Glycycoumarin protects mice against acetaminophen-induced liver injury predominantly via activating sustained autophagy

Background and purpose: Acetaminophen-induced acute liver injury (AILI) is the most frequent cause of acute liver failure in developed countries. Given the significant limitations associated with N-acetyl cysteine, the only antidote used to treat AILI, the development of novel therapeutic approaches that can offer a wide range of therapeutic time-windows is clearly needed. Glycycoumarin (GCM), a natural coumarin purified from liquorice, has been previously demonstrated to possess potent hepatoprotective effects. In the present study, we aimed to investigate the therapeutic potential of GCM against AILI.

Experimental approach: Acetaminophen (300 mg·kg^-1 ) was administered to male C57BL/6 mice, with and without GCM. Serum transaminases, haematoxylin and eosin staining and Western blot were used to assess hepatic damage.

Key results: GCM (50 mg·kg^-1 ) was highly effective against acetaminophen-induced hepatotoxicity. Moreover, GCM was superior to N-acetyl cysteine, in terms of the dosage and the therapeutic time-windows. Further mechanistic investigations revealed that the therapeutic action of GCM was not a result of inhibition of acetaminophen metabolic activation or associated with Nrf2. Instead, the protective effect of GCM appeared to be predominantly dependent on sustained activation of Autophagy, which attenuated acetaminophen-induced mitochondrial oxidative stress and JNK activation.

Conclusions and implications: Collectively, our results indicate that GCM alleviated acetaminophen-induced oxidative stress through activating Autophagy, thereby protecting against AILI. Our findings suggest that GCM has potential as a novel therapeutic agent for treating AILI.