Soy sauce increased the oxidative stress tolerance of nematode via p38 MAPK pathway

Biological effects of Maillard reaction products: Use of Caenorhabditis elegans as an in vivo model

Maillard reaction products (MRPs), including melanoidins and volatile odor compounds, are associated with distinct flavors and colors during food processing and cooking. Although MRPs have health benefits, such as antioxidant activity, they are also associated with pathophysiological effects. Several in vivo models, especially rodents, are used to demonstrate physiological effects. Caenorhabditis elegans (C. elegans), an easy-to-rear free-living nematode with a short lifespan, has been used as a promising in vivo organism for the evaluation of functional properties in food components, including antiaging, antioxidant, and antiobesity properties. Furthermore, the high olfactory discrimination of this organism allows for the basic elucidation of behavior and regulation of aging. In this minireview, I discuss the various attributes of C. elegans that make it a promising in vivo model for studying the biological effects of MRPs.

Insight of Silkworm Pupa Oil Regulating Oxidative Stress and Lipid Metabolism in Caenorhabditis elegans

Silkworm pupa oil (SPO) contains unsaturated fatty acids, tocopherols, and phytosterols, which can regulate serum total cholesterol or be used as an antioxidant. In this study, we investigated the impacts of SPO on the antioxidant stress and lipid metabolism of Caenorhabditis elegans. The lifespan of the C. elegans fed with different SPO concentrations was determined. The levels of endogenous reactive oxygen species (ROS) were analyzed with the fluorescent probe method. The activity of antioxidant enzymes and the content of malondialdehyde (MDA) were analyzed. The transcription level of specific mRNA was characterized with q-PCR. The survival time of the mutant strain under oxidative stress was determined by daf-2 (CB1370) mutant, sod-3 (GA186) mutant, and skn-1 (EU31) mutant. As for the lipid metabolism, the lipid accumulation was determined with an Oil-Red-O (ORO) staining. The transcription level of specific mRNA was determined by q-PCR. The results showed that the SPO feeding enhanced the activities of antioxidant enzyme by upregulating the expression of the genes skn-1, and sod-3 to decrease the production of ROS and MDA, which prolonged the life of nematodes treated with juglone. ORO staining analysis indicated the feeding of SPO decreased intestinal fat accumulation, downregulated expression of fat-5, fat-6, fat-7, and nhr-80, and upregulated age-1 and tph-1 expression. Conclusively, SPO enhanced the antioxidant capacity by regulating the skn-1 and sod-3 expression of antioxidant gene and reducing the fat accumulation by the insulin/IGF signaling pathway and nuclear hormone receptor nhr-80 signaling pathway of nematodes. This study provides new evidence for the antioxidant and lipid-lowering mechanisms of SPO in C. elegans.

Transport of Amino Acids in Soy Sauce Desalination Process by Electrodialysis

Soy sauce is a common condiment that has a unique flavor, one that is derived from its rich amino acids and salts. It is known that excessive intake of high-sodium food will affect human health, causing a series of diseases such as hypertension and kidney disease. Therefore, removing sodium from the soy sauce and retaining the amino acids is desirable. In this study, electrodialysis (ED) was employed for the desalination of soy sauce using commercial ion exchange membranes (IEMs). The influence of the current density and initial pH on the desalination degree of the soy sauce was explored. Results showed that the optimal desalination condition for ED was reached at a current density of 5 mA/cm² and pH of 5, with the desalination degree of 64% and the amino acid loss rate of 29.8%. Moreover, it was found that the loss rate of amino acids was related to the initial concentration and molecular structure. In addition, the amino acid adsorption by IEMs was explored. Results implied that the molecular weight and structure affect amino acid adsorption. This study illustrated that the ED process can successfully reduce the salt content of the soy sauce and retain most of the amino acids without compromising the original flavor.

Revealing the antiaging effects of cereal- and food oil-derived active substances by a Caenorhabditis elegans model

Cereal grains and oils contain various functional ingredients, such as amino acids, peptides, polyphenols, dietary fiber, linoleic acid, and natural pigments. Their biological activities are of great significance. Benefiting from its robust genetic function and simple cultivation, Caenorhabditis elegans, as one of the most important model organisms has been widely used to screen antiaging substances and investigate the underlying molecular mechanisms. In this paper, the recent advances in the use of C. elegans in antiaging research into active substances from cereals and oils will be assessed, and their potential signal transduction mechanisms will be systematically reviewed. This research aims to provide a theoretical reference for the use of active substances from cereals and oils to prevent and delay aging and aging-associated diseases.

Chinese Traditional Fermented Soy Sauce Exerts Protective Effects against High-Fat and High-Salt Diet-Induced Hypertension in Sprague-Dawley Rats by Improving Adipogenesis and Renin-Angiotensin-Aldosterone System Activity

Although high-fat and high-salt diets are considered risk factors for hypertension, the intake of salty soybean-based fermented foods has beneficial effects. This study explored the potential of Chinese traditional fermented soy sauce (CTFSS) in preventing hypertension by analyzing its effects on adipogenesis and the renin-angiotensin-aldosterone system (RAAS). Male Sprague-Dawley (SD) rats were divided into four groups (n = 6): normal diet (ND), high-fat diet (HD), high-fat diet with saline (HDS, NaCl-8%), and high-fat diet with Chinese traditional soy sauce (HDCTS, NaCl-8%). Each group is administrated 12 weeks by oral gavage as 10 mL/kg dose, respectively. CTFSS supplementation resulted in significantly lower body weight, epididymal fat weight, and systolic blood pressure. Additionally, it decreased the serum total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), renin, angiotensin II (Ang II), angiotensin-converting enzyme (ACE), and aldosterone levels. It also increased the urinary volume and improved sodium and potassium ion balance. The gene levels showed significant enhancements in the mRNA levels of renin-angiotensin-aldosterone system-related and adipogenesis-related genes. In addition, CTFSS may prevent hypertension-associated kidney injury. Therefore, this study demonstrates that CTFSS has no harmful effects on hypertension. In contrast, the beneficial effects of CTFSS intake in ameliorating hypertension were shown.