Determining the Interaction Behavior of Calf Thymus DNA with Anastrozole in the Presence of Histone H1: Spectroscopies and Cell Viability of MCF-7 Cell Line Investigations

Exploring the interaction between calf thymus DNA and 11H-Indeno[1,2-b]quinoxalin-11-one Thiosemicarbazones: Spectroscopies and in vitro antitumor activity

Understanding the interactions between small molecules and calf thymus deoxyribonucleic acid (ctDNA) is critical for certain aspects of drug discovery. In this study, three 11H-indeno[1,2-b]quinoxalin-11-one thiosemicarbazones were synthesized and their interaction with ctDNA was examined through various spectroscopic techniques, including ultraviolet (UV) spectroscopy, fluorescence spectroscopy, and circular dichroism (CD) spectrum, and through physicochemical methods, including viscosity measurements. In addition, the effects of these thiosemicarbazone compounds 4a, 4b and 4c on several cancer cell lines were explored. The results of UV absorption, fluorescence quenching and CD experiments indicated that compounds 4a, 4b and 4c primarily bound to ctDNA by an intercalation. This mode of interaction was further corroborated by viscosity measurements. Docked poses of compound 4a revealed that it formed a crucial N position hydrogen bond with the DNA receptor. The chemical structure of compound 4a was further confirmed by X-ray crystallographic analysis. Through biological evaluation, it was found that the in vitro cytotoxicity of three compounds agreed with the order of their binding strength to ctDNA, indicating that the antitumor activity of these compounds correlated with their binding affinity to ctDNA.

Epigenetic Impact of Curcumin and Thymoquinone on Cancer Therapeutics

Today, one of the most prevalent reasons for death among people is carcinoma. Because it is still on the increase throughout the world, there is a critical need for in- -depth research on the pathogenic mechanisms behind the disease as well as for efficient treatment. In the field of epigenetics, gene expression alterations that are inherited but not DNA sequence changes are investigated. Three key epigenetic changes, histone modifications, DNA methylation and non-coding RNA (ncRNA) expression, are principally responsible for the initiation and progression of different tumors. These changes are interconnected and constitute many epigenetic changes. A form of polyphenolic chemical obtained from plants called curcumin has great bioactivity against several diseases, specifically cancer. A naturally occurring substance called thymoquinone is well-known for its anticancer properties. Thymoquinone affects cancer cells through a variety of methods, according to preclinical studies. We retrieved information from popular databases, including PubMed, Google Scholar, and CNKI, to summarize current advancements in the efficiency of curcumin against cancer and its epigenetic regulation in terms of DNA methylation, histone modifications, and miRNA expression. The present investigation offers thorough insights into the molecular processes, based on epigenetic control, that underlie the clinical use of curcumin and thymoquinone in cancerous cells.

Bisphenol pollutants bind with human hair keratin: Combining evidence from fluorescence spectroscopy and molecular docking

Bisphenols, including bisphenol A (BPA) and its analogs such as bisphenol F (BPF), bisphenol S (BPS), tetrabromobisphenol A (TBBPA), tetrachlorobisphenol A (TCBPA) and tetrabromobisphenol S (TBBPS), are typical endocrine disruptors widely used in plastic production. However, until now, the occurrence mechanisms of these bisphenols in hair, a non-invasive material for human biomonitoring, have been inadequately explored. This study employed fluorescence spectroscopy and molecular docking to investigate the interactions between these 6 bisphenols and hair keratin. The findings revealed that these bisphenols quenched keratin's intrinsic fluorescence in a concentration-dependent manner and exhibited a mixed quenching mechanism. Their binding constants to keratin at 308 K range from 6.98 × 102 to 7.24 × 106 M-1, with a spontaneous binding mode observed. Halogenated bisphenols demonstrated a higher binding affinity to keratin compared to non-halogenated bisphenols, with bromobisphenols showing a greater affinity than chlorinated bisphenols. The combined results from fluorescence and molecular docking suggest that hydrogen bonding and hydrophobic interactions are the predominant forces driving the binding of bisphenols to hair keratin. These insights first provide a novel perspective on understanding the mechanisms of small molecular pollutants deposition in hair, marking an important step toward utilizing hair as a biomonitoring tool.

The early prognostic value of the 1-4-day BCM/PA trend after admission in neurocritical patients

The purpose of this study was to investigate early stage dynamic changes in relevant indicators in neurocritical patients to identify biomarkers that can predict a poor prognosis at an early stage (1-4 days after admission). This study retrospectively collected clinical data, inflammatory indicators, and nutritional indicators from 77 patients at the neurology intensive care unit. The 3-month modified Rankin scale score was used as the outcome indicator. A linear mixed model was used to analyze changes in inflammatory indicators and nutritional indicators in neurocritical patients over time from 1-4 days after admission. Logistic regression was used to determine the independent risk factors for a poor prognosis in neurocritical patients and to construct a predictive model. The predictive efficacy of the model was verified using leave-one-out cross-validation and decision curve analysis methods. The analysis results showed that 1-4 days after admission, the inflammatory indicators of white blood cell and absolute monocyte counts and the nutritional indicators of body cell mass(BCM), fat-free mass, body cell mass/phase angle (BCM/PA), intracellular water, extracellular water, and skeletal muscle index increased overall, while the nutritional indicators of albumin and visceral fat area decreased overall. The logistic multivariate regression model showed that the Charlson comorbidity index (CCI) (odds ratio (OR) = 2.526, 95% CI [1.202, 5.308]), hemoglobin (Hb)(on admission)-Hb(min) (OR = 1.049, 95% CI [1.015, 1.083), BCM(on admission) (OR = 0.794, 95% CI [0.662, 0.952]), and the change in BCM/PA 1-4 days after admission (OR = 1.157, 95% CI [1.070, 1.252]) were independent risk factors for a poor prognosis in neurocritical patients. The predictive analysis showed that the predictive power of Model 1 with BCM/PA (area under the curve (AUC) = 0.95, 95% CI (0.90, 0.99)) was 93%, 65%, 141%, and 133% higher than that of Model 2 without BCM/PA, the CCI, the APACHE II score, and the NRS2002 score (all P < 0.05), respectively. The CCI, Hb(on admission)-Hb(min), BCM(on admission), and an increase in BCM/PA 1-4 days after admission were independently associated with a poor prognosis in neurocritical patients. Of these variables, BCM/PA may be a valid indicator for early stage prediction of a poor prognosis in neurocritical patients.

Spectroscopic and Molecular Docking Studies of the Interaction of Non-steroidal Anti-inflammatory Drugs with a Carrier Protein: an Interesting Case of Inner Filter Effect and Intensity Enhancement in Protein Fluorescence

Interaction of diclofenac and indomethacin with lysozyme was studied using several spectroscopic and molecular docking methods. Difference UV-visible spectra showed that the absorption profile of lysozyme changed when both diclofenac and indomethacin were mixed with the former. The sequential addition of both drugs to the lysozyme solution caused the decrease of the intrinsic fluorescence of the latter, however, when the data were corrected for inner filter effect, an enhancement in the fluorescence of lysozyme was detected. Accordingly, the fluorescence enhancement data were analyzed using Benesi-Hildebrand equation. Both, diclofenac and indomethacin showed good interaction with lysozyme, although, the association constants of indomethacin were nearly two-fold higher as compared to that of diclofenac. The binding was slightly more spontaneous in case of indomethacin and the major forces involved in the binding of both drugs with lysozyme were hydrogen bonding and hydrophobic interactions. Secondary structural analysis revealed that both drugs partially unfolded lysozyme. Results obtained through molecular docking were also in good agreement with the experimental outcomes. Both, diclofenac and indomethacin, are bounded at the same site inside lysozyme which is located in the big hydrophobic cavity of the protein.

Molecular insight on the binding of halogenated organic phosphate esters to human serum albumin and its effect on cytotoxicity of halogenated organic phosphate esters

Halogenated Organic Phosphate Esters (OPEs) are commonly found in plasticizers and flame retardants. However, they are one kind of persistent contaminants that can pose a significant threat to human health and ecosystem as new environmental estrogen. In this study, two representative halogenated OPEs, tris(1,3-dichloro-2-propyl) phosphate (TDCP) and tris(2,3-dibromopropyl) phosphate (TDBP), were selected as experimental subjects to investigate their interaction with human serum albumin (HSA). Despite having similar structures, the two ligands exhibited contrasting effects on enzyme activity of HSA, TDCP inhibiting enzyme activity and TDBP activating it. Furthermore, both TDCP and TDBP could bind to HSA at site I, interacted with Arg222 and other residues, and made the conformation of HSA unfolded. Thermodynamic parameters indicated the main driving forces between TDBP and HSA were hydrogen bonding and van der Waals forces, while TDCP was mainly hydrophobic force. Molecular simulations found that more hydrogen bonds of HSA-TDBP formed during the binding process, and the larger charge area of TDBP than TDCP could partially account for the differences observed in their binding abilities to HSA. Notably, the cytotoxicity of TDBP/TDCP was inversely proportional to their binding ability to HSA, implying a new method for determining the cytotoxicity of halogenated OPEs in vitro.

Interaction of 3,9-disubstituted acridine with single stranded poly(rA), double stranded poly(rAU) and triple stranded poly(rUAU): molecular docking - A spectroscopic tandem study

RNA plays an important role in many biological processes which are crucial for cell survival, and it has been suggested that it may be possible to inhibit individual processes involved in many diseases by targeting specific sequences of RNA. The aim of this work is to determine the affinity of novel 3,9-disubstited acridine derivative 1 with three different RNA molecules, namely single stranded poly(rA), double stranded homopolymer poly(rAU) and triple stranded poly(rUAU). The results of the absorption titration assays show that the binding constant of the novel derivative to the RNA molecules was in the range of 1.7-6.2 × 104 mol dm-3. The fluorescence and circular dichroism titration assays revealed considerable changes. The most significant results in terms of interpreting the nature of the interactions were the melting temperatures of the RNA samples in complexes with the 1. In the case of poly(rA), denaturation resulted in a self-structure formation; increased stabilization was observed for poly(rAU), while the melting points of the ligand-poly(rUAU) complex showed significant destabilization as a result of the interaction. The principles of molecular mechanics were applied to propose the non-bonded interactions within the binding complex, pentariboadenylic acid and acridine ligand as the study model. Initial molecular docking provided the input structure for advanced simulation techniques. Molecular dynamics simulation and cluster analysis reveal π - π stacking and the hydrogen bonds formation as the main forces that can stabilize the binding complex. Subsequent MM-GBSA calculations showed negative binding enthalpy accompanied the complex formation and proposed the most preferred conformation of the interaction complex.

Astaxanthin Binding Affinity to DNA: Studied By Fluorescence, Surface Plasmon Resonance and Molecular Docking Methods

Carotenoid astaxanthin (Ax), a pink-red pigment, with its anti-oxidative feature, is useful as a therapeutic element for numerous diseases. The purpose of this study is to investigate the binding affinity of Ax to double strand (ds) DNA evaluated by using the fluorescence spectroscopy, surface plasmon resonance (SPR) and docking approaches. The fluorescence results show that Ax can quench the intensity of DNA fluorescence via a static quenching way. In the SPR method, for affinity evaluation, DNA molecules were attached on a gold sensor surface. Using different amounts of ds DNA, the kinetic values KD, KA, and Ka were calculated. The Van't Hoff equation was used to estimate thermodynamic parameters including enthalpy (∆H), entropy (∆S) and Gibbs free energy (∆G) changes. The obtained results for KD in SPR (6.89×10-5 M) and fluorescence (KD=0.76×10-5 M) methods were in line with each other. Thermodynamic studies were carried out at four different temperatures, and the resulted negative data for ΔH and ΔS displayed that the main binding strength in the interaction of Ax with DNA was hydrogen bonding. ΔG value calculated by fluorescence method was near -38 kJ. mol-1 and using the docking method, estimated -9.95 kcal. mol-1 (-41.63 kJ. mol-1) which shows the binding behavior has an exothermic and spontaneous mechanism. Molecular docking results confirmed that the side chains of Ax interact specifically with base pairs and the DNA backbone.

Influence of myoglobin on the antibacterial activity of carvacrol and the binding mechanism between the two compounds

BACKGROUND

Myoglobin (MB), a pigmentation protein, can adversely affect the antibacterial activity of carvacrol (CAR) and weaken its bacteriostasis effect. This study aimed to clarify the influence of MB on the antibacterial activity of CAR and ascertain the mechanism involved in the observed influence, especially the interaction between the two compounds.

RESULTS

Microbiological analysis indicated that the presence of MB significantly suppressed the antibacterial activity of CAR against Listeria monocytogenes. Ultraviolet-visible spectrometry and fluorescence spectroscopic analysis confirmed the interaction between CAR and MB. The stoichiometric number was determined as ~0.7 via double logarithmic Stern-Volmer equation analysis, while thermodynamic analysis showed that the conjugation of the two compounds occurred as an exothermal reaction (ΔH° = -32.3 ± 11.4 kJ mol-1 and ΔS° = -75 J mol-1  K-1 ). Circular dichroism, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy showed hydrogen bonding in the carvacrol-myoglobin complex (CAR-MB). Molecular docking analysis confirmed that amino acid residues, including GLY80 and HIS82, were most likely to form hydrogen bonds with CAR, while hydrogen bonds represented the main driving force for CAR-MB formation.

CONCLUSION

CAR antibacterial activity was significantly inhibited by the presence of MB in the environment due to the notable reduction in the effective concentration of CAR caused by CAR-MB formation. © 2023 Society of Chemical Industry.

Fascin - F-actin interaction studied by molecular dynamics simulation and protein network analysis

Actin bundles are an important component of cellular cytoskeleton and participate in the movement of cells. The formation of actin bundles requires the participation of many actin binding proteins (ABPs). Fascin is a member of ABPs, which plays a key role in bundling filamentous actin (F-actin) to bundles. However, the detailed interactions between fascin and F-actin are unclear. In this study, we construct an atomic-level structure of fascin - F-actin complex based on a rather poor cryo-EM data with resolution of 20 nm. We first optimized the geometries of the complex by molecular dynamics (MD) simulation and analyzed the binding site and pose of fascin which bundles two F-actin chains. Next, binding free energy of fascin was calculated by MM/GBSA method. Finally, protein structure network analysis (PSNs) was performed to analyze the key residues for fascin binding. Our results show that residues of K22, E27, E29, K41, K43, R110, R149, K358, R408 and K471 on fascin are important for its bundling, which are in good agreement with the experimental data. On the other hand, the consistent results indicate that the atomic-level model of fascin - F-actin complex is reliable. In short, this model can be used to understand the detailed interactions between fascin and F-actin, and to develop novel potential drugs targeting fascin.Communicated by Ramaswamy H. Sarma.

Binding divergence of polystyrene nanoparticles with serum albumin caused by surface functionalization

Using a combination of spectroscopy, we devised an integrated structural strategy to comprehensively profile the molecular details of the impact of differently functionalized (plain, aminated, and carboxylated) polystyrene nanoparticles (PSNPs) on human serum albumin (HSA). The binding isotherms obtained from fluorescence and UV-vis absorption measurements demonstrate that surface functionalization can distinguish the interaction of PSNPs with HSA. Three-dimensional fluorescence and circular dichroism analysis of the effect of interaction with PSNPs on the native conformation and secondary structures of the protein reveals a diminution in the skeleton structure of HSA induced by the PSNPs. In accordance with this, it is discovered that the esterase activity of protein-PSNPs aggregates is diminished compared to that of the native protein. The carboxylated PSNPs exhibited the strongest protein binding and perturbation effects compared to other particles. Plain PSNPs exhibited significant hydrophobic interaction properties, as evidenced by spectral blue shifts and a diminished Stokes shift in the three-dimensional fluorescence assay. Our results exclusively highlight that the hydrophobic and surface charge characteristics of PSNPs govern the extent of interaction with the protein, which is beneficial to understanding microplastic toxicology.

Molecular insights into α-glucosidase inhibition and antiglycation properties affected by the galloyl moiety in (-)-epigallocatechin-3-gallate

BACKGROUND

Diabetes mellitus poses a substantial threat to public health due to rising morbidity and mortality. α-Glucosidase is one of the key enzymes affecting diabetes. Herein, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epigallocatechin (EGC) were applied to clarify the role of the galloyl moiety of tea polyphenols in the inhibition of glycation and α-glucosidase activity. The structure-activity relationship of the galloyl moiety in EGCG on α-glucosidase was investigated in terms of inhibition kinetics, spectroscopy, atomic force microscopy and molecular docking. A bovine serum protein-fructose model was employed to determine the effect of the galloyl moiety on glycation.

RESULTS

The results indicated that the introduction of a galloyl moiety enhanced the capacity of EGCG to inhibit glycation and α-glucosidase activity. The IC50 value of EGC is approximately 2400 times higher than that of EGCG. Furthermore, the galloyl moiety in EGCG altered the microenvironment and secondary structure of α-glucosidase, resulting in a high binding affinity of EGCG to α-glucosidase. The binding constant of EGCG to α-glucosidase at 298 K is approximately 28 times higher than that of EGC.

CONCLUSION

Overall, the galloyl moiety of EGCG plays a crucial role in inhibiting glycation and α-glucosidase activity, which helps to enhance the molecular understanding of the structure and function of the polyphenol galloyl moiety in the science of food and agriculture. © 2023 Society of Chemical Industry.

Virtual screening and invitro evaluation of cyclooxygenase inhibitors from Tinospora cordifolia using the machine learning tool

Tinospora cordifolia has a variety of compounds, and some of these compounds may have anti-inflammatory and antioxidant properties. In the present study, we identified the compounds in the leaf extract of T. cordifolia through Gas Chromatography-Mass Spectrometry (GC-MS) analysis and found the various metabolites. The compounds are screened virtually using a machine learning model, followed by molecular docking and simulation study to identify top-hit compounds as cyclooxygenase (COX) inhibitors. The molecular docking revealed that the compound 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione (CID:545303) exhibited the lowest binding energies of -7.1 and -6.8 kcal/mol against COX 1 and COX 2 respectively. The interactions are favored by hydrogen bonding and hydrophobic interaction inside the binding pocket. The 100 ns MD simulation study for these compounds was performed to know the stability and found the RMSD around 2 Å and around 1.0 Å with minimal fluctuations indicating a stable complex throughout the simulation of 100 ns. Based on these findings, we proposed 7,9-Di-tertbutyl- 1-oxaspiro (4,5) deca-6,9-diene-2,8-dione could be used as a dual inhibitor of COX enzymes and a drug-like molecule for treating inflammation after evaluation of their biological properties. The methanolic extract of T. cordifolia was subjected to in vitro DPPH, ABTS, nitric oxide, anti-microbial, COX, and LOX inhibition activity. The results exhibited possible positive effects against the above activities.Communicated by Ramaswamy H. Sarma.

Biological interaction of Pt complex with imidazole derivative as an anticancer compound with DNA: Experimental and theoretical studies

This investigation is applied to find out interesting information on DNA binding mode with Pt(II) derivative of two N, N bidentate ligands in treating cancer. Thus, one new water-soluble platinum complex with FIP and phen with a new formula of [Pt(phen)(FIP)](NO3)2 was prepared and specified. DFT data can be used to evaluate geometry parameters. Based on the ADMET prediction, this complex can be considered a drug-like agent. Cytotoxicity property was evaluated against some human cancerous MCF7, A549, and HCT116 cell lines. Accumulation of Pt complex, cisplatin, and oxaliplatin in each cancerous cell was determined, which is probably related to their lipophilicity and solubility properties. The binding mode of the complex to ct-DNA was investigated by fluorescence spectroscopy, circular dichroism, and molecular docking simulation. The viscosity of DNA by different concentrations of EB and Pt complex titration shows Pt complex interacts with DNA via groove binding like the spectroscopic binding result. In the MD study, DNA helix, RMSD, and RMSF analysis showed that DNA stability decreased and that the majority of residues left the initial state. DNA increased residual deviations and flexibility are linked to an increase in its gyratory radius, which is consistent with the findings of the experiments.

Experimental and theoretical approaches to interactions between DNA and purine metabolism products

Deoxyribonucleic acid (DNA) is a significant target for small organic and inorganic drug molecules. Understanding the DNA interaction mechanism of these molecules is vital for new drug designs. In this work, interactions between xanthine (XT), theophylline (TP), and theobromine (TB) with calf-thymus double-strained DNA (dsDNA) were monitored via an experimental and theoretical approach. Experimentally, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used on the surface of the NiO/MWCNT/NNaM/PGE electrochemical platform in vitro. Kinetic parameters, including diffusion coefficients, surface concentrations, and standard heterogeneous rate constants, were measured in the absence and presence of DNA using scan rate studies. In the presence of DNA, kinetic parameters were observed to be reduced significantly. Thermodynamic parameters, such as DNA binding constants and standard free Gibbs energies, were calculated for each molecule using the CV and DPV techniques. Both techniques suggested a binding affinity order of XT > TB > TP. Theoretically, density functional theory was applied for geometry optimization, natural bond orbital analyses, and molecular orbital energies of XT, TP, and TB. Experimental and theoretical binding affinities confirm each other. The most energetically stable ligand-DNA complexes expressed that XT, TP, and TB interact with dsDNA via minor groove binding mode, using mostly hydrogen bonds.

Molecular dynamics simulation and in vitro digestion to examine the impact of theaflavin on the digestibility and structural properties of myosin

In this study, the interaction mechanism between theaflavin and myosin was explored to confirm the potential application of theaflavin in the meat protein system. A series of theaflavin and myosin solutions were prepared for spectroscopic studies. Spectroscopy results showed that theaflavins formed complexes with myosin and affected the microenvironment of myosin. And that addition of theaflavin cause static quenching of the myosin solution. Theaflavin and bovine myosin combined through hydrophobic interaction to form a complex, and gradually increasing the temperature was conducive to the binding of theaflavin and bovine myosin. This interaction results in a decrease in the α -helix content of myosin. Molecular dynamics simulation results confirmed that hydrophobic interactions and hydrogen bonds made the protein structure more compact and stable. And the in vitro digestion process was simulated. The results showed that the addition of theaflavin could significantly reduce the digestibility of myosin.

Investigation on the interaction of aromatic organophosphate flame retardants with human serum albumin via computer simulations, multispectroscopic techniques and cytotoxicity assay

Organophosphate flame retardants (OPFRs) are newly emerging estrogenic environmental pollutants, which attracted widespread public interest owing to their potential threats to human. Here, the interaction between two typical aromatic OPFRs, TPHP/EHDPP and HSA was researched by different experiments. Experimental results indicated that TPHP/EHDPP can insert the site I of HSA and be encircled by several amino acid residues, Asp451, Glu292, Lys195, Trp214 and Arg218 played vital roles in this binding process. At 298 K, the Ka value of TPHP-HSA complex was 5.098 × 104 M-1, and the Ka value of EHDPP-HSA was 1.912 × 104 M-1. Except H-bonds and van der Waals forces, the π-electrons on the phenyl ring of aromatic-based OPFRs played a pivotal role in maintaining the stability of the complexes. The content alterations of HSA were observed in the present of TPHP/EHDPP. The IC50 values of TPHP and EHDPP were 157.9 μM and 31.14 μM to GC-2spd cells, respectively. And the existence of HSA has a regulatory effect on the reproductive toxicity of TPHP/EHDPP. In addition, the results of present work implied Ka values of OPFRs and HSA are possible to be a useful parameter for evaluating their relative toxicity.

Exploring the binding effect and mechanism of glycyrrhizin to ovomucin by combining spectroscopic analysis and molecular docking

Ovomucin (OVM) is an ideal natural macromolecular glycoprotein extracted from eggs with good adhesion. Based on the defect that glycyrrhizin (GL) has good antiviral activity but fast metabolism, this study aimed to explore the binding effect and mechanism of GL to OVM, using multi-spectroscopic techniques, isothermal titration calorimetry (ITC), and molecular docking. The adhesion ability of OVM to the hydrophilic interface and GL was first demonstrated by dual polarization interferometry (DPI) analysis and binding capacity assay, and the OVM-GL complex exhibited a similar affinity for the spike protein of COVID-19. The spectroscopic results show that GL can quench the inherent fluorescence and change the glycosidic bond and secondary structure of OVM. The ITC measurements suggested that the binding was exothermic, the hydrogen bond was the dominant binding force for forming OVM-GL. Finally, molecular docking results indicated that GL has hydrogen bond interaction with several amino acid residues located in α-OVM and β-OVM while embedding into the hydrophobic pocket of OVM via hydrophobic interactions. In conclusion, OVM can adhere to the hydrophilic interface and bind to GL through hydrogen bonding and hydrophobic interactions to form a stable complex, that is expected to be helpful in virus prophylaxis.

Spectroscopic, calorimetric and cytotoxicity studies on the combined binding of daunorubicin and acridine orange to a DNA tetrahedron

Chemotherapy-phototherapy (CTPT) combination drugs co-loaded by targeted DNA nanostructures can achieve controlled drug delivery, reduce toxic side effects and overcome multidrug resistance. Herein, we constructed and characterized a DNA tetrahedral nanostructure (MUC1-TD) linked with the targeting aptamer MUC1. The interaction of daunorubicin (DAU)/acridine orange (AO) alone and in combination with MUC1-TD and the influence of the interaction on the cytotoxicity of the drugs were evaluated. Potassium ferrocyanide quenching analysis and DNA melting temperature assays were used to demonstrate the intercalative binding of DAU/AO to MUC1-TD. The interactions of DAU and/or AO with MUC1-TD were analyzed by fluorescence spectroscopy and differential scanning calorimetry. The number of binding sites, binding constant, entropy and enthalpy changes of the binding process were obtained. The binding strength and binding sites of DAU were higher than those of AO. The presence of AO in the ternary system weakened the binding of DAU to MUC1-TD. In vitro cytotoxicity studies demonstrated that the loading of MUC1-TD augmented the inhibitory effects of DAU and AO and the synergistic cytotoxic effects of DAU + AO on MCF-7 cells and MCF-7/ADR cells. Cell uptake studies showed that the loading of MUC1-TD was beneficial in promoting the apoptosis of MCF-7/ADR cells due to its enhanced targeting to the nucleus. This study has important guiding significance for the combined application of DAU and AO co-loaded by DNA nanostructures to overcome multidrug resistance.

Insight into the binding interactions of fluorenone-pendent Schiff base with calf thymus DNA

A novel fluorenone appended Schiff base (L) has been synthesized and utilized for studying the binding interactions with Calf Thymus DNA (ct-DNA). The mechanism of binding with ct-DNA was explored by employing various spectroscopic techniques viz. UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, gel-electrophoresis, circular dichroism (CD), melting studies, viscosity arrays and molecular modelling methodology. The interpretation of UV-vis absorbance spectra pointed to binding of L within minor groove of ct-DNA with the binding constant of K_b = 0.15 × 10⁴ M^-1. Dye-displacement studies with Rhodamine-B (RhB) and Ethylene Bromide (EB) in fluorescence spectroscopy verified the groove binding mode of interaction between L and ct-DNA. Melting studies, circular dichroism, and viscosity studies further elucidated the binding modes of L with ct-DNA. Thermodynamic variable measurements taken at various temperatures such as ΔG^⁰, ΔH^⁰, and ΔS^⁰ revealed that hydrophobic forces played a significant role in the binding process. The meticulous computational interaction demonstrated by molecular docking confirmed the minor groove binding of L with ct-DNA.

An insight into the mixed quantum mechanical-molecular dynamic simulation of a ZnII-Curcumin complex with a chosen DNA sequence that supports experimental DNA binding investigations

An important aspect of research pertaining to Curcumin (HCur) is the need to arrest its degradation in aqueous solution and in biological milieu. This may be achieved through complex formation with metal ions. For this reason, a complex of HCur was prepared with Zn^II, that is not likely to be active in redox pathways, minimizing further complications. The complex is monomeric, tetrahedral, with one HCur, an acetate and a molecule of water bound to Zn^II. It arrests degradation of HCur to a considerable extent that was realized by taking it in phosphate buffer and in biological milieu. The structure was obtained by DFT calculations. Stable adduct formation was identified between optimized structures of HCur and [Zn(Cur)] with DNA (PDB ID: 1BNA) through experiments validated with multiscale modeling approach. Molecular docking studies provide 2D and 3D representations of binding of HCur and [Zn(Cur)] through different non-covalent interactions with the nucleotides of the chosen DNA. Through molecular dynamics simulation, a detailed understanding of binding pattern and key structural characteristics of the generated DNA-complex was obtained following analysis by RMSD, RMSF, radius of gyration, SASA and aspects like formation of hydrogen bonds. Experimental studies provide binding constants for [Zn(Cur)] with calf thymus DNA at 25 °C that effectively helps one to realize its high affinity towards DNA. In the absence of an experimental binding study of HCur with DNA, owing to its tendency to degrade in solution, a theoretical analysis of the binding of HCur to DNA is extremely helpful. Besides, both experimental and simulated binding of [Zn(Cur)] to DNA may be considered as a case of pseudo-binding of HCur to DNA. In a way, such studies on interaction with DNA helps one to identify HCur's affinity for cellular target DNA, not realized through experiments. The entire investigation is an understanding of experimental and theoretical approaches that has been compared continuously, being particularly useful when a molecule's interaction with a biological target cannot realized experimentally.

Binding of dicoumarol analog with DNA and its antioxidant studies: A biophysical insight by in-vitro and in-silico approaches

DNA is the major target for a number of pharmaceutical drugs. The interaction of drug molecules with DNA plays a major role in pharmacokinetics and pharmacodynamics. Bis-coumarin derivatives have diverse biological properties. Here, we have explored the antioxidant activity of 3,3'-Carbonylbis (7-diethylamino coumarin) (CDC) using DPPH, H₂O_2, and superoxide scavenging studies followed by its binding mode in calf thymus-DNA (CT-DNA) using several biophysical methods including molecular docking. CDC exhibited comparable antioxidant activity to standard ascorbic acid. The UV-Visible and fluorescence spectral variations indicate the CDC-DNA complex formation. The binding constant in the range of 10⁴ M^-1 was obtained from spectroscopic studies at room temperature. The fluorescence quenching of CDC by CT-DNA suggested a quenching constant (K_SV) of 10³ to 10⁴ M^-1 order. Thermodynamic studies at 303, 308, and 318 K revealed the observed quenching as a dynamic process besides the spontaneity of the interaction with negative free energy change. Competitive binding studies with site markers like ethidium bromide, methylene blue, and Hoechst 33258 reflect CDC's groove mode of interaction. The result was complemented by DNA melting study, viscosity measurement, and KI quenching studies. The ionic strength effect was studied to interpret the electrostatic interaction and found its insignificant role in the binding. Molecular docking studies suggested the binding location of CDC within the minor groove of CT-DNA, complementing the experimental result.

Superparamagnetic iron oxide nanoparticles target BxPC-3 cells and silence MUC4 for theranostics of pancreatic cancer

PURPOSE

Superparamagnetic iron oxide nanoparticles (SPION) are excellent magnetic resonance imaging (MRI) contrast agents. Mucin 4 (MUC4) acts as pancreatic cancer (PC) tumor antigen and influences PC progression. Small interfering RNAs (siRNAs) are used as a gene-silencing tool to treat a variety of diseases.

METHODS

We designed a therapeutic probe based on polyetherimide-superparamagnetic iron oxide nanoparticles (PEI-SPION) combined with siRNA nanoprobes (PEI-SPION-siRNA) to assess the contrast in MRI. The biocompatibility of the nanocomposite, and silencing of MUC4 were characterized and evaluated.

RESULTS

The prepared molecular probe had a particle size of 61.7 ± 18.5 nmand a surface of 46.7 ± 0.8mVand showed good biocompatibility in vitro and T2 relaxation efficiency. It can also load and protect siRNA. PEI-SPION-siRNA showed a good silencing effect on MUC4.

CONCLUSION

PEI-SPION-siRNA may be beneficial as a novel theranostic tool for PC.

Targeting genomic DNAs and oligonucleotide on base specificity: A comparative spectroscopic, computational and in vitro study

Drug discovery in targeted nucleic acid therapeutics encompass several stages and rigorous challenges owing to less specificity of the DNA binders and high failure rate in different stages of clinical trials. In this perspective, we report newly synthesized ethyl 4-(pyrrolo[1,2-a]quinolin-4-yl)benzoate (PQN) with minor groove A-T base pair binding selectivity and encouraging in cell results. This pyrrolo quinolin derivative has shown excellent groove binding ability with three of our inspected genomic DNAs (cpDNA 73 % AT, ctDNA58% AT and mlDNA 28 % AT) with varying A-T and G-C content. Notably in spite of similar binding patterns PQN have strong binding preference with A-T rich groove of genomic cpDNA over the ctDNA and mlDNA. Spectroscopic experiments like steady state absorption and emission results have established the relative binding strengths (K_abs = 6.3 × 10⁵ M^-1, 5.6 × 10⁴ M^-1, 4.3 × 10⁴ M^-1 and K_emiss = 6.1 × 10⁵ M^-1, 5.7 × 10⁴ M^-1 and 3.5 × 10⁴ M^-1 for PQN-cpDNA, PQN-ctDNA and PQN-mlDNA respectively) whereas circular dichroism and thermal melting studies have unveiled the groove binding mechanism. Specific A-T base pair attachment with van der Waals interaction and quantitative hydrogen bonding assessment were characterized by computational modeling. In addition to genomic DNAs, preferential A-T base pair binding in minor groove was also observed with our designed and synthesized deca-nucleotide (primer sequences 5^/-GCGAATTCGC-3^/ and 3^/-CGCTTAAGCG-5^/). Cell viability assays (86.13 % in 6.58 μM and 84.01 % in 9.88 μM concentrations) and confocal microscopy revealed low cytotoxicity (IC₅₀ 25.86 μM) and efficient perinuclear localization of PQN. We propose PQN with excellent DNA-minor groove binding capacity and intracellular permeation properties, as a lead for further studies encompassing nucleic acid therapeutics.

Carbon dots in breadcrumbs: Effect of frying on them and interaction with human serum albumin

This research confirmed the existence of carbon dots (CDs) in breadcrumbs before frying, and CDs could be significantly affected by frying. The content of CDs increased from 0.013 ± 0.002% to 1.029 ± 0.002%, and the fluorescence quantum yield increased from 1.82 ± 0.01% to 3.16 ± 0.002% after frying at 180℃ for 5 min. The size reduced from 3.32 ± 0.71 nm to 2.67 ± 0.48 nm, and the content of N increased from 1.58% to 2.53%. In addition, the interaction of the CDs and human serum albumin (HSA) through electrostatic and hydrophobic induces the increase of α-helix structure and the change of the amino acid microenvironment of HSA. CDs corona, which may have physiological significance, was found through the transmission electron microscope.

Characterizing the binding interactions between virgin/aged microplastics and catalase in vitro

Microplastics (MPs) undergo physical, chemical, and biological aging in the environment, leading to changes in their physicochemical properties, affecting migration characteristics and toxicity. Oxidative stress effects induced by MPs in vivo have been extensively studied, but the toxicity difference between virgin and aged MPs and the interactions between antioxidant enzymes and MPs in vitro have not been reported yet. This study investigated the structural and functional changes of catalase (CAT) induced by virgin and aged PVC-MPs. It was shown that light irradiation aged the PVC-MPs, and the aging mechanism was photooxidation, resulting in a rough surface and appearing holes and pits. Because of the changes in physicochemical properties, aged MPs had more binding sites than virgin MPs. Fluorescence and synchronous fluorescence spectra results suggested that MPs quenched the endogenous fluorescence of CAT and interacted with tryptophane and tyrosine residues. The virgin MPs had no significant effect on the skeleton of CAT, while the skeleton and the polypeptide chains of CAT became loosened and unfolded after binding with the aged MPs. Moreover, the interactions of CAT with virgin/aged MPs increased the α-helix and decreased the β-sheet contents, destroyed the solvent shell, and resulted in a dispersion of CAT. Due to the large size, MPs cannot enter the interior of CAT and have no effects on the heme groups and activity of CAT. The interaction mechanism between MPs and CAT may be that MPs adsorb CAT to form the protein corona, and aged MPs had more binding sites. This study is the first comprehensive investigation of the effect of aging on the interaction between MPs and biomacromolecules and highlights the potential negative effects of MPs on antioxidant enzymes.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Phytoestrogens, novel dietary supplements for breast cancer

While endocrine therapy is considered as an effective way to treat breast cancer, it still faces many challenges, such as drug resistance and individual discrepancy. Therefore, novel preventive and therapeutic modalities are still in great demand to decrease the incidence and mortality rate of breast cancer. Numerous studies suggested that G protein-coupled estrogen receptor (GPER), a membrane estrogen receptor, is a potential target for breast cancer prevention and treatment. It was also shown that not only endogenous estrogens can activate GPERs, but many phytoestrogens can also function as selective estrogen receptor modulators (SERMs) to interact GPERs. In this review, we discussed the possible mechanisms of GPERs pathways and shed a light of developing novel phytoestrogens based dietary supplements against breast cancers.

Interaction of an anticancer benzopyrane derivative with DNA: Biophysical, biochemical, and molecular modeling studies

BACKGROUND

SIMR1281 is a potent anticancer lead candidate with multi- target activity against several proteins; however, its mechanism of action at the molecular level is not fully understood. Revealing the mechanism and the origin of multitarget activity is important for the rational identification and optimization of multitarget drugs.

METHODS

We have used a variety of biophysical (circular dichroism, isothermal titration calorimetry, viscosity, and UV DNA melting), biochemical (topoisomerase I & II assays) and computational (molecular docking and MD simulations) methods to study the interaction of SIMR1281 with duplex DNA structures.

RESULTS

The biophysical results revealed that SIMR1281 binds to dsDNA via an intercalation-binding mode with an average binding constant of 3.1 × 10⁶ M^-1. This binding mode was confirmed by the topoisomerases' inhibition assays and molecular modeling simulations, which showed the intercalation of the benzopyrane moiety between DNA base pairs, while the remaining moieties (thiazole and phenyl rings) sit in the minor groove and interact with the flanking base pairs adjacent to the intercalation site.

CONCLUSIONS

The DNA binding characteristics of SIMR1281, which can disrupt/inhibit DNA function as confirmed by the topoisomerases' inhibition assays, indicate that the observed multi-target activity might originate from ligand intervention at nucleic acids level rather than due to direct interactions with multiple biological targets at the protein level.

GENERAL SIGNIFICANCE

The findings of this study could be helpful to guide future optimization of benzopyrane-based ligands for therapeutic purposes.

Binding of Tetrabromobisphenol A and S to Human Serum Albumin Is Weakened by Coexisting Nanoplastics and Environmental Kosmotropes

Human serum albumin (HSA) was used as a model protein to explore the effects of brominated flame retardant (BFR) binding and the corona formation on polystyrene nanoplastics (PNs). Under physiological conditions, HSA helped to disperse PNs but promoted the formation of aggregates in the presence of tetrabromobisphenol A (TBBPA, ΔD_h = 135 nm) and S (TBBPS, ΔD_h = 256 nm) at pH 7. At pH 4, these aggregates became larger with fewer electrostatic repulsion effects (ΔD_h = 920 and 691 nm for TBBPA and TBBPS, respectively). However, such promotion effects as well as BFR binding are different due to structural differences of tetrabromobisphenol A and S. Environmental kosmotropes efficiently stabilized the structure of HSA and inhibited BFR binding, while the chaotropes favored bioconjugated aggregate formation. Such effects were also verified in natural seawater. The newly gained knowledge may help us anticipate the behavior and fate of plastic particles and small molecular pollutants in both physiological and natural aqueous systems.

Dissecting the Enantioselective Neurotoxicity of Isocarbophos: Chiral Insight from Cellular, Molecular, and Computational Investigations

Chiral organophosphorus pollutants are found abundantly in the environment, but the neurotoxicity risks of these asymmetric chemicals to human health have not been fully assessed. Using cellular, molecular, and computational toxicology methods, this story is to explore the static and dynamic toxic actions and its stereoselective differences of chiral isocarbophos toward SH-SY5Y nerve cells mediated by acetylcholinesterase (AChE) and further dissect the microscopic basis of enantioselective neurotoxicity. Cell-based assays indicate that chiral isocarbophos exhibits strong enantioselectivity in the inhibition of the survival rates of SH-SY5Y cells and the intracellular AChE activity, and the cytotoxicity of (S)-isocarbophos is significantly greater than that of (R)-isocarbophos. The inhibitory effects of isocarbophos enantiomers on the intracellular AChE activity are dose-dependent, and the half-maximal inhibitory concentrations (IC₅₀) of (R)-/(S)-isocarbophos are 6.179/1.753 μM, respectively. Molecular experiments explain the results of cellular assays, namely, the stereoselective toxic actions of isocarbophos enantiomers on SH-SY5Y cells are stemmed from the differences in bioaffinities between isocarbophos enantiomers and neuronal AChE. In the meantime, the modes of neurotoxic actions display that the key amino acid residues formed strong noncovalent interactions are obviously different, which are related closely to the molecular structural rigidity of chiral isocarbophos and the conformational dynamics and flexibility of the substrate binding domain in neuronal AChE. Still, we observed that the stable "sandwich-type π-π stacking" fashioned between isocarbophos enantiomers and aromatic Trp-86 and Tyr-337 residues is crucial, which notably reduces the van der Waals' contribution (ΔG_vdW) in the AChE-(S)-isocarbophos complexes and induces the disparities in free energies during the enantioselective neurotoxic conjugations and thus elucidating that (S)-isocarbophos mediated by synaptic AChE has a strong toxic effect on SH-SY5Y neuronal cells. Clearly, this effort can provide experimental insights for evaluating the neurotoxicity risks of human exposure to chiral organophosphates from macroscopic to microscopic levels.

Probing the behavior and kinetic studies of amphiphilic acrylate copolymers with bovine serum albumin

This article presents that acrylate copolymers are the potential candidate against the adsorption of bovine serum albumin (BSA). A series of copolymers poly(methyl methacrylate) (pMMA), poly(3-sulfopropyl methacrylate-co-methyl methacrylate) p(SPMA-co-MMA), and poly(dimethylaminoethyl methacrylate-co-methyl methacrylate) p(DMAEMA-co-MMA) were synthesized via free radical polymerization. These amphiphilic copolymers are thermally stable with a glass transition temperature (Tg) 50-120 °C and observed the impact of surface charge on amphiphilic copolymers to control interactions with the bovine serum albumin (BSA). These copolymers pMD1 and pMS1 have surface charges, - 56.6 and - 72.6 mV at pH 7.4 in PBS buffer solution that controls the adsorption capacity of bovine serum albumin (BSA) on polymers surface. Atomic force microscopy (AFM) analysis showed minimum roughness of 0.324 nm and 0.474 nm for pMS1 and pMD1. Kinetic studies for BSA adsorption on these amphiphilic copolymers showed the best fitting of the pseudo-first-order model that showed physisorption and attained at 25 °C and pH 7.4 within 24 h.

The interaction mechanism of candidone with calf thymus DNA: A multi-spectroscopic and MD simulation study

In this investigation, the effects of candidone on the structure and conformation of DNA were evaluated by spectroscopic methods, molecular dynamics simulation, and molecular docking studies. Fluorescence emission peaks, ultraviolet-visible spectra, and molecular docking exhibited the complex formation between candidone and DNA in a groove-binding mode. Fluorescence spectroscopy results also showed a static quenching mechanism of DNA in the presence of candidone. Moreover, thermodynamic parameters demonstrated that candidone spontaneously bound to DNA with a high binding affinity. The hydrophobic interactions were the dominant forces over the binding process. Based on the Fourier transform infrared data candidone tended to attach to the A-T base pairs of the minor grooves of DNA. The thermal denaturation and circular dichroism measurements displayed that candidone caused a slight change in the DNA structure, which was confirmed by the molecular dynamics simulation results. According to the obtained findings from the molecular dynamic simulation, the structural flexibility and dynamics of DNA were altered to a more extended structure.

In silico Study of the Proteins Involved in the Persistence of Brucella spp

BACKGROUND

One of the major problems with Brucella infections is its tendency to become chronic and recurrent, providing a hindrance to the management of this infection. It has been proposed that chronicity is greatly affected by a phenomenon called persistence in bacteria. Several mechanisms are involved in bacterial persistence, including the type II toxin-antitoxin system, the SOS and oxidative and stringent responses.

METHODS

In this in silico study, these persistence mechanisms in Brucella spp. were investigated.

RESULTS

The structure and the interactions between modules involved in these systems were designed, and novel peptides that can interfere with some of these important mechanisms were developed.

CONCLUSION

Since peptide-based therapeutics are a new and evolving field due to their ease of production, we hope that peptides developed in this study, as well as the information about the structure and interactions of modules of persistence mechanisms, can further be used to design drugs against Brucella persister cells in the hope of restraining the chronic nature of Brucellosis.

Integrating transcriptomics and network analysis-based multiplexed drug repurposing to screen drug candidates for M2 macrophage-associated castration-resistant prostate cancer bone metastases

Metastatic castration-resistant prostate cancer (CRPC) has long been considered to be associated with patient mortality. Among metastatic organs, bone is the most common metastatic site, with more than 90% of advanced patients developing bone metastases (BMs) before 24 months of death. Although patients were recommended to use bone-targeted drugs represented by bisphosphonates to treat BMs of CRPC, there was no significant improvement in patient survival. In addition, the use of immunotherapy and androgen deprivation therapy is limited due to the immunosuppressed state and resistance to antiandrogen agents in patients with bone metastases. Therefore, it is still essential to develop a safe and effective therapeutic schedule for CRPC patients with BMs. To this end, we propose a multiplex drug repurposing scheme targeting differences in patient immune cell composition. The identified drug candidates were ranked from the perspective of M2 macrophages by integrating transcriptome and network-based analysis. Meanwhile, computational chemistry and clinical trials were used to generate a comprehensive drug candidate list for the BMs of CRPC by drug redundancy structure filtering. In addition to docetaxel, which has been approved for clinical trials, the list includes norethindrone, testosterone, menthol and foretinib. This study provides a new scheme for BMs of CRPC from the perspective of M2 macrophages. It is undeniable that this multiplex drug repurposing scheme specifically for immune cell-related bone metastases can be used for drug screening of any immune-related disease, helping clinicians find promising therapeutic schedules more quickly, and providing reference information for drug R&D and clinical trials.

A molecular simulation study of hepatitis B virus core protein and the nuclear protein allosteric modulators of phthalazinone derivatives

Hepatitis B virus, causing hepatitis, cirrhosis, liver failure, and liver cancer, poses a serious threat to human health, and the currently approved drugs still cannot eliminate the virus completely. HBV core protein allosteric modulators (CpAMs) with a phthalazinone structure which targets the HBV core (HBc) protein have been seen as a new kind of drug because of their excellent antiviral effects. This study explores the structure-activity relationship and binding mechanism of phthalazinone molecules through three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking, molecular dynamics, and binding free energy calculation and decomposition studies. In addition, CoMFA and CoMSIA models revealed that the steric field, the hydrophobic field, and the hydrogen bond acceptor field may play important roles in the binding process. The molecular docking and dynamics disclosed the most likely binding pose of phthalazinone derivatives with the HBc protein. The binding free energy calculation and decomposition analysis indicated that the van der Waals force was the driving force and that ValE124, ThrD109, ThrE128, LeuD140, IleD105, PheD110, ThrD33, and TrpD102 were the key residues. This study provides an important theoretical basis for the design and optimization of phthalazinone compounds.

4-Chloro-1,2-phenylenediamine induced structural perturbation and genotoxic aggregation in human serum albumin

4-Chloro-1,2-phenylenediamine (4-Cl-OPD) is a halogenated aromatic diamine used as a precursor in permanent hair color production. Despite its well-documented mutagenic and carcinogenic effects in various in vitro and in vivo models, its role in fibrillar aggregate formation and their genotoxic effect in therapeutic proteins has received less attention. The significance of human serum albumin (HSA) arises from its involvement in bio-regulatory and transport processes. HSA misfolding and aggregation are responsible for some of the most frequent neurodegenerative disorders. We used various complementary approaches to track the formation of amyloid fibrils and their genotoxic effect. Molecular dynamics study demonstrated the complex stability. The impact of 4-Cl-OPD on the structural dynamics of HSA was confirmed by Raman spectroscopy, X-ray diffraction, HPLC and SDS-PAGE. Fibrilllar aggregates were investigated using Congo red assay, DLS, and SEM. The genotoxic nature of 4-Cl-OPD was confirmed using plasmid nicking assay and DAPI staining, which revealed DNA damage and cell apoptosis. 4-Cl-OPD provides a model system for studying fibrillar aggregation and their genotoxic potential in the current investigation. Future studies should investigate the inhibition of the aggregation/fibrillation process, which may yield valuable clinical insights.

4-Chloro-1,2-phenylenediamine induced structural perturbation and genotoxic aggregation in human serum albumin

4-Chloro-1,2-phenylenediamine (4-Cl-OPD) is a halogenated aromatic diamine used as a precursor in permanent hair color production. Despite its well-documented mutagenic and carcinogenic effects in various in vitro and in vivo models, its role in fibrillar aggregate formation and their genotoxic effect in therapeutic proteins has received less attention. The significance of human serum albumin (HSA) arises from its involvement in bio-regulatory and transport processes. HSA misfolding and aggregation are responsible for some of the most frequent neurodegenerative disorders. We used various complementary approaches to track the formation of amyloid fibrils and their genotoxic effect. Molecular dynamics study demonstrated the complex stability. The impact of 4-Cl-OPD on the structural dynamics of HSA was confirmed by Raman spectroscopy, X-ray diffraction, HPLC and SDS-PAGE. Fibrilllar aggregates were investigated using Congo red assay, DLS, and SEM. The genotoxic nature of 4-Cl-OPD was confirmed using plasmid nicking assay and DAPI staining, which revealed DNA damage and cell apoptosis. 4-Cl-OPD provides a model system for studying fibrillar aggregation and their genotoxic potential in the current investigation. Future studies should investigate the inhibition of the aggregation/fibrillation process, which may yield valuable clinical insights.

Immunomodulator Vitamin C: An Adjuvant Therapy in Second Wave of Coronavirus Disease 2019

Since its sudden outbreak in December 2019 in Wuhan, A pandemic of SARS-CoV-2 has been announced. Vitamin C is a water-soluble vitamin with anti-oxidant and immunity-boosting properties. Vitamin C acts as a nutritional supplement profoundly impacting the immune response to the second or third wave of the coronavirus disease (COVID-19). Vitamin C efficacy as an adjuvant treatment for inflammation and symptoms associated with COVID-19 infection should be investigated further. This report sheds light on the available information on the current clinical trials and pharmacotherapy related to COVID-19. Information available on Pubmed, EMBASE, Scopus, Web of Science databases and EU clinical trials regarding the use of therapeutic agents in patients with COVID-19 was used to perform analysis. Data was taken from 18 clinical trials available in the U.S. National Library of Medicine. All trials that are active, completed, or in the process of recruiting are included in data. Because of majority of clinical trials are still ongoing, specific results and high-quality clinical evidence are lacking. Before being standardised for use, the protocol must undergo large randomised clinical studies using a variety of existing medications and potential therapies. The pivotal role played by vitamins C in maintaining our immune system, is quite apparent. This review is an attempt to summarize the available information regarding the use of vitamin C as an adjuvant therapy in COVID-19 patients.

Starch and chitosan-based antibacterial dressing for infected wound treatment via self-activated NO release strategy

In this work, a positively charged chitosan-grafted-polyarginine (CS-N-PArg) as the macro-molecular NO donor, and a negatively charged acetalated starch (AcSt-O-PAsp) as a glucose donor, have been synthesized. To achieve the multi-enzymatic cascade system for local generation of self-supply glucose to increase the H₂O₂ concentration for the subsequent oxidization of L-Arg into NO, the designed positively charged CS-N-PArg, negatively charged AcSt-O-PAsp, glucoamylase (GA) and glucose oxidase (GOx) are absorbed and assembled in the pore of the gelatin sponge via electrostatic interaction to establish a smart antibacterial dressings (CS/St + GOx/GA). Once stimulated by Escherichia coli (E. coli)-infected wounds (a slightly acidic environment), the cascade reaction system can sequentially induce to generate glucose, H₂O₂ and NO, which exhibits a meaningful alternative idea for a high-performance antibacterial therapy.

Imperative persistent interaction analysis of anticancer noscapine-ionic liquid with calf thymus DNA

In this study, we have shown the interaction between opium poppy alkaloid noscapine-based ionic liquid [Pip-Nos]OTf and ct-DNA using UV-visible absorption spectroscopy, fluorescence spectroscopy, CD, and computational studies. The absorption spectra showed a hypochromic shift with no shift in the absorption maxima suggesting groove or electrostatic binding. Fluorescence spectra showed an enhancement in fluorescence emission suggesting that the probable mode of binding should be groove binding. Ethidium bromide (EB) competitive and Ionic strength study showed the absence of intercalative and electrostatic modes of interaction. Further, CD analysis of ct-DNA suggested a groove binding mode of interaction of [Pip-Nos]OTf with ct-DNA. [Pip-Nos]OTf displayed a strong binding with the target ct-DNA with a molecular docking score of -41.47 kJ/mol with all 3D coordinates and full conformation. Also, molecular binding contact analyses depicted the stable binding of drug and ct-DNA with potential hydrogen bonds and hydrophobic interactions. The structural superimposition dynamics analysis showed the stable binding of [Pip-Nos]OTf with the ct-DNA model through RMSD statistics. Moreover, the ligand interaction calculations revealed the involvement of large binding energy along with a high static number of molecular forces including the hydrogen bonds and hydrophobic interactions in their complexation. These significant results report the potency of [Pip-Nos]OTf and its important futuristic role in cancer therapeutics.

Functionalized SPION immobilized on graphene-oxide: Anticancer and antiviral study

The progressive and fatal outbreak of some diseases such as cancer and coronavirus necessitates using advanced materials to bring such devastating illnesses under control. In this study, graphene oxide (GO) is decorated by superparamagnetic iron oxide nanoparticles (SPION) (GO/SPION) as well as polyethylene glycol functionalized SPION (GO/SPION@PEG), and chitosan functionalized SPION (GO/SPION@CS). Field emission scanning electron microscopic (FESEM) images show the formation of high density uniformly distributed SPION nanoparticles on the surface of GO sheets. The structural and chemical composition of nanostructures is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The saturation magnetization of GO/SPION, GO/SPION@PEG and GO- SPION@CS are found to be 20, 19 and 8 emu/g using vibrating sample magnetometer. Specific absorption rate (SAR) values of 305, 283, and 199 W/g and corresponding intrinsic loss power (ILP) values of 9.4, 8.7, and 6.2 nHm2kg-1 are achieved for GO/SPION, GO/SPION@PEG and GO/SPION@CS, respectively. The In vitro cytotoxicity assay indicates higher than 70% cell viability for all nanostructures at 100, 300, and 500 ppm after 24 and 72 h. Additionally, cancerous cell (EJ138 human bladder carcinoma) ablation is observed using functionalized GO/SPION under applied magnetic field. More than 50% cancerous cell death has been achieved for GO/SPION@PEG at 300 ppm concentration. Furthermore, Surrogate virus neutralization test is applied to investigate neutralizing property of the synthesized nanostructures through analysis of SARS-CoV-2 receptor-binding domain and human angiotensin-converting enzyme 2 binding. The highest level of SARS-CoV-2 virus inhibition is related to GO/SPION@CS (86%) due to the synergistic exploitation of GO and chitosan. Thus, GO/SPION and GO/SPION@PEG with higher SAR and ILP values could be beneficial for cancer treatment, while GO/SPION@CS with higher virus suppression has potential to use against coronaviruses. Thus, the developed nanocomposites have a potential in the efficient treatment of cancer and coronavirus.

Deciphering the nature of binding of dexlansoprazole with DNA: Biophysical and docking approaches

Drugs, in general, exhibit their pharmacological activity in binding with intracellular targets. Numerous anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Dexlansoprazole (DLP) is a heterocyclic compound containing benzimidazole moiety and a proton pump inhibitor used to treat gastroesophageal reflux disease. The interaction of dexlansoprazole with calf thymus DNA (ct-DNA) has been studied using biophysical methods. The UV-Visible studies revealed a binding constant of 2.15 ± 0.3 × 104 M^-1 which is close to the value of 2.44 ± 0.3 × 10⁴ M^-1 obtained from the fluorescence studies. Competitive displacement studies using the fluorescence spectroscopic method with ethidium bromide and Hoechst as DNA markers suggested the groove binding mode of DLP in ct-DNA. The groove binding mode of DLP in ct-DNA was complemented by the results of viscosity and DNA melting studies. Further studies on the effect of ionic strength and potassium iodide on DLP binding with ct-DNA supported the observed binding mode. Circular dichroism studies reflected no significant conformational variation in ct-DNA after the interaction. The binding mode obtained from the experimental studies was corroborated by the molecular docking studies that showed the position of DLP in the minor groove of ct-DNA along with the receptor interface restudies involved in the interaction.

Intercalation of diafenthiuron insecticide with calf thymus DNA: spectroscopic and molecular dynamics analysis

A series of biophysical experiments like UV-Vis, fluorescence, circular dichroism (CD), competitive displacement assays, voltammetric studies, viscosity measurements and denaturation effect and metadynamics simulation studies were performed to establish the mode of binding of diafenthiuron (DF) insecticide with calf thymus DNA (CT-DNA). Analysis of absorption and fluorescence spectra in Tris-HCl buffer of pH 7.4 indicates the formation of a complex between DF and CT-DNA and the binding constant of which is in the order of 10⁴ M^-1. Competitive displacement assay with ethidium bromide (EB) and Hoechst 33258 suggests that the most probable mode of binding of DF with CT-DNA may be via intercalation mode. The results of other experiments such as CD spectral studies, viscosity measurements and the effect of denaturation agent urea support the intercalation of DF with CT-DNA. Thermodynamic parameters (ΔH^o, ΔS^o and ΔG^o) reveal that hydrogen bonds (H-bonds) or van der Waals (vdW) force is the main binding force in the spontaneous interaction between DF and CT-DNA. Molecular dynamics (MD) simulation studies confirmed the intercalation of DF into the base pairs of CT-DNA.Communicated by Ramaswamy H. Sarma.