Phenazines Modulate Gastrointestinal Metabolism and Microbiota

Abstract Background: Natural and synthetic phenazines are ubiquitously occurred in environment and have been used for various therapeutic purposes in human, animals and agriculture, and the widespread use makes residue problem in environment and foods increasingly serious. However, the metabolic and comprehensive impacts of phenazines on the digestive tract are poorly understood, particularly the microbial pyocyanin (PYO), the most representative phenazines produced by Pseudomonas . Here, we utilized PYO as the representative of phenazines to study the effects on digestive tract. Results: Metabolic kinetic analysis showed that PYO exhibited low oral bioavailability in both rats and swine model, revealing a restriction of PYO in gut and might cause impacts on digestive tract. PYO was subsequently found to induce intestinal barrier destruction including inflammation and reactive oxygen species (ROS) accumulation in duodenum. Microbiome analysis showed that PYO caused gut microbiota dysbiosis by decreasing the symbiotic bacteria and increasing the opportunistic pathogenic bacteria. Additionally, the integral and dysfunctional assessment of liver demonstrated that PYO induced liver inflammation and metabolic disorder. Metabolism analysis further confirmed that PYO could be metabolized by both gut microbiota and liver, and all metabolites retained the nitrogen-containing tricyclic structural skeleton of phenazines, which was the core bioactivity of phenazine compounds, indicating all the outcomes were due to the intrinsic characteristic of phenazine structure. Conclusions: PYO were low oral bioavailable and all the metabolites retained the nitrogen-containing tricyclic structural skeleton, final resulting in the damages to digestive tract including intestinal barrier destruction, gut microbiota dysbiosis, liver damages and metabolic disorder. These findings elucidated the effect of phenazines on digestive tract in vivo and shed light on the rational design of phenazines for the development and application of such compounds in future.