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3D pose of aspartame in LOX-1's active site. The Fe cation is represented in orange and the green and cyan dotted lines indicate aspartame's interactions with the active site's residues. Aspartame interacts with the cavity through p-p stacking between its aromatic ring and the indole ring of Trp500, while it forms pication interactions between its charged amino group and the aromatic residues His499 and His504 of the active site.
Source publication
Repurposing existing drugs, as well as natural and artificial sweeteners for novel therapeutic indications could speed up the drug discovery process since numerous associated risks and costs for drug development can be surpassed. In this study, natural and artificial sweeteners have been evaluated by in silico and experimental studies for their pot...
Contexts in source publication
Context 1
... values that account for the various conformers were within a range of 7.85 as well as the XP GScore values differed only by 0.64 kcal/mol. Aspartame in its best pose conformation ( Figure 2) interacts strongly with the binding site of the protein. The strength of this binding is also related to the distances of the atoms participating in each interaction. ...
Context 2
... strength of this binding is also related to the distances of the atoms participating in each interaction. These interactions, leading to the stabilization of the complex, include pp stacking between the indole group of Trp500 and the aromatic ring of aspartame (3.14 Å), the formation of two pications between the amino group of aspartame and the two histidine residues of the active site, His499 and His504 (4.76 Å and 3.61 Å respectively) and the formation of a salt bridge between the Fe cation and the carboxyl group of the molecule (3.84 Å), which is better illustrated in Figure 2. The low binding energy in the cavity is also a result of the orientation of the lipophilic part of the molecule (aromatic ring and methyl ester) towards the hydrophobic residues of the cavity (i.e. ...
Context 3
... analysis revealed important insights for aspartame's binding to LOX's active site. During the MD simulations, aspartame adopts a more favorable pose inside LOX's cavity and it is found to reside closer to the catalytic Fe cation in comparison with the docking pose ( Figure S2). In particular, MD simulation is initiated with aspartame in spatial vicinity with catalytic Fe (3.84 Å), while we observe that in the predominant pose aspartame has approached the catalytic site and the distance between Fe and the carboxyl group of aspartame is measured 2.2 Å, as illustrated in Figure 4a. ...
Context 4
... molecular profile of aspartame inside LOX-1's cavity proposed by STD NMR experiments is in accordance with the results derived from the in silico studies. As illustrated in Figure S2, depicting aspartame in LOX's cavity (predominant MD cluster), the aromatic ring (H1-H5) forms a p-p stacking interaction with Phe557, while the alkyl chain of the molecule (H10, H11, H12) carrying the carboxyl-and the aminofunctional groups resides deep inside the cavity and interacts in the residues of the Fe-complex and Gln495. ...
Citations
... Though our assessment of inflammatory factors and concentrations in vitro was partial, lending insights into potential anti-inflammatory effects, our optimism persists. This can be further supported by the extant literature that corroborates the viability of ASP decoration for designing potential anti-inflammatory agents [104]. Our study lays a foundation for subsequent research and the formulation of fresh therapeutic avenues, such as employing ASP_Au NPs as adjuncts in treating drugresistant bacterial wound infections. ...
Background
Carbapenem-resistant Enterobacteriaceae (CRE) present substantial challenges to clinical intervention, necessitating the formulation of novel antimicrobial strategies to counteract them. Nanomaterials offer a distinctive avenue for eradicating bacteria by employing mechanisms divergent from traditional antibiotic resistance pathways and exhibiting reduced susceptibility to drug resistance development. Non-caloric artificial sweeteners, commonly utilized in the food sector, such as saccharin, sucralose, acesulfame, and aspartame, possess structures amenable to nanomaterial formation. In this investigation, we synthesized gold nanoparticles decorated with non-caloric artificial sweeteners and evaluated their antimicrobial efficacy against clinical CRE strains.
Results
Among these, gold nanoparticles decorated with aspartame (ASP_Au NPs) exhibited the most potent antimicrobial effect, displaying minimum inhibitory concentrations ranging from 4 to 16 µg/mL. As a result, ASP_Au NPs were chosen for further experimentation. Elucidation of the antimicrobial mechanism unveiled that ASP_Au NPs substantially elevated bacterial reactive oxygen species (ROS) levels, which dissipated upon ROS scavenger treatment, indicating ROS accumulation within bacteria as the fundamental antimicrobial modality. Furthermore, findings from membrane permeability assessments suggested that ASP_Au NPs may represent a secondary antimicrobial modality via enhancing inner membrane permeability. In addition, experiments involving crystal violet and confocal live/dead staining demonstrated effective suppression of bacterial biofilm formation by ASP_Au NPs. Moreover, ASP_Au NPs demonstrated notable efficacy in the treatment of Galleria mellonella bacterial infection and acute abdominal infection in mice, concurrently mitigating the organism's inflammatory response. Crucially, evaluation of in vivo safety and biocompatibility established that ASP_Au NPs exhibited negligible toxicity at bactericidal concentrations.
Conclusions
Our results demonstrated that ASP_Au NPs exhibit promise as innovative antimicrobial agents against clinical CRE.
Graphical Abstract
... Though our assessment of in ammatory factors and concentrations in vitro was partial, lending insights into potential anti-in ammatory effects, our optimism persists. This can be further supported by the extant literature that corroborates the viability of ASP decoration for designing potential anti-in ammatory agents [99] . Our study lays a foundation for subsequent research and the formulation of fresh therapeutic avenues, such as employing ASP_Au NPs as adjuncts in treating drug-resistant bacterial wound infections. ...
Background
Carbapenem-resistant Enterobacteriaceae (CRE) present substantial challenges to clinical intervention, necessitating the formulation of novel antimicrobial strategies to counteract them. Nanomaterials offer a distinctive avenue for eradicating bacteria by employing mechanisms divergent from traditional antibiotic resistance pathways and exhibiting reduced susceptibility to drug resistance development. Non-caloric artificial sweeteners, commonly utilized in the food sector, such as saccharin, sucralose, acesulfame, and aspartame, possess structures amenable to nanomaterial formation. In this investigation, we synthesized gold nanoparticles decorated with non-caloric artificial sweeteners and evaluated their antimicrobial efficacy against clinical CRE strains.
Results
Among these, gold nanoparticles decorated with aspartame (ASP_Au NPs) exhibited the most potent antimicrobial effect, displaying minimum inhibitory concentrations ranging from 4 to 16 µg/mL. As a result, ASP_Au NPs were chosen for further experimentation. Elucidation of the antimicrobial mechanism unveiled that ASP_Au NPs substantially elevated bacterial reactive oxygen species (ROS) levels, which dissipated upon ROS scavenger treatment, indicating ROS accumulation within bacteria as the fundamental antimicrobial modality. Furthermore, findings from membrane potential assessments suggested that ASP_Au NPs may represent a potential antimicrobial modality via depolarization of bacterial membranes. In addition, experiments involving crystal violet demonstrated effective suppression of bacterial biofilm formation by ASP_Au NPs. Moreover, ASP_Au NPs demonstrated notable efficacy in the treatment of Galleria mellonella bacterial infection and acute abdominal infection in mice, concurrently mitigating the organism's inflammatory response. Crucially, evaluation of in vivo safety and biocompatibility established that ASP_Au NPs exhibited negligible toxicity at bactericidal concentrations.
Conclusions
Our results demonstrated that ASP_Au NPs exhibit promise as innovative antimicrobial agents against clinical CRE.
... Via similar effects, aspartame can also influence inflammatory and immune cells such as neutrophils and lymphocytes, decreasing neutrophil adhesion and phagocytic index, and increasing antibody titres and soluble immune complexes [11]. Effects on some key enzymes, such as the inhibition of lipoxygenase-1 isoform by aspartame with half-inhibitory concentrations of 50 M [8], may contribute to these complex immunomodulatory effects. Other neurobiochemical and behavioural changes induced by aspartame consumption, particularly at high doses and over extended periods of time, have been reported [12]. ...
... Via similar effects, aspartame can also influence inflammatory and immune cells such as neutrophils and lymphocytes, decreasing neutrophil adhesion and phagocytic index, and increasing antibody titres and soluble immune complexes [11]. Effects on some key enzymes, such as the inhibition of lipoxygenase-1 isoform by aspartame with half-inhibitory concentrations of 50 M [8], may contribute to these complex immunomodulatory effects. Other neurobiochemical and behavioural changes induced by aspartame consumption, particularly at high doses and over extended periods of time, have been reported [12]. ...
Within the last 40 years, aspartame (L-aspartyl-L-phenylalanyl-methylester) became a very popular artificial sweetener, being introduced in over 6000 food products worldwide, including solid foods, beverages, and drugs for oral administration. However, its safety and toxicity have been subject of concern since its discovery, due to potentially harmful effects of its intestinal decomposition products: aspartate, phenylalanine, and methanol. Neuropsychological effects have been reported occasionally, such as headache, blurred vision, insomnia, torpor, memory loss, nausea, speech impairment, personality changes, loss of energy, hyperactivity, hearing problems. Our aim in the present study was to determine the effects of aspartame at various concentrations on the viability of cells transiently transfected with the combination of N-methyl-D-aspartate (NMDAR) ionotropic glutamate receptor subunits NR1+NR2b, as well as to prove direct activation of NMDAR currents by aspartame via whole-cell patch-clamp experiments. CHO-K1 cells transfected with NR1+NR2b via plasmid constructs containing the two genes fused with enhanced green fluorescent protein (eGFP) gene were exposed for 2-4 h to aspartame in progressive decimal dilutions (0.1 µM to 10 mM) and assessed by flow cytometry after propidium iodide (PI) staining, showing increased percentages of dead cells (PI+) at aspartame concentrations of 1 µM or higher, while non-transfected cells featured increased PI+ percentages at aspartame concentrations above 1 mM. We also showed in HEK293T cells transfected by electroporation with the same plasmid combination (NR1+NR2b) transient outward NMDAR currents at +40 mV elicited by brief pulses of glutamate 100 µM or aspartame 100 µM. Rezumat În ultimii 40 ani, aspartamul a devenit un îndulcitor artificial popular, fiind introdus la nivel mondial în peste 6000 alimente, băuturi și medicamente pentru administrare orală. Totuși, siguranța și toxicitatea sa au fost subiecte de interes încă de la descoperire, datorită potențialelor efecte nocive ale produșilor săi de descompunere intestinală: aspartat, fenilalanină, metanol. Efecte neuropsihice au fost raportate uneori, precum cefalee, vedere neclară, insomnie, torpoare, pierderi de memorie, greață, tulburări de vorbire, schimbarea personalității, pierderea energiei, hiperactivitate, tulburări auditive. Scopul nostru a fost de a determina efectele aspartamului la diverse concentrații asupra viabilității celulelor transfectate tranzient cu combinația de subunități de receptor de N-metil-D-aspartat (NMDAR) NR1+NR2b, şi de a demonstra direct activarea de către aspartam a NMDAR în experimente de whole-cell patch-clamp. Celule CHO-K1 transfectate cu NR1+NR2b prin plasmide conținând cele 2 gene cuplate cu eGFP au fost expuse 2-4 h la diluții decimale progresive de aspartam (0,1 µM-10 mM) și măsurate prin citometrie în flux după marcare cu iodură de propidiu (PI), arătând procentaje crescute de celule moarte (PI+) la concentrații de aspartam peste 1 µM, în timp ce celulele netransfectate au avut procentaje crescute PI+ la concentrații de aspartam peste 1 mM. De asemenea, am evidențiat în celule HEK293T transfectate prin electroporare cu aceleași plasmide (NR1+NR2b), curenți outward prin receptori NMDA la +40 mV declanșați de pulsuri scurte de glutamat 100 µM sau aspartam 100 µM.
... The rapid increase in computer capabilities and storage in conjunction with the theory and algorithm development, increase the size of the molecular systems which can be calculated via multiscaling approaches. The most populous ones need the use of highperformance computer facilities employing QM/MM and QM/MM/MD approaches, which have been developed not only for biomolecular systems but also for modeling a variety of complex systems, i.e., inorganic/organometallic, liquids, solid-state, etc., see for instance [179][180][181][182][183][184][185][186][187][188][189][190][191]. ...
The multiscaling quantum mechanics/molecular mechanics (QM/MM) approach was introduced in 1976, while the extensive acceptance of this methodology started in the 1990s. The combination of QM/MM approach with molecular dynamics (MD) simulation, otherwise known as the QM/MM/MD approach, is a powerful and promising tool for the investigation of chemical reactions’ mechanism of complex molecular systems, drug delivery, properties of molecular devices, organic electronics, etc. In the present review, the main methodologies in the multiscaling approaches, i.e., density functional theory (DFT), semiempirical methodologies (SE), MD simulations, MM, and their new advances are discussed in short. Then, a review on calculations and reactions on metalloproteins is presented, where particular attention is given to nitrogenase that catalyzes the conversion of atmospheric nitrogen molecules N₂ into NH₃ through the process known as nitrogen fixation and the FeMo-cofactor.
... NGI25 binds strongly in spatial proximity with catalytic Fe of LOX cavity and interacts with many of the critical residues of the active site, as it is also observed in several in silico studies for LOX inhibition (Chontzopoulou et al., 2021;Kuca et al., 2018). Moreover, the interactions that NGI forms with the critical residues of BCHE's active site are quite similar in a variety of BCHE's inhibitors that have been discovered in bibliography (Begum et al., 2018;Chontzopoulou et al., 2021;Katsori et al., 2011;Vrontaki et al., 2015). ...
... NGI25 binds strongly in spatial proximity with catalytic Fe of LOX cavity and interacts with many of the critical residues of the active site, as it is also observed in several in silico studies for LOX inhibition (Chontzopoulou et al., 2021;Kuca et al., 2018). Moreover, the interactions that NGI forms with the critical residues of BCHE's active site are quite similar in a variety of BCHE's inhibitors that have been discovered in bibliography (Begum et al., 2018;Chontzopoulou et al., 2021;Katsori et al., 2011;Vrontaki et al., 2015). Hence, NGI25 could serve as an important agent to guide the drug design against Alzheimer and other neurological diseases. ...
The structure assignment and conformational analysis of cinnamic derivative N-benzyl-N-(2-(cyclohexylamino)-2-oxoethyl) cinnamamide (NGI25) was carried out through Nuclear Magnetic Resonance (NMR) spectroscopy, Molecular Dynamics (MD) and Quantum Mechanics (QM), i.e. semiempirical and Density Functional Theory (DFT) calculations. Moreover, Homonuclear (COSY, NOESY) and heteronuclear (HSQC, HMBC) experiments were applied to assign its protons and carbons. After structure identification, NGI25 was subjected to computational calculations to reveal its most favorable conformations. In particular, MD studies were performed in two different solvents, DMSO of intermediate polarity and hydrophobic CHCl3. The obtained results suggest that NGI25 adopts similar conformations in both environments. In particular, the two aromatic rings of the molecule reside in spatial vicinity, while they remain quite distant from the cyclohexane. 2D NOESY experiments confirmed the in silico MD and QM calculations. Finally, molecular docking calculations were performed in order to reveal possible enzyme-targets for NGI25. Swiss target module was used to guide the discovery of new targets based on the structure of NGI. Indeed, it was predicted that NGI25 inhibited butyrylcholinesterase (BCHE) and lipoxygenase (LOX). Molecular docking experiments, followed by Molecular Dynamics studies, confirmed the favorable binding of NGI25 to both enzymes.
Communicated by Ramaswamy H. Sarma
The study of natural products as potential drug leads has gained tremendous research interest. Quercetin is one of those natural products. It belongs to the family of flavonoids and, more specifically, flavonols. This review summarizes the beneficial pharmaceutical effects of quercetin, such as its anti-cancer, anti-inflammatory, and antimicrobial properties, which are some of the quercetin effects described in this review. Nevertheless, quercetin shows poor bioavailability and low solubility. For this reason, its encapsulation in macromolecules increases its bioavailability and therefore pharmaceutical efficiency. In this review, a brief description of the different forms of encapsulation of quercetin are described, and new ones are proposed. The beneficial effects of applying new pharmaceutical forms of nanotechnology are outlined.
Aspartame is the methyl-ester of the aspartate-phenylalanine dipeptide. Over time, it has become a very popular artificial sweetener. However, since its approval by the main food safety agencies, several concerns have been raised related to neuropsychiatric effects and neurotoxicity due to its ability to activate glutamate receptors, as well as carcinogenic risks due to the increased production of reactive oxygen species. Within this review, we critically evaluate reports concerning the safety of aspartame. Some studies evidenced subtle mood and behavioral changes upon daily high-dose intake below the admitted limit. Epidemiology studies also evidenced associations between daily aspartame intake and a higher predisposition for malignant diseases, like non-Hodgkin lymphomas and multiple myelomas, particularly in males, but an association by chance still could not be excluded. While the debate over the carcinogenic risk of aspartame is ongoing, it is clear that its use may pose some dangers in peculiar cases, such as patients with seizures or other neurological diseases; it should be totally forbidden for patients with phenylketonuria, and reduced doses or complete avoidance are advisable during pregnancy. It would be also highly desirable for every product containing aspartame to clearly indicate on the label the exact amount of the substance and some risk warnings.
Aspartame is the methyl-ester of the aspartate-phenylalanine dipeptide. Over time it became a very popular artificial sweetener. However, since its approval by the main food safety agencies, several concerns have been raised related to neuropsychiatric effects and neurotoxicity, due to its ability to activate glutamate receptors, as well as carcinogenic risks by increased production of reactive oxygen species. Within this review we critically evaluated reports concerning the safety of aspartame. Some studies evidenced subtle mood and behavioral changes upon daily high-dose intake below the admitted limit. Epidemiology studies also evidenced associations between daily aspartame intake and higher predisposition for malignant diseases like non-Hodgkin lymphomas and multiple myelomas, particularly in males, but association by chance still could not be excluded. While the debate over the carcinogenic risk of aspartame is ongoing, it is clear that its use may pose some dangers in peculiar cases, such as patients with seizures or other neurological diseases; it should be totally forbidden for patients with phenylketonuria, and reduced doses or complete avoidance are advisable during pregnancy. It would be also highly desirable for every product containing aspartame to clearly indicate on the label the exact amount of the substance and some risk warnings.
Aspartame has been studied extensively and evaluated for its safety in foods and beverages yet concerns for its potential carcinogenicity have persisted, driven primarily by animal studies conducted at the Ramazzini Institute (RI). To address this controversy, an updated systematic review of available human, animal, and mechanistic data was conducted leveraging critical assessment tools to consider the quality and reliability of data. The evidence base includes 12 animal studies and >40 epidemiological studies reviewed by the World Health Organization which collectively demonstrate a lack of carcinogenic effect associated with any tumor type. Assessment of >1360 mechanistic endpoints, including many guideline-based genotoxicity studies, demonstrate a lack of activity associated with endpoints grouped to key characteristics of carcinogens. Other non-specific mechanistic data (e.g., mixed findings of oxidative stress across study models, tissues, and species) do not provide evidence of a biologically plausible carcinogenic pathway associated with aspartame. Taken together, available evidence supports that aspartame consumption is not carcinogenic in humans and that the inconsistent findings of the RI studies may be explained by flaws in study design and conduct (despite additional analyses to address study limitations), as acknowledged by authoritative bodies.
