Polysaccharide from Mulberry Fruit (Morus alba L.) Protects against Palmitic-Acid-Induced Hepatocyte Lipotoxicity by Activating the Nrf2/ARE Signaling Pathway

Abstract

This study was aimed to investigate the protective effects of three different mulberry fruit polysaccharide fractions (MFP-I, MFP-II, and MFP-III) against palmitic acid (PA)-induced hepatocyte lipotoxicity and characterize the functional polysaccharide fraction using gel permeation chromatography, high-performance liquid chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analyses. MFP-I, MFP-II, and MFP-III were isolated from mulberry fruit by stepwise precipitation with 30, 60, and 90% ethanol, respectively. MFP-II at 0.1 and 0.2 mg/mL dramatically attenuated PA-induced hepatic lipotoxicity, while MFP-I and MFP-III showed weak protection. It was demonstrated that MFP-II not only increased nuclear factor erythroid-2-related factor 2 (Nrf2) phosphorylation and its nuclear translocation, thereby activating the Nrf2/ARE signaling pathway, but also enhanced heme oxygenase 1, NAD(P)H:quinone oxidoreductase 1, and γglutamate cysteine ligase gene expressions and promoted catalase and glutathione peroxidase activities, which protected hepatocytes against PA-induced oxidative stress and lipotoxicity. Further investigation indicated that the molecular weight of MFP-II was 115.0 kDa, and MFP-II mainly consisted of galactose (30.5%), arabinose (26.2%), and rhamnose (23.1%). Overall, our research might provide in-depth insight into mulberry fruit polysaccharide in ameliorating lipid metabolic disorders.

Select Polyphenol-Rich Berry Consumption to Defer or Deter Diabetes and Diabetes-Related Complications

“…MBEs in HFD-fed male Sprague-Dawley rats prevented non-alcoholic fatty liver disease (NAFLD) by downregulating lipid/cholesterol homeostasis-related genes (FAS, ACC, GPAT, and SREBP-1) and suppressing the lipid oxidation biomarkers MDA and 4-hydroxynonenal [ 105 , 106 ]. Hu et al [ 275 ] demonstrated that MBE increased nuclear factor erythroid-2-related factor 2 (Nrf2) phosphorylation and nuclear translocation, activating the Nrf2/antioxidant response element signaling pathway, which increased quinone oxidoreductase 1, HO-1, and NAD(P)H expression and promoted antioxidant enzymatic activities, thus protecting hepatocytes against palmitic acid-induced lipo-toxicity and oxidative stress.…”

Mulberries: A Promising Fruit for Phytochemicals, Nutraceuticals, and Biological Activities

“…Oral feeding of mulberry fruit to rats shows a decrease in the levels of liver enzymes, hydroxyproline, hyaluronidase, ALT (Alanine aminotransferase), AST (aspartate aminotransferase) and collagen type 3 (Li et al, 2016). Further, Hu et al (2019) isolated the three different mulberry fruit polysaccharide fractions (MFP-I, MFP-II, and MFP-III) through stepwise precipitation with 30%, 60%, and 90% ethanol, respectively, and evaluated their protective efficacy against palmitic acid (PA)induced hepatocyte lipotoxicity. It was observed among all the MFPs, MFP-II significantly reduced PA-induced hepatic lipotoxicity at 0.1 and 0.2 mg/mL while other two (MFP-I and MFP-III) displayed weak protection.…”

Response Surface Methodology for Optimization of Process Parameters and Antioxidant Properties of Mulberry (Morus alba L.) Leaves by Extrusion

“…These active components contain reactive oxygen species (ROS) scavengers [4,9,10]. Substantial previous evidences indicated that MLs could be a potential functional ingredient for the production of healthy foods [5][6][7]. However, the leaves of black mulberry varieties are generally discarded because they are planted only for fruit, and the leaves are not advisable for use as food even for silkworms [11].…”

“…Recently, mulberry leaves (MLs) have been recognized as edible with medicinal properties owing to their phytochemical content [ 4 ]. Phytochemical studies have shown that MLs are a rich source of a variety of constituents, including flavonoids [ 3 , 5 ], polysaccharides [ 1 , 6 ], alkaloids [ 7 ], and 1-deoxynojirimycin [ 8 ]. Besides, several different flavonol (i.e., quercetin and kaempferol) glycosides have been reported as antioxidant constituents in MLs.…”