When middle-aged mice popped a traditional Japanese obesity medicine in their food, something unexpected happened — not only did they lose weight, but they also showed less of the dangerous scar tissue that makes organs stiff and unhealthy.Researchers at the University of Osaka, working with the company Kobayashi Pharmaceutical, wanted to know whether Bofutsushosan — a Kampo medicine made from 18 different herbs and minerals — could protect aging bodies from a problem called fibrosis. Fibrosis happens when scar-like tissue builds up in fat and organs like the liver and heart, making them work less well over time. The condition gets worse with both aging and obesity.
The team fed 63-week-old male mice (roughly middle-aged in mouse years) a high-fat diet for eight weeks. Half the mice got food mixed with 2 percent Bofutsushosan, while the other half ate regular high-fat food. By the end of the study, mice taking the medicine weighed 14.8 percent less than the untreated mice. They also had smaller fat stores, less fat buildup in their livers, and fewer signs of scarring in their fat and liver tissue.
Because losing weight alone can improve fibrosis, the researchers also tested the medicine on fat-cell precursors in petri dishes. There, too, Bofutsushosan tamped down signals that drive scar-tissue formation.
Next came a deeper dive into the 18 ingredients. Four showed especially strong anti-scarring power: Forsythiae Fructus, Zingiberis Rhizoma, Rhei Rhizoma, and Scutellariae Radix. One mineral, Sal Mirabilis, seemed to work in the opposite direction in cell cultures — though the researchers stressed this does not mean it causes fibrosis in living bodies or in people taking the medicine. A modified formula leaving out Sal Mirabilis, or using more of the four beneficial herbs, suppressed scarring markers even more strongly in the lab. Those updated versions have not yet been tested in animals or humans.
Ayano Onishi, the study's lead author, said Bofutsushosan is best known for helping with obesity, but the findings suggest it may also fight the tissue scarring that comes with aging and weight gain. She said understanding how each ingredient works could guide future research into Kampo medicines. The team is quick to note this was a preclinical study in mice and cells — not a human trial. No one should change how they use the medicine based on these results.
Still, the researchers say the work offers a scientific foundation for studying how multicomponent traditional medicines actually function, and it opens a door toward potential future treatments for fibrosis linked to obesity and aging.