Hexane-Isopropanolic Extract of Tungrymbai, a North-East Indian fermented soybean food prevents hepatic steatosis via regulating AMPK-mediated SREBP/FAS/ACC/HMGCR and PPAR\u03b1/CPT1A/UCP2 pathways

Anjum Dihingia,Jatin Kalita,Prachurjya Dutta,Prasenjit Manna,Jijnasa Bordoloi

doi:10.1038/s41598-018-27607-7

Abstract

This study for the first time examined the prophylactic role of Tungrymbai, a well-known fermented soybean food of North-East India, against hepatic steatosis. Treatment with hexane-isopropanolic (2:1, HIET) but not hydro-alcoholic (70% ethanol, HAET) extract dose-dependently (0.1, 0.2, or 0.3 µg/mL) reduced the intracellular lipid accumulation as shown by lower triglyceride levels and both Oil Red O and Nile Red staining in palmitate (PA, 0.75 mM)-treated hepatocytes. Immunobloting, mRNA expression, and knock-down studies demonstrated the role of AMPK-mediated SREBP/FAS/ACC/HMGCR and PPARα/CPT1A/UCP2 signaling pathways in facilitating the beneficial role of HIET against lipid accumulation in PA-treated hepatocytes. Animal studies further showed a positive effect of HIET (20 µg/kg BW, 8 weeks, daily) in regulating AMPK/SREBP/PPARα signaling pathways and reducing body weight gain, plasma lipid levels, and hepatic steatosis in high fat diet (HFD)-fed mice. Histological analyses also revealed the beneficial effect of HIET in reducing hepatic fat accumulation in HFD mice. Chemical profiling (HRMS, IR, and HPLC) demonstrated the presence of menaquinone-7 (vitamin K2) as one of the bio-active principle(s) in HIET. Combining all, this study demonstrates the positive effect of HIET on reducing hepatic steatosis via regulating AMPK/SREBP/PPARα signaling pathway.

Highlights

The liver plays a major role in modulating lipid metabolism and maintaining lipid homeostasis
To determine the effect of hydro-alcoholic (70% ethanol, HAET) and hexane-isopropanolic (2:1, HIET) extracts of Tungrymbai on intracellular lipid accumulation, hepatocytes were treated with different doses of HAET and HIET (0.1, 0.2, or 0.3 μg/mL) with or without palmitate (PA, 0.75 mM)
Results showed that treatment with HIET but not HAET significantly inhibited the Oil Red O accumulation in PA-treated hepatocytes in a dose-dependent manner (Fig. 1B,D)

Summary

Introduction

The liver plays a major role in modulating lipid metabolism and maintaining lipid homeostasis. Non-alcoholic fatty liver disease (NAFLD) is gaining acceptance as a major health burden in the developed countries. It is highly associated with obesity and insulin resistance and is considered as the hepatic manifestation of metabolic syndrome[1,2,3]. Various studies reported that fermented soybean foods and their functional components, including isoflavonoids, unsaturated fatty acids, and small peptides, could provide protection against chronic diseases, like obesity, type 2 diabetes, hypertension and carcinogenesis[5,6]. Tungrymbai is a well-known naturally fermented soybean food commonly consumed in the state of Meghalaya, North- East India, and it serves as a cheap source of high protein food in local diet[8]. The bioactive principle has been identified by using different spectroscopic and chromatographic analyses, like high resolution mass spectroscopy (HRMS), infrared spectroscopy (IR), and high-performance liquid chromatography (HPLC)

Methods

Results

Conclusion