Regulatory effect of volatile compounds in fermented alcoholic beverages on gut microbiota and serum metabolism in a mouse model

Ethanol (EtOH) is the main risk factor for alcoholic liver disease. However, fermented alcoholic beverages contain not only ethanol but also various volatile compounds. Currently, the effects of volatile compounds in ethanol-containing fermented beverages on gut microbiota and host metabolism are largely unclear. To fill this gap, we constructed an 8-week mice model using three types of Baijiu (a traditional fermented alcoholic beverage), sterile water and ethanol as controls. Results revealed that three types of Baijiu contain various volatiles, mainly belonging to esters, alcohols, and acids. All of Baijiu caused the lower levels of liver injury in mice than EtOH (at the same EtOH concentration) by phenotypic, biochemical and pathological analysis. We observed that Baijiu volatiles affect the gut microbiota structure and serum metabolomic patterns of mice. Compared with EtOH, Baijiu feeding profoundly increased the relative abundance of Lactobacillus (the highest relative abundance in the Baijiu-fed group was 11.16 ± 1.52%, and in the EtOH-fed group it was 1.80 ± 0.66%). Esters, acids and phenols in volatiles showed strong positive correlations (P < 0.01, R > 0.6) with Lactobacillus. Moreover, Baijiu feeding significantly (P < 0.05) enriched serum metabolites related to bioenergy (i.e., D-glucose, the highest fold change was 1.16) and anti-inflammatory activity (i.e., arachidonic acid, the highest fold change was 1.43) as compared to EtOH. Finally, the microbial and metabolic function analysis showed that volatiles will enhance the citrate cycle and biosynthesis of unsaturated fatty acid pathways. Overall, these data demonstrated the potential of volatile compounds for attenuating the progress of alcoholic liver disease by regulating the gut microbiota and host metabolism.