Effect of ultraviolet-irradiated modified gallic acid (UVC-GA) on the intestinal microbiota of mice

Ultraviolet-irradiated modified gallic acid (UVC-GA) has good antioxidant effects and can inhibit the heterocyclic amine formation during high-temperature food processing, but whether it has an impact on the gut microbiota after consumption remains unclear. The metagenomic techniques and mathematical statistical methods were employed to explore the effects of UVC-GA on the diversity, abundance, phylogenetic pattern, carbohydrate-active enzyme (CAZ y ) genes, and specific beneficial bacteria of the gut microbiota in mice. The results showed that the Aitchison distance value ( p = 0.019) and Bray-Curtis distance value ( p = 0.047) in the UVC-GA group had significant changes, and its distribution was much higher than those of Vc. The Shannon and Simpson indices in the UVC - GA group were significantly higher than those in Vc ( p = 0.003 and p = 0.022 respectively). UVC - GA promoted the phylogenetic clustering of gut microbiota in mice. In the UVC - GA group's gut microbiota, the CAZ y expression levels based on PCoA 1 of Aitchison and Bray - Curtis increased. Moreover, significant changes in metabolic pathways included the synthesis of dTDP - N - acetylglucosamine and flavin, sucrose degradation, and sulfoglycolysis. Additionally, the CLR abundances of five beneficial bacteria increased significantly while one harmful bacteria decreased substantially. This study showed that UVC - GA could maintain intestinal microbiota health by improving gut microbiota abundance and diversity, promoting specific beneficial microbiota colonization and growth in a phylogenetic clustering pattern, and enhancing related CAZ y genes expression. The study found UVC - GA is more effective than Vc in improving intestinal health. Moreover, in this study's experimental framework, no intestinal microbiota dysregulation was detected in the UVC - GA group after 12 - week gavage. Also, UVC - GA had no obvious toxic effect on the intestinal microbiota, providing a scientific basis for its practical use. Ultraviolet-irradiated modified gallic acid (UVC-GA) was investigated in mice. UVC-GA enhanced gut microbiota abundance, diversity, and phylogenetic clustering, increased CAZ y expression, promoted beneficial bacteria growth, and inhibited harmful bacteria, suggesting its potential for improving intestinal health. • UVC-GA enhances abundance/diversity and promotes phylogenetic clustering of beneficial bacteria. • UVC-GA upregulates CAZ y gene expression, promoting dTDP-N-acetylglucosamine/flavin synthesis and sucrose/sulfoglycolysis degradation. • UVC-GA significantly increased 5 beneficial bacteria and reduced 1 harmful bacteria without significant cytotoxicity. • UVC-GA maintains intestinal health via phylogenetic clustering, enhancing microbiota-host interaction and metabolic function safely.