Traditional Japanese medicine Bofutsushosan, widely used to treat obesity, may also protect aging tissues from destructive fibrosis, according to a preclinical study published in Phytomedicine. Researchers at the University of Osaka and Kobayashi Pharmaceutical Co., Ltd. found that the multi-ingredient formula reduced scar-like tissue buildup in the liver and fat tissue of mice fed a high-fat diet.
Bofutsushosan Reduces Fat Deposits and Liver Fibrosis in Mice
Aging and obesity often drive chronic inflammation and fibrosis, making organs like the liver, heart, and kidneys stiff and less functional. To test whether Bofutsushosan alters this process, researchers fed 63-week-old male mice a high-fat diet supplemented with 2% Bofutsushosan for eight weeks, according to the study. Mice receiving the formula weighed 14.8% less than untreated mice by the end of the experiment. They also consumed less food, maintained smaller fat deposits, exhibited less fat accumulation in the liver, and showed fewer fibrosis-related tissue changes.
Because weight loss inherently improves fibrosis, the research team cultured fat-cell precursors to isolate direct cellular effects. In those cultured cells, Bofutsushosan suppressed multiple fibrosis-related signals and partially inhibited the TGF-β/SMAD2/3 pathway, a primary driver of scar tissue formation. Lead author Ayano Onishi noted that while the medicine is best known for weight control, these findings point to a potential role in managing aging- and obesity-linked fibrosis.
Did you know?
Bofutsushosan is a traditional Kampo medicine composed of 18 different crude-drug ingredients. Until this study, the specific contribution of each component to anti-fibrotic activity remained largely unclear.
Evaluating the 18 Ingredients of Kampo Medicine
To determine which components drove the anti-fibrotic activity, the research team tested all 18 crude-drug ingredients separately in cell cultures. Four ingredients demonstrated particularly strong anti-fibrotic properties: Forsythiae Fructus, Zingiberis Rhizoma, Rhei Rhizoma, and Scutellariae Radix, according to the published data. Conversely, certain mineral ingredients—notably Sal Mirabilis—exhibited the opposite effect under identical cell-culture conditions.
Researchers emphasized that the behavior of Sal Mirabilis in a lab dish does not mean the mineral promotes fibrosis within the human body or during standard clinical use. When the team increased the concentration of the four active anti-fibrotic ingredients—with or without removing Sal Mirabilis—the modified formulas produced an even stronger suppression of fibrosis-related markers in cells. However, these adjusted formulas have not yet been tested in animal models or human clinical trials.
Future Outlook and Clinical Limitations
The study provides a new scientific foundation for understanding how multi-component Kampo medicines function at a molecular level. Yet, the current results remain strictly preclinical. Researchers stress that the findings do not support altering approved formulas, changing dosages, or modifying medical treatments without professional guidance.
Future investigations will require extensive animal and human studies to verify whether manipulating these specific botanical ingredients can translate into safe and effective treatments for fibrosis. Onishi emphasized that human clinical trials are essential before any of these insights can be applied to patient care.
Frequently Asked Questions
What is Bofutsushosan?
Bofutsushosan is a traditional Japanese Kampo medicine containing 18 crude-drug ingredients, widely prescribed in Japan to manage obesity.
How does Bofutsushosan affect fibrosis?
Preclinical research shows that the medicine can reduce scar-like tissue buildup in the liver and fat tissue of mice and suppress fibrosis signaling pathways in cultured cells.
Are these findings applicable to humans yet?
No. The results are based on animal models and cell cultures. Researchers state that human clinical trials are necessary before changing any medical treatments.