UV-visible Spectrophotometric Studies Research Articles

The UV-Vis spectrophotometric studies of natural dye absorption on a <i>Sida-rhombifolia</i>/Cotton blended fabric

The environmental considerations in natural dye have gained prominence in the contemporary textile processing industry. Natural dyes have been exploited from a variety of plants. Some of these natural dyes have no substantive for cellulose fabrics so requires assistance of mordant during its application. Techniques were developed to extract dyes from red sandal wood (RSW) and avocado seed (AS) for the dyeing of Sida-rhombifolia blended fabric (SRBF). Solvent (ethanol and acetone) extraction method was found suitable for the dye extraction from red sandal wood and avocado seed. UV-Vis spectrophotometric studies were investigated on the dye absorption. Dyeing with RSW exhibited better rate of absorbance colour than AS dye. The concentration of each dye was determined using a calibration curve. The R2 = 0.9669 for RSW and R2 = 0.9895 for AS values accompanied the calibration curve and were considered good. Absorbance/ exhaustion of dyes were determined and characterization was done by carrying out kinetic/equilibrium absorption and the thermodynamic absorption of isotherms. The kinetic and thermodynamic studies of red sandal wood dyes have higher rate of dyeing and higher affinity value of 28.3KJ/mol-1 at 80°C for SRBF than avocado seeds with affinity value of 14.09KJ/ mol-1 . The enthalpy and entropy of dyeing were also found to be positive for both dyes, hence confirming the increasing randomness at the solid/solution interface during the absorption of dyes. Washing and Rubbing Fastness properties were investigated according to the British Standard (EN BS 20105). The results ranged from 4-5 according to grey scale standard indicating that the colour on a dyed fabric can strongly resist fading out when washed or rubbed against a white fabric. It can be concluded that natural plants in Cameroon have considerable potentials as a source of natural dye.

Hydrocortisone UV-Vis Spectrophotometric Study: Stability, Determination of Its Acidity Constants and Quantification

Hydrocortisone UV-Vis Spectrophotometric Study: Stability, Determination of Its Acidity Constants and Quantification

In vitro and In vivo Interaction of Ketorolac Tromethamine and Cefixime Trihydrate

Drug-drug interaction, a major impediment towards safe and effective pharmacotherapy, often leads to adverse outcome or therapeutic failure if not properly identified. The present study employed a number of in vitro and in vivo methods to conduct a thorough investigation of the interaction potential between ketorolac tromethamine (nonsteroidal anti-inflammatory drug) and cefixime trihydrate (beta-lactam antibiotic). UV-Visible spectrophotometry, FTIR and DSC were carried out to analyze the interaction of ketorolac and cefixime in vitro. UV-visible spectrophotometric study at different pH showed hyperchromic shift and blue shift (hypsochromic shift) in the mixture of the studied drugs compared to ketorolac alone. In contrast, only hyperchromic shift was found in the mixture when compared to cefixime alone. In DSC study, the melting endotherm of ketorolac tromethamine shifted from 169.62°C to 149.99°C in the 1:1 mixture. Again, the FTIR spectrum showed that in 1:1 mixture, the lactam (C=O) band of cefixime trihydrate shifted from 1771.68 cm-1 to 1718.63 cm-1, the amide carbonyl band (-CONH) moved from 1669.45 cm-1 to 1616.4 cm-1 and the -OH band moved from 3296.46 cm-1 to 3397.72 cm-1 which might be indicative of interaction between these two drugs. The in vivo study in rat model was designed to determine whether cefixime has any significant impact on the analgesic activity of ketorolac. In vitro antimicrobial effect was also performed to evaluate the effect of ketorolac on cefixime. The findings from these study suggested that neither ketorolac nor cefixime imparted any deleterious impact on the biological property of each other which might indicate that co-administration of ketorolac and cefixime are therapeutically effective and safe. Dhaka Univ. J. Pharm. Sci. 22(2): 137-146, 2023 (December)

Transmittance characteristics of transparent hydrophobic acrylic foldable intraocular lenses that were in vivo for a prolonged period of time: A UV visible spectrophotometric study.

To record experimental data on the spectral transmittance characteristics of transparent hydrophobic acrylic foldable IOLs, which were in vivo for a prolonged period of time and explanted under clinical indications and also to compare the data with that of corresponding control and crystalline lens along with review of the relevant literature. Material and make of each of the explanted intraocular lenses (IOLs) as well as pre-explantation clinical status of the eyes were confirmed from the medical record. The transmittance of wavelength from 185 to 900 nm of each of the selected IOLs was measured using Shimadzu UV 2600 UV visible (UV-Vis) spectrophotometer in double-beam configuration and probe version 2.16 software. The data obtained were statistically analyzed. The mean transmittance of 12 clinically explanted IOLs at spectral range 300-700 nm was 49.5% ± SD 6.9%. This value was 10% and 38% less than the corresponding clear (59% ± SD 0.4%) and yellow (87.5% ± SD 0.4%) control, respectively. The mean transmittance of the analytes in the UV range was 43.3 ± SD 6.9%, and it was almost similar to the control. The data showed wide variations without good correlation, and it matches with the human crystalline lens at the age range of 50-60 years. All eyes were otherwise healthy, and none had age-related macular degeneration. In comparison with fresh IOL with a yellow filter, light transmittance at the spectral range 300-700 nm was found decreased in all the IOLs, which were in vivo for an average period of 12.25 ± 4.4 years. All IOLs transmitted variable amounts of UV radiation. More data are required for further analysis on the subject.

Development and Validation of RP-HPLC Method for Simultaneous Estimation of Gallic Acid, Scopoletin, Umbelliferone, and Imperatorin in Bael avaleha

Bael avaleha is a semisolid ayurvedic formulation containing the fruit of bael, which acts as an anthelmintic to treat diarrhea, dysentery, and IBS. It strengthens the gastrointestinal tract, heals ulcers, and alleviates abdominal pain. The avleha contains excess sugar, which can result in faster absorption of active ingredients in the biological system. Researchers have begun scrutinizing ayurvedic formulations for quality and consistency, with quality testing being conducted to ensure that the quality of ayurvedic formulations adheres to ayurvedic standards. Phytochemical fingerprinting by spectroscopic and chromatographic techniques is becoming more popular in assessing the efficacy of ayurvedic products. Previous studies evaluated phenolic compounds, flavonoids, monoterpenes, and sesquiterpenes in Bael fruit using Gas Chromatography Mass Spectrometry (GC-MS), HPTLC, and HPLC methods.This study evaluated marketed bael avaleha formulations (BA I and II) for organoleptic characteristics, physical parameters, and phytoconstituents. A UV-vis spectrophotometric study was conducted for quantitative analysis of phytochemicals. The extract of bael avaleha formulations BA I and BA II were found to have a total phenolic content of 42.34 ± 0.090 mg GAE/g and 38.52 ± 0.065 mg GAE/g, a flavonoid content of 14.34 ± 0.070 mg QE/g and 12.42 ± 0.086 mg QE/g, sugar content of 69.44 ± 0.020 mg Glu/g and 67.18 ± 0.065 mg Glu/g, and a reducing sugar content of 31.34 ± 0.025 mg Glu/g and 29.08 ± 0.047 mg Glu/g, respectively. The Fourier transform infrared (FTIR) spectra of extract of bael avaleha formulations were recorded in region 4000–400 cm−1 and confirmed the presence of hydroxy group, aromatic C-H stretch, C=C and C-O group. RP-HPLC method was developed and used for the estimation of gallic acid, scopoletin, umbelliferone, and imperatorin in the extract of Bael avaleha formulations

Green synthesis of multifunctional MgO@AgO/Ag2O nanocomposite for photocatalytic degradation of methylene blue and toluidine blue.

Introduction: In this paper, MgO@AgO/Ag2O nanoparticles were greenly synthesized, the current idea is to replace the harmful chemical technique with an ecofriendly synthesis of metal oxide nanoparticles (NPs) utilizing biogenic sources. Methods: The current investigation was conducted to create silver oxide NPs decorated by MgO NPs (namely, MgO@AgO/Ag2O nanocom-posite) using the leaves extract of Purslane (Portulaca Oleracea) as the reducing and capping agent. The nanopowder was investigated by means of X-ray diffraction, scanning electron mi-croscope, BET surface area, Fourier transform infrared, and UV-vis spectrophotom-eter studies. XRD studies reveal the monophasic nature of these highly crystalline silver nano-particles. SEM studies the shape and morphology of the synthesis AgO/Ag2O and MgO@AgO/Ag2O NPs. The presence of magnesium and oxygen was further confirmed by EDS profile. Results and discussion: The surface area was found to be 9.1787 m2/g and 7.7166 m2/g, respectively. FTIR analysis showed the presence of specific functional groups. UV-vis spectrophotometer studies show the absorption band at 450nm due to surface plasmon resonance. The results have also indicated the high performance of the greenly synthesized AgO/Ag2O NPs and MgO@AgO/Ag2O NPs for photocatalytic activity dye degradation (methylene blue and toluidine blue).

Exploration of Spectroscopic Study of Screen-Printed Tungsten Oxide: Tin Oxide Nano-Composite Powder Fired at High Temperature

Abstract: Thick films of pure Tin oxide (SnO2) and composite 1%, 3%, 5%, 7% and 9 % tungsten oxide (WO3) incorporated into pure Tin oxide (SnO2) were prepared with standard screen printing technique. All samples were prepared on glass substrate and subjected to drying and firing at 5000C at 5 hours in muffle furnace. Thick films of tin oxide (SnO2) and composite 1%, 3%, 5%, 7% and 9 % Tungsten Oxide (WO3) incorporated into pure tin oxide (SnO2) were examined for Scanning Electron Microscopy (S.E.M), Energy Dispersive X-ray Analysis (E.D.A.X), X-ray diffraction (X.R.D), Fourier Transform infra-Red (F.T.I.R) and Ultra-Violet-visible spectroscopy (U.V) to investigate surface morphology, elemental analysis, crystalline Phases of films, vibrational and spectroscopic study respectively. The spectrophotometric parameters such as absorbance and absorption coefficient were also a part of investigation. The UV-visible spectrophotometric study was encountered in terms of absorbance and absorption coefficient along with varying percentage composition.

Observation of Protonation-Induced Spin State Switching in a Cyanido-Bridged {Fe2Co2} Molecular Square.

The self-assembly of [Co(MeTPyA)(CH3COO)]PF6 (1) and [Fe(bbp)(CN)3]2- affords a cyanido-bridged square-shaped {Fe2Co2} tetranuclear complex, [{Co(MeTPyA)(μ2-NC)2Fe(bbp)(CN)}2]·3H2O (2; MeTPyA = tris((3,5-dimethylpyrazol-1-yl)methyl)amine and H2bbp = bis(2-benzimidazolyl)pyridine). The possibility of inducing an intramolecular electron transfer coupled spin transition in 2 by employing protonation as an external stimulant is explored. UV-visible spectrophotometric measurements, electrochemical and 1H NMR studies establish that a reversible intramolecular electron transfer coupled spin transition can be triggered in 2 upon addition of either acid or base.

Development, Characterization and Valuable Use of Novel Dosimeter Film Based on PVA Polymer Doped Nitro Blue Tetrazolium Dye and AgNO3 for the Accurate Detection of Low X-ray Doses.

Currently, the uncontrolled exposure of individuals to X-rays during medical examinations represents a substantial danger that threatens both medical professionals and patients. Therefore, radiation dosimetry for low X-ray doses is a very important control of radiation practice in medical diagnostic radiology. In line with this, the current study proposes a valuable dosimeter-based PVA thin film doubly doped with silver nitrate salt and nitro blue tetrazolium dye. The nanocomposite film was prepared via a simple casting method and the different processing parameters were optimized. The performance of radiation detection was evaluated according to optical, chromic, chemical and structural changes after exposure to variable low X-ray doses (0, 2, 4, 10 and 20 mGy). The different film labels exhibited an excellent stability behavior in dark and light upon 30 days of storage. The UV-Vis spectrophotometric study showed a gradual increase in the maximum absorbance as a function of the dose and the corresponding response curve confirmed this linear variation (R = 0.998). A clear structural modification was recorded via X-ray diffraction (XRD) analysis revealing the increase in crystallinity with the level of the dose received by the nanocomposite films. Microscopic surface analysis via SEM assessments revealed a significant morphological change in PVA/Ag+/NBT films exposed to increased radiation doses and typical dendrites growing in needle- or tree-like microstructures appeared with a high X-ray dose. Finally, the nanocomposite films before and after irradiation were evaluated via a spectrocolorimetric study and the different CIELab coordinates, the color difference, as well as the color strength, showed a linear correlation with the intensity of the applied dose. This new dosimeter design could, therefore, provide a promising and efficient alternative for prompt and accurate detection of low X-rays doses in diagnostic radiology.

Phase Studies and Efficient Recovery of Inorganic Metal Salts from the Microemulsion System Using a Sugar-Based Non-Ionic Surfactant

Abstract In the present work, the phase behaviour of the microemulsion system formulated by using water, organic solvent, and a sugar-based non-ionic surfactant was investigated in detail. We have used a sugar-based non-ionic surfactant for formulation of microemulsion, as it is a greener alternative for the formulation of a microemulsion system, owing to the following aspects: a) better physicochemical properties as compared to that of the conventional non-ionic surfactants, b) non-toxicity, and c) biodegradability. The extraction of heavy metal ions from the metal complexes as well as the recovery efficiency of heavy metal ions using a microemulsion system has been investigated. The maximum absorbance values of metal ions, after recovery from the metal complexes, were measured. Moreover, the UV-Visible spectrophotometric studies revealed that the absorbance increases with an increase in metal ion concentration in the aqueous phase while its value decreases with an increase in the concentration of potassium thiocyanate in the aqueous phase after the extraction of the metal ions from the metal complexes. Furthermore, it has also been evaluated that 4.0 mol/L potassium thiocyanate is the optimum concentration required for efficient recovery of 0.05 mol/L cobalt ion as well as nickel ions. The recovery efficiency of cobalt ions was found to be 97%, whereas that of nickel ions was determined to be 94% respectively. In addition to being an environmentally friendly approach, the present work is an economically viable option too, as it deals with the studies related to the extraction and efficient recovery of metal ions.

Studies on redox and axial ligand properties of Meso-Mn(III) porphyrin by cyclic voltammetry and UV–Visible spectrophotometry

Manganese (III) complex with meso-5,10,15,20-Tetrakis(2,5-dimethoxy-phenyl) porphyrin, Mn[T(2,5-(OCH3)2)PP], has been prepared utilizing meso-5,10,15,20-Tetrakis(2,5-dimethoxyphenyl)porphyrin, [T(2,5-(OCH3)2)PP], and Manganese (II) acetate by complexation method. The prepared complex is characterized by UV–Vis spectrophotometric and cyclic voltammetric (CV) studies. The formation of Mn(III) porphyrin complex may be due to a significant metal-porphyrin π interaction. In Mn(III) porphyrin, Mn is in high spin d4 configuration. The strongest σ bonding amongst the Mn and the porphyrin with four pyrrole nitrogen donors is responsible for the octahedral geometry. The change in geometry of the complex from octahedral to tetragonal is due to the presence of two axial amines supplied by the addition of secondary amine. Addition of primary amine leads to the formation of square pyramidal Mn(II) porphyrin, wherein the central metal atom is in high-spin d5 configuration with the occupied d(x2-y2) orbital whose orbital energy is low. This indicates that Mn(III) will be out of the plane of porphyrin. The change in the oxidation state of the central manganese atom and shape of the complex were supported by UV–Vis spectrophotometric studies. Cyclic voltammogram confirmed the oxidation and reduction behaviors of Mn porphyrin complex and the oxidation of Mn(III) into Mn(IV) at 0.3209 V.

Alginate and Gum Arabic Coated Iron Oxide Nanoparticles as an Efficient Drug Carrier Agent

Multifunctional iron oxide nanoparticles have a vast and emerging scope in the field of nanotechnology. Out of numerous techniques available to develop multifunctional magnetite nanoparticles, co-precipitation is considered as one of the most efficient and economical techniques. Bare magnetite nanoparticles could be functionalized to act as multifunctional nanoparticles with the help of some suitable and biocompatible coating materials. In present study, surface functionalization of magnetic iron oxide nanoparticles has been carried out with alginate and gum Arabic, respectively. For the confirmation of surface functionalization, the synthesized multifunctional magnetite nanoparticles were characterized FTIR spectroscopy and thermogravimetric analysis. Further, the drug loading efficiency of these surface coated iron oxide nanoparticles has been evaluated with the help of UV-visible spectrophotometric studies

FTIR and UV-Visible Spectrophotometric Derivatization Studies of Artemether

This study was aimed at confirmation of the purity and identity of the artemether and development of an ultraviolet spectrophotometric method for the assaying of artemether utilizing p-nitroaniline as a derivatizing agent. Melting point and Fourier transform infrared spectrophotometer (FTIR) methods were used to confirm the purity and identity of the artemether used in the study. The derivatization process was carried out between 100 µg/ml of the artemether and 500 µg/ml of p-nitroaniline in different molarities (0.5, 1, 2, 3, 4, 5M) of HCl at 60ºC for 45 mins. The melting point ranged between 86-89ºC and the FTIR determination revealed a band at 3169.978 cm-1 due to O-H stretching vibration and C-H stretching at 2996.039 cm-1. There was no observed difference in wavelength between the p-nitroaniline spectrum and the spectra of the derivatized products in different molarities of HCl. p-nitroaniline may not be a proper derivatization reagent for the assay of artemether in pure or dosage form.

Role of Citric Acid/Glycine-Reinforced Nanometal Oxide for the Enhancement of Physio-chemical Specifications in Catalytic Properties

The present study has focused the synthesis of Fe3O4–ZnO and citric acid/glycine-modified Fe3O4–ZnO nanocomposites by co-precipitation followed by sol–gel method. The structural elucidation of modified Fe3O4-ZnO nanocomposites has revealed by XRD, SEM-EDX, FT-IR, and UV-Vis spectrophotometer studies. The analytical studies have revealed that the average crystallite size found to be 10–47 nm with spherical shape on smooth surface. The band gap energy range has found to be 1.52 to 3.12 eV. The catalytic activity of synthesized nanocomposites has undergone the oxidation of benzaldehyde, and the antibacterial activity has done using gram-negative bacteria Escherichia coli. The experimental results have concluded that the citric acid–iron oxide nanocomposite has showed the higher yield in oxidation reaction and the citric acid–iron oxide nanocomposite has showed higher efficiency in antibacterial activity comparatively.

Highly Stable Silver(I) Complexes with Cyclen-Based Ligands Bearing Sulfide Arms: A Step Toward Silver-111 Labeled Radiopharmaceuticals.

With a half-life of 7.45 days, silver-111 (βmax 1.04 MeV, Eγ 245.4 keV [Iγ 1.24%], Eγ 342.1 keV [Iγ 6.7%]) is a promising candidate for targeted cancer therapy with β– emitters as well as for associated SPECT imaging. For its clinical use, the development of suitable ligands that form sufficiently stable Ag+-complexes in vivo is required. In this work, the following sulfur-containing derivatives of tetraazacyclododecane (cyclen) have been considered as potential chelators for silver-111: 1,4,7,10-tetrakis(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO4S), (2S,5S,8S,11S)-2,5,8,11-tetramethyl-1,4,7,10-tetrakis(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO4S4Me), 1,4,7-tris(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO3S), 1,4,7-tris(2-(methylsulfanyl)ethyl)-10-acetamido-1,4,7,10-tetraazacyclododecane (DO3SAm), and 1,7-bis(2-(methylsulfanyl)ethyl)-4,10,diacetic acid-1,4,7,10-tetraazacyclododecane (DO2A2S). Natural Ag+ was used in pH/Ag-potentiometric and UV–vis spectrophotometric studies to determine the metal speciation existing in aqueous NaNO3 0.15 M at 25 °C and the equilibrium constants of the complexes, whereas NMR and DFT calculations gave structural insights. Overall results indicated that sulfide pendant arms coordinate Ag+ allowing the formation of very stable complexes, both at acidic and physiological pH. Furthermore, radiolabeling, stability in saline phosphate buffer, and metal-competition experiments using the two ligands forming the strongest complexes, DO4S and DO4S4Me, were carried out with [111Ag]Ag+ and promising results were obtained.

Synthesis and characterization of CuS, CuS/graphene oxide nanocomposite for supercapacitor applications

Supercapacitors or electrochemical capacitors are receiving greater interest because of their high-power density, long life, and low maintenance. We have synthesized CuS nanoparticles and graphene oxide (CuS–GO) nanocomposites for supercapacitor applications because of their low cost and excellent electrochemical properties. The phase purity of each material was determined using powder XRD studies. The bandgap was determined by UV-visible spectrophotometric studies. Scanning electron microscope and transmission electron microscope images revealed the nano-scale morphology of the synthesized particles. All the electrochemical measurements were conducted in a standard three-electrode configuration, using a platinum wire as the counter electrode and Hg/HgO as the reference electrode. CuS and its composites with graphene oxide on nickel foam were used as working electrodes. All the electrochemical measurements were performed in 3M KOH solution. The CuS–GO nanocomposite electrode showed a specific capacitance of 250 F/g, 225 F/g, 182 F/g, 166 F/g, 161 F/g, and 158 F/g at a current density of 0.5 A/g, 1 A/g, 5 A/g, 10 A/g, 15 A/g, and 20 A/g, respectively. CuS–GO electrodes showed a specific capacitance retention of 70% after 5000 charge–discharge cycles at a current density of 5 A/g.

A Flow Injection Chemiluminescence Method for the Determination of Retinol in Pharmaceutical Formulations by Using Luminol-Diperiodatoargentate(III) Reaction.

In this paper, a chemiluminescence (CL) method is proposed for retinol determination by combining flow injection (FI) methodology. The CL reaction is based on the oxidation of luminol by diperiodatoargentate(III) (DPA) in the presence of retinol. Under the optimum conditions, the relative CL intensity was linear to the concentration of retinol over the range 5.0×10-3-14 mg L-1 (y=347.26x+2.5944, R2=0.9999, n=8) with limit of detection (LOD) of 1.5×10-3 mg L-1 (S/N=3) and limit of quantification (LOQ) of 5.0×10-3 mg L-1 (S/N=10). The relative standard deviation (RSD) was from 1.04-3.4% over the range studied and injection throughputs of 150 h-1. The method was satisfactorily applied to retinol in pharmaceutical formulation samples. The samples were saponified and extracted with liquid-liquid extraction using ether as an extractant. The possible CL mechanism is supported by CL and UV-visible spectrophotometric studies.

Synthesis, characterization, DNA binding, topoisomerase inhibition, and apoptosis induction studies of a novel cobalt(III) complex with a thiosemicarbazone ligand

In this study, 9-anthraldehyde-N(4)-methylthiosemicarbazone (MeATSC) 1 and [Co(phen)2(O2CO)]Cl·6H2O 2 (where phen = 1,10-phenanthroline) were synthesized. [Co(phen)2(O2CO)]Cl·6H2O 2 was used to produce anhydrous [Co(phen)2(H2O)2](NO3)33. Subsequently, anhydrous [Co(phen)2(H2O)2](NO3)33 was reacted with MeATSC 1 to produce [Co(phen)2(MeATSC)](NO3)3·1.5H2O·C2H5OH 4. The ligand, MeATSC 1 and all complexes were characterized by elemental analysis, FT IR, UV–visible, and multinuclear NMR (1H, 13C, and 59Co) spectroscopy, along with HRMS, and conductivity measurements, where appropriate. Interactions of MeATSC 1 and complex 4 with calf thymus DNA (ctDNA) were investigated by carrying out UV–visible spectrophotometric studies. UV–visible spectrophotometric studies revealed weak interactions between ctDNA and the analytes, MeATSC 1 and complex 4 (Kb = 8.1 × 105 and 1.6 × 104 M−1, respectively). Topoisomerase inhibition assays and cleavage studies proved that complex 4 was an efficient catalytic inhibitor of human topoisomerases I and IIα. Based upon the results obtained from the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on 4T1-luc metastatic mammary breast cancer cells (IC50 = 34.4 ± 5.2 μM when compared to IC50 = 13.75 ± 1.08 μM for the control, cisplatin), further investigations into the molecular events initiated by exposure to complex 4 were investigated. Studies have shown that complex 4 activated both the apoptotic and autophagic signaling pathways in addition to causing dissipation of the mitochondrial membrane potential (ΔΨm). Furthermore, activation of cysteine-aspartic proteases3 (caspase 3) in a time- and concentration-dependent manner coupled with the ΔΨm, studies implicated the intrinsic apoptotic pathway as the major regulator of cell death mechanism.

Molecular docking and experimental investigation of new indole derivative cyclooxygenase inhibitor to probe its binding mechanism with bovine serum albumin

The indole derivative 2-(5-methoxy-2-methyl-1H-indol-3-yl)-N'-[(E)-(3-nitrophenyl) methylidene]acetohydrazide (IND) was synthesized for its therapeutic potential to inhibit cyclooxygenase (COX)-II. Binding if IND to bovine serum albumin (BSA) was investigated was because most drugs bind to serum albumin in-vivo. Fluorescence, UV–vis spectrophotometry and molecular modeling methodologies were employed for studying the interaction mechanism. The intrinsic fluorescence of BSA was quenched by BSA and the quenching mechanism involved was static quenching. The binding constants between IND and BSA at the three studied temperatures (298, 301 and 306 K) were 1.09 × 105, 4.36 × 104 and 1.23 × 104 L mol−1 respectively. The most likely site for binding IND to BSA was Site I (subdomain IIA). The analysis of thermodynamic parameter revealed the involvement of hydrogen bonding and van der Waals forces in the IND-BSA interaction. Synchronous fluorescence spectroscopic (SFS) and UV–vis spectrophotometric studies suggested conformational change in BSA molecule post interaction to IND. Molecular docking and the experimental results corroborated one another. The study can prove as an insight for future IND drug development.

Thermodynamic stability and structure in aqueous solution of the [Cu(PTA)4]+ complex (PTA = aminophosphine‑1,3,5‑triaza‑7‑phosphaadamantane)

The chemistry of copper(I) with water-soluble phosphines is an emergent area of study which has the objective of finding ligands that stabilize copper in its lower oxidation state. Cu(I) has been found relevant in the mechanism of copper transports into cells, and the accessibility of this oxidation state has implications in oxidative stress processes. For these reasons the possibility to deal with stable, water soluble copper(I) is an attractive approach for devising new biologically relevant metal-based drugs and chelating agents. Here we present the X-ray absorption spectroscopy (XAS) and UV–visible spectrophotometric study of the [Cu(PTA)4]BF4 complex (PTA = aminophosphine‑1,3,5‑triaza‑7‑phosphaadamantane). In particular, we have studied the stability of the [Cu(PTA)n]+ species (n = 2–4) in aqueous medium, and their speciation as a function of the total [Cu(PTA)4]BF4 concentration by means of competitive UV–visible spectrophotometric titrations using metallochromic indicators. Also, the structure in solution of the Cu(I)/PTA species and the nature of the first coordination sphere of the metal were studied by transformed XAS. Both techniques allowed to study samples with total [Cu(PTA)4]BF4 concentration down to 68–74 μM, possibly relevant for biological applications. Overall, our data suggest that the [Cu(PTA)n]+ species are stable in solution, among which [Cu(PTA)2]+ has a remarkable thermodynamic stability. The tendency of this last complex to form adducts with N-donor ligands is demonstrated by the spectrophotometric data. The biological relevance of PTA towards Cu(I), especially in terms of chemotreatments and chelation therapy, is discussed on the basis of the speciation model the Cu(I)/PTA system.