Inhibition of protein glycoxidation and advanced glycation end-product formation by barnyard millet (Echinochloa frumentacea) phenolics

The Impact of Thermal Treatment and In Vitro Digestion on Antioxidant Activity and Anti-Glycation Properties of Antioxidant Crude Extract From Hot and Cold Brew Spent Coffee Ground

The ethanoic extract of hot-brew spent-coffee ground (HSCG) and cold-brew spent-coffee ground (CSCG) were prepared with ultrasound-assisted extraction and subjected to thermal processes and in vitro digestion prior to analyze the inhibition ability of advanced glycation end products (AGEs) formation, a potential risk factor for Alzheimer's disease. The obtained HSCG and CSCG extracts contained mainly chlorogenic acid derivatives, according to liquid chromatography-mass spectrometer chromatogram. The glycation process was performed by using bovine serum albumin (BSA)/ glucose system with 3 weeks incubation. In the presence of HSCG and CSCG extracts at 250 μg/mL, after thermal treatment (pasteurization and sterilization) and in vitro digestion, the glycation process through the fructosamine, AGEs, and amyloid cross β structure formation was monitored, and these extracts exhibited an anti-glycation property at early and advanced stages after pasteurization and in vitro digestion compared to no thermal treatment. However, at high temperature of sterilization, the suppress of anti-glycation property had resulted and were related with the amount of antioxidant and the ability of antioxidant scavenging as presented in a dose manner. The calculated % caffeine bio-accessibility of HSGC extracts was 65.8%, 64.8%, and 52.4% in non-thermal, pasteurized, and sterilized samples while the higher bio-accessibility was found in CSCG sample as of 67.4, 66.6, and 63.1, respectively. A high correlation of TPC values, thermal treatments and in vitro digestions with the AGEs was detected. Polyphenols and caffeine content in these extracts were found to be responsible for the AGEs and amyloid cross β structure inhibition which might potentially reduce the risk of Alzheimer's disease.

Influence of hydroxyl substitution on the inhibition of flavonoids in advanced glycation end-products formation in glucose-lysine-arginine Maillard reaction models

Advanced glycation end products (AGEs) generated from the Maillard reaction (MR) during food processing in the human physiological environment, have been proven to be significantly associated with various chronic metabolic diseases. In this study, 18 flavonoids were investigated to study their effects on AGEs formation during MR within a glucose-lysine-arginine model system. Five AGEs- Nε-carboxymethyl-lysine (CML), Nε-carboxyethyl-lysine (CEL), pyrraline, pentosidine, and argpyrimidine-were determined by high-performance liquid chromatography-mass spectrometry, with inhibitory rates ranging between 0 % and 71.35 %. Isorhamnetin and naringenin exhibited the strongest inhibitory effect on the formation of CML and CEL, respectively, whereas myricetin exhibited the strongest inhibitory effect on pyrraline, pentosidine, and argpyrimidine formation. In addition, each flavonoid was reacted with glyoxal (GO) and methylglyoxal (MGO) to investigate their trapping activities and adducts. The results showed that the 18 flavonoids could effectively clear GO and MGO, with clearance rates of 1.03 %-71.42 % and 0.93 %-69.37 % for GO and MGO, respectively. Six flavonoids-chrysin, naringenin, apigenin, luteolin, diosmetin, and kaempferol-could form adduct products with mono-/di-MGO, with flavonoid to mono-/di-MGO adduct ratios of approximately 6:1, 2:1, 8:1, 23:1, 10:1, and 3:1, respectively. The number and site of phenolic hydroxyl groups, as well as methoxy substitution on the B-ring in flavonoids, had little effect, but phenolic hydroxyl groups at the C-3 position in the C-ring impeded adduct formation. The flavonoids lowered the degradation of glucose itself, and decreased ammonia-induced degradation and Amadori rearrangement product oxidation due to their antioxidant activities, and they trapped the reactive 1,2-di‑carbonyl species via nucleophilic addition reaction to form AGEs.

A Comparative Study on Physicochemical Properties and Biological Activities of Polysaccharides from Coreopsis tinctoria Buds Obtained by Different Methods

In this study, the polysaccharides of Coreopsis tinctoria buds (CTBPs) were extracted by hot water, ultrasound, alkali solution, and acid solution, and the four kinds of extracted polysaccharides were denoted Hw, Ultra, Al, and Ac. Then, the Hw were degraded by ultrasound, an alkali solution, and an acid solution, and the three resultant kinds of polysaccharides were denoted Ultra-Post-proc, Al-Post-proc, and Ac-Post-proc. The study comprehensively compared and analyzed the physical and chemical characteristics, structural properties, and in vitro activities of each polysaccharide. The extraction and treatment methods significantly affected the chemical composition, molecular weight (Mw) and potential of the CTBPs. The contents of carbohydrates, total phenol, and protein in Al were the highest, at 78.79 ± 0.62%, 81.69 ± 0.70 mg GAE/g and 4.82 ± 0.10%, respectively. The different methods did not change the monosaccharide composition of CTBPs, but affected the monosaccharide proportion and reduced the Mw of CTBPs. The absolute zeta potential value of Al was the highest, indicating that the solution was the most stable. CTBPs had the characteristic structure of polysaccharides, and Al-Post-proc had a triple helix structure. Additionally, CTBPs also had good water and oil holding abilities, as well as bile acid binding ability. CTBPs displayed good activity in vitro, among which Al possessed the best α-glucosidase inhibitory activity and the strongest free radical scavenging ability, and also well inhibited the generation of glycosylation products and protein oxidation products in the bovine serum albumin (BSA)-fructose model. These findings provide support for a theoretical basis for the application of polysaccharide from Coreopsis tinctoria bud in pharmaceutical and functional foods.

Dietary AGEs and food allergy: insights into the mechanisms of AGEs-induced food allergy and mitigation strategies

Food allergy (FA) is a significant public health concern, with over one billion individuals globally affected, and its prevalence continues to rise. Advanced glycation end products (AGEs) are common hazards in various diet. Recent investigations have shown that AGEs could influence the pathogenesis of FA by interacting with AGEs receptors. This paper provides a comprehensive review of recent advances on diet AGEs, summarized the mechanisms of AGEs in regulating food allergy and mitigation strategies, analyzed the limitations of current research on AGEs and prospected the future research. AGEs could combine with the receptors for AGEs (RAGE) to induce oxidative stress, inflammation and allergic signaling pathways. AGEs can affect allergen epitopes and conformation and regulate intestinal flora in a non-receptor-dependent manner, as well as affect the intestinal barrier and Th1/Th2 immune balance through receptor-dependent pathways to regulate food allergy. Currently, the approaches to reduce the AGEs-induced food allergy mainly depended on improving food processing methods (e.g., low temperature, short time, low pH and non-thermal processing methods), natural AGEs inhibitors and RAGE inhibitors. This review elucidates the influences of AGEs on food allergy and mitigation strategies, which could provide novel insights into reducing food allergy induced by diet AGEs.

Heat-Processed Diet Rich in Advanced Glycation End Products Induced the Onset and Progression of NAFLD via Disrupting Gut Homeostasis and Hepatic Lipid Metabolism

Epidemiologic studies have suggested an association between the consumption of dietary advanced glycation end products (dAGEs) and the incidence of nonalcoholic fatty liver disease (NAFLD). However, the precise mechanism by which dAGEs induce NAFLD development, particularly the pathogenic role of the gut-liver axis, remains poorly understood. In this study, by establishing a high-AGE diet (HAD)-fed C57BL/6 mouse model, we employed multiomics approaches combined with a series of biological analyses to investigate the effect of HAD on NAFLD in vivo. Our results showed that exposure to HAD led to fat accumulation, oxidative stress, inflammation, and fibrosis in the liver of mice. Transcriptome analysis further revealed that HAD exposure disrupted lipid metabolism and activated inflammation-related signaling pathways in the liver. Additionally, exposure to HAD induced perturbations in gut homeostasis, as evidenced by the compromised gut barrier function, reduced probiotic abundance, and increases in pathogenic bacterial proportions. Dysbiosis of gut homeostasis may further act as a trigger for the initiation and progression of NAFLD via the gut-liver axis. This study sheds light on the underlying mechanisms through which dAGEs contribute to the development of NAFLD and helps to understand the detrimental effects of food ultraprocessing products in modern diets. Future studies are needed to explore the in-depth mechanisms related to the gut-liver axis to consolidate our conclusions.

Unlocking the nutraceutical potential of Corylus avellana L. shells: microwave-assisted extraction of phytochemicals with antiradical and anti-diabetic properties

BACKGROUND

In recent years, the demand for high-quality natural extracts to be included in nutraceutical formulations has increased sharply. Hazelnut (Corylus avellana L.) shells (HZS) are underrated agricultural by-products that could be exploited as a source of active ingredients with pro-healthy properties. In the present study, a fully green microwave-assisted extraction (MAE) method was established for the first time aiming to recover bioactive constituents from HZS with significant nutraceutical value. Key MAE parameters, including ethanol in water concentration, microwave power, irradiation time and solvent-to-powder ratio, were optimized through response surface methodology utilizing a Box-Behnken design to achieve the highest total phenolic content and antioxidant/antiradical activities in the final extract.

RESULTS

The optimal MAE conditions (28% v/v ethanol/water, 270 s, 670 W, and 37 mL g-1) yielded an extract with significant scavenging capacity against reactive oxygen species and remarkable inhibitory activity towards both α-amylase (IC50 = 7.73 μg mL-1) and α-glucosidase (IC50 = 49.44 μg mL-1), demonstrating stronger hypoglycaemic properties than the anti-diabetic drug acarbose. Additionally, fluorescence spectroscopy results highlighted the ability of the optimized extract from HZS (OHS-E) to counteract advanced glycation end-product formation throughout the glycation cascade in a dose-dependent manner. Liquid chromatography/electrospray ionization-tandem mass spectrometry profiling unveiled the presence of fatty acids and phenolic compounds, including lignans, flavonoids, gallic acid derivatives and diarylheptanoids. Lastly, the biocompatibility of OHS-E was attested on HT29-MTX and Caco-2 intestinal cells.

CONCLUSION

Altogether, these findings encourage the potential application of OHS-E as an effective nutraceutical component against type 2 diabetes mellitus and oxidative stress. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Protein-bound AGEs derived from methylglyoxal induce pro-inflammatory response and barrier integrity damage in epithelial cells by disrupting the retinol metabolism

Advanced glycation end-products (AGEs) are complex and heterogeneous compounds widely present in processed foods. Previous studies evidenced the adverse effects of AGEs on gut homeostasis, but the precise pathological mechanisms and molecular pathways responsible for the disruption of intestinal barrier integrity by AGEs remain incompletely elucidated. In this study, protein-bound AGEs (BSA-MGO), the most common type of dietary AGE, were prepared by methylglyoxal-mediated glycation, and an in vitro human epithelial colorectal adenocarcinoma (Caco-2) cell model was employed to evaluate the impact of protein-bound AGEs on gut epithelial function. Results showed that exposure to BSA-MGO significantly increased the permeability of Caco-2 cell monolayers as evidenced by the decreased transepithelial electrical resistance value, increased paracellular transport of FITC-dextran, and down-regulated tight-junction proteins. In parallel, BSA-MGO induced pro-inflammatory responses and oxidative stress in the monolayers. Transcriptomic profiling further revealed that BSA-MGO disrupted the retinol metabolism, thereby contributing to the barrier integrity damage in epithelial cells. Overall, these results provide valuable insights into the disrupting effects of dietary AGEs on intestinal barrier function, and the perturbed pathways present potential targets for further exploration of the molecular mechanisms underlying the detrimental effect of processed foods on gut health.

Chilean papaya (Vasconcellea pubescens A. DC.) residues as a source of bioactive compounds: Chemical composition, antioxidant capacity, and antiglycation effects

The Chilean papaya (Vasconcellea pubescens A.DC.) is a climacteric fruit that grows in the north and center of Chile. During its processing, residues formed mainly by mucilage and seeds are produced and mostly discarded, despite being a potential source of bioactive metabolites. This work aimed to apply untargeted metabolic analysis by HPLC-DAD-QToF to study the chemical composition of ethyl acetate and methanol extracts from Chilean papaya residues and evaluate their antioxidant and antiglycation capacities. Twenty-three metabolites were tentatively identified in papaya residues, including one carboxylic acid, one glycosylated hydroquinone, four flavan-3-ols, three proanthocyanidins, twelve glycosylated flavonols, one carbohydrate, and one alkaloid reported for the first time. The antioxidant capacity measured as the scavenging of DPPH• and ABTS•+ radicals was comparable with that of ascorbic acid. Chilean papaya extracts decreased fluorescent Advanced Glycation End (AGE) products and oxidative modifications in proteins induced by glucose.

Deciphering the inhibitory mechanisms of betanin and phyllocactin from Hylocereus polyrhizus peel on protein glycation, with insights into their application in bread

Protein glycation closely intertwines with the pathogenesis of various diseases, sparking a growing interest in exploring natural antiglycation agents. Herein, high-purity betacyanins (betanin and phyllocactin) derived from Hylocereus polyrhizus peel were studied for their antiglycation potential using an in vitro bovine serum albumin (BSA)-glucose model. Notably, betacyanins outperformed aminoguanidine, a recognized antiglycation agent, in inhibiting glycation product formation across different stages, especially advanced glycation end-products (AGEs). Interestingly, phyllocactin displayed stronger antiglycation activity than betanin. Subsequent mechanistic studies employing molecular docking analysis and fluorescence quenching assay unveiled that betacyanins interact with BSA endothermically and spontaneously, with hydrophobic forces playing a dominant role. Remarkably, phyllocactin demonstrated higher binding affinity and stability to BSA than betanin. Furthermore, the incorporation of betacyanins into bread dose-dependently suppressed AGEs formation during baking and shows promise for inhibiting in vivo glycation process post-consumption. Overall, this study highlights the substantial potential of betacyanins as natural antiglycation agents.

Cereal polyphenols inhibition mechanisms on advanced glycation end products and regulation on type 2 diabetes

Advanced glycation end products (AGEs), the products of non-enzymatic browning reactions between the active carbonyl groups of reducing sugars and the free amines of amino acids, are largely considered oxidative derivatives resulting from diabetic hyperglycemia, which are further recognized as a potential risk for insulin resistance (IR) and type 2 diabetes (T2D). The accumulation of AGEs can trigger numerous negative effects such as oxidative stress, carbonyl stress, inflammation, autophagy dysfunction and imbalance of gut microbiota. Recently, studies have shown that cereal polyphenols have the ability to inhibit the formation of AGEs, thereby preventing and alleviating T2D. In the meanwhile, phenolics compounds could produce different biological effects due to the quantitative structure activity-relationship. This review highlights the effects of cereal polyphenols as a nonpharmacologic intervention in anti-AGEs and alleviating T2D based on the effects of oxidative stress, carbonyl stress, inflammation, autophagy, and gut microbiota, which also provides a new perspective on the etiology and treatment of diabetes.

Advantages of Spray Drying over Freeze Drying: A Comparative Analysis of Lonicera caerulea L. Juice Powders-Matrix Diversity and Bioactive Response

The study investigated the impact of Lonicera caerulea L. juice matrix modification and drying techniques on powder characteristics. The evaluation encompassed phenolics (514.7-4388.7 mg/100 g dry matter), iridoids (up to 337.5 mg/100 g dry matter), antioxidant and antiglycation capacity, as well as anti-ageing properties of powders produced using maltodextrin, inulin, trehalose, and palatinose with a pioneering role as a carrier. Spray drying proved to be competitive with freeze drying for powder quality. Carrier application influenced the fruit powder properties. Trehalose protected the phenolics in the juice extract products, whereas maltodextrin showed protective effect in the juice powders. The concentrations of iridoids were influenced by the matrix type and drying technique. Antiglycation capacity was more affected by the carrier type in juice powders than in extract products. However, with carrier addition, the latter showed approximately 12-fold higher selectivity for acetylcholinesterase than other samples. Understanding the interplay between matrix composition, drying techniques, and powder properties provides insights for the development of plant-based products with tailored attributes, including potential health-linked properties.

Pistachio green hull and pomegranate peel extracts as two natural antiglycation agents

Advanced glycation end products (AGEs) are formed in the final step of the nonenzymatic Maillard reaction, which can contribute to various health problems such as diabetes mellitus, renal failure, and chronic inflammation. Bioactive compounds with antiglycation properties have the potential to inhibit AGE-related diseases. This study investigated the antiglycation potential of pistachio green hull (PGH) and pomegranate peel (PP) extracts, which are polyphenol-rich agro-residues, against fluorescent AGE formation and compared the results with pyridoxine (vitamin B6), metformin, and EDTA (as usual chemical antiglycation agents). The results showed that PGH and PP effectively inhibited the formation of AGEs in bovine serum albumin-glucose (BSA-Glu) and BSA-fructose (BSA-Fru) with antiglycation activities ranging from 92% to 97%. PP extract (with an IC50 of 94 mg ml-1) had a greater antiglycation ability than PGH extract (with an IC50 of 142 mg ml-1). Also, results indicated that the antiglycation activities of the extracts were comparable to that of pyridoxine, and higher than metformin and EDTA. These findings suggest that the two studied extracts can be used for sustainable production of high-added-value food products with a positive effect on consumers' health.

Potential inhibitory effect of highland barley protein hydrolysates on the formation of advanced glycation end-products (AGEs): A mechanism study

Advanced glycation end products (AGEs) can be caused during a glycoxidation reaction. This reaction is associated with complications of diabetes and the consequences of health problems. Therefore, we are exploring the prohibitory effect of highland barley protein hydrolysates (HBPHs) on AGE formation. Herein, first extracted the protein from highland barley with various pH conditions and then hydrolyzed using four different proteolytic enzymes (flavourzyme, trypsin, papain, pepsin) under different degrees of hydrolysis. We assessed three degrees of hydrolysates (lowest, middle, highest) of enzymes used to characterize the antioxidant activity and physicochemical properties. Among all the hydrolysates, flavourzyme-treated hydrolysates F-1, F-2, and F-3 indicated the high ability to scavenge DPPH (IC50 values of 0.97 %, 0.63 %, and 0.90 %), structural and functional properties. Finally, the inhibitory effect of the most active hydrolysates F-1, F-2, and F-3 against the AGEs formation was evaluated in multiple glucose-glycated bovine serum albumin (BSA) systems. Additionally, in a BSA system, F-3 exhibited the strong antiglycation activity, effectively suppressed the non-fluorescent AGE (CML), and the fructosamine level. Moreover, it decreased carbonyl compounds while also preventing the loss of thiol groups. Our results would be beneficial in the application of the food industry as a potential antiglycation agent for several chronic diseases.

Glycation and drug binding by serum albumin

Accumulation of glycation products in patients with hyperglycaemic conditions can lead to their reaction with the proteins in the human system such as serum albumin, haemoglobin, insulin, plasma lipoproteins, lens proteins and collagen among others which have important biological functions. Therefore, it is important to understand if glycation of these proteins affects their normal action not only qualitatively, but also importantly quantitatively. Glycation of human serum albumin can easily be carried out over period of weeks and its drug transportability may be examined, in addition to characterisation of the amadori products. A combination of ultrasensitive isothermal titration calorimetry, differential scanning calorimetry, spectroscopy and chromatography provides structure-property-energetics correlations which are important to obtain mechanistic aspects of drug recognition, conformation of the protein, and role of amadori products under conditions of glycation. The role of advance glycation end products is important in recognition of antidiabetic drugs. Further, the extent of glycation of the protein and its implication on drug transportability investigated by direct calorimetric methods enables unravelling mechanistic insights into role of functionality on drug molecules in the binding process, and hinderance in the recognition process, if any, as a result of glycation. It is possible that the drug binding ability of the protein under glycation conditions may not be adversely affected, or may even lead to strengthened ability. Rigorous studies on such systems with diverse functionality on the drug molecules is required which is essential in deriving guidelines for improvements in the existing drugs or in the synthesis of new molecular entities directed towards addressing diabetic conditions.

κ-Carrageenan inhibits the formation of advanced glycation end products in cakes: Inhibition mechanism, cake characteristics, and sensory evaluation

Inhibiting the formation of advanced glycation end products (AGEs) in the heat-processed food can reduce health risks related to diabetic complications. However, additives used for this purpose may also affect the sensory characteristics of food products. In this study, the effects of six hydrocolloids on the formation of AGEs were evaluated in the lysine-glucose model, with κ-carrageenan exhibited the highest inhibitory activity. Mechanistic investigations indicated that κ-carrageenan conjugated with the key intermediates of AGEs, namely glyoxal (GO) and methylglyoxal (MGO). Subsequently, the inhibitory effect of κ-carrageenan on AGEs formation in cakes was verified. The data showed that κ-carrageenan in cakes significantly inhibited the formation of fluorescent and non-fluorescent AGEs. In addition, analysis of cake characteristics and sensory evaluation showed that cakes with 1% (w/w) κ-carrageenan had the highest quality and overall acceptance. Overall, κ-carrageenan is an effective inhibitor of AGEs formation in heat-processed food.

Nutritional advantages of barnyard millet and opportunities for its processing as value-added foods

Barnyard millet (Echinochloa species) has received appreciable attention for its susceptibility to biotic and abiotic stresses, multiple harvests in a year and rich in micronutrients, fibers and phytochemicals. It is believed that the consumption of barnyard millet can possess various health benefits against diabetes, cardiovascular diseases, obesity, skin problems, cancer and celiac disease. The flour of barnyard millet is gluten-free and can be incorporated into the diet of celiac and diabetic patients. Considering the nutritional value of millet, various millet-based food products like bread, snack, baby foods, millet wine, porridge, fast foods and millet nutrition powder can be prepared. Future research and developments on barnyard millet and its products may help cope with various diseases known to humans. This paper discusses barnyard millet's nutritional and health benefits as whole grain and its value-added products. The paper also provides insights into the processing of barnyard millet and its effect on the functional properties and, future uses of barnyard millet in the field food industry as ready-to-cook and ready-to-eat products as well as in industrial uses, acting as a potential future crop contributing to food and nutritional security.

Comparison of Protective Effects of Phenolic Acids on Protein Glycation of BSA Supported by In Vitro and Docking Studies

Several diabetic complications are associated with forming advanced glycation end products (AGEs). Different chemical and natural compounds are able to prevent the development of these products. In this study, glycosylation was induced as a model by incubating bovine serum albumin (BSA) with glucose. Consequently, BSA was treated with glucose and different concentrations (1.25, 2.5, and 5 μM) of syringic acid, gallic acid, ellagic acid, ferulic acid, paracoumaric acid, and caffeic acid for 4 and 6 weeks. Biochemical experiments comprise measurements of fluorescent AGEs, protein carbonyl contents, total thiol, hemolysis tests, and also malondialdehyde (MDA) levels in RBC. These demonstrated the antiglycating mechanism of these phenolic acids. Most of the phenolic acids used in this study reduced MDA levels and protected thiol residues in protein structures. They also inhibited the formation of fluorescent AGEs and RBC lysis, except gallic acid. Moreover, ferulic acid, paracoumaric acid, and caffeic acid proteins significantly prevent carbonylation. Molecular docking and simulation studies showed that ellagic, caffeic, gallic, and syringic acids could interact with lysine and arginine residues in the active site of BSA and stabilize its structure to inhibit the formation of AGEs. Our results suggest that phenolic acid could be used as a potential phytochemical against protein glycation and related diabetic complications.

Inhibitory effect of Ginkgo biloba seeds peptides on methylglyoxal-induced glycations

The aim of this study was to investigate the antiglycation activity and mechanism of two identified peptides, Valine-Valine-Phenylalanine-Proline-Glycine-Cysteine-Proline-Glutamic acid (VVFPGCPE) and Serine-Valine-Aspartic acid-Aspartic acid-Proline-Arginine-Threonine-Lysine (SVDDPRTL), from Ginkgo biloba seeds protein hydrolysates. Both VVFPGCPE and SVDDPRTL were efficient in bovine serum albumin (BSA)-methylglyoxal (MGO) model to inhibit BSA glycation, while VVFPGCPE showed higher antiglycation activity than SVDDPRTL. In antioxidant assays, VVFPGCPE scavenged more hydroxyl and super anion radicals, and chelated more Fe²⁺. Moreover, VVFPGCPE was more efficient in alleviating glycoxidation since it retained higher content of tryptophan and reduced dityrosine and kynurenine generation. Compared with SVDDPRTL, VVFPGCPE showed better performance in inhibiting protein aggregation and amyloid-like fibrillation formation. Therefore, VVFPGCPE was selected for further mechanism study. The circular dichroism analysis suggested VVFPGCPE could preserve α-helix structure and stabilize protein structure. The MGO trapping assay indicated VVFPGCPE (5 mg/mL) could capture 66.25% MGO within 24 h, and the mass spectrometry revealed VVFPGCPE could trap MGO by forming VVFPGCPE-mono-MGO adducts. Besides, molecular simulations suggested VVFPGCPE could interact with key glycation residues, arginine and lysine residues, of BSA mainly through van der Waals and hydrogen bonds. This study might supply a theoretical basis for the development of VVFPGCPE as an effective antiglycation agent.

Health-Promoting Potential of Millet: A Review

Being a key source of animal food, millet production has been sharply increasing over the last few years in order to cope with the dietary requirements of the ever-increasing world population. It is a splendid source of essential nutrients such as protein, carbohydrates, fat, minerals, vitamins, and also some other bioactive compounds that eventually help through multiple biological activities, including antioxidant, anti-hyperglycemic, anti-cholesterol, anti-hypertensive, anthropometric effects and regulation of gut microbiota composition. These bioactive compounds, nutrients, and functions of cereal grains can be affected by processing techniques such as decortication, soaking, malting, milling, fermentation, etc. This study discusses the nutritional and functional properties of millet-incorporated foods and their impact on health, based on around 150 articles between 2015 and 2022 from the Web of Science, Google Scholar, Food and Agriculture Organization of the United Nations (FAO), Breeding Bid Survey (BBS), and FoodData Central (USDA) databases. Analyzing literature reviews, it is evident that the incorporation of millet and its constituents into foodstuffs could be useful against undernourishment and several other health diseases. Additionally, this review provides crucial information about the beneficial features of millet, which can serve as a benchmark of guidelines for industry, consumers, researchers, and nutritionists.

Inhibitory effects of polyphenols from black chokeberry on advanced glycation end-products (AGEs) formation

Plant-based polyphenols are known to exert mitigating effects on the harmful consequences of advanced glycation. In this study, the antioxidant and antiglycation properties of purified black chokeberry polyphenol and its dominant monomers were studied. The phenolics of black chokeberry had a significant inhibitory effect on glycation products at all stages. The highest inhibition of fructosamine (72.27%) was achieved by chlorogenic acid (CA). Epigallocatechin gallate (EGCG) showed an 84.47% inhibition of α-dicarbonyl and 54.44% inhibition of AGEs (advanced glycation end-products). However, the inhibition of α-dicarbonyl was impacted by the presence of Cu²⁺. In addition, an EGCG-induced increase in the protein α-helical structure to 21.43% was observed. Overall, EGCG was the main component inhibited protein glycosylation in the simulated glycation system. Furthermore, the mechanism of inhibition was a combination of scavenging free radicals, capturing metal ions, and alleviating changes in the secondary structure of proteins.

Effects of lotus seedpod oligomeric procyanidins on the inhibition of AGEs formation and sensory quality of tough biscuits

The advanced glycation end products (AGEs) are formed in baked products through the Maillard reaction (MR), which are thought to be a contributing factor to chronic diseases such as heart diseases and diabetes. Lotus seedpod oligomeric procyanidins (LSOPC) are natural antioxidants that have been added to tough biscuit to create functional foods that may lower the risk of chronic diseases. The effect of LSOPC on AGEs formation and the sensory quality of tough biscuit were examined in this study. With the addition of LSOPC, the AGEs scavenging rate and antioxidant capacity of LSOPC-added tough biscuits were dramatically improved. The chromatic aberration (ΔE) value of tough biscuits containing LSOPC increased significantly. Higher addition of LSOPC, on the other hand, could effectively substantially reduced the moisture content, water activity, and pH of LSOPC toughen biscuits. These findings imply that using LSOPC as additive not only lowers the generation of AGEs, but also improves sensory quality of tough biscuit.

Inhibitory Mechanism of Advanced Glycation End-Product Formation by Avenanthramides Derived from Oats through Scavenging the Intermediates

As a special polyphenolic compound in oats, the physiological function of oat avenanthramides (AVAs) drives a variety of biological activities, and plays an important role in the prevention and treatment of common chronic diseases. In this study, the optimum extraction conditions and structural identification of AVAs from oats was studied. The inhibitory effect of AVAs from oats on advanced glycation end-products (AGEs) in a glucose–casein simulation system was evaluated, and this revealed dose-dependent inhibitory effects. The trapping capacity of AVAs to the α-dicarbonyl compounds of AGE intermediate products was determined by HPLC–MS/MS, and the results indicate that AVA 2c, AVA 2p, and AVA 2f exhibited the ability to capture α-dicarbonyl compounds. More importantly, AVA 2f was found to be more efficient than AVA 2p at inhibiting superoxide anion radical (O₂⁻), hydroxyl radical (OH), and singlet oxygen (¹O₂) radical generation, which may be the main reason that AVA 2f was more efficient than AVA 2p in AGE inhibition. Thus, this research presents a promising application of AVAs from oats in inhibiting the food-borne AGEs formed in food processing.

Short-chain β-manno-oligosaccharides from copra meal: structural characterization, prebiotic potential and anti-glycation activity

Size-exclusion chromatography, HR-ESI-MS and FT-IR of copra meal hydrolyzed by ManB-1601 showed the presence of oligosaccharides (CM-β-MOS) having a degree of polymerisation (DP) between 2 and 4. Thermal decomposition studies of the purified CM-β-MOS (DP 2, 3 and 4) showed mass loss at high temperatures (135.8 °C to 600 °C). DP2, DP3 and DP4 CM-β-MOS were adjudged as un-substituted Manβ-4Man, Manβ-4Manβ-4Man and Manβ-4Manβ-4Manβ-4Man, respectively, using NMR (¹H and ¹³C) studies. During fermentation, purified CM-β-MOS supported the growth of Lactobacillus sp. and inhibited enteropathogens (Escherichia coli, Listeria monocytogenes and Salmonella typhi). Acetate was the predominant short-chain fatty acid produced by Lactobacillus sp. RT-PCR studies of L. plantarum WCFS1 fed with CM-β-MOS showed up-regulation (up to 6.7-fold) of the cellobiose utilization operon (pts23C and pbg6) and oligo-sucrose utilization loci (pts1BCA and agl2). Biochemical (free amino groups, carbonyl and fructosamine content), fluorescence (AGEs-specific and intrinsic) and molecular docking studies suggested the anti-glycation potential of CM-β-MOS.

Mechanistic physicochemical insights into glycation and drug binding by serum albumin: Implications in diabetic conditions

The drug binding ability of serum albumin might get affected as a result of its glycation under diabetic conditions. It requires not only an understanding of the effect of glycation of the protein upon association with the drug, but also calls for an assessment of structure-property-energetics relationships. A combination of ultrasensitive calorimetric, spectroscopic and chromatographic approach has been employed to correlate thermodynamic signatures with recognition, conformation and mechanistic details of the processes involved. An important observation from this work is that 3-(dansylamino) phenyl boronic acid (DnsPBA) assay cannot always determine the extent of glycation as evidenced by MALDI-TOF mass spectra of glycated HSA due to its selectivity for 1,2 or 1,3 cis-diol structures which may be absent in certain AGEs. Protein gets modified post glycation with the formation of advanced glycation end products (AGEs), which are monitored to be targeted by the guanidine group present in anti-diabetic drugs. AGEs formed in the third and fourth week of glycation are significant in the recognition of anti-diabetic drugs. The results with metformin and aminoguanidine suggest that the extent of binding depends upon the number of guanidine group(s) in the drug molecule. Open chain molecules having guanidine group(s) exhibit stronger affinity towards glycated HSA than closed ring entities like naphthalene or pyridine moiety. The observation that the drug binding ability of HSA is not adversely affected, rather strengthened upon glycation, has implications in diabetic conditions. A rigorous structure-property-energetics correlation based on thermodynamic signatures and identification of functional groups on drugs for recognition by HSA are essential in deriving guidelines for rational drug design addressing diabetes.

Influence of Sargassum pallidum and the synergistic interaction mechanism of 6-gingerol and poricoic acid A on inhibiting ovalbumin glycation

This study aimed to investigate the antiglycation capacity of Sargassum pallidum extract on ovalbumin (OVA) glycation, and the interaction mechanism of its active compounds, including 6-gingerol (6G) and poricoic acid A (PA). The results showed that Sargassum pallidum extract, PA and 6G had excellent suppression on the formation of fructosamine, 5-hydroxymethylfurfural (5-HMF), acrylamide and advanced glycation end products (AGEs), which was higher than aminoguanidine (AG). The combination of PA and 6G showed good synergistic effect on inhibiting the formation of AGEs. PA exhibited the strongest inhibition activity for protein glycation products, and the content of 5-HMF and acrylamide decreased from 277.44 and 10.60 μg mL-1 to 208.37 and 5.46 μg mL-1, respectively, at 30.08 × 10-5 M compared with the control group. 6G and PA quenched the fluorescence of OVA with a static mechanism, and enhanced the hydrophilic microenvironment of the tyrosine (Tyr) and tryptophan (Trp) residues. The binding of 6G and PA with OVA was spontaneous and driven by hydrogen bonds and van der Waals interactions. Molecular docking indicated that 6G and PA entered the hydrophobic cavity of OVA, and formed hydrogen bonds with Ser103, Leu101 and Thr 91. These findings suggested that Sargassum pallidum extract, PA and 6G have great potential as antiglycation inhibitors to treat diabetes complications in healthy food.

Evaluation of the Relationship Between Bioactive Components in Seaweeds and Advanced Glycation End-Products Inhibitory Activities Using Principal Component Analysis

This study comprehensively presents the relationship between the bioactive substance of 70% (v/v) aqueous ethanol extract of 38 species of seaweeds (SWEs), and anti-glycation activities. The contents of bioactive substance of SWEs, such as total phenolic, total flavonoid and condensed tannins, were determined through a colorimetric analysis. Among the tested species, Ecklonia bicyclis, Ishige foliacea, and Cladophora urightiana var. minor had the highest amount of total phenolic (255.75 mg GAE/g DW), total condensed tannins (63.36 mg CE/g DW), and total flavonoid content (85.26 mg CE/g DW), respectively. Anti-glycation properties of SWEs were evaluated through advanced glycation end-products (AGEs) formation, AGEs-collagen cross-link formation, and AGEs-collagen cross-link breaking assay. Brown algae species exhibited a more prominent inhibitory activity on AGEs formation and AGEs-collagen cross-links, and the breaking of AGEs-collagen cross-links compared to that exhibited by aminoguanidine and ALT-711 (positive controls). Using principal component analysis, we confirmed that the AGEs formation inhibitory property and AGEs-collagen cross-links breaking activity were closely correlated with total phenolic and the condensed tannin contents contained in SWEs. Therefore, the bioactive substances such as phenolics and condensed tannins in seaweeds can be used as predictive indices in selecting compounds for the development of a therapeutic agent that prevents diabetic complications related to the AGEs. In addition, our results suggest that brown algae species, which contains more bioactive substances than green and red algae species, can be utilized as a promising natural resource for the prevention and alleviation of AGEs-related diabetic complications as AGE inhibitor and cross-links breaker.

Antiamylase, Antiglucosidase, and Antiglycation Properties of Millets and Sorghum from Sri Lanka

The present study evaluated a range of biological activities of selected millet types and sorghum varieties in Sri Lanka in relation to diabetes and its complications management. Five millet types, namely, proso millet, white finger millet, kodo millet, foxtail millet, and finger millet (Oshadha and Rawana), and two sorghum varieties, namely, sweet sorghum and sorghum ICSV 112, were used in this study. Methanolic extracts of whole grains were studied for antiamylase, antiglucosidase, and early- and middle-stage antiglycation and glycation reversing activities in vitro. Tested millets and sorghum showed significant (p < 0.05) and dose-dependent antiamylase (IC₅₀: 33.34 ± 1.11-1446.70 ± 54.10 μg/ml), early-stage antiglycation (IC₅₀: 15.42 ± 0.50-270.03 ± 16.29 μg/ml), middle-stage antiglycation (135.08 ± 12.95-614.54 ± 6.99 μg/ml), early-stage glycation reversing (EC₅₀: 91.82 ± 6.56-783.20 ± 61.70 μg/ml), and middle-stage glycation reversing (393.24 ± 8.68-1374.60 ± 129.30 μg/ml) activities. However, none of the studied millet and sorghum showed antiglucosidase activity. Out of the samples studied, pigmented samples, namely, sweet sorghum, Oshadha, and Rawana, exhibited significantly high (p < 0.05) antiamylase and early- and middle-stage antiglycation and glycation reversing activities compared to other millet and sorghum samples. Interestingly, sweet sorghum exhibited nearly four times potent antiamylase activity compared to the standard drug acarbose (IC₅₀ 111.98 ± 2.68 μg/ml) and sweet sorghum, kodo millet, Oshadha, and Rawana showed comparable early-stage antiglycation activities in comparison to the reference standard Rutin (IC₅₀ 21.88 ± 0.16 μg/ml). Therefore, consumption of whole grains of pigmented millet and sorghum in Sri Lanka may play an important role in the prevention and management of diabetes and its complications. Interestingly, this is the 1^st study to report all the tested biological activities for millet and sorghum in Sri Lanka and the 1^st study to report both early- and middle-stage glycation reversing activities of millet and sorghum worldwide.

Anti-glycation effect of Ecklonia cava polysaccharides extracted by combined ultrasound and enzyme-assisted extraction

The anti-glycation effects of polysaccharides from Ecklonia cava were examined according to extraction method-hot buffer (HP), ultrasound (UP), enzyme (EP), or a combination of ultrasound and enzyme (UEP). The physicochemical properties, monosaccharide compositions, and structural characteristics of the polysaccharides were determined. UP, EP, and UEP had higher fucose and galactose compositions than HP. The FT-IR spectra of samples showed the presence of sulfate esters and 4-sulfate galactose. 1H NMR indicated that alginate was removed by purification. UP, EP, and UEP possessed higher sulfate contents than HP. UEP presented with the highest extraction yield and lowest protein and uronic acid contents. The levels of AGE formation, as well as fructosamine, α-dicarbonyl, and protein carbonyl contents were determined during a 3-week incubation in a BSA/fructose system. UEP and UP effectively inhibited AGE, although the inhibition effect was lower than that of aminoguanidine. However, UP and UEP showed higher inhibition of fructosamine, α-dicarbonyl, and protein carbonyl than aminoguanidine. AGE formation was negatively correlated with sulfate content and some monosaccharide compositions (fucose, galactose, and glucose), but positively correlated with molecular weight. Overall, the present study suggests that UEP is a suitable extraction method for obtaining anti-glycation agents from E. cava.

Chinese bayberry (Myrica rubra) phenolics mitigated protein glycoxidation and formation of advanced glycation end-products: A mechanistic investigation

Protein glycation and formation of advanced glycation end-products (AGEs) impose threats to the human health. This study firstly investigated the inhibition of Chinese bayberry (Myrica rubra) phenolics on AGEs formation through mechanistic analysis. Four common Chinese bayberry cultivars were selected to prepare phenolic-rich extracts (CBEs) and characterized for phenolic composition, and their anti-AGE properties were evaluated in multiple in vitro systems. Total sixteen phenolics were quantified in CBEs by UPLC-ESI-MS/MS. CBEs reduced total and specific fluorescent AGEs formation in various simulating models, and protected the protein from structural modification, oxidation, and cross-linking. Mechanistic analysis unveiled that scavenging of free radicals, inactivation of transition metals, interaction with protein to form complexes, and trapping of reactive α-dicarbonyls to form adducts underlain the mechanisms of the anti-glycative actions of CBEs. Chinese bayberry fruits, especially the cultivars Biqi and Wuzi, may be a promising dietary strategy to mitigate AGEs load in the human body.

Antidiabetic potential of dietary polyphenols: A mechanistic review

Diabetes is a metabolic disorder that has caused enormous harm to the public health worldwide. In this study, we evaluated the potential of phenolic compounds on diabetes management, addressing their mechanisms of action, in addition to discussing the digestion, absorption, metabolism, bioavailability, and toxic effects of these compounds. The intake of phenolic compounds can play a fundamental role on diabetes management, since they can reduce blood glucose levels, oxidative stress, protein glycation, inhibit the activity of dipeptidyl peptidase - IV and other key enzymes related to carbohydrate metabolism, activate various biochemical pathways to improve pancreatic β-cell functions, increase insulin secretion, and improve insulin resistance. In this way, they can be considered a potential strategy in the development of pharmaceutical approaches that aim to reduce complications resulting from the progression of this metabolic pathology.

The noncovalent conjugations of human serum albumin (HSA) with MS/AK and the effect on anti-oxidant capacity as well as anti-glycation activity of Monascus yellow pigments

Monascin (MS) and ankaflavin (AK), as typical yellow lipid-soluble pigments identified from Monascus-fermented products, have been confirmed to possess diverse biological activities such as anti-oxidation, reversing diabetes, and anti-atherosclerosis, and have received increasing attention in recent years. Certainly Monascus-fermented product with a high content of MS/AK is also a concern. The current work explored interactions between MS/AK and human serum albumin (HSA) as well as their influence on the anti-oxidant properties of MS/AK. Moreover, the anti-glycation potential of Monascus-fermented products rich in MS and AK (denoted as Mps) was assessed. The results showed that the fluorescence emission of HSA was quenched by MS/AK through a static quenching mechanism, and MS-HSA and AK-HSA complexes were mainly formed by van der Waals forces and hydrophobic interactions, but AK showed a higher binding affinity than MS. Although the DPPH radical-scavenging abilities of MS-HSA and AK-HSA complexes declined, Mps significantly reduced the formation of fructosamine, α-dicarbonyl compounds and advanced glycation end products (AGEs) in the in vitro glycation model (HSA-glucose). Notably, approximately 80% of fluorescent-AGEs were suppressed by Mps at a concentration of 0.95 mg mL^-1, while aminoguanidine (AG, a reference standard) caused only 65% decrease at the same concentration. Although radical scavenging and metal chelating activities could justify the observed anti-glycation activity of Mps, in-depth research on the structures of other functional compounds present in Mps except MS/AK and reaction mechanisms should be performed. Overall, the present study proved that Mps would be promising sources of food-based anti-glycation agents because of their superior inhibitory effect on AGEs.

Ginsenoside derivatives inhibit advanced glycation end-product formation and glucose-fructose mediated protein glycation in vitro via a specific structure-activity relationship

Ginseng (Panax ginseng and red ginseng) extract has been reported to inhibit the formation of advanced glycation end-products (AGEs); however, the potential inhibitory activity of its major constituents (ginsenosides) against AGE formation is still unknown. In the present study, we investigated the inhibitory effect of ginsenoside derivatives on AGE formation. Herein, we assessed the activity of 22 ginsenosides, most of which significantly inhibited fluorescent AGE formation. Notably, ginsenoside Rh2, ginsenoside Rh1, and compound K exhibited the most potent AGE inhibitory potential with IC₅₀ values of 3.38, 8.42, and 10.85 µM, respectively. The structure- activity relationship revealed that the presence of sugar moieties, hydroxyl groups, and their linkages, and the stereostructure of the ginsenoside skeleton played an important role in the inhibition of AGE formation. Furthermore, the inhibitory activity of the most active ginsenoside Rh2 on fructose-glucose-mediated protein glycation and oxidation of bovine serum albumin (BSA) was explored. Rh2 (0.1-12.5 µM) inhibited the formation of fluorescent AGE and non-fluorescent AGE, as well as the level of fructosamine and prevented protein oxidation by decreasing protein carbonyl formation and protein thiol group modification. Rh2 also suppressed the formation of the β-cross amyloid structure of BSA. Ginsenosides might be promising new anti-glycation agents for the prevention of diabetic complications via inhibition of AGE formation and oxidation-dependent protein damage.

Vitexin Inhibits Protein Glycation through Structural Protection, Methylglyoxal Trapping, and Alteration of Glycation Site

In this study, the antiglycation potential and mechanisms of vitexin were explored in vitro by multispectroscopy, microscope imaging, high-resolution mass spectrometry, and computational simulations. Vitexin was found to show much stronger antiglycation effects than aminoguanidine. The inhibition against the fluorescent advanced glycation end products was more than 80% at 500 μM vitexin in both bovine serum albumin (BSA)-fructose and BSA-methylglyoxal (MGO) models. Treated with 100 and 200 μM vitexin for 24 h, the contents of MGO were reduced to 4.97 and 0.2%, respectively, and only one vitexin-mono-MGO adduct was formed. LC-Orbitrap-MS/MS analysis showed that vitexin altered the glycated sites and reduced the glycation degree of some sites. The mechanisms of vitexin against protein glycation were mainly through BSA structural protection, MGO trapping, and alteration of glycation sites induced by interaction with BSA. These findings provided valuable information about the functional development of vitexin as a potential antiglycation agent.

Millet: A review of its nutritional and functional changes during processing

Millets are a major source of human food, and their production has been steadily increasing in the last decades to meet the dietary requirements of the increasing world population. Millets are an excellent source of all essential nutrients like protein, carbohydrates, fat, minerals, vitamins, and bioactive compounds. However, the nutrients, bioactive compounds, and functions of cereal grains can be influenced by the food preparation techniques such as decortication/dehulling, soaking, germination/malting, milling, fermentation, etc. This study discusses the nutritional and functional changes in millet during different traditional/modern processing techniques, based on more than 100 articles between 2013 and 2020 from Web of Science, Google Scholar, FAO, and USDA databases. Our results concluded that processing techniques could be useful to combat undernourishment and other health issues. Moreover, this review provides detailed information about millet processing, which is advantageous for industry, consumers, and researchers in this area.

Inhibitory mechanism of sinensetin on α-glucosidase and non-enzymatic glycation: Insights from spectroscopy and molecular docking analyses

Inhibition of α-glucosidase and non-enzymatic glycation is regarded as an effective method to prevent and treat type 2 diabetes and its complications. In this study, the inhibition of sinensetin on α-glucosidase and non-enzymatic glycation was studied with multi-spectroscopic techniques and molecular docking analysis. The results of fluorescence spectroscopy analysis indicated that sinensetin quenched the endogenous fluorescence of α-glucosidase in static manner. The binding of sinensetin with α-glucosidase was a spontaneous process primarily driven by hydrophobic interaction. At 298 K, the binding constant was (5.70 ± 0.12) × 10⁴ L·mol^-1 and the binding site number was 1. The conformation of α-glucosidase was altered by sinensetin, which was revealed by circular dichroism (CD), FTIR spectra, synchronous fluorescence and three-dimensional (3D) fluorescence spectroscopy methods. Molecular docking analysis demonstrated that sinensetin interacted with the amino acid residues of α-glucosidase, which might prevent the entrance of substrate, leading to the decrease of catalytic efficiency of α-glucosidase. Furthermore, glycation assays showed that sinensetin stabilized the structure of bovine serum albumins (BSA), interacted with BSA, strongly inhibited the formation of dityrosine, N'-formylkynurenine and advanced glycation end products (AGEs). This study provided useful information concerning sinensetin preventing and treating type 2 diabetes and its related complications.