Extruded sorghum flour (Sorghum bicolor L.) modulate adiposity and inflammation in high fat diet-induced obese rats

Highlights

• Sorghum may be used as a potential functional food for managing obesity.

• Extruded sorghum flour presented potent anti-obesity activities.

• Sorghum regulated lipogenic genes such as FAS, PPAR-γ, and LPL.

Abstract

The aim was to determine the effect of extruded sorghum flour (ESF) on the adiposity and inflammation modulation in obese Wistar rats. Four experimental groups: normal control (AIN-93), obese control (HFD) and two tested groups (replacing 50% of cellulose and 100% of cornstarch by ESF in the HFD - HFDS50; and replacing 100% of cellulose and 100% of cornstarch by ESF in the HFD - HFDS100) were used. The luteolinidin and 5-methoxy-luteliolinidin were the main deoxyanthocianidins identified in ESF. The Lee index, percentage of adiposity, fatty acid synthase gene expression, TNF-α, blood levels of glucose and the adipocyte hypertrophy were lower in the groups treated with ESF when compared to HFD. The groups treated with ESF up-regulated the lipoprotein lipase, peroxisome proliferator activated receptor-γ gene expression and IL-10. ESF has potential as a functional food since it reduced the metabolic risk of obesity associated with adiposity and inflammation.

Introduction

Historically, obesity has been a problem in developed countries. However, overweight and obesity are increasing in developing and underdeveloped countries (WHO, 2014). Worldwide, obesity has more than doubled since 1980. In 2014, more than 1.9 billion adults were classified as overweight. Among those adults, over 600 million were obese (WHO, 2016). Obesity is characterized by the excess of fat mass, which accumulates due to an imbalance between energy intake and energy expenditure, as well as the contribution of environmental and genetic factors (WHO, 2016).

The fat mass in obesity is accompanied by hypertrophy and hyperplasia of the adipocyte. The change in adipocyte differentiation depends on the number of preadipocytes in adipocytes, a process known as adipogenesis (Queiroz et al., 2012). The peroxisome proliferator that activates the receptor-γ (PPAR-γ) is a central regulator of adipogenesis, which also activates the transcription of genes involved in insulin signaling, glucose uptake, and absorption and storage of fatty acids (Brown et al., 2003). Thus, PPAR-γ coordinates the expression of specific adipogenic genes such as fatty acid synthase (FAS) and lipoprotein lipase (LPL). FAS is responsible for the synthesis and accumulation of triglycerides during the differentiation of adipocytes. LPL is the most important regulator for the deposition of triglycerides, which is hydrolyzed to very low density lipoproteins (VLDL) and chylomicrons, releasing fatty acids, which are then uptaken by the adipocytes (Ahn, Lee, Kim, & Ha, 2007).

The consumption of natural antioxidants and the adoption of a healthy diet are the best options to reduce the incidence of obesity and others non communicable disease associated (Barbalho et al., 2011, Barbalho et al., 2011). In this context, sorghum (Sorghum bicolor L.) has been highlighted as a potential food for prevention and modulation of chronic diseases, which is associated with its content of dietary fiber, lipids, phenolic compounds, tannins and flavonoids such as anthocyanins, flavones and flavanones (Cardoso et al., 2015, Moraes et al., 2012). The content of these compounds may vary depending on sorghum processing, such as extrusion cooking, oven drying and conventional stove cooking (Afify et al., 2012, Cardoso et al., 2015).

Isolated sorghum compounds have been investigated in vitro (Devi, Saravanakumar, & Mohandas, 2011) and in vivo (Chung et al., 2011, Moraes et al., 2012), demonstrating antioxidant and anti-inflammatory activity. Few studies have investigated the effect of whole sorghum in oxidative stress and inflammation in animals fed with high fat diets (Moraes et al., 2012). To date, no published studies have related the intake of extruded sorghum flour (ESF) by obese animals with the inflammation and adiposity modulation. This study reported the effect of the extruded sorghum flour added to a high fat diet on the modulation of adiposity and subclinical inflammation in obese Wistar rats.