids promoted the recovery of gut microbiome. And the PI3K/AKT pathway was significantly suppressed by LRH flavonoids.

Conclusions: LRH flavonoids exhibited multifaceted protective effects against DSS-induced UC in mice through mitigating colon inflammation and oxidative stress, restoring epithelial barrier function, and improving the gut microenvironment potentially through modulation of the PI3K/AKT pathway. This finding demonstrated that LRH flavonoids possessed great potential for becoming an excellent drug for the treatment of UC.