p-Coumaric Acid Enhances Hypothalamic Leptin Signaling and Glucose Homeostasis in Mice via Differential Effects on AMPK Activation

Lyophilized Avocado Paste Improves Corn Chips' Nutritional Properties and Sensory Acceptability

Avocado paste (AP) is an industrial byproduct and a potential source of bioactive compounds, so there is great interest in its valorization. The objective of the present study was to evaluate the effects of adding AP to corn chips regarding their nutritional profile and sensory acceptability. Three AP-supplemented corn chip samples were prepared (C-2%, C-6%, and C-10%), along with a control chip (C), whose total phenolics, flavonoids, antioxidant capacity, proximate composition, minerals, fatty acids, and sensory acceptability were evaluated. Regarding the content of phenolic compounds and flavonoids, significant increases were found between all samples (p < 0.05), particularly between C and C-10% (from 0.93 to 3.56 mg GAE/g dw and 1.17 to 6.61 mg QE/g dw, respectively). Their antioxidant capacity also increased significantly (p < 0.05) with all methods used (FRAP, DPPH, ORAC, and TEAC). Regarding the sensory analysis, no significant differences were found (p > 0.05) between C and C-2% in the parameters of smell, color, flavor, and overall acceptability; however, the texture of C-2% was better evaluated. The C-2% sample also had the highest acceptability; 82% of the participants mentioned that they would buy the C-2%, higher than the rest of the samples. These results suggest the feasibility of adding 2% AP as a strategy to improve the nutritional properties of corn chips without compromising their sensory acceptability; therefore, AP may be used as a food ingredient.

P-coumaric Acid: Advances in Pharmacological Research Based on Oxidative Stress

P-coumaric acid is an important phenolic compound that is mainly found in fruits, vegetables, grains, and fungi and is also abundant in Chinese herbal medicines. In this review, the pharmacological research progress of p-coumaric acid in recent years was reviewed, with emphasis on its role and mechanism in oxidative stress-related diseases, such as inflammation, cardiovascular diseases, diabetes, and nervous system diseases. Studies have shown that p-coumaric acid has a positive effect on the prevention and treatment of these diseases by inhibiting oxidative stress. In addition, p-coumaric acid also has anti-tumor, antibacterial, anti-aging skin and other pharmacological effects. This review will provide reference and inspiration for further research on the pharmacological effects of p-coumaric acid.

Novel Effect of p-Coumaric Acid on Hepatic Lipolysis: Inhibition of Hepatic Lipid-Droplets

p-coumaric acid (p-CA), a common plant phenolic acid with multiple bioactivities, has a lipid-lowering effect. As a dietary polyphenol, its low toxicity, with the advantages of prophylactic and long-term administration, makes it a potential drug for prophylaxis and the treatment of nonalcoholic fatty liver disease (NAFLD). However, the mechanism by which it regulates lipid metabolism is still unclear. In this study, we studied the effect of p-CA on the down-regulation of accumulated lipids in vivo and in vitro. p-CA increased a number of lipase expressions, including hormone-sensitive lipase (HSL), monoacylglycerol lipase (MGL) and hepatic triglyceride lipase (HTGL), as well as the expression of genes related to fatty acid oxidation, including long-chain fatty acyl-CoA synthetase 1 (ACSL1), carnitine palmitoyltransferase-1 (CPT1), by activating peroxisome proliferator-activated receptor α, and γ (PPARα and γ). Furthermore, p-CA promoted adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and enhanced the expression of the mammalian suppressor of Sec4 (MSS4), a critical protein that can inhibit lipid droplet growth. Thus, p-CA can decrease lipid accumulation and inhibit lipid droplet fusion, which are correlated with the enhancement of liver lipases and genes related to fatty acid oxidation as an activator of PPARs. Therefore, p-CA is capable of regulating lipid metabolism and is a potential therapeutic drug or health care product for hyperlipidemia and fatty liver.

Combination Therapy of Metformin and p-Coumaric Acid Mitigates Metabolic Dysfunction Associated with Obesity and Non-Alcoholic Fatty Liver Disease in High-Fat Diet Obese C57BL/6 Mice

Metformin (MET) has been demonstrated to have favorable impact on nonalcoholic fatty liver disease (NAFLD); however, the combined effect of this drug with p-coumaric acid (PCA) on liver steatosis is unclear. The aim of the current study was to evaluate the combined effects of MET and PCA on NAFLD in a high-fat diet (HFD)-induced NAFLD mouse model. The obese mice received MET (230 mg/kg), PCA (200 mg/kg) monotherapies, and MET combination with PCA in the diet for 10 weeks. Our results showed that the combination of MET and PCA markedly ameliorated weight gain and fat deposition in HFD fed mice. Furthermore, the combination of MET and PCA lowered liver triglyceride (TG) content which was accompanied by decreased expression of lipogenic and increased expression of β-oxidation related genes and proteins. In addition, combination therapy of MET and PCA mitigated liver inflammation through inhibiting hepatic macrophage infiltration (F4/80), switching macrophage from M1 into M2 phenotype, and ameliorating nuclear factor-κB (NF-κB) activity in comparison with the monotherapy of MET or PCA. Furthermore, we found that MET and PCA combination therapy upregulated thermogenesis-related genes in BAT and sWAT. Combination therapy results in stimulating brown-like adipocyte (beige) formation in the sWAT of HFD mice. Taken together, these findings indicate that MET combined with PCA can improve NAFLD through decreasing lipid accumulation, inhibiting inflammation and inducing thermogenesis, and adipose tissue browning.

Whole grains-derived functional ingredients against hyperglycemia: targeting hepatic glucose metabolism

Type 2 diabetes mellitus (T2DM) is characterized by the dysregulation of glucose homeostasis, resulting in hyperglycemia. However, concerns have been raised about the safety and efficacy of current hypoglycemic drugs due to undesirable side effects. Increasing studies have shown that whole grains (WG) consumption is inversely associated with the risk of T2DM and its subsequent complications. Thus, dietary strategies involving functional components from the WG provide an intriguing approach to restoring and maintaining glucose homeostasis. This review provides a comprehensive understanding of the major functional components derived from WG and their positive effects on glucose homeostasis, demonstrates the underlying molecular mechanisms targeting hepatic glucose metabolism, and discusses the unclear aspects according to the latest viewpoints and current research. Improved glycemic response and insulin resistance were observed after consumption of WG-derived bioactive ingredients, which are involved in the integrated, multi-factorial, multi-targeted regulation of hepatic glucose metabolism. Promotion of glucose uptake, glycolysis, and glycogen synthesis pathways, while inhibition of gluconeogenesis, contributes to amelioration of abnormal hepatic glucose metabolism and insulin resistance by bioactive components. Hence, the development of WG-based functional food ingredients with potent hypoglycemic properties is necessary to manage insulin resistance and T2DM.

Attenuation of hepatic fibrosis by p-Coumaric acid via modulation of NLRP3 inflammasome activation in C57BL/6 mice

A prolonged high-fat and high-sucrose (HFHS) diet induces hepatic inflammation and mediates hepatic stellate cell (HSC) activation, which result in hepatic fibrosis. Aberrant activation of the innate immune system components, such as the NOD-like receptor protein 3 (NLRP3) inflammasome, has been implicated in HSC activation and hepatic fibrosis. We have previously shown that p-coumaric acid (PCA)-enriched peanut sprout extracts exert anti-inflammatory effects. However, it is unknown whether PCA reduces hepatic fibrosis by modulating innate immunity and HSC activation. To test this hypothesis, C57BL/6 male mice were randomly assigned to three groups and fed low-fat (LF) diet (11% calories from fat), high-fat (HF) diet (60% calories from fat, 0.2% cholesterol) with sucrose drink (20% sucrose, HFHS), or HFHS diet with PCA treatment (HFHS+PCA, 50 mg/kg body weight, intraperitoneally) for 13 weeks. The results showed that PCA treatment (1) partly improved systemic insulin sensitivity without altering adiposity, (2) attenuated hepatic signaling pathways associated with NLRP3 inflammasome activation, including toll-like receptor 4 (TLR4)/nuclear factor kappa B (NFκB), and endoplasmic reticulum/oxidative stress, and (3) reduced circulating interleukin (IL)-1β levels. More importantly, PCA ameliorated hepatic fibrosis compared to that in the HFHS group, and the anti-fibrogenic effects of PCA were confirmed in vitro in transforming growth factor β (TGFβ) treated-LX-2 HSCs. The role of PCA in decreased NLRP3 activation and caspase-1 cleavage was recapitulated in primary bone marrow‒derived macrophages. These findings indicate that PCA contributes to the prevention of HFHS diet‒mediated liver fibrosis, partly by attenuating the activation of the NLRP3 inflammasome.

Damp-heat constitution influences gut microbiota and urine metabolism of Chinese infants

Background

As an increasingly popular complementary and alternative approach for early detection and treatment of disease, traditional Chinese medicine constitution (TCMC) divides human beings into those with balanced constitution (BC) and unbalanced constitution, where damp-heat constitution (DHC) is one of the most unbalanced constitutions. Many studies have been carried out on the microscopic mechanism of constitution classification; however, most of these studies were conducted in adults and rarely in infants. Many diseases are closely related to intestinal microbiota, and metabolites produced by the interaction between microbiota and the body may impact constitution classification. Herein, we investigated the overall constitution distribution in Chinese infants, and analyzed the profiles of gut microbiota and urine metabolites of DHC to further promote the understanding of infants constitution classification.

Methods

General information was collected and TCMC was evaluated by Constitutional Medicine Questionnaires. 1315 questionnaires were received in a cross-sectional study to investigate the constitution composition in Chinese infants. A total of 56 infants, including 30 DHC and 26 BC, were randomly selected to analyze gut microbiota by 16S rRNA sequencing and urine metabolites by UPLC-Q-TOF/MS method.

Results

BC was the most common constitution in Chinese infants, DHC was the second common constitution. The gut microbiota and urine metabolites in the DHC group showed different composition compared to the BC group. Four differential genera and twenty differential metabolites were identified. In addition, the combined marker composed of four metabolites may have the high potential to discriminate DHC from BC with an AUC of 0.765.

Conclusions

The study revealed the systematic differences in the gut microbiota and urine metabolites between infants with DHC and BC. Moreover, the differential microbiota and metabolites may offer objective evidences for constitution classification.

Amelioration of radiation-induced liver damage by p-coumaric acid in mice

Radiation-induced liver damage (RILD) is a spiny problem in radiotherapy or other circumstances that exposure to radiation. The need for radioprotective agent is increasing to protect liver tissue. This study aimed to explore the hepatoprotective effect of p-coumaric acid (CA) against RILD. C57BL/6 male mice were exposed to 4 Gy irradiation and administrated with CA for 4 days starting on the same day of irradiation. Mice were sacrificed to obtain blood and liver tissues on day 3.5 or 14 post irradiation, respectively. The blood and liver tissues were collected. As compared with the only irradiated group, CA supplementation improved liver morphology, decreased serum alanine aminotransferase and aspartate aminotransferase, inhibited BCL2-associated X (BAX) protein expression, and improved the mice hematopoietic function. CA at the dose of 100 mg/kg body weight showed better effect compared to the other doses. Thus, CA might possess potential to protect against RILD.

Sub-chronic consumption of a phenolic-rich avocado paste extract induces GLP-1-, leptin-, and adiponectin-mediated satiety in Wistar rats

Avocado paste (AP) is a phenolic-rich byproduct of avocado oil extraction. The effects of sub-chronic consumption of diets supplemented with an AP phenolic extract (PE) were analyzed. A standard diet (SD), high-fat diet (HFD), and these supplemented with PE (SD + PE and HFD + PE) were used. Significantly increased satiety was observed in PE-supplemented groups, according to less food consumption (-15% in SD + PE vs. SD, and -11% in HFD + PE vs. HFD), without changes in weight gain or percentage of adipose tissue. PE-supplemented groups had an increased plasma concentration ( + 16% in SD + PE vs. SD, and +26% in HFD + PE vs. HFD) and relative mRNA expression (+74% in SD + PE vs. SD, and +46% in HFD + PE vs. HFD) of GLP-1; an increase in plasma leptin and adiponectin was independent of their mRNA expression. Our results suggest that AP-derived PE exerts a satiety effect in vivo, possibly mediated by GLP-1, leptin, and adiponectin. PRACTICAL APPLICATIONS: Minimizing food waste is a top priority in most of the world, thus, researchers seek methods to reintroduce industrial fruit and vegetable byproducts into the food processing chain. The present work highlights the potential of avocado byproducts as sources of bioactive phenolic compounds, whose sub-chronic consumption (8 weeks) exerts a satiety action in vivo. Avocado farming is resource-intensive, making it of relevance to producers and processing industries to avoid discarding its byproducts as much as possible.