Hepatoprotective effects of different mulberry leaf extracts against acute liver injury in rats by alleviating oxidative stress and inflammatory response

This study investigated the hepatoprotective effects of various mulberry (Morus alba L.) leaf extracts (MLEs), including mulberry ethanol extract (MEE), aqueous extract (MAE) and a combination extract (MCE) against d-galactosamine (d-GalN)/lipopolysaccharide (LPS)-induced acute liver injury in rats. It aimed to explore the possible molecular mechanism of the liver-protecting function of mulberry leaves and provide a reference for choosing the appropriate extraction method. The results showed that the three extracts contained different amounts of phenolic compounds, 1-deoxynojirimycin (DNJ) and polysaccharides. MLEs markedly improved the pathological status of rat liver tissue, decreased the levels of AST, ALT, TNF-alpha, IL-1 beta, IL-6 and MDA, while increased the levels of GSH, SOD and CAT in the d-GalN/LPS-treated rats at the same time. MEE, with the highest amount of total phenolics, exhibited the highest antioxidant activity corresponding to the protein expression level of Nrf2 and HO-1. MCE significantly suppressed the expression of apoptosis-related dot-like protein (ASC) and Caspase-1 and inhibited the phosphorylation of p38 MAPK and ERK1/2, thereby showing high anti-inflammatory activity. These results indicated that the active components from mulberry leaves protected rats against acute liver injury, attributed to a reduction in both oxidative stress and inflammatory response. The protective effect may be implicated in regulating the Nrf2, NLRP3 and MAPK signaling pathways.