Cellulose nanocrystals from celery stalk as quercetin scaffolds: A novel perspective of human holo-transferrin adsorption and digestion behaviours.

In this study, cellulose nanocrystals (CNCs) were synthesized from celery stalks to be used as the platform for quercetin delivery. Additionally, CNCs and CNCs-quercetin were characterized using the results of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and zeta potential, while their interactions with human holo-transferrin (HTF) were also investigated. We examined their interaction under physiological conditions through the exertion of fluorescence, resonance light scattering, synchronized fluorescence spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, and fluorescence resonance energy transfer techniques. The data from SEM and TEM exhibited the spherical shape of CNCs and CNCs-quercetin and also, a decrease was detected in the size of quercetin-loaded CNCs from 676 to 473 nm that indicated the intensified water solubility of quercetin. The success of cellulose acid hydrolysis was confirmed based on the XRD results. Apparently, the crystalline index of CNCs-quercetin was reduced by the interaction of CNCs with quercetin, which also resulted in the appearance of functional groups, as shown by FTIR. The interaction of CNCs-quercetin with HTF was also demonstrated by the induced quenching in the intensity of HTF fluorescence emission and Stern-Volmer data represent the occurrence of static quenching. Overall, the effectiveness of CNCs as quercetin vehicles suggests its potential suitability for dietary supplements and pharmaceutical products.

Exploring the binding behavior mechanism of vitamin B12 to α-Casein and ß-Casein: multi-spectroscopy and molecular dynamic approaches.

The aim of this study was to investigate the behavior interaction of α-Casein-B12 and ß-Casein-B12 complexes as binary systems through the methods of multiple spectroscopic, zeta potential, calorimetric, and molecular dynamics (MD) simulation. Fluorescence spectroscopy denoted the role ofB12as a quencher in both cases of α-Casein and ß-Casein fluorescence intensities, which also verifies the existence of interactions. The quenching constants of α-Casein-B12 and ß-Casein-B12 complexes at 298 K in the first set of binding sites were 2.89 × 104 and 4.41 × 104 M-1, while the constants of second set of binding sites were 8.56 × 104 and 1.58 × 105 M-1, respectively. The data of synchronized fluorescence spectroscopy at Δλ = 60 nm were indicative of the closer location of ß-Casein-B12 complex to the Tyr residues. Additionally, the binding distance between B12 and the Trp residues of α-Casein and ß-Casein were obtained in accordance to the Förster's theory of nonradioactive energy transfer to be 1.95 nm and 1.85 nm, respectively. Relatively, the RLS results demonstrated the production of larger particles in both systems, while the outcomes of zeta potential confirmed the formation of α-Casein-B12 and ß-Casein-B12 complexes and approved the existence of electrostatic interactions. We also evaluated the thermodynamic parameters by considering the fluorescence data at three varying temperatures. According to the nonlinear Stern-Volmer plots of α-Casein and ß-Casein in the presence of B12 in binary systems, the two sets of binding sites indicated the detection of two types of interaction behaviors. Time-resolved fluorescence results revealed that the fluorescence quenching of complexes are static mechanism. Furthermore, the outcomes of circular dichroism (CD) represented the occurrence of conformational changes in α-Casein and ß-Casein upon their binding to B12 as the binary system. The experimental results that were obtained throughout the binding of α-Casein-B12 and ß-Casein-B12 complexes were confirmed by molecular modeling.Communicated by Ramaswamy H. Sarma.

High-efficient synthesis of carbon quantum dots from orange pericarp as fluorescence turn-on probes for Ca2+ and Zn2+ ion detection and their application in trypsin activity characterization.

Objectives: In this work, we propose an efficient preparation process for the synthesis of natural carbon quantum dots (NCQDs) by the usage of orange pericarp as the carbon natural resource, which is performed through hydrothermal treatment and top-down approaches. Materials and Methods: The structural, morphological, average size, and optical properties of synthesized NCQDs were investigated via dynamic light scattering (DLS), transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), field emission scanning electron microscope (FESEM), energy dispersive x-ray spectroscopy (EDX), ultraviolet-visible spectroscopy (UV-Vis), and fluorescence PL spectra. Results: The shape of obtained NCQDs was observed to be spherical in the results of TEM analysis with an average size of 6-7 nm which confirms NCQDs essence. The signs of a strong peak (absorption) at around 282 nm throughout the UV-vis spectrum have been detected. The provided FTIR spectroscopy confirmed the existence of functional groups above the NCQDs surface. Furthermore, the surface charge of -11 mV through the obtained zeta potential regarding the synthesized NCQDs has been identified. MTT assay on mouse colon carcinoma cells (C26) demonstrated the lack of any signs of toxicity in NCQDs. Conclusion: The obtained NCQDs contain high photo-stability, excellent PL activity, and efficient fluorescent emission based on excitation. The results of kinetic studies revealed the ability of NCQDs to inhibit trypsin activity in a non-competitive model, which qualifies them as potent inhibitors and quenchers of trypsin. It can be suggested that the synthesized NCQDs have the potential of functioning as a sustainable and eco-friendly source for various applications such as sensors for detecting Ca2+ and Zn2+ and trypsin biosensor for determining enzyme activity.

Molecular Dynamics and Multi-Spectroscopic of the Interaction Behavior between Bladder Cancer Cells and Calf Thymus DNA with Rebeccamycin: Apoptosis through the Down Regulation of PI3K/AKT Signaling Pathway.

The interaction of Rebeccamycin with calf thymus (ctDNA) in the absence and presence of H1 was investigated by molecular dynamics, multi-spectroscopic, and cellular techniques. According to fluorescence and circular dichroism spectroscopies, Rebeccamycin interacted with ctDNA in the absence of H1 through intercalator or binding modes, while the presence of H1 resulted in revealing theintercalator, as the dominant role, and groove binding modes of ctDNA-Rebeccamycin complex. The binding constants, which were calculated to be 1.22 × 104 M-1 and 7.92 × 105 M-1 in the absence and presence of H1, respectively, denoted the strong binding of Rebeccamycin with ctDNA. The binding constants of Rebeccamycin with ct DNA in the absence and presence of H1 were calculated at 298, 303 and 308 K. Considering the thermodynamic parameters (ΔH0 and ΔS0), both vander waals forces and hydrogen bonds played predominant roles throughout the binding of Rebeccamycin to ctDNA in the absence and presence of H1. The outcomes of circular dichroism suggested the lack of any major conformational changes in ctDNA upon interacting with Rebeccamycin, except some perturbations in native B-DNA at local level. Additionally, the effect of NaCl and KI on ctDNA-Rebeccamycin complex provided further evidence for the reliance of their interaction modes on substituted groups. The observed increase in the relative viscosity of ctDNA caused by the enhancement of Rebeccamycin confirmed their intercalation and groove binding modes in the absence and presence of H1. Moreover, the assessments of molecular docking simulation corroborated these experimental results and also elucidated the effectiveness of Rebeccamycinin inhibiting and proliferating T24 and 5637 cells. Meanwhile, the ability of Rebeccamycin in inhibiting cell proliferation and tumor growth through the induction of apoptosis by down regulating the PI3K/AKT signaling pathway were provided.

Multi spectroscopic and molecular simulation studies of propyl acridone binding to calf thymus DNA in the presence of electromagnetic force.

Introduction: Here, the interaction behavior between propyl acridones (PA) and calf thymus DNA (ct-DNA) has been investigated to attain the features of the binding behavior of PA with ct-DNA, which includes specific binding sites, modes, and constants. Furthermore, the effects of PA on the conformation of ct-DNA seem to be quite significant for comprehending the medicine's mechanism of action and pharmacokinetics. Methods: The project was accomplished through means of absorbance studies, fluorescence spectroscopy, circular dichroism, viscosity measurement, thermal melting, and molecular modeling techniques. Results: The intercalation of PA has been suggested by fluorescence quenching and viscosity measurements results while the thermal melting and circular dichroism studies have confirmed the thermal stabilization and conformational changes that seem to be associated with the binding. The binding constants of ct-DNA-PA complex, in the absence and presence of EMF, have been evaluated to be 6.19 × 104 M-1 and 2.95 × 104 M-1 at 298 K, respectively. In the absence of EMF, the ∆H0 and ∆S0 values that occur in the interaction process of PA with ct-DNA have been measured to be -11.81 kJ.mol-1 and 51.01 J.mol-1K-1, while in the presence of EMF they were observed to be -23.34 kJ.mol-1 and 7.49 J.mol-1K-1, respectively. These numbers indicate the involvement of multiple non-covalent interactions in the binding procedure. In a parallel study, DNA-PA interactions have been monitored by molecular dynamics simulations; their results have demonstrated DNA stability with increasing concentrations of PA, as well as calculated bindings of theoretical ΔG0. Conclusion: The complex formation between PA and ct-DNA has been investigated in the presence and absence of EMF through the multi spectroscopic techniques and MD simulation. These findings have been observed to be parallel to the results of KI and NaCl quenching studies, as well as the competitive displacement with EB and AO. According to thermodynamic parameters, electrostatic interactions stand as the main energy that binds PA to ct-DNA. Regarding the cases that involve the Tm of ct-DNA, EMF has proved to increase the stability of binding between PA and ct-DNA.

Understanding the binding behavior of Malathion with calf thymus DNA by spectroscopic, cell viability and molecular dynamics simulation techniques: binary and ternary systems comparison.

The interaction between calf thymus DNA (ctDNA) and Malathion in the absence and presence of Histone 1 has been enquired by the means of spectroscopic, viscometry, molecular modeling, and cell viability assay techniques. Malathion is capable of quenching the fluorescence of ct DNA in the absence and presence of H1. The binding constants of Malathion-ctDNA complex in the absence of H1 have been calculated to be 6.62 × 104, 4.31 × 104 and 1.93 × 104 M-1 at 298, 303, and 308 K, respectively that revealed static quenching in complex formation. The observed negative values of enthalpy and entropy changes indicate that the main binding interaction forces were van der Waals force and hydrogen bonding. The binding constant between Malathion and single-stranded ctDNA (ss ctDNA) seemed to be much weaker than that of Malathion and double-stranded ctDNA (ds ctDNA). Furthermore, Malathion can induce detectable alterations in the CD spectrum of ctDNA, along with changes in its viscosity. In the presence of H1, fluorescence quenching of ctDNA-Malathion complex displays dynamic behavior and binding constants were perceived to be 1.66 × 104, 2.93 × 104 and 5.77 × 104 M-1 at 298, 303, and 308 K, respectively. The different of interaction behavior between ctDNA and Malathion in the absence and presence of H1 clearly revealed H1 role in the complex formation and forces change between ctDNA and Malathion. The positive values of enthalpy and entropy changes have suggested that binding process is primarily driven by hydrophobic interactions. The tendency to interact with ss ctDNA, reduced viscosity have designated that the Malathion bound to ctDNA in the presence of H1 is groove binding. The results of molecular docking and molecular dynamics simulation also confirmed potent interactions between Malathion and the macromolecules in the binary and ternary systems.Communicated by Ramaswamy H. Sarma.

Enzyme activity inhibition properties of new cellulose nanocrystals from Citrus medica L. pericarp: A perspective of cholesterol lowering.

As a waste material, the amazing potential of cellulose nanocrystals (CNCs) isolated from Citrus medica L. pericarp in being a natural resource of lingo-cellulosic products has never been investigated before. In the present study, an alkaline pretreatment and a two-step bleaching procedure were applied to conduct the desired acid hydrolysis by the usage of 64% sulfuric acid at 50°C for 105 min. The extracted CNCs were distinguished through the means of transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential, and energy-dispersive X-ray spectroscopy (EDX). The elimination of peaks, which were accountable for the inducement of hemicelluloses and lignin, was confirmed by the FTIR results and were also validated by the outcomes of XRD that proved the gentle removal of non-cellulosic components. The morphology and size of CNCs were indicated through the FESEM and TEM results. In addition, the spherical forms of synthesized CNCs were observed with a diameter of 46 nm throughout the FESEM images, while displaying a value of 42.54 nm as well due to TEM micrographs. The obtained zeta potential displayed a reasonable negative surface charge for CNCs. Furthermore, the cytotoxicity assessment of this product on fibroblast cells was performed to study their susceptibility for bio-medical and cosmetic industrial applications, which resulted in the lack of exhibiting any cytotoxic effects. In conformity to the outcomes of TEM and FESEM, the results of AFM revealed a fine dispersion and spherical form of cellulose nanoparticles. The interaction between HMG-CoA reductase and CNC was studied by the usage of multi-spectroscopic methods and enzyme kinetics to explore the binding mechanism of HMG-CoA reductase-CNC system. Reduced catalytic activity of the occurrence of changes in the secondary structure of HMG-CoA reductase was as a result of interacting with CNC causing a reduction in its catalytic activity.

Evaluation of the binding effect and cytotoxicity assay of 2-Ethyl-5-(4-methylphenyl) pyramido pyrazole ophthalazine trione on calf thymus DNA: spectroscopic, calorimetric, and molecular dynamics approaches.

With advances in new drug therapies, it is essential to understand the interactions between drugs and target molecules. In this study, we applied multiple spectroscopic techniques including absorbance, fluorescence, circular dichroism spectroscopy, viscosity, thermal melting, calorimetric, and molecular dynamics (MD) simulation to study the interaction between 2-Ethyl-5-(4-methylphenyl) pyramido pyrazole ophthalazine trione (PPF) and calf thymus DNA (ct DNA) in the absence or presence of histone H1. PPF exhibits a high binding affinity towards ct DNA in binary and ternary systems. In addition, the result for the binding constant was observed within the range 104 M-1 achieved through fluorescence quenching data, while the values for enthalpy and entropy changes for ct DNA-PPF and (ct DNA-H1) PPF complexes were measured to be -72.54 kJ.mol-1 , -161.14 J.mol-1  K-1 , -85.34 kJ.mol-1 , and -19.023 J.mol-1  K-1 , respectively. Furthermore, in accordance with circular dichroism spectra, the inducement of ct DNA structural changes was observed during binding of PPF and H1 in binary and ternary system forms. The essential roles of hydrogen bonding and van der Waals forces throughout the interaction were suggested using thermodynamic parameters. According to the obtained data, the interaction mode of ct DNA-PPF and (ct DNA-H1) PPF complexes was intercalation binding. Suggested by the MD simulation study, the ct DNA-H1 complex caused a reduction in the stability of the DNA structure in the presence or absence of ligand, which demonstrated that PPF as an intercalating agent can further distort the structure. The information achieved from this study will be very helpful in understanding the effects of PPF on the conformational state of ct DNA in the absence or presence of the H1 molecule, which seems to be quite significant for clarifying the mechanisms of action and its pharmacokinetics.

A novel vision into the binding behavior of curcumin with human serum albumin-holo transferrin complex: molecular dynamic simulation and multi-spectroscopic perspectives.

In this work, we investigated the simultaneous binding of curcumin (CUR) to human serum albumin (HSA) and human-holo transferrin (HTF) in the roles of binary and ternary systems. The binding affinity and binding site of protein-protein interaction were studied by the methods of multiple spectroscopic and molecular dynamics (MD) simulation. According to the results, the measurements for binding constant of HSA-CUR, HTF-CUR and (HSA-HTF) CUR complexes were observed to be 1.51 × 105, 7.93 × 104 and 1.44 × 105 M-1 respectively. Thermodynamic parameters were considered to be set at three varying temperatures including 298, 303, and 308 K. In conformity to the negative values of ΔH0 and ΔS0 the significant roles of hydrogen binding and van der-Waals forces in the formation of complexes are quiet evident. The binding distance between Trp residues of HSA, HTF and HSA-HTF upon interaction with CUR, were acquired by applying the Förster's theory of non-radioactive energy transfer and reported to be 2.04 nm, 1.78 nm, and 1.86 nm, respectively. In accordance with the conductometry and Resonance light scattering (RLS) results, there were different interaction behaviors among the HSA-HTF complex and CUR in ternary system when being compared to the outcomes of binary system. The secondary structure of all three cases increased as the CUR concentration was intensified, which confirmed the inducement of proteins conformational changes through the application of circular dichroism (CD) technique. The experimental results that were acquired throughout the binding of HSA-CUR, HTF-CUR, and (HSA-HTF) CUR complexes were approved by molecular modeling.Communicated by Ramaswamy H. Sarma.

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.

The interaction of calf thymus DNA (ct DNA) with anastrozole, which is acknowledged as an antineoplastic drug, has been enquired into in the absence and presence of histone H1, through the means of absorbance, fluorescence, circular dichroism spectroscopy, viscosity, thermal melting, and molecular modeling techniques. In addition, the effects of anastrozole on MCF 7 cell line have been thoroughly investigated. Fluorescence spectroscopy results have indicated that quenching mechanism of ct DNA-anastrozole are known as static quenching procedures, since the Stern-Volmer quenching constant (KSV) seems to face a decrease as the temperature is enhanced; this is a significant evidence for intercalative binding mode of anastrozole with ct DNA. Regarding the ternary system in the presence of H1, the constant of Stern-Volmer quenching was increased as the temperature was heightened. The thermodynamic parameters suggested that the binding could be characterized as exothermic by negative and positive enthalpy and entropy changes in both binary and ternary systems, respectively. It is vital to mention that hydrogen bonds and hydrophobic contributions play significant roles in anastrozole association to ct DNA in the absence and presence of H1. In accordance to the absorption spectroscopy and melting temperature curve outcomes, the binding mode of anastrozole with ct DNA in absence and presence of H1 was indicative of intercalative and nonintercalative bindings, respectively. The viscosity results as binary and ternary systems, which have been elucidated from a sensitive viscometer, have confirmed the fluorescence spectroscopy determinations. The intercalation of anastrozole to ct DNA seemed to be significantly related to an induced reduction in MCF-7 cell proliferation. The molecular modeling results have suggested that anastrozole could bind to H1 in ct DNA-H1 complex in ternary systems, which supports the conclusions that have been obtained from experimental data.

Analysis of the interaction behavior between Nano-Curcumin and two human serum proteins: combining spectroscopy and molecular stimulation to understand protein-protein interaction.

In this study, we have investigated the effects of Nano-curcumin (Nano-CUR) binding on HSA-HTF interactions as binary and ternary systems, which had been done through multiple spectroscopic and MD simulation. It has been indicated by fluorescence spectroscopy that Nano-CUR is capable of quenching both proteins with a static mechanism. Thermodynamic parameters have been calculated by considering the fluorescence data at different temperatures. The binding constants of HSA-Nano-CUR, HTF-Nano-CUR and (HSA-HTF) Nano-CUR complexes formation were (2.03 ± 0.32)×107 M-1, (2.46 ± 0.32)×106 and (4.54 ± 0.32)×106 M-1 respectively. According to the negative values of ΔH0 and ΔS0, the roles of van-der-Waals forces and hydrogen bond are quite essential throughout this particular binding. Besides, the negative ΔH0 and ΔS0 values of HTF (Nano-CUR) have been larger than those of the HSA (Nano-CUR) and HSA-HTF (Nano-CUR), which demonstrates the higher significance of interaction bonding. As it had been detected through the synchronized fluorescence spectroscopy at Δλ = 60 nm, the position of Nano-CUR with mixed protein in ternary system has been closer to Tyr residues. Relatively, the binding distances between Trp residues of HSA and HTF in HSA (Nano-CUR), HTF (Nano-CUR), and (HSA-HTF Nano-CUR) complexes, which had been procured in accordance with the fluorescence resonance energy transfer (FRET), have been found to be 1.82 nm, 1.87 nm, and 1.92 nm, respectively. We have evaluated the induced conformational changes of two proteins throughout the binding of Nano-CUR to HSA and HTF as binary and ternary systems by employing the CD technique, while the formation of self-assemblies has been studied through MD simulation.

Impact of linker histone in the formation of ambochlorin-calf thymus DNA complex: Multi-spectroscopic, stopped-flow, and molecular modeling approaches.

Objectives: This study aimed to evaluate the role of the linker histone (H1) in the binding interaction between ambochlorin (Amb), and calf thymus DNA (ctDNA) as binary and ternary systems. Materials and Methods: The project was accomplished through the means of absorbance, fluorescence, stopped-flow circular dichroism spectroscopy, viscosity, thermal melting, and molecular modeling techniques. Results: Spectroscopic analysis revealed that although Amb was strongly bound to both ctDNA and ctDNA-H1, it showed a greater tendency to ctDNA in the presence of the linker histone. The obtained thermodynamic parameters revealed that both Amb-ctDNA and Amb-ctDNA-H1 interactions were spontaneous, endothermic, and entropy-favored, and hydrophobic interactions played the main role in the formation and stabilization of complexes. Analysis of the stopped-flow circular dichroism results revealed that the binding process of Amb-ctDNA and Amb-ctDNA-H1 required a time of more than 150 milliseconds to complete. Moreover, Amb-ctDNA complex formation was marginally decelerated in the presence of the linker histone. The docking results suggested that the presence of the linker histone may alter the binding sites of Amb from ctDNA minor grooves to major grooves. Conclusion: All quenching processes were governed by a dynamic mechanism. Additionally, Amb did not stabilize or induce considerable conformational changes in ctDNA and ctDNA-H1 complex upon binding. In silico molecular docking results confirmed that Amb was bound to the double-helical ctDNA and ctDNA-H1 via ctDNA grooves. In summary, some binding properties of the interactions between Amb and ctDNA change in the presence of the linker histone.

A comparison study of the interaction between ß-lactoglobulin and retinol at two different conditions: spectroscopic and molecular modeling approaches.

The interaction between bovin ß-Lactoglobulin (ß-LG) and retinol at two different pH values was investigated by multispectroscopic, zeta potential, molecular modeling, and conductometry measurements. The steady state and polarization fluorescence spectroscopy revealed that complex formation at two different pH values could occur through a remarkable static quenching. According to fluorescence quenching, one set of binding site at pH 2 and two sets of binding sites at pH 7 were introduced for binding of retinol to ß-LG that show the enhancement of saturation score of ß-LG to retinol in dimmer condition. The polarization fluorescence analysis represented that there is more affinity between ß-LG and retinol at pH 7 rather than at pH 2. The effect of retinol on ß-LG was studied by UV-visible, circular dichroism (CD), and synchronous fluorescence, which indicated that retinol induced more structural changes on ß-LG at pH 7. ß-LG-retinol complex formation at two different pH values was recorded via applying resonance light scattering (RLS) and zeta potential. Conductometry and RLS showed two different behaviors of interaction between ß-LG and retinol at two different pH values; therefore, dimmer formation played important roles in different behaviors of interaction between ß-LG and retinol. The zeta potential was the implied combination of electrostatic and hydrophobic forces which are involved in ß-LG-retinol complex at two different pH values, and the hydrophobic interactions play a dominant role in complex formation. Molecular modeling was approved by all experimental results. The acquired results suggested that monomer and dimmer states of ß-LG can be induced by retinol with different behaviors.