Identification of anti-fibrotic components of Bofutsushosan under conditions of age-associated obesity in mice

BACKGROUND: Bofutsushosan (BTS) is a traditional herbal medicine used to reduce body weight, edema, and constipation. Aged individuals often present pro-fibrotic comorbidities such as metabolic dysfunction-associated steatohepatitis (MASH), chronic kidney disease, and heart failure with preserved ejection fraction. Although the weight-reducing effect of BTS is well recognized, its effects under aged conditions remain uncharacterized. PURPOSE: To characterize the anti-fibrotic effects of BTS under age-associated obesity and identify the components responsible. STUDY DESIGN: An aged diet-induced obese mouse model combined with an in vitro TGFβ-induced fibrosis model in 3T3-L1 preadipocytes, followed by component-resolved screening and reformulation of BTS. METHODS: 63-week-old mice were fed a high-fat diet containing 2% BTS for 2 months, and tissues were analyzed by histology and qPCR. In 3T3-L1 preadipocytes, pro-fibrotic gene expression and SMAD2/3 phosphorylation were assessed following treatment with whole BTS, single-component-depleted BTS, or individual components. RESULTS: BTS reduced body weight by 14.8% with decreased food intake, reduced adipose tissue size, and ameliorated hepatic steatosis. Pro-fibrotic genes were reduced in adipose tissue and liver, including 60.6% and 46.2% reductions of Col1a1. BTS suppressed TGFβ-mediated pro-fibrotic gene expression and SMAD2/3 phosphorylation in 3T3-L1 preadipocytes. Among the 18 components, Sal Mirabilis was the primary pro-fibrotic constituent, whereas Forsythiae Fructus, Zingiberis Rhizoma, Rhei Rhizoma, and Scutellariae Radix were anti-fibrotic. A modified formula lacking Sal Mirabilis and supplemented with these four ingredients exerted a stronger anti-fibrotic effect. CONCLUSION: BTS exerts anti-fibrotic effects under age-associated obesity, and its therapeutic potential can be enhanced by removing pro-fibrotic and increasing anti-fibrotic components.