Polyphenol Stilbenes from Fenugreek (Trigonella foenum-graecum L.) Seeds Improve Insulin Sensitivity and Mitochondrial Function in 3T3-L1 Adipocytes.

Gang Li,Yourui Suo,Fangfang Tie,Chengjun Ma,Guangxiang Luan,Zhenhua Wang,Yanfeng He,Honglun Wang

doi:10.1155/2018/7634362

Abstract

Fenugreek (Trigonella foenum-graecum L.) is a well-known annual plant that is widely distributed worldwide and has possessed obvious hypoglycemic and hypercholesterolemia characteristics. In our previous study, three polyphenol stilbenes were separated from fenugreek seeds. Here, we investigated the effect of polyphenol stilbenes on adipogenesis and insulin resistance in 3T3-L1 adipocytes. Oil Red O staining and triglyceride assays showed that polyphenol stilbenes differently reduced lipid accumulation by suppressing the expression of adipocyte-specific proteins. In addition, polyphenol stilbenes improved the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) by promoting the phosphorylation of protein kinase B (AKT) and AMP-activated protein kinase (AMPK). In present studies, it was found that polyphenol stilbenes had the ability to scavenge reactive oxygen species (ROS). Results from adenosine triphosphate (ATP) production and mitochondrial membrane potentials suggested that mitochondria play a critical role in insulin resistance and related signaling activation, such as AKT and AMPK. Rhaponticin, one of the stilbenes from fenugreek, had the strongest activity among the three compounds in vitro. Future studies will focus on mitochondrial biogenesis and function.

Highlights

Fenugreek (Trigonella foenum-graecum L.) is a well-known annual plant that belongs to the legume family and is widely distributed in China, India, and North African countries [1]
We found that polyphenol stilbenes did not have obvious effects on the viability of 3T3L1 preadipocytes at the tested concentrations of 0.1–10 μmol/ L for 48 hr
Insulin resistance seems to be attributed to the progressive failure of Type 2 diabetes mellitus (T2DM) and metabolic syndrome [33]

Summary

Introduction

Fenugreek (Trigonella foenum-graecum L.) is a well-known annual plant that belongs to the legume family and is widely distributed in China, India, and North African countries [1]. The seeds and some of its fractions have been reported to possess a wide range of biological and pharmacological effects [3, 4], including antioxidant [5, 6], hypoglycemic [7,8,9,10], hypercholesterolemia [11,12,13], and immunomodulatory activities [14]. We successfully separated and purified several compounds from fenugreek seed extracts, including unsaturated fatty acids [17], flavonoids, and polyphenolic substances [18, 19]. Several reports are available on the active components in fenugreek, little is known about the impact of polyphenol stilbenes on the glucose and lipid metabolism and its mechanisms of action have not yet been elucidated. To explore the underlying mechanisms of action, modulation of these stilbenes on the AMPK pathway and reactive oxygen species (ROS) was discussed

Materials and Methods

Results

Discussion