Jatrorrhizine from Rhizoma Coptidis exerts an anti-obesity effect in db/db mice

Obesity is closely related to diabetes. Jatrorrhizine (JAT) from Rhizoma Coptidis (RC) can reduce blood glucose and lipid levels. However, the molecular mechanisms for JAT's anti-obesity effect are still not clear.

To explore the effect of JAT in the treatment of obesity and the underlying molecular mechanisms.

db/db mice were used as a typical obese animal model in current study. The anti-obesity effects of five alkaloids from RC were compared by feeding the mice for 8 weeks with a dosage of 105 mg/kg while the dose-dependent study (35 mg/kg and 105 mg/kg) of JAT on obese mice was conducted in another 8-week-long animal experiment. Meanwhile, RNA-seq analysis, in vitro experiments, and western blotting were utilized to predict and confirm the potential pathway that JAT participated in improving obesity.

The experimental results demonstrated that five RC alkaloids caused different degrees of weight loss in db/db obese mice. Among them, JAT showed the best effect. It could significantly reduce the body weight, blood lipid levels, and epididymal fat weight of db/db mice. H&E and Oil red O staining results showed that it could also dramatically improve liver lipid metabolism. The results from RNA-seq suggested that JAT had significantly altered 207 DEGs for the treatment of obesity, among which IRS1 changed the most. Next, GO and KEGG analysis enriched four major lipid metabolism-related pathways: biosynthesis of unsaturated fatty acids, PI3K-AKT signaling pathway, metabolic pathways, and fatty acid elongation. Finally, in vitro experiments and western blotting proved that JAT regulated the expression of IRS1/PI3K/AKT pathway-related proteins in a dose-dependent manner to address obesity.

In conclusion, JAT from RC has an effect on treating obesity, and its anti-obesity effect may be exerted via the IRS1/PI3K/AKT signaling pathway.