Inhibitory Effect of Arachis hypogaea (Peanut) and Its Phenolics against Methylglyoxal-Derived Advanced Glycation End Product Toxicity

Inhibitory effects and mechanisms of phenolic compounds in rapeseed oil on advanced glycation end product formation in chemical and cellular models in vitro

Sinapic acid (SA), canolol (CAO) and canolol dimer (CAO dimer) are the main phenolic compounds in rapeseed oil. However, their possible efficacy against glycation remains unclear. This study aims to explore the impacts of these substances on the formation of advanced glycation end products (AGEs) based on chemical and cellular models in vitro. Based on fluorescence spectroscopy results, three chemical models of BSA-fructose, BSA-methylglyoxal (MGO), and arginine (Arg)-MGO showed that SA/CAO/CAO dimer could effectively reduce AGE formation but with different abilities. After SA/CAO/CAO dimer incubation, effective protection against BSA protein glycation was observed and three different MGO adducts were formed. In MGO-induced HUVEC cell models, only CAO and CAO dimer significantly inhibited oxidative stress and cell apoptosis, accompanied by the regulation of the Nrf2-HO-1 pathway. During the inhibition, 20 and 12 lipid mediators were reversed in the CAO and CAO dimer groups compared to the MGO group.

Ginkgo biloba: A Leaf of Hope in the Fight against Alzheimer's Dementia: Clinical Trial Systematic Review

Alzheimer's disease (AD) is a stealthy and progressive neurological disorder that is a leading cause of dementia in the global elderly population, imposing a significant burden on both the elderly and society. Currently, the condition is treated with medications that alleviate symptoms. Nonetheless, these drugs may not consistently produce the desired results and can cause serious side effects. Hence, there is a vigorous pursuit of alternative options to enhance the quality of life for patients. Ginkgo biloba (GB), an herb with historical use in traditional medicine, contains bioactive compounds such as terpenoids (Ginkgolides A, B, and C), polyphenols, organic acids, and flavonoids (quercetin, kaempferol, and isorhamnetin). These compounds are associated with anti-inflammatory, antioxidant, and neuroprotective properties, making them valuable for cognitive health. A systematic search across three databases using specific keywords-GB in AD and dementia-yielded 1702 documents, leading to the selection of 15 clinical trials for synthesis. In eleven studies, GB extract/EGb 761® was shown to improve cognitive function, neuropsychiatric symptoms, and functional abilities in both dementia types. In four studies, however, there were no significant differences between the GB-treated and placebo groups. Significant improvements were observed in scores obtained from the Mini-Mental State Examination (MMSE), Short Cognitive Performance Test (SKT), and Neuropsychiatric Inventory (NPI). While the majority of synthesized clinical trials show that Ginkgo biloba has promising potential for the treatment of these conditions, more research is needed to determine optimal dosages, effective delivery methods, and appropriate pharmaceutical formulations. Furthermore, a thorough assessment of adverse effects, exploration of long-term use implications, and investigation into potential drug interactions are critical aspects that must be carefully evaluated in future studies.

Peanut (Arachis hypogaea L.) seeds and by-products in metabolic syndrome and cardiovascular disorders: A systematic review of clinical studies

BACKGROUND

Cardiovascular disease (CVDs) is the leading cause of death worldwide. The main risk factors are hypertension, diabetes, obesity, and increased serum lipids. The peanut (Arachis hypogaea L.), also known as the groundnut, goober, pindar, or monkey nut, belongs to the Fabaceae family and is the fourth most cultivated oilseed in the world. The seeds and skin of peanuts possess a rich phytochemical profile composed of antioxidants, such as phenolic acids, stilbenes, flavonoids, and phytosterols. Peanut consumption can provide numerous health benefits, such as anti-obesity, antidiabetic, antihypertensive, and hypolipidemic effects. Accordingly, peanuts have the potential to treat CVD and counteract its risk factors.

PURPOSE

This study aims to critically evaluate the effects of peanuts on metabolic syndrome (MetS) and CVD risk factors based on clinical studies.

METHOD

This review includes studies indexed in MEDLINE-PubMed, COCHRANE, and EMBASE, and the Preferred Reporting Items for a Systematic Review and Meta-Analysis guidelines were adhered to.

RESULTS

Nineteen studies were included and indicated that the consumption of raw peanuts or differing forms of processed foods containing peanut products and phytochemicals could improve metabolic parameters, such as glycemia, insulinemia, glycated hemoglobin, lipids, body mass index, waist circumference, atherogenic indices, and endothelial function.

CONCLUSION

We propose that this legume and its products be used as a sustainable and low-cost alternative for the prevention and treatment of MetS and CVD. However, further research with larger sample sizes, longer intervention durations, and more diverse populations is needed to understand the full benefit of peanut consumption in MetS and CVD.

A Role for Advanced Glycation End Products in Molecular Ageing

Ageing is a composite process that involves numerous changes at the cellular, tissue, organ and whole-body levels. These changes result in decreased functioning of the organism and the development of certain conditions, which ultimately lead to an increased risk of death. Advanced glycation end products (AGEs) are a family of compounds with a diverse chemical nature. They are the products of non-enzymatic reactions between reducing sugars and proteins, lipids or nucleic acids and are synthesised in high amounts in both physiological and pathological conditions. Accumulation of these molecules increases the level of damage to tissue/organs structures (immune elements, connective tissue, brain, pancreatic beta cells, nephrons, and muscles), which consequently triggers the development of age-related diseases, such as diabetes mellitus, neurodegeneration, and cardiovascular and kidney disorders. Irrespective of the role of AGEs in the initiation or progression of chronic disorders, a reduction in their levels would certainly provide health benefits. In this review, we provide an overview of the role of AGEs in these areas. Moreover, we provide examples of lifestyle interventions, such as caloric restriction or physical activities, that may modulate AGE formation and accumulation and help to promote healthy ageing.

Anti-Glucotoxicity Effect of Phytoconstituents via Inhibiting MGO-AGEs Formation and Breaking MGO-AGEs

The therapeutic benefits of phytochemicals in the treatment of various illnesses and disorders are well documented. They show significant promise for the discovery and creation of novel medications for treating a variety of human diseases. Numerous phytoconstituents have shown antibiotic, antioxidant, and wound-healing effects in the conventional system. Traditional medicines based on alkaloids, phenolics, tannins, saponins, terpenes, steroids, flavonoids, glycosides, and phytosterols have been in use for a long time and are crucial as alternative treatments. These phytochemical elements are crucial for scavenging free radicals, capturing reactive carbonyl species, changing protein glycation sites, inactivating carbohydrate hydrolases, fighting pathological conditions, and accelerating the healing of wounds. In this review, 221 research papers have been reviewed. This research sought to provide an update on the types and methods of formation of methylglyoxal-advanced glycation end products (MGO-AGEs) and molecular pathways induced by AGEs during the progression of the chronic complications of diabetes and associated diseases as well as to discuss the role of phytoconstituents in MGO scavenging and AGEs breaking. The development and commercialization of functional foods using these natural compounds can provide potential health benefits.

Anti-cyclooxygenase, anti-glycation, and anti-skin aging effect of Dendrobium officinale flowers’ aqueous extract and its phytochemical validation in aging

Introduction

Dendrobium officinale Kimura et Migo (D. officinale) , widely called as “life-saving immortal grass” by Chinese folk, is a scarce and endangered species. The edible stems of D. officinale have been extensively studied for active chemical components and various bioactivities. However, few studies have reported the well-being beneficial effects of D. officinale flowers (DOF). Therefore, the present study aimed to investigate the in vitro biological potency of its aqueous extract and screen its active components.

Methods

Antioxidant tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), the ferric reducing ability of plasma (FRAP), and intracellular reactive oxygen species (ROS) level analyses in primary human epidermal keratinocytes, anti-cyclooxygenase2 (COX-2) assay, anti-glycation assay (both fluorescent AGEs formation in a BSA fructose/glucose system and glycation cell assay), and anti-aging assay (quantification of collagen types I and III, and SA-β-gal staining assay) were conducted to determine the potential biological effects of DOF extracts and its major compounds. Ultra-performance liquid chromatography-electrospray ionisation-quadrupole-time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS/MS) was performed to investigate the composition of DOF extracts. Online antioxidant post-column bioassay tests were applied to rapidly screen major antioxidants in DOF extracts.

Results and discussion

The aqueous extract of D. officinale flowers was found to have potential antioxidant capacity, anti-cyclooxygenase2 (COX-2) effect, anti-glycation potency, and anti-aging effects. A total of 34 compounds were identified using UPLC-ESI-QTOF-MS/MS. Online ABTS radical analysis demonstrated that 1-O-caffeoyl-β-D-glucoside, vicenin-2, luteolin-6-C-β-D-xyloside-8-C-β--D-glucoside, quercetin-3-O-sophoroside, rutin, isoquercitrin, and quercetin 3-O-(6″-O-malonyl)-β-D-glucoside are the major potential antioxidants. In addition, all selected 16 compounds exerted significant ABTS radical scavenging ability and effective AGE suppressive activities. However, only certain compounds, such as rutin and isoquercitrin, displayed selective and significant antioxidant abilities, as shown by DPPH and FRAP, as well as potent COX-2 inhibitory capacity, whereas the remaining compounds displayed relatively weak or no effects. This indicates that specific components contributed to different functionalities. Our findings justified that DOF and its active compound targeted related enzymes and highlighted their potential application in anti-aging.

Major anthocyanins in elderberry effectively trap methylglyoxal and reduce cytotoxicity of methylglyoxal in HepG2 cell line

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The antiglycation effect of elderberries by methylglyoxal (MGO) trapping was studied.

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Cyanidin-3-glucoside and cyanidin-3-sambubioside were almost totally reacted with MGO.

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Quercetin-3-glucoside and quercetin-3-rutinoside trap MGO in less extent.

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Cyanidin-3,5-diglucoside and cyanidin-5-glucoside-3-sambubioside did not react.

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Elderberries phenols trap MGO decreasing the induced MGO cytotoxicity in HepG2 cells.

The accumulation of advanced glycation end-products (AGEs) in the body is implicated in numerous diseases, being methylglyoxal (MGO) one of the main precursors. One of the strategies to reduce AGEs accumulation might be acting in an early stage of glycation by trapping MGO. Thus, this work aimed to evaluate, for the first time, the potential of elderberries polyphenols to trap MGO, access the formation of MGO adducts, and evaluate the cytoprotection effect in HepG2 and Caco-2 cells. The results demonstrated that monoglycosylated anthocyanins (cyanidin-3-glucoside and cyanidin-3-sambubioside) are very efficient in trapping MGO, forming mono- and di-adducts. Quercetin-3-glucoside and quercetin-3-rutinoside reacted slowly, while diglycosylated anthocyanins did not react. The trapping of MGO by elderberry monoglycosylated anthocyanins significantly decreased the MGO cytotoxicity in HepG2 cells (∼70 % of cell viability), while the effect in Caco-2 cells was lower (∼50 %). Thus, elderberry phenolics present antiglycation potential by trapping MGO.

Therapeutic Potential of Phlorotannin-Rich Ecklonia cava Extract on Methylglyoxal-Induced Diabetic Nephropathy in In Vitro Model

Advanced glycation end-products (AGEs) play a vital role in the pathogenesis of diabetic complications. Methylglyoxal (MGO), one of the major precursors of AGEs, is a highly reactive dicarbonyl compound that plays an important role in the pathogenesis of diabetic nephropathy. This study was designed to evaluate the therapeutic potential of phlorotannin-rich Ecklonia cava extract (ECE) on MGO-induced diabetic nephropathy in in vitro models using mouse glomerular mesangial cells. ECE showed anti-glycation activity via breaking of AGEs-collagen cross-links and inhibition of AGEs formation and AGE-collagen cross-linking formation. The renoprotective effects were determined by assessing intracellular reactive oxygen species (ROS) and MGO accumulation, cell apoptosis, and the Nrf-2/ARE signaling pathway. MGO-induced renal damage, intracellular ROS production level, and MGO-protein adduct accumulation were significantly decreased by pretreating ECE. Moreover, ECE pretreatment exhibited preventive properties against MGO-induced dicarbonyl stress via activation of the Nrf2/ARE signaling pathway and reduction of RAGE protein expression in mouse glomerular mesangial cells. Collectively, these results indicated potential anti-glycation properties and prominent preventive effects of ECE against MGO-induced renal damage. Additionally, ECE may be utilized for the management of AGE-related diabetic nephropathy.

Antidiabetic Medicinal Plants Used in Democratic Republic of Congo: A Critical Review of Ethnopharmacology and Bioactivity Data

Several studies have been conducted and published on medicinal plants used to manage Diabetes Mellitus worldwide. It is of great interest to review available studies from a country or a region to resort to similarities/discrepancies and data quality. Here, we examined data related to ethnopharmacology and bioactivity of antidiabetic plants used in the Democratic Republic of Congo. Data were extracted from Google Scholar, Medline/PubMed, Scopus, ScienceDirect, the Wiley Online Library, Web of Science, and other documents focusing on ethnopharmacology, pharmacology, and phytochemistry antidiabetic plants used in the Democratic Republic of Congo from 2005 to September 2021. The Kew Botanic Royal Garden and Plants of the World Online web databases were consulted to verify the taxonomic information. CAMARADES checklist was used to assess the quality of animal studies and Jadad scores for clinical trials. In total, 213 plant species belonging to 72 botanical families were reported. Only one plant, Droogmansia munamensis, is typically native to the DRC flora; 117 species are growing in the DRC and neighboring countries; 31 species are either introduced from other regions, and 64 are not specified. Alongside the treatment of Diabetes, about 78.13% of plants have multiple therapeutic uses, depending on the study sites. Experimental studies explored the antidiabetic activity of 133 plants, mainly in mice, rats, guinea pigs, and rabbits. Several chemical classes of antidiabetic compounds isolated from 67 plant species have been documented. Rare phase II clinical trials have been conducted. Critical issues included poor quality methodological protocols, author name incorrectly written (16.16%) or absent (14.25%) or confused with a synonym (4.69%), family name revised (17.26%) or missing (1.10%), voucher number not available 336(92.05%), ecological information not reported (49.59%). Most plant species have been identified and authenticated (89.32%). Hundreds of plants are used to treat Diabetes by traditional healers in DRC. However, most plants are not exclusively native to the local flora and have multiple therapeutic uses. The analysis showed the scarcity or absence of high-quality, in-depth pharmacological studies. There is a need to conduct further studies of locally specific species to fill the gap before their introduction into the national pharmacopeia.

Methylglyoxal-derived hemoglobin advanced glycation end products induce apoptosis and oxidative stress in human umbilical vein endothelial cells

The presence of excess glucose promotes hemoglobin glycation via the biochemical modification of hemoglobin by dicarbonyl products. However, the precise effects of Hb-AGEs in human umbilical vein endothelial cells (HUVECs) are not known to date. Therefore, we investigated the tentative effects of Hb-AGEs in HUVECs. Initially, we used the AGE formation assay to examine the selectivity of MGO toward various proteins. Among all proteins, MGO-Hb-AGEs formation was higher compared to the formation of other dicarbonyl-mediated AGEs. Our next data demonstrated that treatment with 0.5 mg/mL of Hb-AGEs-4w significantly reduced cell viability in HUVECs. Further, we evaluated the role of MGO in conformational and structural changes in Hb. The results showed that Hb demonstrated a highly altered conformation upon incubation with MGO. Moreover, Hb-AGEs-4w treatment strongly increased ROS production, and decreased mitochondrial membrane potential in HUVECs, and moderately reduced the expression of phosphorylated forms of p-38 and JNK. We observed that Hb-AGEs-4w treatment increased the number of apoptotic cells and the Bax/Bcl-2 ratio and cleaved the nuclear enzyme PARP in HUVECs. Finally, Hb-AGEs also inhibited migration and proliferation of HUVECs, thus be physiologically significant in endothelial dysfunction. Taken together, our data suggest that Hb-AGEs may play a critical role in inducing vascular endothelial cell damage. Therefore, this study may provide a plausible explanation for the potential Hb-AGEs in human endothelial cell dysfunction of diabetic patients.

Novel advances in inhibiting advanced glycation end product formation using natural compounds

Advanced glycation end products (AGEs) are a group of complex compounds generated by nonenzymatic interactions between proteins and reducing sugars or lipids. AGEs accumulate in vivo and activate various signaling pathways closely related to the occurrence of various chronic metabolic diseases. In this paper, we describe the process through which AGEs are formed, the classification of AGEs, and biological effects of AGEs on human health. Most importantly, we review recent progress in natural compound-based AGE formation inhibitors. Major classes of natural inhibitors, including polyphenols, polysaccharides, terpenoids, vitamins and alkaloids, have been described. Their mechanisms of action have been summarized as scavenging free radicals, chelating metal ions, capturing active carbonyl compounds, protecting protein glycation sites, and lowering blood glucose levels. Although these natural compounds have good antiglycation activity, to date, they are not widely used in the clinic, likely because of their low content levels. However, these natural compounds and their molecular frameworks will play a valuable role in inspiring drug discovery.

Sulforaphane Inhibits MGO-AGE-Mediated Neuroinflammation by Suppressing NF-κB, MAPK, and AGE-RAGE Signaling Pathways in Microglial Cells

Advanced glycation end products (AGEs) are produced through the binding of glycated protein or lipid with sugar, and they are known to be involved in the pathogenesis of both age-dependent and independent neurological complications. Among dicarbonyl compounds, methylglyoxal (MGO), which is produced from glucose breakdown, is a key precursor of AGE formation and neurotoxicity. Several studies have shown the toxic effects of bovine serum albumin (BSA)-AGE (prepared with glucose, sucrose or fructose) both in in vitro and in vivo. In fact, MGO-derived AGEs (MGO-AGEs) are highly toxic to neurons and other cells of the central nervous system. Therefore, we aimed to investigate the role of MGO-AGEs in microglial activation, a key inflammatory event, or secondary brain damage in neuroinflammatory diseases. Interestingly, we found that sulforaphane (SFN) as a potential candidate to downregulate neuroinflammation induced by MGO-AGEs in BV2 microglial cells. SFN not only inhibited the formation of MGO-AGEs, but it did not show breaking activity on the MGO-mediated AGEs cross-links with protein, indicating that SFN could potentially trap MGO or inhibit toxic AGE damage. In addition, SFN significantly attenuated the production of neuroinflammatory mediators induced by MGO-AGEs in BV2 microglial cells. SFN also lowered the expression levels of AGE receptor (RAGE) in microglial cells, suggesting that SFN could downregulate MGO-AGE-mediated neurotoxicity at the receptor activation level. Altogether, our current study revealed that SFN might show neuropharmacological potential for downregulating MGO-AGEs-mediated neuronal complications thorough attenuating AGE formation and neuroinflammatory responses induced by MGO-AGEs in vitro.

Dicarbonyl Stress and S-Glutathionylation in Cerebrovascular Diseases: A Focus on Cerebral Cavernous Malformations

Dicarbonyl stress is a dysfunctional state consisting in the abnormal accumulation of reactive α-oxaldehydes leading to increased protein modification. In cells, post-translational changes can also occur through S-glutathionylation, a highly conserved oxidative post-translational modification consisting of the formation of a mixed disulfide between glutathione and a protein cysteine residue. This review recapitulates the main findings supporting a role for dicarbonyl stress and S-glutathionylation in the pathogenesis of cerebrovascular diseases, with specific emphasis on cerebral cavernous malformations (CCM), a vascular disease of proven genetic origin that may give rise to various clinical signs and symptoms at any age, including recurrent headaches, seizures, focal neurological deficits, and intracerebral hemorrhage. A possible interplay between dicarbonyl stress and S-glutathionylation in CCM is also discussed.

Psoralea corylifolia L. Seed Extract Attenuates Methylglyoxal-Induced Insulin Resistance by Inhibition of Advanced Glycation End Product Formation

Accumulation of advanced glycation end products (AGEs) in the body has been implicated in the pathogenesis of metabolic conditions, such as diabetes mellitus. Methylglyoxal (MGO), a major precursor of AGEs, has been reported to induce insulin resistance in both in vitro and in vivo studies. Psoralea corylifolia seeds (PCS) have been used as a traditional medicine for several diseases, but their potential application in treating insulin resistance has not yet been evaluated. This study is aimed at investigating whether PCS extract could attenuate insulin resistance induced by MGO. Male C57BL/6N mice (6 weeks old) were administered 1% MGO in their drinking water for 18 weeks, and the PCS extract (200 or 500 mg/kg) was orally administered daily from the first day of the MGO administration. We observed that both 200 and 500 mg/kg PCS extract treatment significantly improved glucose tolerance and insulin sensitivity and markedly restored p-Akt and p-IRS1/2 expression in the livers of the MGO-administered mice. Additionally, the PCS extract significantly increased the phosphorylation of Akt and IRS-1/2 and glucose uptake in MGO-treated HepG2 cells. Further studies showed that the PCS extract inhibited MGO-induced AGE formation in the HepG2 cells and in the sera of MGO-administered mice. PCS extract also increased the expression of glyoxalase 1 (GLO1) in the liver tissue of MGO-administered mice. The PCS extract significantly decreased the phosphorylation of ERK, p38, and NF-κB and suppressed the mRNA expression of proinflammatory molecules including TNF-α and IL-1β and iNOS in MGO-administered mice. Additionally, we demonstrated that the PCS extract attenuated oxidative stress, as evidenced by the reduced ROS production in the MGO-treated cells and the enhanced expression of antioxidant enzymes in the liver of MGO-administered mice. Thus, PCS extract ameliorated the MGO-induced insulin resistance in HepG2 cells and in mice by reducing oxidative stress via the inhibition of AGE formation. These findings suggest the potential of PCS extract as a candidate for the prevention and treatment of insulin resistance.