Adzuki Bean MY59 Extract Reduces Insulin Resistance and Hepatic Steatosis in High-Fat-Fed Mice via the Downregulation of Lipocalin-2

Abstract

Adzuki bean is well known as a potential functional food that improves metabolic complications from obesity and diabetes. Lipocalin-2 (LCN2) has been implicated to have an important role in obesity and diabetes. However, the protective roles of adzuki bean MY59 extract (ABE) on insulin resistance and hepatic steatosis are not fully understood. In the present study, we investigated the effects of ABE on LCN2 expression in high-fat diet (HFD)-fed mice. ABE reduced HFD-induced fat mass and improved insulin resistance. In addition to hepatic steatosis, HFD-fed mice showed many apoptotic cells and neutrophils in the epididymal fat pads. However, these findings were significantly reduced by ABE supplementation. In particular, we found that increased LCN2 proteins from serum, epididymal fat pads, and liver in HFD-fed mice are significantly reduced by ABE. Furthermore, ABE reduced increased heme oxygenase-1 and superoxide dismutase-1 expressions in adipose tissue and liver in HFD-fed mice. We found that hepatic nuclear factor-kappa B (NF-κB) p65 expression in HFD-fed mice was also reduced by ABE. Thus, these findings indicate that ABE feeding could improve insulin resistance and hepatic steatosis by decreasing LCN2-mediated inflammation and oxidative stress in HFD-fed mice.

The Potential of the Adzuki Bean (Vigna angularis) and Its Bioactive Compounds in Managing Type 2 Diabetes and Glucose Metabolism: A Narrative Review

“…Hyperglycemia is one of the T2D-related outcomes for studying the effectiveness of diabetes management. High-fat diets have been found to contribute to higher blood glucose levels, and various studies have used high-fat diets as one of the means to induce high blood glucose in mice [ 10 , 36 , 37 , 38 , 39 ]. All these investigations found that supplementing high-fat diets with adzuki bean flour could improve such conditions.…”

“…Mice that received an adzuki bean extract in their diet were found to have better glucose regulation and pancreatic function [ 10 , 38 , 39 ]. An animal study providing 3-week-old male C57BL/6 mice with a high-fat diet consisting of 45% kcal from fat found that the high-fat diet significantly increased fasting blood glucose level, serum insulin, insulin resistance, and the Langerhans islet area of β-cells ( p < 0.05) [ 38 ]. Adding 200 mg/kg BW/day of adzuki bean extract to the high-fat diet of the mice significantly reduced the increased parameters ( p < 0.05).…”

“…Another study found that consuming 150 g cooked adzuki beans/kg diet with a high-fat diet had similar benefits for liver function [ 32 ]. Moreover, providing 200 mg adzuki bean extract/kg BW/day to mice on a high-fat diet significantly reduced the increased serum alanine aminotransferase caused by the high-fat diet ( p < 0.05) [ 38 ]. Lee et al [ 38 ] found that consuming 200 mg/kg BW/day of adzuki bean extract could significantly reduce hepatic inflammation in the mice ( p < 0.05), and, therefore, improve liver function.…”

“…Moreover, providing 200 mg adzuki bean extract/kg BW/day to mice on a high-fat diet significantly reduced the increased serum alanine aminotransferase caused by the high-fat diet ( p < 0.05) [ 38 ]. Lee et al [ 38 ] found that consuming 200 mg/kg BW/day of adzuki bean extract could significantly reduce hepatic inflammation in the mice ( p < 0.05), and, therefore, improve liver function. Similarly, consuming adzuki bean flour supplements could improve the liver damage caused by diabetes [ 10 ].…”

Comparison of the anti-diabetic effects of various grain and legume extracts in high-fat diet and streptozotocin-nicotinamide-induced diabetic rats

“…A few animal studies have investigated the anti-diabetic effects of organic solvent extracts from oats [ 21 ], sorghum [ [22] , [23] , [24] ], adzuki bean [ 25 , 26 ], and black soybean [ 27 , 28 ]. However, there is limited research comprehensively evaluating the effects of extracts on not only hyperglycemia but also insulin sensitivity and pancreas damage.…”