Natural Sunlight-Mediated Emodin Photoinactivation of Aeromonas hydrophila.

Aeromonas hydrophila can be a substantial concern, as it causes various diseases in aquaculture. An effective and green method for inhibiting A. hydrophila is urgently required. Emodin, a naturally occurring anthraquinone compound, was exploited as a photo-antimicrobial agent against A. hydrophila. At the minimum inhibitory concentration of emodin (256 mg/L) to inactivate A. hydrophilia in 30 min, an 11.32% survival rate was observed under 45 W white compact fluorescent light irradiation. In addition, the antibacterial activity under natural sunlight (0.78%) indicated its potential for practical application. Morphological observations demonstrated that the cell walls and membranes of A. hydrophila were susceptible to damage by emodin when exposed to light irradiation. More importantly, the photoinactivation of A. hydrophila was predominantly attributed to the hydroxyl radicals and superoxide radicals produced by emodin, according to the trapping experiment and electron spin resonance spectroscopy. Finally, a light-dependent reactive oxygen species punching mechanism of emodin to photoinactivate A. hydrophila was proposed. This study highlights the potential use of emodin in sunlight-mediated applications for bacterial control, thereby providing new possibilities for the use of Chinese herbal medicine in aquatic diseases prevention.

Psyllium Fibre Inclusion in Gluten-Free Buckwheat Dough Improves Dough Structure and Lowers Glycaemic Index of the Resulting Bread.

The demand for gluten-free (GF) bread is steadily increasing. However, the production of GF bread with improved baking quality and enhanced nutritional properties remains a challenge. In this study, we investigated the effects of adding psyllium fibre (PSY) in varying proportions to buckwheat flour on the dough characteristics, bread quality, and starch digestion properties of GF bread. Our results demonstrate that incorporating PSY contributes to the formation of a gluten-like network structure in the dough, leading to an increase in the gas holding capacity from 83.67% to 98.50%. The addition of PSY significantly increased the specific volume of the bread from 1.17 mL/g to 3.16 mL/g. Bread containing PSY displayed superior textural characteristics and colour. Our study also revealed that the inclusion of PSY reduced the digestibility of starch in GF bread. These findings highlight the positive impact of incorporating PSY into GF bread, suggesting its potential in guiding the production of GF bread with a lower glycaemic index. This may be particularly beneficial for individuals seeking to regulate their blood sugar levels or adopt a low-glycaemic diet.

Natural Sweetener, Glycyrrhetinic Acid 3-O-Mono-beta-d-glucuronide, for Postprandial Hyperglycemia Management.

This study examines the inhibitory effects of a range of sweeteners on α-glucosidase. Our findings revealed that only one natural sweetener, namely, glycyrrhetinic acid 3-O-mono-beta-d-glucuronide (GAMG), derived from licorice, exhibited a mixed-type inhibition against α-glucosidase with a IC50 value of 0.73 ± 0.05 mg/mL. The fluorescence intensity of α-glucosidase was quenched by GAMG in the formation of an α-glucosidase-GAMG complex. GAMG has been shown to induce conformational changes in α-glucosidase, likely through hydrogen bonding, van der Waals force, and alkyl-alkyl interactions with amino acid residues, including Arg 281, Leu 283, Trp 376, Asp 404, Asp 443, Trp 481, Asp 518, Phe 525, Ala 555, and Asp 616. Additional animal validation experiments demonstrated that GAMG slowed starch digestion, thereby attenuating the postprandial glycemic response. Taken together, these findings provide evidence that GAMG is a natural sweetener with potent inhibitory activity that selectively targets α-glucosidase. This study supports the use of GAMG as a natural sweetener, which holds a high biological value and may be beneficial for managing postprandial hyperglycemia.

Natural Sweetener Glycyrrhetinic Acid Monoglucuronide Improves Glucose Homeostasis in Healthy Mice.

Noncaloric or low-caloric sweeteners have become popular worldwide, although debates persist regarding their impact on health. To investigate whether the sweeteners are favorable for glucose homeostasis, our study assessed the effects of glycyrrhetinic acid monoglucuronide (GAMG) and several commonly used sweeteners [glycyrrhetinic acid (GA), stevioside, erythritol, sucralose, and aspartame] on glycometabolism and elucidated the underlying mechanisms. The C57BL/6J male mice were exposed to different sweeteners for 10 weeks, and our results showed that GAMG significantly reduced fasting blood glucose (FBG) levels (FBG-control: 3.81 ± 0.42 mmol/L; FBG-GAMG: 3.37 ± 0.38 mmol/L; p < 0.05) and the blood glucose levels 15 and 30 min after sucrose or maltose loading (p < 0.05). Furthermore, it improved glucose tolerance (p = 0.028) and enhanced insulin sensitivity (p = 0.044), while the other sweeteners had negligible or adverse effects on glucose homeostasis. Subsequent experiments showed that GAMG inhibited α-glucosidases potently (IC50 = 0.879 mg·mL-1), increased three SCFA-producing bacteria and SCFAs levels (p < 0.05), and promoted the gene expression of SCFA receptor GPR43 (p = 0.018). These results suggest that GAMG may regulate blood glucose by inhibiting α-glucosidases and modulating gut microbial SCFAs. Our findings prove that GAMG, beneficial to blood glucose regulation, is a promising natural sweetener for future utilization.

Modified whey protein isolate gel prepared by thermal aggregation combined with transglutaminase crosslinking achieves Casein-like slow digestion in vitro and in vivo.

Our study aimed to fabricate a modified slow-digestive whey protein isolate (WPI), which can supply enough branched-chain amino acids (BCAAs) during long-term fasting. The WPI aqueous solution (10 % w/v) was treated by heat (80 ℃) to unfold the protein tertiary structure, and subsequently treated with transglutaminase to form a gel via cross-linking. The powder of the WPI gel was obtained by spray drying, which can dissolve in water easily and self-assemble into gels again. This modified WPI contained protein aggregates with high molecular weight, and kept a stable gel-like structure under simulated gastric digestion conditions (pH = 3, 37 ℃). A dense honeycomb internal microstructure of the freeze-dried gel was observed. Further, we found that the WPI gel successfully achieved a casein-like digestible ratio (37.37 %) and released more BCAAs (0.18 mg/mL) than casein during the 4 h of in vitro simulated digestion based on the INFOGEST method. Finally, our results showed that the C57BL/6 mice oral administrated with the modified WPI gel had consistently higher BCAAs concentration (0.052 mg/mL) in their blood serum than the mice with normal WPI intake during the 6 h of in vivo digestion.

Diet-mediated metaorganismal relay biotransformation: health effects and pathways.

In recent years, the concept of metaorganism expands our insight into how diet-microbe-host interactions contribute to human health and diseases. We realized that many biological metabolic processes in the host can be summarized into metaorganismal relay pathways, in which metabolites such as trimethylamine-N­oxide, short-chain fatty acids and bile acids act as double-edged swords (beneficial or harmful effects) in the initiation and progression of diseases. Pleiotropic effects of metabolites are derived from several influencing factors including dose level, targeted organ of effect, action duration and species of these metabolites. Based on the pleiotropic effects of metabolites, personalized therapeutic approaches including microecological agents, enzymatic regulators and changes in dietary habits to govern related metabolite production may provide a new insight in promoting human health. In this review, we summarize our current knowledge of metaorganismal relay pathways and elaborate on the pleiotropic effects of metabolites in these pathways, with special emphasis on related therapeutic nutritional interventions.

[Hydrogen Sulfide Ameliorates Myocardial Injury Caused by Sepsis Through Suppressing ROS-Mediated Endoplasmic Reticulum Stress].

Objective: To investigate the effect of hydrogen sulfide (H 2S) on reactive oxygen species (ROS)-mediated endoplasmic reticulum stress in myocardial injury caused by sepsis. Methods: A sepsis model was induced in Sprague-Dawley (SD) rats by cecal ligation and puncture (CLP). The rats were randomly divided into sham operation (sham) group, sepsis (CLP) group, and sepsis+sodium hydrosulfide (NaHS) (CLP+NaHS) group. The left ventricular function of the rats was observed with echocardiography and their plasma H 2S levels were measured. Lactate dehydrogenase (LDH), malondialdehyde (MDA), glutathione (GSH) levels were measured and HE staining was done to evaluate the level of myocardial oxidative stress in rats. HE staining was done to observe the morphological changes of rat myocardium, and transmission electron microscope was used to observe the ultrastructure of myocardial mitochondria. Western blot was done to examine changes in the expression of two endogenous hydrogen sulfide synthases, cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfur transferase (3-MST), and changes in the expression of endoplasmic reticulum stress (ERS) marker proteins, including phosphorylated (p) protein kinase R-like endoplasmic reticulum kinase (p-PERK), p-eukaryotic translation initiation factor 2α (p-eIF2α), p-inositol requires enzyme 1α (IRE1α), recombinant activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP). TUNEL staining was performed to observe the changes of cardiomyocyte apoptosis in rats. Results: Left ventricular ejection fraction (LVEF), left ventricular shortening fraction (LVFS) and plasma H 2S decreased in septic rats ( P<0.05). Plasma H 2S exhibited linear correlation with LVEF and LVFS ( r 2=0.62 and r 2=0.64, all P<0.05). The ROS levels were significantly elevated in rats of the CLP group. In addition, these rats showed increased level of LDH ( P<0.05), increased expression of MDA ( P<0.05), and decreased expression of GSH ( P<0.05). Inflammatory cell infiltration and cardiomyocyte edema were observed in HE staining. Transmission electron microscopic observation revealed significant mitochondrial damage, observable mitochondrial edema, and cristae structure dissolution. The Western blot results showed that the expression levels of CSE and 3-MST decreased ( P<0.05), while the ERS marker proteins, including p-PERK, p-eIF2, IRE1α, ATF4, and CHOP, were expressed at increased levels ( P<0.05). TUNEL staining showed significant increase of apoptosis in cardiomyocytes ( P<0.05). After NaHS treatment, LVEF and LVFS increased ( P<0.05) and plasma H 2S increased in septic rats ( P<0.05). Myocardial oxidative stress levels decreased. HE staining and transmission electron microscopy showed improved myocardial morphology. Mitochondrial damage was reduced and CSE and 3-MST levels were significantly increased ( P<0.05). The expression of p-PERK, p-eIF2α, p-IRE1α, and CHOP proteins decreased ( P<0.05). A decrease in cardiomyocyte apoptosis levels was observed by TUNEL staining ( P<0.05). Conclusion: H 2S reduces septic cardiomyocyte apoptosis by inhibiting ROS-mediated ERS, thereby improving myocardial dysfunction in sepsis.

H2S regulation of ferroptosis attenuates sepsis­induced cardiomyopathy.

Ferroptosis is a non­apoptotic form of cell death mediated by reactive oxygen species (ROS). Iron metabolism disorders play a key role in sepsis­induced cardiomyopathy (SIC). While hydrogen sulfide (H2S) inhibits SIC, it is unknown if it does so by controlling ferroptosis. The present study evaluated whether sodium hydrosulfide (NaHS), an H2S donor, alleviates SIC by decreasing ferroptosis. Lipopolysaccharide (LPS) was employed to induce an in vitro model of septic myocardial injury in rat H9c2 cardiomyocytes. The myocardial injury model of septic rats was established by cecal ligation and puncture (CLP). Cardiomyocyte injury was evaluated using Cell Counting Kit­8 and myocardial enzyme assay and hematoxylin and eosin (H&E) staining. The cardiac function of rats was assessed using echocardiography and changes in myocardial fibers and mitochondria were evaluated using H&E staining and transmission electron microscopy, respectively. Fe2+, glutathione and malondialdehyde levels in cardiomyocytes were detected using assay kits, ROS and mitochondrial membrane potential changes were detected using fluorescent probes and ferroptosis and Beclin 1 (BECN1) signaling pathway­associated protein expression levels were semi­quantified using western blotting. NaHS decreased ferroptosis of H9c2 cells induced by LPS and decreased injury of myocardial cells by improving iron metabolism disorder and oxidative stress levels. Furthermore, in vivo results demonstrated that NaHS attenuated CLP­induced septic myocardial ferroptosis and significantly improved cardiac dysfunction in septic rats compared with the CLP group. NaHS was demonstrated to attenuate sepsis­induced myocardial cell and tissue injury by significantly inhibiting the phosphorylation of BECN1 and significantly increasing expression levels of the ferroptosis regulatory proteins solute carrier family 7 member 11 and glutathione peroxidase 4. The results of the present study suggested that by regulating the BECN1 signaling pathway, NaHS may decrease the incidence of myocardial ferroptosis, thereby improving SIC.

Maximizing the peroxidase-like activity of Pd@PtxRu4-x nanocubes by precisely controlling the shell thickness and their application in colorimetric biosensors.

Although the application of nanoscale artificial enzymes in various industries is an attractive way to circumvent the intrinsic drawbacks of natural enzymes, their catalytic constant (Kcat) as a critical reaction parameter is far from satisfactory. Presented here is the rational design and fabrication of a unique peroxidase mimic catalyst based upon Pd@PtxRu4-x (1 ≤ x ≤ 3) prepared by coating PtRu alloy as conformal, ultrathin shells on Pd nanocrystals. Benefiting from an optimal Pt/Ru ratio and well-defined {100} facets, together with confining the Pt-Ru alloy to a shell of averagely 3.3-atomic-layer thick (i.e. Pd@Pt-Ru3.3L), the nanocrystals exhibit the highest catalytic activity and kinetics (1.2 × 106 s-1), resulting in a significant increase of catalytic activity compared with the classical PtRu nanozyme (3.6 × 103 s-1) and horseradish peroxidase (4.0 × 103 s-1), respectively. The following density functional theory calculations demonstrate that the origin of the superior catalytic performance could be attributed to the modulation of the adsorption behavior of the key reaction intermediates on the surface. As a proof of concept, its peroxidase mimicking ability is adopted for sensing glucose and glutathione molecules in human serum, with a long linear range and high selectivity. This work opens new horizons for the future development of advanced catalysts based upon alloy nanocrystals for various applications.

Natural edible materials made of protein-functionalized aerogel particles for postprandial hyperglycemia management.

α-Amylase inhibitors (α-AIs) delay digestion of dietary starch by inhibiting α-amylase in the gut, thereby reducing the postprandial glycemia, which is beneficial to the patients with obesity and diabetes. The proteinaceous α-AIs from wheat can effectively control starch digestion and regulate postprandial hyperglycemia. However, their gastric intolerance remains a challenge, which limits its commercial production and industrial application. In this study, sodium alginate/chitosan aerogels loaded with wheat protein α-AIs were prepared and evaluated as potential transportation and protection matrices for important components in food or pharmaceutical applications. Specifically, the biodegradable aerogel cross-linked with sodium alginate-chitosan-calcium chloride, has a large surface area and open porous structure, which can adsorb staple wheat proteins as an integrated edible material to block around 88,660 U/g of α-amylase activity. The aerogel particles were able to protect the activity of wheat α-AIs in the stomach, leading to the slow passage of the wheat α-AIs through the small intestine to inhibit starch digestion more effectively. Animal experiments further showed that the postprandial blood glucose levels in rats were effectively controlled through delayed increase, after administration of wheat protein-functionalized aerogel particles loaded with wheat α-AIs, which are natural biological macromolecules. This is a novel, safe, and economical method for the prevention and pretreatment of diabetes.

Sepsis causes heart injury through endoplasmic reticulum stress-mediated apoptosis signaling pathway.

Endoplasmic reticulum stress (ERS), arising from the loss of dynamic balance in endoplasmic reticulum function under stress and inflammation, has been implicated in the progression of sepsis. Multiple organ failure caused by sepsis still has a high mortality rate, of which the heart is one of the more damaged organs. In this research, a rat model of sepsis was set up by cecal ligation and puncture (CLP); serum myocardial enzyme levels were measured using an automated biochemical analyzer, inflammatory cytokine levels were measured by ELISA kit, and cardiac histology and cardiomyocyte apoptosis were measured by hematoxylin and eosin (H&E) staining and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to assess the extent of myocardial damage. Western blot was used to detect expression of related proteins. The results showed that serum myocardial enzymes and pro-inflammatory factors were elevated in septic rats, and the increase was most significant in the CLP 24 h group. At the same time, the myocardium of septic rats had a histopathologic abnormality. After CLP, levels of endoplasmic reticulum stress related protein were upregulated. After 12 and 24 hours, the density of apoptotic cells in the myocardium of CLP-treated rats increased significantly, and the expression of apoptosis-related proteins changed significantly. This suggests that the unfolded protein response occurs during sepsis and causes damage to the heart muscle. Endoplasmic reticulum stress-mediated apoptotic signaling pathway is one of the causes of cardiac injury caused by sepsis, and may be a key to clinical prevention of cardiac dysfunction caused by sepsis.

Bioavailability Based on the Gut Microbiota: a New Perspective.

The substantial discrepancy between the strong effects of functional foods and various drugs, especially traditional Chinese medicines (TCMs), and the poor bioavailability of these substances remains a perplexing problem. Understanding the gut microbiota, which acts as an effective bioreactor in the human intestinal tract, provides an opportunity for the redefinition of bioavailability. Here, we discuss four different pathways associated with the role of the gut microbiota in the transformation of parent compounds to beneficial or detrimental small molecules, which can enter the body's circulatory system and be available to target cells, tissues, and organs. We further describe and propose effective strategies for improving bioavailability and alleviating side effects with the help of the gut microbiota. This review also broadens our perspectives for the discovery of new medicinal components.

Glycyrrhetic Acid 3-O-Mono-ß-d-glucuronide (GAMG): An Innovative High-Potency Sweetener with Improved Biological Activities.

Glycyrrhetic acid 3-O-mono-ß-d-glucuronide (GAMG) is an important derivative of glycyrrhizin (GL) and has attracted considerable attention, especially in the food and pharmaceutical industries, due to its natural high sweetness and strong biological activities. The biotransformation process is becoming an efficient route for GAMG production with the advantages of mild reaction conditions, environmentally friendly process, and high production efficiency. Recent studies showed that several ß-glucuronidases (ß-GUS) are key GAMG-producing enzymes, displaying a high potential to convert GL directly into the more valuable GAMG and providing new insights into the generation of high-value compounds. This review provides details of the structural properties, health benefits, and potential applications of GAMG. The progress in the development of the biotransformation processes and fermentation strategies to improve the yield of GAMG is also discussed. This work further summarizes recent advances in the enzymatic synthesis of GAMG using ß-GUS with emphasis on the physicochemical and biological properties, molecular modifications, and enzymatic strategies to improve ß-GUS biocatalytic efficiencies. This information contributes to a better framework to explore production and application of bioactive GAMG.