Spectroscopic Methods Research Articles

A novel Pt2+ complex containing 1,4-benzodioxan-6-amine: Stability, DNA binding, and antitumor effects against human breast cancer cells

In this work, a new platinum(II) complex was prepared by the reaction of K2PtCl4 with 1,4-benzodioxan-6-amine (bda) at room temperature in the molar ratio 2:1 (L:M). The complex was characterized by physicochemical (elemental analysis, TGA/DTA, and conductivity measurements) and spectroscopic methods (UV–Vis, FTIR, 1H, 13C and 195Pt NMR). According to the spectroscopic data, two bda ligands coordinate to the platinum ion in a monodentate manner through the nitrogen atom to give the complex cis-[PtCl2(bda)2]. Stability studies were carried out under different conditions and showed that the complex is stable in pure DMF, although it undergoes slow solvolysis in DMSO. The interaction of this complex with calf thymus DNA (CT-DNA) was studied using circular dichroism (CD), electronic absorption and fluorescence spectroscopy. The complex binds to CT-DNA with a Kb value of 1.06 ​× ​103 ​M−1 and according to data from CD and fluorescence spectroscopy, appears to interact with DNA by electrostatic forces and or other no intercalative binding mode. Compared to cisplatin, the complex exhibited good cytotoxic activity and selectivity against the MCF-7 tumor cell line, displaying an IC50 value of 17.33 ​± ​1.1 ​μM, as well as inhibited MCF-7 ​cells migration.

A novel Swiss-roll counterflow micro-combustor: Experimental investigation of flame dynamic characteristics by spectroscopy and RGB image processing methods

In this study, a novel Swiss roll counterflow micro-combustor is developed to improve flame stability, preheating, and heat recovery. The study experimentally investigates the combustion characteristics of methane-oxygen mixtures in a constant-temperature aluminum chamber over a range of equivalence ratios using spectroscopic methods and RGB image processing. The results indicate that this micro-combustion flame is a cool flame with an inverse relationship between variations of flame thickness and flame length. Furthermore, the study explores the behavior of some radicals, including OH*, CH*, C2* , H2O*, and CO2* and their radiation intensity, which are influenced by the equivalence ratio and mass flow rate of fuel to the oxidizer, as well as other factors such as flame surface area and heat transfer from the wall. RGB image processing is also utilized to investigate the changes of CH* and C2* in channels G and B, respectively. The study shows a strong correlation between the visible light intensity of the flame and the R channel. The results demonstrate that for the equivalence ratios Between 1.93 and 2.26, the radiation intensity of the radicals is relatively stable, which makes it applicable for micro-combustors.

Fluorescence in depth: integration of spectroscopy and imaging with Raman, IR, and CD for advanced research.

Fluorescence spectroscopy serves as a vital technique for studying the interaction between light and fluorescent 
molecules. It encompasses a range of methods, each presenting unique advantages and applications. This 
technique finds utility in various chemical studies. This review discusses Fluorescence spectroscopy, its branches 
such as Time-Resolved Fluorescence Spectroscopy (TRFS) and Fluorescence Lifetime Imaging Microscopy 
(FLIM), and their integration with other spectroscopic methods, including Raman, Infrared (IR), and Circular 
Dichroism (CD) spectroscopies. By delving into these methods, we aim to provide a comprehensive 
understanding of the capabilities and significance of fluorescence spectroscopy in scientific research, highlighting 
its diverse applications and the enhanced understanding it brings when combined with other spectroscopic 
methods. This review looks at each technique's unique features and applications. It discusses the prospects of their 
combined use in advancing scientific understanding and applications across various domains.

Using urea-shifting to create a natural blue, antioxidant emulsifier from phycocyanin

Phycocyanin (PC) is an algae-derived blue protein that can serve as an antioxidant emulsifier and colorant. Urea was used as an emulsification aid by balancing PC’s hydrophilic-lipophilic character and was removed by dialysis after emulsification processes. With increasing concentration, urea gradually dissociated and denatured the PC polymers. By using spectroscopic methods, the aromatic amino acids and chromophores appeared to fold inward, and the secondary helix structure devolved into the unordered structure. Structural changes caused the hydrophilic PC to become more hydrophobic, resulting in an increase of its emulsifying capacity with a concomitant cost to PC’s natural blue color. The partially denatured PC increased the amount of PC surface adsorption at the O/W interface by 39.89% of adsorbing percentage and the O/W interfacial protein concentration was 1.56 mg m-2, resulting in finer and more dispersed emulsion droplets. Therefore, although the denaturation resulted in a partial weakening of the protein’s antioxidant properties (from 7.70 to 5.54 nmol L-1 Trolox equivalent), the stabilized droplets allowed the emulsions to exhibit higher apparent antioxidant properties (from 7.80 to 7.87 nmol L-1 Trolox equivalent). In the 37 °C storage stability evaluation, emulsions with lower starting urea concentrations remained blue longer, while those with higher starting urea concentrations remained more stable to long-term storage and showed lower oxidation levels. The urea concentration of 5 M was chosen because it maintained a relatively stronger blue color while keeping the emulsion more stable and protecting the oils from further oxidation.

Evaluation of inhibition performance of methylimidazolium ionic liquids on surface of mild steel in sulfuric acid

In the present study, the microwave irradiation approach was used to synthesize two methylimidazolium-based ionic liquids (MImILs), specifically 1-Heptyl-3-methylimidazolium bromide [HMImBr] and 1-Benzyl-3-methylimidazolium bromide [BzMImBr]. Several spectroscopic methods have been used to characterize the produced compounds. Gravimetric and electrochemical techniques were employed to examine their ability to prevent corrosion of the mild steel in a 0.5 M sulfuric acid solution. Amongst all the evaluated ionic liquids, [BzMImBr] having an aromatic ring instead of hexyl ((–CH2)5–CH3) hydrocarbon of [HMImBr] manifests better inhibition efficiency of 95.49 % at 1000 ppm concentration. The experimental ionic liquids negatively impact both the anodic and cathodic Tafel reactions, exhibiting mixed-type inhibition properties, as demonstrated by the findings of the potentiodynamic polarization investigations. Through their adsorption employing their electron-rich centres, the examined ionic liquids create a corrosion-protective covering, and their adsorption follows the Langmuir isotherm model. Negative values of ΔGads indicate the spontaneous nature of [HMImBr] and [BzMImBr] adsorption, whereas values between −20 and −40 KJ mol−1 indicate the physio-chemisorption mode of adsorption. Energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and field emission-scanning electron microscopy (FE-SEM) techniques were used to assess and evaluate surface morphology. The DFT-based analysis indicates that aromatic rings played a significant role in the charge sharing (donation and acceptance) in [BzMImBr].

Quantitative analysis of heme and hemoglobin for the detection of intravascular hemolysis

BackgroundIntravascular hemolysis is associated with massive release of hemoglobin and consequently labile heme into the blood, resulting in prothrombotic and proinflammatory events in patients. Though heme is well-known to participate in these adverse effects, it is not monitored. Instead, haptoglobin and hemoglobin serve as clinical biomarkers. The quantification of labile heme together with hemoglobin, however, should be considered in clinical diagnosis as well, to obtain a complete picture of the hemolytic state in patients. So far, quantification techniques for labile heme were not yet systematically analyzed and compared for their clinical application potential, especially in the presence of hemoglobin. ResultsTwo commercial assays (Heme Assay Kit®, Hemin Assay Kit®) and five common approaches (pyridine hemochromogen assay, apo-horseradish peroxidase-based assay, UV/Vis spectroscopy, HPLC, mass spectrometry) were analyzed concerning their linearity, accuracy, and precision, as well as their ability to distinguish between hemoglobin-bound heme and labile heme. Further, techniques for the quantification of hemoglobin (Harboe method, SLS method, Hemastix®) were included to study their selectivity for hemoglobin and potential interference by the presence of labile heme. Both, indirect and direct approaches were suitable for the determination of a wide concentration of heme (∼0.02–45 μM) and hemoglobin (∼0.002–17 μM). A clear distinction between hemoglobin-bound heme and labile heme with one method was not possible. Thus, a novel combined approach is presented and applied to human and porcine plasma samples for the determination of hemoglobin and labile heme. SignificanceOur results demonstrate the need to develop improved techniques to differentiate labile and protein-bound heme for early detection of intravascular hemolysis. Here, we present a novel strategy by combining two spectroscopic methods, which is most reliable as an easy-to-use tool for the determination of hemoglobin and heme levels in plasma samples for the diagnosis of intravascular hemolysis and in basic biomedical research.

Synthesis, spectroscopic characterization, DFT analysis and molecular docking of Mn(II), Co(II) and Ni(II) complexes of hydrazone derived from 5-chloroisatin and 2,4-dinitrophenylhydrazine

Octahedral Co(II), Mn(II) and Ni(II) complexes have been synthesized with a tridentate ONC-donor hydrazone ligand 5‑chloro-3-(2-(2,4-dinitrophenyl)hydrazono)indolin-2-one (H2L). The chemical structures of the complexes were elucidated by spectroscopic methods. The spectral data show an octahedral geometry where a cyclometallation was formed through deprotonation of the 6-C-H carbon of the 2,4-dinitrophenyl ring with O and azomethine N coordinating to the metal atom. DFT calculations were used to investigate the structures and the electronic properties of the complexes and their optimized structures were generated. Molecular docking studies on the transmissible gastroenteritis virus protease (4F49) and the COVID-19 main protease (6LU7) revealed that Ni(II) complex displayed the highest binding affinity (-9.7 kcal/mol and -8.2 kcal/mol) to the active site of proteins 4F49 and 6LU7 respectively. The protein-complex interactions studied for all the compounds exhibit favourable binding affinities, surpassing the -5.0 kcal/mol threshold reported in the literature. These studies indicate that Ni(II), Co(II) and Mn(II) cyclometallated complexes of the hydrazone ligand are potential inhibitors of SARS-CoV-2 and the gastroenteritis virus.

Quantitative Study on a Simple Electrochemical dsDNA-Pregabalin Biosensor; Multi-Spectroscopic, Molecular Docking and Modelling Studies

Pregabalin (PGB) is a γ-aminobutyric acid (GABA) alkylated analog prescribed to treat neuropathic pain, fibromyalgia, and postherpetic neuralgia. Using analytical, spectroscopic methods and molecular docking and molecular dynamics (MD) simulations, a detailed experimental and theoretical investigation was conducted into the binding process and interactions between PGB and double-stranded fish sperm deoxyribonucleic acid (dsDNA). It was evident from the collected experimental results that PGB binds with ds-DNA. PGB attaches to dsDNA via minor groove binding, as demonstrated by the results of electrochemical studies, UV–Vis absorption spectroscopy, and replacement study with ethidium bromide and Hoechst-32588. PGB's binding constant (Kb) with dsDNA, as determined by the Benesi-Hildebrand plot, is 2.41×104 ± 0.30 at 298K. The fluorescence investigation indicates that PGB and dsDNA have a binding stoichiometry (n) of 1.21 ± 0.09. Molecular docking simulations were used in the research to computational determination of the interactions between PGB and dsDNA. The findings demonstrated that minor groove binding was the mechanism by which PGB interacted with dsDNA. Based on the electrochemically responsive PGB-dsDNA biosensor, we developed a technique for low-concentration detection of PGB utilizing differential pulse voltammetry (DPV). The voltammetric analysis of the peak current decrease in the deoxyadenosine oxidation signals resulting from the association between PGB and dsDNA enabled a sensitive estimation of PGB in pH 4.80 acetate buffer. The deoxyguanosine oxidation signals exhibited a linear relationship between 2 and 16μM PGB. The values for the limit of detection (LOD) and limit of quantitation (LOQ) were 0.57μM and 1.91μM, respectively.

Highly oxygenated cyclohexenes from Uvaria dac Pierre ex Finet & Gagnep. and their α-glucosidase inhibitory activity

Phytochemical investigations of the twig and leaf extracts of Uvaria dac Pierre ex Finet & Gagnep. resulted in the isolation and identification of five new highly oxygenated cyclohexenes, uvaridacols M − Q (1–3, 5, and 6), and six known compounds (4 and 7–11). All new structures were elucidated by spectroscopic methods and HRESITOFMS data. The absolute configuration of 1, 5, and 6 was confirmed by single X-ray diffraction analysis with Cu Kα radiation. In contrast, other compounds were established by comparing their specific rotation and ECD spectra with those of known compounds. Some of the isolated compounds with sufficient quantity were evaluated for their α-glucosidase inhibitory activity. Of these, (−)-1,6-desoxypipoxide (10) showed α-glucosidase inhibitory activities with an IC50 value of 28.6 μM. The in silico molecular docking of active compounds was also studied.

Synthesis and DFT-Optimized Structures of Hydrazonal-Based Compound: Biological Activity and Molecular Docking

Distinctive quinolinyl hydrazonal-based compound was synthesized by an azo-coupling reaction of an enaminonitrile (piperidinylacrylonitrile) with the diazonium salt of 8-aminoquinoline. The synthesized compound was characterized by different spectroscopic methods and displayed distinctive solvatochromism. The possible tautomeric transformation of the arylhydrazonal was studied using DFT quantum chemical calculations revealing that the E→Z tautomerization was a spontaneous exothermic process and its equilibrium constant (Keq) was high with positive power. Thus, the Z-tautomer is more favorable than E-tautomer. This study looks at arylhydrazonal's multiple biological actions, showing its substantial promise in antibacterial, antifungal, anticancer, and enzyme inhibition applications. The arylhydrazonal exhibited concentration-dependent strong antibacterial action against Gram-positive and negative bacteria. Moreover, it showed a comparable concentration-dependent antifungal efficiency against C. albicans and A. fumigatus, and close to fluconazole's potency against A. fumigatus. The arylhydrazonal exhibits significant anticancer action, targeting skin and breast cancer cells, suggesting lesser harm to normal cells. In comparison with acetazolamide (AZA), It inhibited carbonic anhydrase isozymes IX and XII with substantial potency against CA-XII. Molecular docking investigations demonstrated the compound's interactions with proteins such 1D2S, 1AS0, 4WW8, and 5Fl4, revealing different binding energies, RMSD values, and stable configurations via hydrogen bonding and π-H stacking interactions. These results highlight the compound's potential as a therapeutic agent in a variety of clinical applications, calling for more study into its development and clinical usage.

Dihydrophenanthropyrans derived from the pseudobulbs of Pholidota chinensis alleviates neutrophilic inflammation by inhibiting MAPKs and calcium

Five dihydrophenanthropyrans (1–5) were isolated from the pseudobulbs of Pholidota chinensis, among which 1,3-di(4′-hydroxybenzy)-imbricatin (3) was isolated from the nature for the first time. Their structures were elucidated and established through various spectroscopic methods. These compounds exhibited a potent inhibition effect on both N-formyl-methionyl-leucyl-phenylalanine (fMLF)-induced superoxide anion generation and elastase release with IC50 values ranging from 0.23 to 7.63 μM. Furthermore, dihydrophenanthropyrans (1–3) also demonstrated a dose-dependent reactive oxygen species (ROS) scavenging effect. In addition, dihydrophenanthropyrans (2–3) exhibited a dose-dependent reduction in the intracellular Ca2+ concentration ([Ca2+]i) in fMLF-activated human neutrophils. Moreover, dihydrophenanthropyrans (1–3) selectively inhibited the phosphorylation of c-Jun N-terminal kinases (JNKs) and p38, while only dihydrophenanthropyran (1) inhibited the phosphorylation of extracellular signal-regulated kinases (ERKs) in fMLF-activated human neutrophils. Notably, dihydrophenanthropyrans (1–3) did not affect protein kinase B (AKT) activity in these cells. These findings highlight the potent anti-inflammatory capabilities of dihydrophenanthropyrans, manifested through their ability to inhibit superoxide anion generation, suppress elastase release, and selectively modulate key signaling pathways in human neutrophils. This suggests that dihydrophenanthropyrans hold significant promise as therapeutic agents for conditions associated with neutrophil-mediated inflammation.

Pentacyclic triterpenoids as potential ACL inhibitors from the rare medicinal plant Semiliquidambar cathayensis

An extensive phytochemical investigation on the rare medicinal plant Semiliquidambar cathayensis (family: Hamamelidaceae) led to the isolation of four new (1–4, named semiliquidacids A–D, respectively) and 25 related known pentacyclic triterpenoids. The new structures with absolute configurations were elucidated by spectroscopic methods, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analysis. Compound 1 represents the first naturally occurring ursane-type triterpenoid featuring an uncommon C-25 formyl group. Compound 4 and oleanolic acid (13) exhibited remarkable inhibitory effects against the ATP-citrate lyase (ACL, an emerging drug target for hyperlipidemia and related metabolic disorders) with IC50 values of 6.5 and 11.9 μM, respectively. The molecular interaction and binding mode between the bioactive triterpenoids and ACL were elaborated by conducting a molecular docking study. Meanwhile, the chemotaxonomic significance of the isolated triterpenoids has been briefly discussed.

Carbonized black pepper spike and its alginate composite for effective batch and column adsorption of uranium from water

The United Nations Sustainable Development Group (UNSDG) mandates clean water as one of its goals for 2030. In this context, we have adopted a sustainable pathway using black pepper spike, an agricultural waste material to synthesise a novel, eco-friendly adsorbent (Black Pepper spike Carbon, PPC) through microwave induced carbonization (MWI) for remediation of uranium from ground water. This material was also suitably modified into its calcium alginate composite beads (PPA) and used for fixed-bed column adsorption study. The physico-chemical properties of the adsorbents were analyzed using various analytical and spectroscopic methods. A maximum adsorption capacity of 333.33 mg g−1 was obtained for PPC from Langmuir model. The column variables were evaluated and an adsorption capacity of 191.5 mg g−1was realized with PPA using the Thomas model. With good selectivity and regeneration capacity, the adsorbents synthesized in this work provide a sustainable solution towards effective remediation of uranium from environmental water samples as an application study.

New chelating quinoxalyl hydrazone derivative, as tridentate ligand for complexation with Co(II), Ni(II), and Cu(II) ions. Development of antitumor, antimicrobial, and DNA reactivity

With the facile condensed carbonyl gourp of 2-hydorxybenzaldehyde with the amino group of quinoxalyl-2-carbohydrazide, a new chelating quinoxalyl hydrazone derivative ligand (H2Lpx) was constructed. Its coordination behavior towards three divalent Co2+, Ni2+, and Cu2+ ions was discovered by building up three new metallo-organic complexes (CoLpx, NiLpx, and CuLpx, respectively). Confirmation of their chemical structure was formulated by applying different spectroscopic methods, as well as, the micro-elemental (C,H,N) and thermogravimetric analyses, the conductance, and magnetic evaluations. The inhibition behavior of the free ligand and its metallo-organic complexes against the cell growth of six entitled microorganisms (three fungal and three bacterial types) and three tumors of humans was estimated considering the effective role of the divalent metal ions (Co2+, Ni2+, and Cu2+ ions in their metallo-organic complexes). The interacting nature of H2Lpx, CoLpx, NiLpx, and CuLpx, with calf thymus DNA (ctDNA) was manifested within the viscometric, spectrophotometric titrations and gel electrophoresis.The three complexes (CoLpx, NiLpx, and CuLpx) exposed a respectable inhibition attitude more than that of H2Lpx depending on the inhibition zone areas of the microbial series growth in mm and the half-inhibited concentration in µM (IC50) for the tumor cell lines’ growth. Establishing of the interacted modes between H2Lpx and MLpx with ctDNA was built upon the shifts of the spectral scans for their solutions. In addition, chromism type, Gibb’s free energy, and binding constant values (ΔGb≠ and Kb, respectively) helped to distinguish their interacted modes, which supported DNA damage. The bio-action of MLpx complexes was highly modified compared to that of H2Lpx towards ctDNA.

Enantioselective high-performance liquid chromatographycombined with spectroscopic methods and theoretical calculations: A valid strategy to determine the absolute configuration of eugenol derivatives.

The absolute configuration of three chiral eugenol derivatives was assigned by a multi-step methodology based on enantioselective HPLC combined with spectroscopic and theoretical calculations. Milligram amounts of enantiopure forms used for stereochemical characterization were isolated by HPLC on the immobilized amylose-based chiral stationary phase Chiralpak IG using normal phase elution conditions. The absolute configuration was indirectly determined for one of the three compounds by 1H NMR via methoxy-α-trifluoromethyl-α-phenylacetic acid derivatization (Mosher's acid). Comparison of the experimental and predicted electronic circular dichroism spectra confirmed the stereochemical assignment by Mosher's method and extended the absolute configuration assignment to two other chiral compounds.

Immunomodulatory activities of polysaccharides isolated from Amauroderma rugosum (Blume and T. Nees) Torrend and their structural characterization

Amauroderma rugosum (Blume and T. Nees) Torrend is a traditionally well-known mushroom that is used for the treatment of cancer. In order to evaluate the pharmacological activities of A. rugosum polysaccharides, the mushroom powder was subjected to hot water extraction and pure polysaccharides (ARPs) were isolated by gel-filtration method. Three important APRs called ARP-1, ARP-2 and ARP-5 were identified with average molecular weights of 1494, 450, and 7 kDa respectively. Their antioxidant abilities were estimated by examining free radical scavenging potential against 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid radical (ABTS●+), 2,2-diphenyl-1-picrylhydrazyl radical (DPPH●), and hydroxyl radical. Immunomodulatory potentials of these ARPs were determined using murine macrophage cells. These polysaccharides exhibited high antioxidant abilities and stimulated mouse macrophages leading to the generation of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Excellent activities were displayed by ARP-1 and APR-2. Gas Chromatography and Spectroscopic (FT-IR and NMR) methods were employed in order to carry out their structural characterisation. The two high molecular weight ARPs (ARP-1 and ARP-2) displayed β-(1→3)-D-glucan backbone structure with branching of β-(1→6)-D-glucopyranosyl. These observations suggest high potential of ARPs for immunotherapeutic applications.

A new concept of ternary aqueous electrolytes based on lithium 4,5-dicyanoimidazolate hydrates

A new concept of aqueous electrolytes based on heterocyclic anions (hydrated anionic triplet electrolyte, HATE) has been presented. Structural studies showed that dimeric lithium 4,5-dicyanoimidazolate (LiTDI) dihydrate molecules, in the presence of acetonitrile, form an ionic system preserved in high concentrations and solid states. X-ray diffraction measurements show that electroneutral dihydrate units can coordinate additional lithium cations acting as charge carriers. The crystalline ionic phase was characterized using spectroscopic, thermal, and electrochemical methods and was used to prepare model electrolytes based on LiTDI hydrates. Linear sweep voltammetry and impedance spectroscopy measurements show, in this system, the depletion of water activity, high conductivity, and reversible cycling of full cells comprising examined electrolytes. We will prove that a concentrated triplet solution acts similarly to the anhydrous electrolyte; regardless of the concentration, it reaches high ionic conductivity values (12-16 mS/cm at room temperature) and is electrochemically stable.

New lactate- and pyruvate-containing polysaccharide and rhamnomannan with xylose residues from the cell wall of Rathayibacter oskolensis VKM Ac-2121T

The cell wall of endophytic strain Rathayibacter oskolensis VKM Ac-2121T (family Microbacteriaceae, class Actinomycetes) was found to contain neutral and acidic glycopolymers. The neutral polymer is a block-type rhamnomannan partially should be substitutied by xylose residues, [→2)-α-[β-D-Xylp-(1→3)]-D-Manp-(1→3)-α-D-Rhap-(1→]∼30 [→2)-α-D-Manp-(1→3)-α-D-Rhap-(1→]∼45. The acidic polymer has branched chain, bearing lactate and pyruvate residues, →4)-α-D-[S-Lac-(2―3)-α-L-Rhap-(1→3)]-D-Manp-(1→3)-α-D-[4,6-R-Pyr]-D-Galp-(1→3)-β-D-Glcp-(1→. The structures of both glycopolymers were not described in the Gram-positive bacteria to date. The glycopolymers were studied by chemical and NMR spectroscopic methods. The results of this study provide new data on diversity of bacterial glycopolymers and may prove useful in the taxonomy of the genus Rathayibacter and for understanding the molecular mechanisms of interaction between plants and plant endophytes.

De novo design and preparation of Copper(II)–based chemotherapeutic anticancer drug candidates with Boc–glycine and N,N–donor ligands: DNA binding, cleavage profile, and cytotoxic therapeutic response against MCF–7, PC–3, and HCT–116 cells

Two new copper(II) complexes [Cu(Boc–glycine)(2,2–bipyridyl)2]NO31 and [Cu(Boc–glycine)(1,10–phenanthroline)2]NO32 were prepared, and thoroughly characterized by multiple spectroscopic methods. The SC X–ray diffraction studies revealed that the complexes crystallized in triclinic (P 1¯) system with distorted square pyramidal and octahedral geometry in 1 and 2, respectively. To predict the anticancer potential of the drug candidates 1 and 2, binding studies with the ct–DNA were performed by using various complimentary biophysical methods. The drug candidates 1 and 2 interact strongly with DNA exhibiting ‘hypochromic’ effect in the absorbance bands at 300 nm implicating non–covalent intercalation binding mode that could be induced by the presence of strong recognition domain ligand (phen) which is known to ‘wedge–in’ in-between the bases of DNA helix. The intrinsic binding constant, Kb values were quantified by employing Wolfe–Shimer equation, and were found to be 0.10(±0.14) × 105 M−1 and 1.53 × 106(±0.1) M−1, respectively, showing higher binding propensity of 2 as compared to 1. pBR322 plasmid DNA cleavage studies of the complexes 1 and 2 showed that the complexes induced single–strand cleavage of DNA at a low concentration of 20 µM and 15 µM which mediated via an oxidative mechanism. The cytotoxicity activity of complexes was evaluated against MCF–7, PC–3, and HCT–116 cancer cells and the complexes displayed exceptionally good cytotoxicity against the tested cell lines (1, HCT–116:IC50 = 0.6 ± 0.02 μM and 2, MCF–7:IC50 = 1.91 ± 0.1 μM).

Discovering the anti-diabetic potential of thiosemicarbazone derivatives: In vitro α-glucosidase, α-amylase inhibitory activities with molecular docking and DFT investigations

This work describes the synthesis of para-substituted thiosemicarbazone derivatives by refluxing 4-ethoxybenzaldehyde (1) and 4-nitrobenzaldehyde (2) with thiosemicarbazide in ethanol with acetic acid catalyst. The resultant thiosemicarbazones were then treated with various phenacyl bromides to get the product compounds. 1H NMR and EI-MS spectroscopic methods were employed to confirm the structures of these derivatives and screened the compounds for their in vitro α-glucosidase and α-amylase inhibitory activities. Six compounds (4e, 3e, 3c, 3b, 4b, and 4c) exhibited highest α-glucosidase activity in the range of IC50 values of 2.81 ± 1.92 to 16.16 ± 0.15 µM. Similar to this, five compounds (3e, 4e, 3b, 3c, and 4c) attributed excellent inhibitory activity in the range of IC50 values from 3.12 ± 0.13 to 16.56 ± 0.17 µM against the α-amylase enzyme when compare with the standard acarbose. The density functional theory (DFT) study demonstrated the stability, bioactivity, and charge transfer of the compounds, while the molecular docking analysis has provided significant understanding of how the compounds interact with the enzymes. These findings provide prospective directions for the development of innovative therapeutic candidates to regulate postprandial glucose levels in diabetic patients.