Effects of myofibril-palatinose conjugate as a phosphate substitute on meat emulsion quality

The objective of this study was to investigate a replacement for phosphate in meat products. Protein structural modification was employed in this study, and grafted myofibrillar protein (MP) with palatinose was added to meat emulsion without phosphate. Here, 0.15% of sodium polyphosphate (SPP) was replaced by the same (0.15%) concentration and double (0.3%) the concentration of grafted MP. Although the thermal stability was decreased, the addition of transglutaminase could increase stability. The rheological properties and pH also increased with the addition of grafted MP and transglutaminase. The addition of grafted protein could be perceived by the naked eye by observing a color difference before cooking, but it was not easy to detect after cooking. The cooking loss, emulsion stability, water holding capacity, lipid oxidation, and textural properties improved with the addition of grafted MP. However, the excessive addition of grafted MP and transglutaminase was not recommended to produce a high quality of phosphate replaced meat emulsion, and 0.15% was identified as a suitable addition ratio of grafted MP.

Methods to Isolate Muscle Stem Cells for Cell-Based Cultured Meat Production: A Review

Cultured meat production relies on various cell types, including muscle stem cells (MuSCs), embryonic stem cell lines, induced pluripotent cell lines, and naturally immortalized cell lines. MuSCs possess superior muscle differentiation capabilities compared to the other three cell lines, making them key for cultured meat development. Therefore, to produce cultured meat using MuSCs, they must first be effectively separated from muscles. At present, the methods used to isolate MuSCs from muscles include (1) the pre-plating method, using the ability of cells to adhere differently, which is a biological characteristic of MuSCs; (2) the density gradient centrifugation method, using the intrinsic density difference of cells, which is a physical characteristic of MuSCs; and (3) fluorescence- and magnetic-activated cell sorting methods, using the surface marker protein on the cell surface of MuSCs, which is a molecular characteristic of MuSCs. Further efficient and valuable methods for separating MuSCs are expected to be required as the cell-based cultured meat industry develops. Thus, we take a closer look at the four methods currently in use and discuss future development directions in this review.

Effect of Crude Polysaccharides from Ecklonia cava Hydrolysate on Cell Proliferation and Differentiation of Hanwoo Muscle Stem Cells for Cultured Meat Production

Ecklonia cava, a brown seaweed native to the East Asian coast, is known for its unique composition, including polysaccharides, polyphenols, and phlorotannins. Fucoidan is a sulfated polysaccharide widely used as a functional ingredient in foods. This study obtained crude polysaccharides (ECC_CPS) from E. cava celluclast enzymatic hydrolysate using ethanol precipitation. ECC_CPS increased cell viability during the proliferation of Hanwoo muscle satellite cells (HMSCs). The effect of ECC_CPS on the expression of proliferation-related markers was confirmed as MYF5 and MYOD expression significantly increased, whereas PAX7 expression was maintained. The evaluation of cell migration activity has a major impact on cell proliferation and differentiation, and the cell migration index significantly increased with ECC_CPS treatment (p < 0.01). This was related to the HGF/MET pathway and FAK pathway. Treatment with ECC_CPS promoted differentiation at the cell differentiation stage, thereby increasing the expression of differentiation markers, such as MYH2, MYH7, and MYOG (p < 0.001 or p < 0.01). Therefore, our findings imply that crude polysaccharide obtained from E. cava can be an additive ingredient that enhances the proliferation and differentiation of muscle satellite cells used in the manufacture of cultured meat products.

Glyoxal-derived advanced glycation end products (GO-AGEs) with UVB critically induce skin inflammaging: in vitro and in silico approaches

Advanced glycation end products (AGEs) have potential implications on several diseases including skin inflammation and aging. AGEs formation can be triggered by several factors such as UVB, glyoxal and methylglyoxal etc. However, little attention has been paid to glyoxal-derived AGEs (GO-AGEs) and UVB-induced skin inflammaging, with none have investigated together. This study aimed to investigate the possible role of GO-AGEs and UVB in skin inflammaging focusing on revealing its molecular mechanisms. The effects of GO-AGEs in the presence or absence of UVB were studied by using enzyme linked immunosorbent assay, western blotting, qPCR, flow cytometry and in silico approaches. In HaCaT cells, GO-AGEs in the presence of UVB irradiation (125 mJ/cm2) dramatically enhanced the release of different pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) with further activation of RAGE signaling pathways (NF-κB, COX 2, and IL- 1β) and increased oxidative stress also noticed in NHEK cells. In NHDF cells, extracellular matrix disruption noted via increasing matrix metalloproteinase release and decreasing collagen type 1 and SIRT1 expression. Besides that, the docking scores obtained from the molecular docking study support the above-mentioned results. This study strongly suggests the pivotal role of GO-AGEs in skin inflammaging and illuminates novel molecular pathways for searching most effective and updated anti-aging therapy.

Effects of Natural Extract Mixtures on the Quality Characteristics of Sausages during Refrigerated Storage

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

The Antioxidant Activity of Undaria pinnatifida Sporophyll Extract Obtained Using Ultrasonication: A Focus on Crude Polysaccharide Extraction Using Ethanol Precipitation

Undaria pinnatifida, a marine biological resource from which antioxidants such as polysaccharides can be obtained, is primarily distributed in the coastal areas of East Asia. Reactive oxygen species (ROS) are essential for physiological processes; however, excess ROS levels in the body result in cellular oxidative damage. Several extraction methods exist; however, factors such as long extraction times and high temperatures degrade polysaccharides. Therefore, this study aimed to increase the yield of U. pinnatifida sporophyll extract (UPE), a U. pinnatifida byproduct, using ultrasonication, an environmentally friendly extraction method, and identify UPE components with antioxidant activity. UPE_2, 4, 6, and 8 extracts were obtained at extraction times of 2, 4, 6, and 8 h, respectively. UPE_8 had the highest yield (31.91%) and polysaccharide (69.22%), polyphenol, (8.59 GAE μg/mg), and fucoxanthin contents (2.3 μg/g). UPE_8 showed the greatest protective and inhibitory effects on ROS generation in H2O2-damaged Vero cells. Ethanol precipitation of UPE_8 confirmed that UPE_8P (precipitate) had superior antioxidant activity in Vero cells compared to UPE_8S (supernatant). UPE_8P contained a large amount of polysaccharides, a major contributor to the antioxidant activity of UPE_8. This study shows that UPE_8 obtained using ultrasonication can be a functional food ingredient with excellent antioxidant activity.

CLK2 in GABAergic neurons is critical in regulating energy balance and anxiety-like behavior in a gender-specific fashion

Introduction

Cdc2-like kinase (CLK2) is a member of CLK kinases expressed in hypothalamic neurons and is activated in response to refeeding, leptin, or insulin. Diet-induced obesity and leptin receptor-deficient db/db mice lack CLK2 signal in the hypothalamic neurons. The neurotransmiter gamma-aminobutyric acid (GABA) is among the most prevalent in the central nervous system (CNS), particularly in the hypothalamus. Given the abundance of GABA-expressing neurons and their potential influence on regulating energy and behavioral homeostasis, we aimed to explore whether the deletion of CLK2 in GABAergic neurons alters energy homeostasis and behavioral and cognitive functions in both genders of mice lacking CLK2 in Vgat-expressing neurons (Vgat-Cre; Clk2loxP/loxP) on chow diet.

Methods

We generated mice lacking Clk2 in Vgat-expressing neurons (Vgat-Cre; Clk2loxP/loxP) by mating Clk2loxP/loxP mice with Vgat-IRES-Cre transgenic mice and employed behavior, and physiological tests, and molecular approaches to investigate energy metabolism and behavior phenotype of both genders.

Results and discussion

We showed that deletion of CLK2 in GABAergic neurons increased adiposity and food intake in females. The mechanisms behind these effects were likely due, at least in part, to hypothalamic insulin resistance and upregulation of hypothalamic Npy and Agrp expression. Besides normal insulin and pyruvate sensitivity, Vgat-Cre; Clk2loxP/loxP females were glucose intolerant. Male Vgat-Cre; Clk2loxP/loxP mice showed an increased energy expenditure (EE). Risen EE may account for avoiding weight and fat mass gain in male Vgat-Cre; Clk2loxP/loxP mice. Vgat-Cre; Clk2loxP/loxP mice had no alteration in cognition or memory functions in both genders. Interestingly, deleting CLK2 in GABAergic neurons changed anxiety-like behavior only in females, not males. These findings suggest that CLK2 in GABAergic neurons is critical in regulating energy balance and anxiety-like behavior in a gender-specific fashion and could be a molecular therapeutic target for combating obesity associated with psychological disorders in females.

Structural characteristics of resistant starch-enriched rice during digestion and its effects on gut barrier function in high-fat induced obese mice

Dietary supplementation with indigestible carbohydrates is known to improve the gut environment and prevent obesity and inflammatory diseases by modulating the gut microbiota. In previous work, we established a method for the production of resistant starch (RS)-enriched high-amylose rice (R-HAR) using citric acid. The present study aimed to evaluate changes in structural characteristics during digestion of R-HAR and its effects on the gut health. A three-step in vitro digestion and fermentation model was used, then, RS content, scanning electron microscopy, and branch chain length distribution were analyzed during in vitro digestion. During the digestion of R-HAR, the RS content increased, and the structure was predicted to have a greater impact on the gut microbiota and gut environment. To study the intestinal health effects of R-HAR, its anti-inflammatory and gut barrier integrity activities were assayed in HFD-induced mice. Intake of R-HAR suppressed colonic shortening and inflammatory responses induced by HFD. Furthermore, R-HAR exhibited gut barrier protective activity with an increase in tight junction protein levels. We determined that R-HAR may be a potentially beneficial intestinal environment improver, which may have various implications in the food industry as rice.

LRP1 mediates leptin transport by coupling with the short-form leptin receptor in the choroid plexus

Adipocyte-derived leptin enters the brain to exert its anorexigenic action, yet its transport mechanism is poorly understood. Here we report that LRP1 (low-density lipoprotein receptor-related protein-1) mediates the transport of leptin across the blood-CSF barrier in Foxj1 expressing cells highly enriched at the choroid plexus (ChP), coupled with the short-form leptin receptor, and LRP1 deletion from ependymocytes and ChP cells leads to leptin resistance and hyperphagia, causing obesity. Thus, LRP1 in epithelial cells is a principal regulator of leptin transport in the brain.

Structural, physicochemical, and immune-enhancing properties of edible insect protein isolates from Protaetia brevitarsis larvae

Edible insects are promising future food resources globally. Herein, the structural, physicochemical, and bio-functional properties of edible insect protein isolates (EPIs) extracted from Protaetia brevitarsis larvae were investigated. The results showed that EPIs have a high total essential amino acid content; moreover, β-sheet is the major secondary protein structure. The EPI protein solution was highly soluble and electrically stable and did not aggregate easily. In addition, EPIs exhibited immune-enhancing properties; EPI treatment of macrophages induced the activation of macrophages and consequently promoted the production of pro-inflammatory mediators (NO, TNF-α, and IL-1β). Moreover, macrophage activation of EPIs was confirmed to occur through the MAPK and NF-κB pathways. In conclusion, our results suggest that the isolated P. brevitarsis protein can be fully utilized as a functional food material and alternative protein source in the future food industry.

Fucoidan from Sargassum autumnale Inhibits Potential Inflammatory Responses via NF-κB and MAPK Pathway Suppression in Lipopolysaccharide-Induced RAW 264.7 Macrophages

Fucoidans are sulfate-rich polysaccharides with a wide variety of beneficial biological activities. The present study aimed to highlight the anti-inflammatory activity of fucoidan from the brown seaweed Sargassum autumnale (SA) against lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. Among the isolated fucoidan fractions, the third fraction (SAF3) showed a superior protective effect on LPS-stimulated RAW 264.7 cells. SAF3 inhibits nitric oxide (NO) production and expression of prostaglandin E-2 (PGE2) via downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) expression in LPS-induced RAW 26.7 cells. SAF3 treatment decreased pro-inflammatory cytokines IL-1β, TNF-α, and IL-6 expression in LPS-induced cells. LPS stimulation activated NF-κB and MAPK signaling cascades in RAW 264.7 cells, while treatment with SAF3 suppressed them in a concentration-dependent manner. Existing outcomes confirm that SAF3 from S. autumnale possesses potent anti-inflammatory activity and exhibits good potential for application as a functional food ingredient or for the treatment of inflammation-related disorders.

Fucoidan from Sargassum thunbergii obtained via step gradient ethanol precipitation indicate potential anti-obesity and anti-hepatic steatosis in vitro 3T3-L1 and HepG2 cells and in vivo high-fat diet-induced obesity mice

This study investigated the potential lipid inhibitory and anti-obesity effects of compounds derived from Sargassum thunbergii in vitro and in vivo. We prepared a Celluclast-assisted hydrolysate from Sargassum thunbergii (STC) and three fractional ethanol precipitates (STCF1, STCF2, STCF3). We investigated their proximate composition, and anti-obesity effects in vitro and in vivo. STC and STCFs all significantly reduced intracellular lipid accumulation in PA-treated 3T3-L1 and HepG2 cells. STC, STCF1, and STCF3 had profound anti-obesity effects on high fat diet (HFD)-fed obesity model mice. Oral administration of STC, STCF1, and STCF3 significantly reduced body weight and white adipose tissue (WAT) mass. Furthermore, serum lipid levels were significantly decreased. Additionally, adipose specific hormone levels (adiponectin and fibroblast growth factor-21 (FGF-21)) were significantly decreased, and serum insulin levels were also decreased by STC, STCF1, and STCF3 treatment. A mechanistic study revealed that the adipogenesis and lipolysis associated proteins in epididymal adipose tissue, and free fatty acid oxidation in liver tissues were effectively regulated by STC, STCF1, and STCF3. Overall, our findings show the potent anti-obesity effects of STC, STCF1, and STCF3, achieved by regulation of adipogenesis, lipolysis, and the fatty acid oxidation pathway in HFD-treated obesity model mice.

Effects of Blanching Methods on Nutritional Properties and Physicochemical Characteristics of Hot-air Dried Edible Insect Larvae

Global meat consumption is increasing worldwide, however, supply remains lacking. Several alternative protein sources, such as cultured meat, plant-based protein production, and edible insects, have been proposed to overcome this shortage. Interestingly, edible insects are characterized by superior digestive and absorptive qualities that make them the ideal replacement for traditional protein production. This study aims to further the processing ability of insect protein by investigating the effects of various pre-treatment methods, such as blanching (HB), roasting (HR), and superheated steam (HS), on the nutritional properties and physicochemical characteristics of proteins extracted from Hermetia illucens larvae. The drying rate, pH value, color analysis, amino and fatty acid profile, as well as bulk density, shear force, and rehydration ratios of the above pre-treatment methods, were explored. HS was found to have the highest drying rate and pH value analysis showed that HB and HS samples have significantly higher values compared to the other modalities. Raw edible insects had the highest value in the sum of essential amino acid (EAA) and EAA index when compared to EAAs. HB and HS showed significantly lower bulk density results, and HS showed the highest shear force and the highest value in rehydration ratio, regardless of immersion time. Therefore, taking the above results together, it was found that blanching and superheated steam blanching pre-treatment were the most effective methods to improve the processing properties of H. illucens after hot-air drying.

Effect of Grafted Insect Protein with Palatinose on Quality Properties of Phosphate-Free Meat Emulsion

Due to concerns about the negative effects of phosphate on human health, the development of phosphate substitutes is an active area of research. Among the various methods, the structural modification of proteins has previously been established. In this study, we used grafting technology. Extracted insect protein was grafted with palatinose (GI), and 0.1 and 0.15% of GI were added to a phosphate-free meat emulsion mixed with 0.1% of eggshell powder (ES). The pH, myofibrillar protein solubility, and apparent viscosity increased with the addition of GI and ES (p < 0.05). Color values were also affected by GI and ES addition (decreased CIE L* and CIE a* and increased CIE b*; p < 0.05), while cooking loss was only improved by the addition of ES and not GI. Although the total fluid separated more than negative control (p < 0.05), the addition of ES improved emulsion stability and total expressible fluid separation and the fat separation reduced with addition of GI and ES (p < 0.05). Lipid oxidation was inhibited by the addition of GI and ES (p < 0.05). Moreover, the protein molecular weight distribution under 20 kDa was modified by the addition of GI, and the hardness and springiness of treatments decreased. In conclusion, the addition of GI and ES might be used to improve cooking loss, emulsion stability, and antioxidants, while the textural properties should be further researched.

Antioxidant potential of low molecular weight fucoidans from Sargassum autumnale against H2O2-induced oxidative stress in vitro and in zebrafish models based on molecular weight changes

In this study, we investigated the potential antioxidant abilities of low-molecular weight fucoidans from enzyme-assisted hydrolysates of Sargassum autumnale, based on molecular weight changes, in vitro and in vivo. The yield and free radical-scavenging activities of enzyme-assisted hydrolysates of S. autumnale were screened. The protamex-assisted hydrolysate of S. autumnale (SAP) presented the highest yield and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity; therefore, it was chosen for fucoidan purification. Three fucoidan fractions were observed in SAP, and their antioxidant activity was assessed. Fucoidan fraction 3 of protamex-assisted hydrolysate of S. autumnale (SAPF3) offered significant protection against H2O2-induced oxidative stress, and was structurally and physically similar to commercial fucoidan. Fucose and low-molecular weight fucoidans were highly concentrated in SAPF3. The results of our study show that SAPF3, a low-molecular weight fucoidan from S. autumnale, possesses strong antioxidant properties and may be an effective alternative to antioxidant agents in the functional food industry.

Isolation and Characterization of Efficient Active Compounds Using High-Performance Centrifugal Partition Chromatography (CPC) from Anti-Inflammatory Activity Fraction of Ecklonia maxima in South Africa

Ecklonia maxima is a brown seaweed, which is abundantly distributed in South Africa. This study investigated an efficient approach using high-performance centrifugal partition chromatography (HPCPC), which has been successfully developed for the isolation and purification of phlorotannins, eckmaxol, and dieckol from the ethyl acetate fraction of E. maxima (EEM). We evaluated EEM for its inhibitory effect against lipopolysaccharide (LPS)-induced inflammatory responses in zebrafish embryos. The separation of eckmaxol and dieckol from samples of EEM using HPCPC was found to be of high purity and yield under an optimal solvent system composed of n-hexane:ethyl acetate:methanol:water (2:7:3:7, v/v/v/v). To evaluate the anti-inflammatory efficacy of EEM containing active compounds, zebrafish embryos exposed to LPS were compared with and without EEM treatment for nitric oxide (NO) production, reactive oxygen species (ROS) generation, and cell death two days after fertilization. These evaluations indicate that EEM alleviated inflammation by inhibiting cell death, ROS, and NO generation induced by LPS treatment. According to these results, eckmaxol and dieckol isolated from brown seaweed E. maxima could be considered effective anti-inflammatory agents as pharmaceutical and functional food ingredients.

Effects of loquat (Eriobotrya japonica Lindl.) leaf extract with or without ascorbic acid on the quality characteristics of semi-dried restructured jerky during storage

Deterioration of jerky during storage is a major concern; this is usually combated with natural or synthetic antioxidants. This study aimed to evaluate the quality characteristics of semi-dried restructured jerky with and without loquat leaf extract (LE) powder and ascorbic acid (AA) during storage for 180 days. The jerkies were formulated with 0%, 0.15%, and 0.3% LE and/or 0.05% AA (Control, no antioxidant; AA, 0.05% AA; LE 0.15, 0.15% loquat LE; LE 0.15-AA, 0.15% loquat LE+0.05% AA; LE 0.3, 0.3% loquat LE; LE0.3-AA, 0.3% loquat LE+0.05% AA). LE is a phenolic compound, whose 1,1-diphenyl-2-picrylhydarzyl radical scavenging activity and metal chelating activity were found to be higher than AA. All antioxidant combinations having higher LE concentration and containing AA were effective in delaying protein and lipid oxidation compared to the control or AA. At the end of storage period, LE 0.15-AA and AA had higher CIE a* and lower shear force than the control. Therefore, the combination of 0.15% LE and 0.05% AA can result in reduced protein and lipid oxidation without any negative effect on the quality characteristics of semi-dried restructured jerky.

Dietary fucoidan from a brown marine algae (Ecklonia cava) attenuates lipid accumulation in differentiated 3T3-L1 cells and alleviates high-fat diet-induced obesity in mice

Fucoidan from marine algae is used as a functional ingredient in the food. Here, we purified fucoidan fractions from a crude polysaccharide obtained after the crude polysaccharide of celluclast-assisted hydrolysate from Ecklonia cava (ECC). We evaluated the effect of ECC on lipid accumulation in differentiated 3T3-L1 adipocytes and investigated its anti-obesity effects in vivo in high-fat diet (HFD)-induced obese mice. In vitro Oil Red O staining revealed that treatment with ECC and its purified fucoidan fractions of celluclast assisted hydrolysate from Ecklonia cava (ECFs) remarkably reduced lipid accumulation in 3T3-L1 cells. ECF3 contained the highest contents of polysaccharides and sulfate compared with other fucoidan fractions. ECF3 treatment significantly reduced lipid accumulation in 3T3-L1 cells. Oral administration of ECC significantly reduced body weight, body weight gain, serum lipid content, and total white adipose tissue mass. Histological analysis revealed that ECC reduced lipid accumulation in EAT and liver tissues. Our findings suggest that the anti-obesity effects of ECC are associated with suppressing lipid accumulation in white adipose tissues and increased energy expenditure by upregulating the expression of thermogenic UCP1 and UCP3 in BAT. These results indicate that ECC and its ECFs possess anti-obesity properties and can be used in food and nutraceutical industries.

Effect of hydrocolloids on functionality of Protaetia brevitarsis proteins

In this study, the effects of various hydrocolloids on the functionality of extracted proteins from Protaetia brevitarsis were investigated. Gel solubility, apparent viscosity, thermal properties, microstructure, textural properties, foaming properties, and emulsion properties were estimated and compared among treatments. Although all hydrocolloids enhanced the protein gelling properties compared with those of the control protein, the protein-polysaccharide complex in samples treated with a hydrocolloid with a lower solubility of hydrophobic bonds and disulfide bonds showed a more compact microstructure with high textural properties, apparent viscosity, and emulsion stability. By contrast, hydrocolloids with a high solubility of hydrophobic bonds increased the foaming properties and showed high thermal stability of the insect proteins. These results indicate that hydrocolloids should be carefully selected when in complex with edible insect proteins according to their purpose as gelling or foaming agents.

Natural Extracts as Inhibitors of Microorganisms and Lipid Oxidation in Emulsion Sausage during Storage

Food additives are required to maintain the freshness and quality of foods, particularly meats. However, chemical additives may not be preferred by consumers, and natural materials with antimicrobial and antioxidant effects may be used as replacements for common chemical additives. Accordingly, in this study, we compared the antimicrobial and antioxidant activities of natural compounds extracted with ethanol and hot water, and emulsion sausage prepared with natural ethanol extracts was analyzed for pH, color, thiobarbituric acid reactive substances (TBARS), and Clostridium perfringens growth during storage. The antimicrobial activities of 49 natural extract candidates against Listeria monocytogenes, C. perfringens, Salmonella spp., and Escherichia coli were analyzed, and six natural materials with excellent antibacterial activities, i.e., Elaeagnus umbellata Thunb. f. nakaiana (Araki) H. Ohba, Punica granatum L., Ecklonia cava, Nelumbo nucifera Gaertner, and Schisandra chinensis (Turcz.) Baill., and Rubus coreanus Miq. were evaluated to determine their total polyphenol contents and DPPH radical scavenging activities. The total polyphenol contents of ethanol extracts were higher than those of hot water extracts, whereas DPPH radical scavenging activity was found to be higher in hot water extracts. The TBARS values of emulsion sausages were significantly increased as storage time increased, and the TBARS values of emulsion sausages prepared with natural extracts were lower than those of control sausages. Natural extract-treated emulsion sausages showed a 99% reduction in bacterial contents compared with untreated sausages on day 2, with greater than 99.9% reduction after day 3. Thus, these results demonstrated that natural extracts could have applications as natural preservatives in meat products.

Inhibitory effect of Saccharomyces cerevisiae extract obtained through ultrasound-assisted extraction on melanoma cells

Although the immune enhancing effect of yeast has been widely reported, studies specifically investigating its effects on skin cancer are lacking. Therefore, this study aimed to develop a yeast extract capable of inhibiting melanoma cells using ultrasound technology, which can lyse the cell walls allowing subsequent rapid yeast extraction. To compare the extraction efficiency across different extraction methods, the total yield, as well as total glucan, α-glucan, and β-glucan yields were measured. Ultrasound-assisted extract of yeast (UAEY) was found to effectively inhibit melanoma cell growth and proliferation as well as the expression of cyclin D1 and c-myc, in vitro. Additionally, the extract reduced melanoma tumor volume and cyclin D1 levels in BALB/c nu/nu mice. The optimal extraction conditions were 0.2 M NaOH, 3 h, 70 °C, 20 kHz, and 800 W, resulting in an increased total extraction and β-glucan yields of 73.6% and 7.1%, respectively, compared with that achieved using a conventional chemical (0.5 M NaOH) extraction method. Taken together, the results of this study suggest that UAEY may represent an effective anti-skin cancer agent.

Effects of High Hydrostatic Pressure on Technical Functional Properties of Edible Insect Protein

The objective of this study was to determine the effects of high pressure to investigate the technical functional properties of the protein solution extracted from an edible insect, Protaetia brevitarsis seulensis. High pressure processing was performed at 0 (control), 100, 200, 300, 400, and 500 MPa at 35°C. The essential amino acid index of the control was lower (p<0.05) than that of the P. brevitarsis seulensis extract treated with 100 MPa. The SDS-PAGE patterns tended to become faint at approximately 75 kDa and thicker at approximately 37 KDa after high pressure treatment. The protein solubility and pH of the protein tended to increase as the hydrostatic pressure levels increased. The instrument color values (redness and yellowness) of the P. brevitarsis seulensis protein treated with high pressure were lower (p<0.05) than those of the control. The forming capacity of the protein solution with P. brevitarsis seulensis treated with high pressure was higher (p<0.05) than that of the control. In conclusion, we confirmed that the technical functional properties of edible insect proteins extracted under high pressure of 200 MPa are improved. Our results indicate that high pressure can improve the technical functional properties of proteins from edible insects.

Development of an ultrasonic system for industrial extraction of unheated sesame oil cake

Sesame is a popular functional food in Asia. However, research on sesame seed oil cake compounds and their extraction methods is lacking. Ultrasound technology was applied to develop an efficient extraction method for this purpose. First, pilot-scale extraction from sesame oil cake was performed and optimized using response surface methodology. The extract obtained using optimized conditions (0% ethanol for 4 h at 20°C) showed the highest yield (45.1%) and inhibitory effect on reactive oxygen species (ROS; 55.1%). Compared to extracts obtained by conventional extraction methods, those obtained by ultrasound technology exhibited a higher extraction yield, greater antioxidant effect, and increased lignan content. Based on pilot-scale experiments, an industrial-scale ultrasonic extraction system was designed to extract a 2.1-ton solution at once. The extract contained sesaminol 1,2-diglucoside (4.6 mg/g) as the major component and showed 28.3% ROS inhibition activity. Our industrial ultrasound-assisted extraction method has potential application for other compounds.

Lipid Inhibitory Effect of (-)-loliolide Isolated from Sargassum horneri in 3T3-L1 Adipocytes: Inhibitory Mechanism of Adipose-Specific Proteins

Sargassum horneri (S. horneri) is a well-known brown seaweed widely distributed worldwide. Several biological activities of S. horneri have been reported. However, its effects on lipid metabolism and the underlying mechanisms remain elusive. In the present study, we examined the inhibitory effect of the active compound "(-)-loliolide ((6S,7aR)-6-hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydro-1-benzofuran-2(4H)-one (HTT))" from S. horneri extract on lipid accumulation in differentiated adipocytes. MTT assays demonstrated that (-)-loliolide is not toxic to 3T3-L1 adipocytes in a range of concentrations. (-)-loliolide significantly reduced intracellular lipid accumulation in the differentiated phase of 3T3-L1 adipocytes as shown by Oil Red O staining. Western blot analysis revealed that (-)-loliolide increased the expression of lipolytic protein phospho-hormone-sensitive lipase (p-HSL) and thermogenic protein peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1). Additionally, (-)-loliolide decreased expression of adipogenic and lipogenic proteins, including sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid-binding protein 4 (FABP4) in 3T3-L1 adipocytes. These results indicate that (-)-loliolide from S. horneri could suppress lipid accumulation via regulation of antiadipogenic and prolipolytic mechanisms in 3T3-L1 cells. Considering the multifunctional effect of (-)-loliolide, it can be useful as a lipid-lowering agent in the management of patients who suffer from obesity.

Fucoxanthin-rich fraction from Sargassum fusiformis alleviates particulate matter-induced inflammation in vitro and in vivo

Particulate matter (PM) contributes to air pollution and primarily originates from unregulated industrial emissions and seasonal natural dust emissions. Fucoxanthin (Fx) is a marine natural pigment from brown macroalgae that has been shown to have various beneficial effects on health. However, the effects of Fx on PM-induced toxicities in cells and animals have not been assessed. In this study, we investigated the anti-inflammatory potential of the Fx-rich fraction (FxRF) of Sargassum fusiformis against PM-mediated inflammatory responses. The FxRF composition was analyzed by rapid-resolution liquid chromatography mass spectrometry. Fx and other main pigments were identified. FxRF attenuated the production of inflammatory components, including prostaglandin E2 (PGE2), cyclooxygenase-2, interleukin (IL)-1β, and IL-6 from PM-exposed HaCaT keratinocytes. PM exposure also reduced the levels of nitric oxide (NO), tumor necrosis factor-α, inducible nitric oxide synthase (iNOS), and PGE2 in PM-exposed RAW264.7 macrophages. Additionally, the culture medium from PM-exposed HaCaT cells induced upregulation of NO, iNOS, PGE2, and pro-inflammatory cytokines in RAW264.7 macrophages. FxRF also significantly decreased the expression levels of factors involved in inflammatory responses, such as NO, reactive oxygen species, and cell death, in PM-exposed zebrafish embryos. These results demonstrated the potential protective effects of FxRF against PM-induced inflammation both in vitro and in a zebrafish model.

Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.

LRP1 regulates food intake and energy balance in GABAergic neurons independently of leptin action

Low-density lipoprotein receptor-related protein 1 (LRP1) is a member of LDL receptor family that plays a key role in systemic glucose and lipid homeostasis. LRP1 also regulates energy balance in the hypothalamus by mediating leptin's anorexigenic action, although the underlying neurocircuitry involved is still unclear. Because GABAergic neurons are a major mediator of hypothalamic leptin action, we studied the role of GABAergic LRP1 in energy balance and leptin action using mice lacking LRP1 in Vgat- or AgRP-expressing neurons (Vgat-Cre; LRP1^loxP/loxP or AgRP-Cre; LRP1^loxP/loxP). Here, we show that LRP1 deficiency in GABAergic neurons results in severe obesity in male and female mice fed a normal-chow diet. This effect is most likely due to increased food intake and decreased energy expenditure and locomotor activity. Increased adiposity in GABAergic neuron-specific LRP1-deficient mice is accompanied by hyperleptinemia and hyperinsulinemia. Insulin resistance and glucose intolerance in these mice are occurred without change in body weight. Importantly, LRP1 in GABAergic neurons is not required for leptin action, as evidenced by normal leptin's anorexigenic action and leptin-induced hypothalamic Stat3 phosphorylation. In contrast, LRP1 deficiency in AgRP neurons has no effect on adiposity and caloric intake. In conclusion, our data identify GABAergic neurons as a key neurocircuitry that underpins LRP1-dependent regulation of systemic energy balance and body-weight homeostasis. We further find that the GABAergic LRP1 signaling pathway modulates food intake and energy expenditure independently of leptin signaling and AgRP neurons.

Anti-obesity effects of red seaweed, Plocamium telfairiae, in C57BL/6 mice fed a high-fat diet

This study aimed to demonstrate the anti-obesity effect of Plocamium telfairiae (PT), a red seaweed. Different percentages of ethanol (0%, 20%, 40%, 60%, 80%, and 100%) were used for the preparation of PT extract. Furthermore, 3T3-L1 cells were used to determine the percentage of ethanol for optimal anti-adipogenesis of PT, and the anti-obesity properties of the optimized extract of PT (PTE) (40%) was assessed in obese mice. The results indicate that 40% ethanol extract (40 PTE) significantly decreased fat accumulation and suppressed the expression of major adipogenesis factors such as peroxisome proliferator-activated receptor-γ (PPAR-γ), sterol regulatory element-binding protein 1 (SREBP-1), CCAAT/enhancer-binding protein (C/EBP)-α, and phosphorylated ACC (pACC) in 3T3-L1 cells. Furthermore, in the high-fat diet-induced obese mice, 40 PTE significantly reduced the weights of white adipose tissue, as well as the levels of triglyceride, total cholesterol, adiponectin, and insulin in the serum. Liver histopathology showed that steatosis decreased in all the PTE treatment groups. The adipogenesis-related proteins, PPAR-γ and SREBP-1, were also significantly decreased in PTE treatment groups. Additionally, 40 PTE increased mRNA expression of mitochondrial uncoupling proteins (UCP)-1 and UCP-3 in brown adipose tissue. These findings provide evidence that 40 PTE can alleviate lipid droplet accumulation in 3T3-L1 adipocytes and obese C57BL/6 mice, indicating that PTE has strong anti-obesity effects and could be used as a therapeutic agent or a component of pharmaceutical drugs and functional foods.

Particulate Matter-Induced Inflammation/Oxidative Stress in Macrophages: Fucosterol from Padina boryana as a Potent Protector, Activated via NF-κB/MAPK Pathways and Nrf2/HO-1 Involvement

Fucosterol is a phytosterol that is abundant in marine brown algae and is a renowned secondary metabolite. However, its ability to protect macrophages against particulate matter (PM) has not been clarified with regard to inflammation; thus, this study aimed to illustrate the above. Padina boryana, a brown algae that is widespread in Indo-Pacific waters, was applied in the isolation of fucosterol. Isolation was conducted using silica open columns, while identification was assisted with gas chromatography-mass spectroscopy (GC-MS) and NMR. Elevated levels of PM led the research objectives toward the implementation of it as a stimulant. Both inflammation and oxidative stress were caused due the fact of its effect. RAW 264.7 macrophages were used as a model system to evaluate the process. It was apparent that the increased NO production levels, due to the PM, were mediated through the inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines (i.e., interleukin-6 (IL-6), interleukin-1 (IL-1β) and tumor necrosis factor-α (TNF-α), including prostaglandin E2 (PGE2)). Further, investigations provided solid evidence regarding the involvement of NF-κB and mitogen-activated protein kinases (MAPKs) in the process. Oxidative stress/inflammation which are inseparable components of the cellular homeostasis were intersected through the Nrf2/HO-1 pathway. Conclusively, fucosterol is a potent protector against PM-induced inflammation in macrophages and hence be utilized as natural product secondary metabolite in a sustainable manner.

Anti-Obesity Effects of Sargassum thunbergii via Downregulation of Adipogenesis Gene and Upregulation of Thermogenic Genes in High-Fat Diet-Induced Obese Mice

Obesity is a metabolic disease characterized by an increased risk of type 2 diabetes, hypertension, and cardiovascular disease. We have previously reported that compounds isolated from brown alga, Sargassum thunbergii (ST; Sargassum thunbergii (Mertens ex Roth) Kuntze), inhibit adipogenesis in 3T3-L1 cells. However, the in vivo anti-obesity effects of these compounds have not been previously reported. Therefore, the objective of this study was to determine the effects of ST on weight loss, fat accumulation, as well as risk factors for type 2 diabetes and cardiovascular disease in high-fat diet (HFD)-induced obese mice. ST treatment significantly decreased body weight and fat accumulation in HFD-induced obese mice, while reducing insulin and factors related to cardiovascular diseases (triglyceride and total cholesterol) in serum. ST-induced downregulation of PPARγ in white adipose tissue, and upregulation of the thermogenic genes, UCP-1 and UCP-3, in brown adipose tissue was also observed. In addition, oral administration of ST reduced the occurrence of fatty liver, as well as the amount of white adipose tissue in HFD mice. Cumulatively, these results suggest that ST exerts anti-obesity effects and may serve as a potential anti-obesity therapeutic agent.

Fucoidan from acid-processed Hizikia fusiforme attenuates oxidative damage and regulate apoptosis

We had observed in our previous study that the active fucoidan (JHCF4), isolated from the crude fucoidan in acid-processed Hizikia fusiforme, possessed an anticancer effect. In this study, the antioxidant effect of JHCF4 was evaluated. Among the fractions, JHCF4 showed the highest scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals, as well as protective effect against reactive oxygen species (ROS) in 2, 2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-treated Vero cells. Furthermore, JHCF4 showed a protective activity against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Our results showed that JHCF4 can up-regulate Bcl-xL, down-regulate Bax and cleave caspase-3 with increased concentrations in AAPH-induced Vero cells. JHCF4 induced anti-apoptosis via a mitochondria-mediated pathway. Additionally, JHCF4 was selected for further in vivo screening in a zebrafish model, which markedly decreased ROS generation and lipid peroxidation. Thus, JHCF4 showed a potential protective activity against AAPH-induced ROS both in vitro and in the zebrafish model.

Apolipoprotein J is a hepatokine regulating muscle glucose metabolism and insulin sensitivity

Crosstalk between liver and skeletal muscle is vital for glucose homeostasis. Hepatokines, liver-derived proteins that play an important role in regulating muscle metabolism, are important to this communication. Here we identify apolipoprotein J (ApoJ) as a novel hepatokine targeting muscle glucose metabolism and insulin sensitivity through a low-density lipoprotein receptor-related protein-2 (LRP2)-dependent mechanism, coupled with the insulin receptor (IR) signaling cascade. In muscle, LRP2 is necessary for insulin-dependent IR internalization, an initial trigger for insulin signaling, that is crucial in regulating downstream signaling and glucose uptake. Of physiologic significance, deletion of hepatic ApoJ or muscle LRP2 causes insulin resistance and glucose intolerance. In patients with polycystic ovary syndrome and insulin resistance, pioglitazone-induced improvement of insulin action is associated with an increase in muscle ApoJ and LRP2 expression. Thus, the ApoJ-LRP2 axis is a novel endocrine circuit that is central to the maintenance of normal glucose homeostasis and insulin sensitivity.

Hepatokines are proteins secreted by the liver that can regulate whole body metabolism. Here the authors identify apolipoprotein J as a hepatokine that regulates muscle glucose metabolism and insulin resistance through a low-density lipoprotein receptor-related protein−2 mediated mechanism in mice.

Silk peptide production from whole silkworm cocoon using ultrasound and enzymatic treatment and its suppression of solar ultraviolet-induced skin inflammation

Silk fibroin, which is derived from sericin through degumming, is mainly used as a biomaterial. However, interest in functional verification and industrial applications of sericin has been growing for several years. We used ultrasonication to simplify the extraction process of the silk peptide under low salt conditions at 20 °C, instead of using the conventional conditions of high salt and temperature. The concentration of the silk peptide was measured to determine the optimized extraction time and solvent, which were 4 h and 0.1 N NaOH, respectively. The molecular weight of the enzyme-treated silk peptide was measured using SDS-PAGE and GPC. Silk peptide treated with papain after ultrasound had a molecular weight of less than 5 kDa, and the papain treated-silk peptide reduced solar ultraviolet-induced COX-2 expression through inhibition of ERK phosphorylation. This is the first study investigating simultaneous extraction of fibroin and sericin, which can be used for mass production of food materials.

Anti-Obesity Effects of Grateloupia elliptica, a Red Seaweed, in Mice with High-Fat Diet-Induced Obesity via Suppression of Adipogenic Factors in White Adipose Tissue and Increased Thermogenic Factors in Brown Adipose Tissue

Obesity is a serious metabolic syndrome characterized by high levels of cholesterol, lipids in the blood, and intracellular fat accumulation in adipose tissues. It is known that the suppression of adipogenic protein expression is an effective approach for the treatment of obesity, and regulates fatty acid storage and transportation in adipose tissues. The 60% ethanol extract of Grateloupia elliptica (GEE), a red seaweed from Jeju Island in Korea, was shown to exert anti-adipogenic activity in 3T3-L1 cells and in mice with high-fat diet (HFD)-induced obesity. GEE inhibited intracellular lipid accumulation in 3T3-L1 cells, and significantly reduced expression of adipogenic proteins. In vivo experiments indicated a significant reduction in body weight, as well as white adipose tissue (WAT) weight, including fatty liver, serum triglycerides, total cholesterol, and leptin contents. The expression of the adipogenic proteins, SREBP-1 and PPAR-γ, was significantly decreased by GEE, and the expression of the metabolic regulator protein was increased in WAT. The potential of GEE was shown in WAT, with the downregulation of PPAR-γ and C/EBP-α mRNA; in contrast, in brown adipose tissue (BAT), the thermogenic proteins were increased. Collectively, these research findings suggest the potential of GEE as an effective candidate for the treatment of obesity-related issues via functional foods or pharmaceutical agents.

Anti-Obesity Effect of Diphlorethohydroxycarmalol Isolated from Brown Alga Ishige okamurae in High-Fat Diet-Induced Obese Mice

Diphlorethohydroxycarmalol (DPHC) is one of the most abundant bioactive compounds in Ishige okamurae. The previous study suggested that DPHC possesses strong in vitro anti-obesity activity in 3T3-L1 cells. However, the in vivo anti-obesity effect of DPHC has not been determined. The current study explored the effect of DPHC on high-fat diet (HFD)-induced obesity in C57BL/6J mice. The results indicated that oral administration of DPHC (25 and 50 mg/kg/day for six weeks) significantly and dose-dependently reduced HFD-induced adiposity and body weight gain. DPHC not only decreased the levels of triglyceride, low-density lipoprotein cholesterol, leptin, and aspartate transaminase but also increased the level of high-density lipoprotein cholesterol in the serum of HFD mice. In addition, DPHC significantly reduced hepatic lipid accumulation by reduction of expression levels of the critical enzymes for lipogenesis including SREBP-1c, FABP4, and FAS. Furthermore, DPHC remarkably reduced the adipocyte size, as well as decreased the expression levels of key adipogenic-specific proteins and lipogenic enzymes including PPARγ, C/EBPα, SREBP-1c, FABP4, and FAS, which regulate the lipid metabolism in the epididymal adipose tissue (EAT). Further studies demonstrated that DPHC significantly stimulated the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in both liver and EAT. These results demonstrated that DPHC effectively prevented HFD-induced obesity and suggested that DPHC could be used as a potential therapeutic agent for attenuating obesity and obesity-related diseases.

Characterization and screening of anti-tumor activity of fucoidan from acid-processed hijiki (Hizikia fusiforme)

The aim of this study was to investigate the antiproliferative effects of fucoidan from three regional hijiki (Hizikia fusiforme) samples (Zhejiang-China, Jeju-Korea [JH], and Wando-Korea) in East Asia. Hijiki was processed using 1% citric acid to decrease heavy metal content. The JH sample was separated using diethylaminoethyl-cellulose-ion exchange chromatography to obtain four active fractions (JHCF1-JHCF4) and their monosaccharide composition was detected using high-performance liquid chromatography. The structure of the crude polysaccharides and four fucoidan fractions was analyzed using Fourier-transform infrared spectroscopy. JHCF4 showed the highest fucose and sulfate content and decreased Hep3B cell growth in 48 h with a half-maximal inhibitory concentration of 33.53 ± 2.50 μg/ml, which represented the strongest anticancer activity. Further, nuclear staining with Hoechst 33342 and acridine orange-ethidium bromide staining demonstrated that the anticancer activity of JHCF4 was mediated by apoptosis. Moreover, JHCF4 down-regulated B-cell lymphoma extra-large, while up-regulating Bcl-2-associated X protein, caspase-3, and apoptotic bodies to different degrees in Hep3B cells. JHCF4 induced apoptosis via the generation of reactive oxygen species along with the concurrent loss of mitochondrial membrane potential, indicating the potential role of the mitochondria-mediated pathway. Therefore, these results indicate that JHCF4 exhibited antiproliferative effects on the investigated cancer cell lines.

Antioxidant properties of a sulfated polysaccharide isolated from an enzymatic digest of Sargassum thunbergii

The protective effect of sulfated polysaccharides (PS-4) isolated from Sargassum thunbergii against oxidative stress in cells and zebrafish was investigated. To begin, a variety of enzymatic extraction methods were used, including five carbohydrases and four proteases. Among the enzymatic extracts, the S. thunbergii Celluclast-assisted extract (STC) demonstrated the strongest scavenging activities against hydrogen peroxide (H2O2). Five polysaccharide fraction (PS-1 to 5) were isolated from STC and purified using ion exchange column chromatography. The antioxidant activity of these fractions was then assessed. PS-4 demonstrated the most promising free radical scavenging and antioxidant activity. PS-4 had a higher content of sulfated polysaccharide than STC. Thus, increasing the proportion of sulfated polysaccharides may be attributed to protection against H2O2-mediated cell damage and oxidative stress in cell lines and in zebrafish. These results suggest that PS-4 could be a potent antioxidant agent in functional foods and cosmetics.

Inhibition of Adipogenesis by Diphlorethohydroxycarmalol (DPHC) through AMPK Activation in Adipocytes

The purpose of this study was to investigate the antiobesity effect and the mechanism of action of diphlorethohydroxycarmalol (DPHC) isolated from Ishige okamurae in 3T3-L1 cells. The antiobesity effects were examined by evaluating intracellular fat accumulation in Oil Red O-stained adipocytes. Based on the results, DPHC dose-dependently inhibited the lipid accumulation in 3T3-L1 adipocytes. DPHC significantly inhibited adipocyte-specific proteins such as SREBP-1c, PPARγ, C/EBP α, and adiponectin, as well as adipogenic enzymes, including perilipin, FAS, FABP4, and leptin in adipocytes. These results indicated that DPHC primarily acts by regulating adipogenic-specific proteins through inhibiting fat accumulation and fatty acid synthesis in adipocytes. DPHC treatment significantly increased both AMPK and ACC phosphorylation in adipocytes. These results indicate that DPHC inhibits the fat accumulation by activating AMPK and ACC in 3T3-L1 cells. Taken together, these results suggest that DPHC can be used as a potential therapeutic agent against obesity.

Rho-kinase/AMPK axis regulates hepatic lipogenesis during overnutrition

Obesity is a major risk factor for developing nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common form of chronic liver disease and is closely associated with insulin resistance, ultimately leading to cirrhosis and hepatocellular carcinoma. However, knowledge of the intracellular regulators of obesity-linked fatty liver disease remains incomplete. Here we showed that hepatic Rho-kinase 1 (ROCK1) drives obesity-induced steatosis in mice through stimulation of de novo lipogenesis. Mice lacking ROCK1 in the liver were resistant to diet-induced obesity owing to increased energy expenditure and thermogenic gene expression. Constitutive expression of hepatic ROCK1 was sufficient to promote adiposity, insulin resistance, and hepatic lipid accumulation in mice fed a high-fat diet. Correspondingly, liver-specific ROCK1 deletion prevented the development of severe hepatic steatosis and reduced hyperglycemia in obese diabetic (ob/ob) mice. Of pathophysiological significance, hepatic ROCK1 was markedly upregulated in humans with fatty liver disease and correlated with risk factors clustering around NAFLD and insulin resistance. Mechanistically, we found that hepatic ROCK1 suppresses AMPK activity and a ROCK1/AMPK pathway is necessary to mediate cannabinoid-induced lipogenesis in the liver. Furthermore, treatment with metformin, the most widely used antidiabetes drug, reduced hepatic lipid accumulation by inactivating ROCK1, resulting in activation of AMPK downstream signaling. Taken together, our findings establish a ROCK1/AMPK signaling axis that regulates de novo lipogenesis, providing a unique target for treating obesity-related metabolic disorders such as NAFLD.

Sargassum horneri (Turner) C. Agardh ethanol extract inhibits the fine dust inflammation response via activating Nrf2/HO-1 signaling in RAW 264.7 cells

BACKGROUND

Among the different kinds of pollution, air pollution continues to increase globally. East Asia is considered to be significantly affected. As a result, the populations in these regions face serious health issues including respiratory disorders. This study investigated the impact of fine dust (FD) particles (CRM No. 28) on macrophage cells as a model for alveolar lung cells.

METHODS

The research focused on inflammation and oxidative stress induced by FD and Sargassum horneri (Turner) C. Agardh ethanol extract (SHE) as a potential treatment. S. horneri is a type of brown algae that has demonstrated anti-inflammatory effects against RAW 264.7 macrophages in previous studies. MTT, Griess, ELISA, western blotting, and mRNA expression analyses using PCR techniques were used in this study.

RESULTS

The optimum FD concentration was determined to be 125 μg mL- 1. FD particles stimulated inflammatory mediators production (iNOS, COX-2, and PGE2) and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), leading to NO production. These mediators were dose-dependently downregulated by treatment with SHE. IL-6 and TNF-α were identified as biomarkers for FD. SHE treatment induced HO-1 and Nrf2 activity in a dose-dependent manner under FD stimulation. This confirmed the cytoprotective effect against oxidative stress induced via FD. Furthermore, treatment of the cells with a p38 MAPK inhibitor (SB202190) induced FD-stimulated NO production.

CONCLUSIONS

The results suggest that SHE increases macrophage cellular resistance to FD-induced inflammation and oxidative stress, probably via the p38 MAPK pathway and Nrf2/HO-1 expression.

Anti-inflammation effects of 8-oxo-9-octadecenoic acid isolated from Undaria peterseniana in lipopolysaccharide-stimulated macrophage cells

The aim of this study was to investigate the anti-inflammatory activity of 8-oxo-9-octadecenoic acid (OOA) isolated from Undaria peterseniana by examining its ability to inhibit the lipopolysaccharide (LPS)-induced production of inflammatory mediators in RAW 264.7 macrophage cells. We found that OOA significantly suppressed the LPS-induced production of nitric oxide (NO) and inflammatory cytokines. OOA downregulated the LPS-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 proteins. With respect to proinflammatory signaling pathways, OOA inhibited LPS-induced mitogen-activated protein kinase signaling by inhibiting the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Moreover, OOA inhibited LPS-induced nuclear factor (NF)-κB signaling by reducing the phosphorylation of IκB-α and p50 proteins. These results indicate that OOA significantly reduces proinflammatory signaling, which results in reduced expression of cytokines and proinflammatory mediators. Taken together, these results suggest that OOA has potent anti-inflammatory effects and could be considered an effective anti-inflammatory agent.

3-Chloro-4,5-dihydroxybenzaldehyde inhibits adipogenesis in 3T3-L1 adipocytes by regulating expression of adipogenic transcription factors and AMPK activation

Obesity is a serious health issue in many industrialized countries. It is a medical condition with excessive levels of fat accumulated in adipocytes. The objective of the present study was to determine the inhibitory effect of 3-chloro-4,5-dihydroxybenzaldehyde (CDB) on adipogenesis in 3T3-L1 adipocyte cells. CDB suppressed the differentiation and decreased lipid accumulation and triglycerides contents in 3T3-L1 adipocytes. Its suppression effect on fat accumulation was mediated via expression of adipogenesis factors (C/EBPα, SREBP-1c, PPARγ, and adiponectin) during adipocyte differentiation in white adipocyte cells. CDB's ability to suppress fat accumulation was increased in a concentration-dependent manner. It inhibited fatty acid synthesis related proteins including FAS, FABP4, leptin, and perilipin. It also increased expression of phosphorylated AMPK in adipocytes cells. These observations suggest that CDB has potential anti-obesity effect with ability to improve metabolic diseases.

Circulating ApoJ is closely associated with insulin resistance in human subjects

OBJECTIVE

Insulin resistance is a major risk factor for type 2 diabetes. ApolipoproteinJ (ApoJ) has been implicated in altered pathophysiologic states including cardiovascular and Alzheimer's disease. However, the function of ApoJ in regulation of glucose homeostasis remains unclear. This study sought to determine whether serum ApoJ levels are associated with insulin resistance in human subjects and if they change after interventions that improve insulin sensitivity.

METHODS

Serum ApoJ levels and insulin resistance status were assessed in nondiabetic (ND) and type 2 diabetic (T2D) subjects. The impacts of rosiglitazone or metformin therapy on serum ApoJ levels and glucose disposal rate (GDR) during a hyperinsulinemic/euglycemic clamp were evaluated in a separate cohort of T2D subjects. Total ApoJ protein or that associated with the HDL and LDL fractions was measured by immunoblotting or ELISA.

RESULTS

Fasting serum ApoJ levels were greatly elevated in T2D subjects (ND vs T2D; 100±8.3 vs. 150.6±8.5AU, P<0.0001). Circulating ApoJ levels strongly correlated with fasting glucose, fasting insulin, HOMA-IR, and BMI. ApoJ levels were significantly and independently associated with HOMA-IR, even after adjustment for age, sex, and BMI. Rosiglitazone treatment in T2D subjects resulted in a reduction in serum ApoJ levels (before vs. after treatment; 100±13.9 vs. 77±15.2AU, P=0.015), whereas metformin had no effect on ApoJ levels. The change in ApoJ levels during treatment was inversely associated with the change in GDR. Interestingly, ApoJ content in the LDL fraction was inversely associated with HOMA-IR.

CONCLUSION

Serum ApoJ levels are closely correlated with the magnitude of insulin resistance regardless of obesity, and decrease along with improvement of insulin resistance in response only to rosiglitazone in type 2 diabetes.

3β-Hydroxy-Δ5-steroidal congeners from a column fraction of Dendronephthya puetteri attenuate LPS-induced inflammatory responses in RAW 264.7 macrophages and zebrafish embryo model

Bioactive compounds from marine organisms and their action mechanisms have provided new insights into medicinal and natural product research. Here, we report the identification of 3β-hydroxy-Δ5-steroidal congeners from a purified column fraction (DPCMH24) of the soft coral Dendronephthya puetteri harvested from Jeju, South Korea. DPCMH24 exerted strong anti-inflammatory effects through a dose-dependent decrease in the levels of nitric oxide (NO) in LPS-induced RAW 264.7 macrophages (IC₅₀ value = 6.54 ± 0.38 μg mL⁻¹). Further, DPCMH24 attenuated the levels of PGE₂ and the pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6. The above effects were mediated via the inhibition of nuclear factor κB activation and mitogen-activated protein kinase pathways. In vivo evaluation indicated that DPCMH24 reduced NO, iNOS, COX-2, ROS production and cell death in LPS-induced zebrafish embryos, confirming its anti-inflammatory potential. The constituent compounds were identified by GC-MS/MS analysis. These findings suggest that the steroidal congeners from D. puetteri may offer ample therapeutic potential against LPS-induced inflammation.

Bioactive compounds from marine organisms and their action mechanisms have provided new insights into medicinal and natural product research.