ß-patchoulene protects against non-alcoholic steatohepatitis via interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation in rats.

Non-alcoholic steatohepatitis (NASH), an extreme progressive subtype of metabolic associated fatty liver disease, is well characterized by hepatic steatosis, injury and inflammation. It causes irreversible hepatic damage and there are no approved interventions for it. ß-PAE, a representatively pharmacological active substance isolated from Pogostemon cablin, has been indicated to alleviate hepatic steatosis and injury through modulating lipid metabolism in rats with simple steatosis. However, its protection against NASH remains unclear. Here, this study explored the potential effect of ß-PAE against high-fat diet-induced NASH in rats. The results displayed that ß-PAE significantly reduced the gains of body weight and epididymal adipose tissue, liver index and attenuated liver histological damages in NASH rats. It also markedly alleviated hepatic inflammation by inhibiting NLRP3 inflammasome activation. In NASH, the active NLRP3 inflammasome is caused by hepatic lipid abnormal accumulation-induced oxidative stress. Excessive oxidative stress results in hepatic histanoxia, which exacerbates lipid metabolism disorders by elevating CD36 to suppress AMPK signalling pathways. Moreover, the lipid accumulation led by lipid metabolism dysfunction intensifies oxidative stress. A vicious circle is formed among oxidative stress, histanoxia and lipid accumulation, eventually, but ß-PAE effectively interrupted it. Interestingly, soluble CD36 (sCD36) was tightly associated not only with hepatic steatosis and injury but also with inflammation. Collectively, ß-PAE exerted a positive effect against NASH by interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation, and sCD36 may be a promising non-invasive tool for NASH diagnosis.

ß-patchoulene simultaneously ameliorated dextran sulfate sodium-induced colitis and secondary liver injury in mice via suppressing colonic leakage and flora imbalance.

Ulcerative colitis (UC) often occurs accompanied by colonic leakage and flora imbalance, resulting in secondary liver injury (SLI). SLI, in turn, aggravates UC, so the treatment of UC should not ignore it. ß-patchoulene (ß-PAE), a tricyclic sesquiterpene isolated from Pogostemon cablin, has been reported to exert a protective effect in gastrointestinal disease in our previous studies. However, its protection against UC and SLI remains unknown. Here we explored the protective effect and underlying mechanism of ß-PAE against dextran sulfate sodium-induced UC and SLI in mice. The results indicated that ß-PAE significantly reduced disease activity index, splenic index and attenuated the shortening of colonic length in UC mice. It alleviated colonic pathological changes and apoptosis through protecting tight junctions, reducing neutrophil aggregation, and inhibiting the release of pro-inflammatory cytokines and adhesion molecules. These effects of ß-PAE were associated with the inhibition of TLR4/MyD88/NF-κB and ROCK1/MLC2 signalling pathway. UC-induced colonic leakage caused abnormally high LPS levels to result in SLI, and ß-PAE markedly inhibited it. ß-PAE simultaneously ameliorated SLI with reduced biomarker levels of endotoxin exposure and hepatic inflammation. High levels of LPS were also associated with flora imbalance in UC mice. However, ß-PAE restored the diversity of gut microbiota and altered the relative abundance of characteristic flora of UC mice. Escherichia-dominated gut microbiota of UC mice was changed to Oscillospira-dominated after ß-PAE treatment. In conclusion, pharmacological effects of ß-PAE on UC and SLI were mainly contributed by suppressing colonic leakage and flora imbalance. The findings may have implications for UC treatment that not neglect the treatment of SLI.