Ferulic Acid and Anthocyanin from Colored Maize Correlated with Prevention of High-Fat Induced Obesity in Mice by Modulating Lipid, Glucose and Inflammatory Pathways

Abstract

Abstract Objectives To compare the anti-obesity efficacy of different concentrations of phenolic-rich water extract from purple maize pericarp (PPE) in a murine model of obesity for 12 weeks. Methods Forty C57BL/6 mice (n = 10/group) were randomized: standard diet (SD), high-fat diet (HFD), HFD + 200 mg PPE/kg BW (200 PPE), and HFD + 500 mg PPE/kg BW (500 PPE). PPE contained mainly ferulic acid, anthocyanins, and other phenolics (total phenolics: 448.5 µg/mg dry weight, DW). Body weight was measured weekly. Blood glucose and triglycerides were determined biweekly. After 12 weeks, liver and adipose tissue were collected. Protein expression was performed in blood plasma. A gene array was performed on adipose tissue and liver. Histological analyses were performed in adipose tissue and liver. Results Bodyweight (−27.9%), blood glucose (−26.5%), and blood triglycerides (−22.1%) were most attenuated (P < 0.05) in the 500 PPE group compared to HFD and 200 PPE groups. At the end of the study, the animals from HFD group became hyperinsulinemic (2.1 ng/mL), whereas the treatment with 200 PE (1.6 ng/mL), and 500 PE (1.1 ng/mL) had lower (P < 0.05) insulin levels. Also, 500 PPE group had reduced (P < 0.05) plasma protein levels of TNF-α, MCP-1, resistin, and leptin compared to the HFD group. Fatty liver disease scores were highest for the HFD group (8.4), followed by 200 PPE (6.1), 500 PPE (2.7), and SD (0.4) groups. Relative adipose tissue was lower (P < 0.05) in 200 PPE (7.6%), 500 PPE (8.0%), and SD (0.8%), compared to HFD (12.1%) group. The diameter of adipocytes was significantly reduced (P < 0.05) in 200 PPE (79.1 µm) and 500 PPE (61.8 µm) groups, compared to the HFD (92.8 µm) group. In the 500 PPE group compared to HFD group, important genes were modulated related to adipogenesis (MMP3 fold-change, [FC] = 7.4), inflammation (NFKB1, FC = −1.8), and glucose metabolism (SLC2A4, FC = 23.6) in adipose tissue. In liver, 500 PPE group showed modulation of genes related to gluconeogenesis (PEPCK, FC = −2.9), lipogenesis (FAS, FC = −2.4), and β-oxidation (CPT, FC = 3.1). Conclusions Results suggested that the administration of a phenolic-rich extract from colored maize prevented obesity mainly through the modulation of TLR and AMPK signaling pathways reducing adipogenesis and adipose inflammation, and promoting energy expenditure. Funding Sources University of Illinois NIFA-USDA-HATCH.