Exploring the anti-fibrotic effects of safflower in systemic sclerosis based on metabolomics and gut microbiota analyses

Background Systemic sclerosis (SSc) is a complex autoimmune disease characterized by inflammation, fibrosis, and multi-organ involvement. Traditional botanical drugs have long been used empirically to manage fibrotic and inflammatory conditions, yet their pharmacological effects remain incompletely understood. Objective The aim of this study was to investigate the effects of an aqueous extract of safflower on fibrotic and inflammatory phenotypes, gut microbiota composition, and fecal metabolic profiles in a bleomycin-induced murine model of systemic sclerosis. Methods A murine model of systemic sclerosis (SSc) was established by bleomycin (BLM) induction, followed by safflower intervention for 28 days. The therapeutic effects of safflower on SSc-associated fibrosis and inflammation were evaluated by hematoxylin–eosin (HE) staining, Masson’s trichrome staining, collagen fiber quantification, and enzyme-linked immunosorbent assay of inflammatory mediators (IL-1β, IL-13, and Lipopolysaccharide). Gut microbiota composition and fecal metabolic profiles were analyzed using 16S rRNA gene sequencing and untargeted UHPLC–QTOF–MS-based metabolomics to explore the potential mechanisms associated with the anti-fibrotic effects of safflower in systemic sclerosis. Results Safflower aqueous extract alleviated bleomycin-induced systemic sclerosis phenotypes, including dermal sclerosis, multi-organ collagen deposition, and inflammatory responses in skin, lung, and colon tissues. Untargeted fecal metabolomics revealed that safflower intervention significantly modulated metabolic pathways primarily related to central carbon metabolism, amino acid and protein metabolism, and steroid hormone biosynthesis. Furthermore, 16S rRNA gene sequencing demonstrated that safflower partially restored gut microbial richness and diversity and reversed systemic sclerosis–associated dysbiosis by increasing the relative abundance of putatively beneficial taxa (e.g., Cyanobacteria , Chloroflexi , Acidobacteria , and Nitrospirae) while reducing inflammation-associated genera, including Deferribacteres , Odoribacter , Akkermansia , Helicobacter , and Prevotellaceae _NK3B31_group . These results suggest that the anti-fibrotic effects of safflower are associated with integrated modulation of gut microbiota and metabolic profiles. Conclusion Safflower alleviated fibrotic and inflammatory phenotypes in systemic sclerosis, which may be associated with the modulation of gut microbiota composition and metabolic homeostasis.