Deacetylasperulosidic Acid Methyl Ester Ameliorates Carbon Tetrachloride-Induced Liver Fibrosis by Suppressing Inflammation and Modulating Gut Microbiota

Liver fibrosis is an excessive wound-healing response triggered by chronic liver injury. It may eventually progress to cirrhosis, liver failure or liver cancer. Currently, there are no effective therapeutic strategies available. Deacetylasperulosidic acid methyl ester (DAM), a natural iridoid compound derived from Rubiaceae plants, possesses potential anti-inflammatory activity. However, its role in liver fibrosis and the underlying mechanisms remain unclear. Given the critical involvement of inflammation and gut microbiota dysbiosis in the development of liver fibrosis, this study aimed to investigate whether DAM could ameliorate liver fibrosis by modulating hepatic inflammation and intestinal dysbiosis. Using a carbon tetrachloride (CCl₄)-induced liver fibrosis model in mice, we evaluated DAM's effects via histopathology, serum biochemical assays, liver fibrosis marker detection, intestinal barrier analysis and 16S rRNA gene sequencing. DAM treatment significantly alleviated hepatic histopathological damage, reduced serum levels of ALT, AST and γ-GT, inhibited hepatic collagen deposition (HA, LN, IV-C and PC Ⅲ) and reduced the expression of the fibrotic markers α-SMA and Col1a1. Furthermore, DAM markedly inhibited the hepatic expression of the pro-inflammatory cytokines TNF-α, IL-1β and IL-6, demonstrating its anti-inflammatory properties. DAM also attenuated intestinal structural damage, enhanced the expression of tight junction proteins Claudin-1, ZO-1 and Occludin, and improved intestinal barrier integrity, thereby reducing endotoxin translocation. 16S rRNA gene sequencing further revealed that DAM improved CCl₄-induced gut microbiota dysbiosis by reducing the abundance of pro-inflammatory genera such as Faecalibaculum and Dubosiella, thereby contributing to the restoration of microbial homeostasis. Collectively, DAM effectively ameliorates CCl₄-induced liver fibrosis by modulating hepatic inflammation and gut microbiota dysbiosis and may serve as a promising candidate for the prevention and treatment of liver fibrosis.