Lactiplantibacillus plantarum FEED8 Biosynthesis of Pyranoanthocyanin (Cyanidin-3-glucoside-4-vinylcatechol) Improves Oxidative Stress and Inflammation of the Gut Microbiome in Cadmium-Exposed Mice

The study is to explore the biosynthesis of cyanidin-3-glucoside-4-vinylcatechol (C3G_VC) through Lactiplantibacillus plantarum-fermented caffeic acid and cyanidin-3-glucoside (C3G) extract (molar ratio = 1:30) in the model medium. C3G_VC was isolated and purified by a venusil ASB-C18 column with a medium-pressure liquid chromatography (MPLC) system. The chemical structure of C3G_VC was identified by high-performance liquid chromatography (HPLC), which showed the maximum absorption wavelength of 505.57 nm. This study showed that Cd exposure of mice induced liver damage, oxidative stress, and inflammation of the gut microbiome. Our findings demonstrated that C3G_VC intervention in Cd-exposed mice significantly mitigated oxidative stress injury by declining the malondialdehyde (MDA) level and increasing the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in the liver, meanwhile alleviating liver injury by decreasing the bile acid (BA) level and accelerating the excretion of fecal BA. Moreover, the Cd_C3G_VC group showed elevated levels of mRNA expression of pro-inflammatory cytokines (IL6, IL1β, and TNF-α) and inhibited BA synthesis (CYP7A1) in Cd-exposed mice. The fermentation results in vitro showed that C3G_VC had a higher residue than that of cyanidin-3-glucoside. The 16S rRNA high-throughput sequencing disclosed that C3G_VC intervention in Cd-exposed mice significantly increased the abundance of Faecalibaculum and unidentified_Lachnospiraceae. It is noteworthy that the C3G_VC supplement increased the abundance of Akkermansia. Overall, this study demonstrated that C3G_VC intervention in Cd-exposed mice had the potential to decrease the occurrence of inflammatory and oxidative stress and maintain bile acid homeostasis by regulating gut microflora.