Total flavonoids extracted from the leaves of Murraya paniculata (L.) Jack prevents acetaminophen-induced liver injury by activating Keap1/Nrf2 and PI3K/AKT/mTOR signaling pathway

Ethnopharmacological relevance: In regions such as China and Southeast Asia, leaves of the traditional Chinese medicinal herb Murraya paniculata (L.) Jack are highly valued for their ability to detoxify and reduce swelling, promote blood circulation, and alleviate pain. These properties are harnessed in traditional healing practices, where the herb is aligned with the liver and stomach meridians in Chinese medicine. Consequently, extracts from the leaves of Murraya paniculata (L.) Jack are believed to ameliorate various liver-related ailments. Despite its widespread use, there is a paucity of research demonstrating the protective effect of total Flavonoids extracted from the leaves of Murraya paniculata (L.) Jack (TFMP) in relieving acetaminophen-induced acute liver injury (ALI).

Aim of the study: This study aimed to investigate the hepatoprotective effects and probable mechanisms of action of TFMP in acetaminophen-induced acute liver damage.

Materials and methods: Experimental Animals were randomized into four groups of 10 each and then orally pretreated with 0.5% carboxymethyl cellulose or TFMP for seven consecutive days. ALI was induced using acetaminophen (APAP, 300 mg/kg). Hematoxylin and eosin (H&E) staining and serum markers were used to evaluate liver damage. Immunofluorescence, western blotting, biochemical kit testing, immunohistochemistry, and qPCR were used to evaluate acetaminophen metabolism, oxidative damage, and hepatocyte death.

Results: TFMP considerably lowered the liver-related transaminase activity and reduced pathological liver damage. By triggering the kelch-like ECH-associated protein 1 (Keap1)/nuclear erythroid related factor 2 (Nrf2) signaling pathway in hepatic tissue, antioxidative Enzymes, such as superoxide dismutase (SOD) and catalase (CAT), and glutathione (GSH) were elevated and malondialdehyde (MDA) content was diminished. Based on western blotting and immunohistochemistry examinations, TFMP could boost Nrf2 accumulation within liver tissue and modulate Nrf2 entry into the nucleus, increasing the proteins involved in heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO1) expression. Furthermore, TFMP promoted the expression of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2) while reducing the expression of pro-apoptotic proteins such as Bcl2-associated X (Bax). Overall, TFMP attenuated hepatocyte Apoptosis by activating the PI3K/Akt/mTOR pathway.

Conclusion: This study shows that TFMP reduces APAP-induced acute liver damage by a mechanism that affected the APAP metabolic process in vivo and activated the PI3K/Akt/mTOR and Keap1/Nrf2 signaling pathways to exert anti-apoptotic and antioxidant effects. Thus, TFMP may be a viable option for preventing APAP-induced liver damage.

Acetaminophen; Acute liver injury; Hepatocyte apoptosis; Murraya paniculata (L.) Jack; Oxidative stress; Phytotherapy.