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During the current study, the new aminothiazole Schiff base ligands (S1) and (S2) were designed by reacting 1,3-thiazol-2-amine and 6-ethoxy-1,3-benzothiazole-2-amine separately with 3-methoxy-2-hydroxybenzaldehyde in good yields (68–73%). The ligands were characterized through various analytical, physical, and spectroscopic (FT-IR, UV–Vis, 1H and 13C NMR, and MS) methods. The ligands were exploited in lieu of chelation with bivalent metal (cobalt, nickel, copper, and zinc) chlorides in a 1:2 (M:L) ratio. The spectral (UV–Vis, FT-IR, and MS), as well as magnetic, results suggested their octahedral geometry. The theoretically optimized geometrical structures were examined using the M06/6-311G+(d,p) function of density function theory. Their bioactive nature was designated by global reactivity parameters containing a high hardness (η) value of 1.34 eV and a lower softness (σ) value of 0.37 eV. Different microbial species were verified for their potency (in vitro), revealing a strong action. The Gram-positive Micrococcus luteus and Gram-negative Escherichia coli gave the highest activities of 20 and 21 mm for compounds (8) and (7), respectively. The antifungal activity against the Aspergillus niger and Aspergillus terreus species gave the highest activities of 20 and 18 mm for compounds (7) and (6), respectively. The antioxidant activity, evaluated as DPPH and ferric reducing power, gave the highest inhibition (%) as 72.0 ± 0.11% (IC50 = 144 ± 0.11 μL) and 66.3% (IC50 = 132 ± 0.11 μL) for compounds (3) and (8), respectively. All metal complexes were found to be more biocompatible than free ligands due to their chelation phenomenon. The energies of LUMOs had a link with their activities.

During this report, the synthesis, characterization, medicinal, and molecular modeling of newly synthesized, bidentate sulfonamide metal (VO2+, Co2+, Ni2+, Cu2+, and Zn2+) chelates are consulted. The octahedral geometry is assigned to all the metal chelates except the oxo-vanadium compouns having square pyramidal arrangement. The geometry optimization and other theoretical studies are performed by Density Functional Theory (DFT) techniques by using B3LYP, SDD, and LSDA functions at WB97XD/LanLD2Z basis sets. The antimicrobial assays are carried out for the bacterial (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae) and fungal (Aspergillus flavus and Aspergillus niger) strains showing the activity of 11–29 mm with the highest one for compound (2) and (4) respectively. The enzyme inhibitory profiles against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, and HIV-protease had the 57 ± 0.12–77 ± 0.11% inhibition with the highest one for compound (5). The highest antioxidant activity was found as 94.2 ± 0.12, 96 (DPPH %), 93.3 ± 0.10 (ferric reducing power %), and 88.70 ± 0.11 (total phenols mg GAE/g) for compound (5), (3), and (2) respectively. All the compounds may be applicable orally, according to their in silico intake, delivery, metabolic processes, digestion, and toxic effects (ADME) data. They are also discovered to be non-tumorigenic and non-irritant. The drug-likeness results of the compounds are found to be in an acceptable range for their employment as drug candidates. The cobalt and zinc compounds were found to be more bioactive than other compounds. The bioactivity and energies of LUMOs had a fair relationship with each other with chelation to play its role for enhanced potency.

The scientific interest in developing new complexes as inhibitors of bacterial biofilm related infections is constantly rising. The present work describes the chemical synthesis, structural and biological scrutiny of a triazole Schiff base ligand and its corresponding complexes. Triazole Schiff base, (2-methoxy-4-[(1H-1,2,4-triazol-3-ylimino)methyl]phenol) was synthesized from the condensation reaction of 3-amino-1,2,4-triazole and 4-hydroxy-3-methoxybenzaldehyde in an equimolar ratio. The triazole ligand (H2L) was characterized by physical (solubility, color, melting point), spectroscopic [UV–visible (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR) and mass spectra (MS)] and micro analysis to evaluate their elemental composition. The bidentate ligand was complexed with transition metal [VO(IV), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 1:2 molar ratio. The complexes were characterized by physical (color, solubility, decomposition temperature, conductance and magnetic moment), FT-IR, UV–Vis and elemental analysis. Thermal stability and fluorescence properties of the compounds were also determined. Density functional theory based theoretical calculations were accomplished to gain more insight into spectroscopic properties. The frontier molecular orbital analysis revealed that the ligand was less reactive with reduced electron donating capability and more kinetic stability than complexes. The as-synthesized compounds were scrutinized for anti-bacterial and anti-fungal activity against selected strains. Cobalt complex exhibited highest antibacterial activity against Escherichia coli and nickel complex has shown highest antifungal activity against Aspergillus niger. All the compounds also showed good antioxidant activity. The theoretical results reflect consistency with the experimental findings signifying that such compounds could be the promising chemical scaffolds in the near future against microbial infectious.

Contamination of organic and inorganic compounds has become one of the increasing concerns due to their detrimental effects on the environment and human health. The presence of such organic and inorganic compounds in wastewater poses a challenge in water remediation. Herein, we report successful preparation of Ag@CdO nanocomposite via green methodology to remove Brilliant green from wastewater. The synthesized Ag@CdO nanocomposite was characterized using various analytical studies. SEM–EDS study of Ag@CdO nanocomposite showed an agglomerated spherical shape with signatures of Cd, Ag, and O, and XRD displays characteristic crystallinity. A Zeta potential value − 17.5 mV reveals excellent stability. TEM examination showed an average particle size of 7 nm and 50 nm for bare AgNPs and Ag@CdO nanocomposite, respectively. The maximum photodegradation was obtained in 90 min with Ag@CdO nanocomposite and AgNPs. The maximum degradation efficiency of AgNPs and Ag@CdO nanocomposite was found to be 90% and 96%, respectively, under optimum conditions of temperature; 55 °C and pH 6. In addition, Ag@CdO nanocomposite could be readily regenerated and reused at least 5 times without significant performance loss. Thus, the premeditated photocatalytic Ag@CdO nanocomposite-based platform can further be exploited for remediation of different organic effluents from industrial wastewaters. Furthermore, this work opens new avenues for the enhancement of photocatalytic efficiency of many catalysts already under observation.

The efficacy of specific molecular acceptors in photovoltaic devices is determined by their chemical composition. Multiscale computations are required to protect investigation design and, as a result, efforts and money are saved. Using multiscale computer simulations, the influence of sp2-hybridized nitrogen substitutions at the interior or outer location of the internal center, carbonyl group, and terminating group of specific molecular acceptors is explored. The electronic behavior is studied using quantum molecular modeling. End-capping with nitrogen has greatly reduced the energy of electron rearrangement. The transfer integral plus excited state behavior shows a significant difference. Nitrogen alteration at the terminating group location, on the other hand, is an effective approach to boost electronic conductivity. The characteristics of the acceptor with their composites with 2,2'-((4-heptyl-4,9,9-trihexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene)bis(3-oxo-2,3-dihydro-1H-indene-1-yl-2-ylidene)dimalononitrile (IDIC) donor are also investigated using molecular dynamics. To investigate the mixing of specified specific molecular acceptors is determined. According to the radial distribution function, idic4 has a tighter packing alongside IDIC3 and IDIC4. Nitrogen modification at end capping has been discovered by all analyses.

Meteloxetin (1), a new phenolic amino-oxetane, and eight known new source phenols (2–9) have been bioassay-directed isolated from methanolic extract of Datura metel Linn. Their structures were elucidated through modern spectroscopic data. The plant extract showed the significant inhibition potential against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and its dichloromethane (DCM) fraction exhibited the remarkable inhibition potentials against AChE with IC50 (inhibition concentration) value 1.32 ± 0.02 µg/ml and BChE with IC50 value 1.13 ± 0.01 µg/ml, when compared with the standard drug eserine (AChE, IC50 0.04 ± 0.01 µg/ml) and galanthamine (BChE, IC50 0.92 ± 0.01 µg/ml). The bioactive DCM fraction was subjected to systematic isolation protocol to isolate the 1–9 compounds, and all were subjected to evaluate their AChE and BChE inhibition potentials. From these isolates, compound 1 showed the effective inhibition potential against BChE with IC50 value 0.84 ± 0.03 µg/ml and excellent inhibition potential against AChE with IC50 value 0.07 ± 0.02 µg/ml. This strong inhibition potential of 1 is due to the presence of amino-oxetane groups in it. The in silico studies indicate that oxetane rings contain high-energy oxygen, which makes it a marvelous pharmacophore with diverse biological potentials. The potent nature of compound 1 has also been evaluated by exploring its electronic properties, molecular electrostatic potential and Hirshfeld analysis by density functional theory.

During the present investigation, two new sulfonamide-based Schiff base ligands, 4-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}-N-(1,3-thiazol-2-yl)benzene-1-sulfonamide (L1) and 4-{[1-(2-hydroxyphenyl)ethylidene]amino}-N-(1,3-thiazol-2-yl)benzene-1-sulfonamide (L2), have been synthesized and coordinated with the transition metals (V, Fe, Co, Ni, Cu and Zn). The ligands were characterized by their physical (color, melting point, yield and solubility), spectral (UV–Vis, FT-IR, LC–MS, 1H NMR and 13C NMR) and elemental data. The structures of the metal complexes (1)–(12) were evaluated through their physical (magnetic and conductance), spectral (UV–Vis, FT-IR and LC–MS) and elemental data. The molecular geometries of ligands and their selected metal complexes were optimized at their ground state energies by B3LYP level of density functional theory (DFT) utilizing 6-311+G (d, p) and LanL2DZ basis set. The first principle study has been discussed for the electronic properties, the molecular electrostatic possibilities as well as the quantum chemical identifiers. An obvious transition of intramolecular charge had been ascertained from the occupied to the unoccupied molecular orbitals. The UV–Vis analysis was performed through time-dependent density functional theory (TD-DFT) by CAM-B3LYP/6-311+G (d, p) function. The in vitro antimicrobial activity was studied against two fungal (Aspergillus niger and Aspergillus flavus) and four bacterial (Staphylococcus aureus, Klebsiela pneumoniae, Escherichia coli and Bacillus subtilis) species. The antioxidant activity was executed as antiradical DPPH scavenging activity (%), total iron reducing power (%) and total phenolic contents (mg GAE g−1). Additionally, enzyme inhibition activity was done against four enzymes (Protease, α-Amylase, Acetylcholinesterase and Butyrylcholinesterase). All the synthetic products exhibited significant bioactivity which were found to enhance upon chelation due to phenomenon of charge transfer from metal to ligand.

Herein, we report a simple and ecofriendly synthesis of ZnO nanoparticles (ZnO NPs) employing Digera muricata along with bioassay studies of synthesized NPs. The ZnO NPs obtained were indicated by a colour change from yellow to almost faint yellow giving whitish tinge and supported by the appearance of UV-Vis band at 373 nm and were characterized by using Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray (EDX), and scanning electron microscopy (SEM). The FT-IR spectrum confirmed the presence of biomolecules fabricated on ZnO NPs as indicated by the absorption bands at 1,378 for C–O cm−1, and ZnO NPs were also evident from the absorption bands at 440 and 670 cm−1, the former being the result of symmetric vibration of hexagonal ZnO and the latter belonged to a very weak vibration of ZnO. Its surface morphology was confirmed by SEM, and the zinc and oxygen bonds were confirmed by EDX analysis giving sharp signals for Zn and oxygen with At% of 17.58 and 30.49, respectively. The antimicrobial activity of ZnO nanoparticles was determined by the agar well diffusion method against pathogenic bacterial and fungal strains using imipenem and miconazole as standards. The results reflected that ZnO NPs enhanced the activity of plant extracts against all employed algal (E. coli, S. faecalis, P. aeruginosa, K. pneumonia, S. aureus, and B. subtilis) and fungal (T. mentogrophytes, E. floccosum, A. niger, M. canis, and F. culmorum) strains. The antibacterial and antifungal activities of extracts were enhanced by the formation of ZnO NPs. The results indicated that Digera muricata extract contains effective reducing agents for green synthesis of Digera muricata fabricated ZnO NPs, which are more potent antimicrobial than the plant extract and showed almost similar inhibition against lipoxygenase, i.e., the IC50 value of 83.82 ± 1.15, comparable to the standard.

Organic solar cells (OSCs) with bulk heterojunction (BHJ) structures consisting of electron-donor and electron-acceptor materials have achieved impressive progress over the past decade, demonstrating their great potential in practical applications. In this study, we have designed five fullerene-free acceptor-based molecules containing indaceno-dithiophene as a central core moiety. We studied the optoelectronic features of these newly architecture molecules by using DFT and TD-DFT approaches. For the investigation of the optoelectronic characteristics of the reference and newly designed molecules, we performed different parameters including FMO's, absorption maxima, excitation energy, transition density matrix (TDM) along with binding energy, dipole moment, the partial density of states, charge mobility, and charge transfer analysis. Among all engineered molecules, SK1 has proven to be the most efficient solar cell due to its promising optoelectronic and photovoltaic properties. SK1 reveals smaller band-gap (E

Biologically active triazole Schiff base ligand 2,4-dichloro-6-[(1H-1,2,4-triazol-3-ylimino)methyl]phenol (A) has been synthesized by the condensation reaction of an equimolar amount of 1H-1,2,4-triazole-3-amine and 3,5-dichlorosalicylaldehyde and then it coordinated with salts of metals [VO(IV), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 2:1 molar ratio to derive a series of transition metal chelates (1)-(6). All the compounds were characterized by various physical, spectral, analytical techniques and elemental analysis. Spectral characterization and magnetic moment data of complexes revealed square pyramidal geometry for vanadium complex and octahedral for remaining (2)-(6) complexes. Quantum chemical calculation has been carried out to explore optimized geometry and electronic structure of the ligand. Density functional theory (DFT) with B3LYP/6-311+g(d,p) method was performed to determine vibrational bands, frontier molecular orbitals (FMOs) and natural bond analysis (NBO) of the ligand. NBO analysis showed that the ligand bears higher molecular stability because of hyper conjugate interactions. Computational study results revealed that there was a close interaction of theoretical and experimental spectroscopic data. Global reactivity descriptors calculated by the energies of FMOs, indicated ligand to be bioactive. The synthesized compounds were studied for antibacterial, antifungal, antioxidant and antiglycation activity and the results revealed that ligand has remarkable activity which considerably increased upon chelation. KEY WORDS: Triazole ligand, Transition metal chelates, Antibacterial, Antifungal, Antioxidant, Computational study Bull. Chem. Soc. Ethiop. 2020, 34(2), 335-351 DOI: https://dx.doi.org/10.4314/bcse.v34i2.11

Recently, there has been increased microbial and multidrug resistance in clinical field that negatively affects health because it leads to a variety of diseases due to inefficient mode of action as...

The Aerva plants are exceptionally rich in phytochemicals and possess therapeutics potential. Phytochemical screening shows that Aerva persica (Burm.f.) Merr. contains highest contents i.e., total phenolics, flavonoids, flavonols, tannins, alkaloids, carbohydrates, anthraquinones and glycosides. In-vitro antibacterial and enzymatic (carbonic anhydrase) inhibition studies on methanol extracts of A. persica indicated the presence of biological active constituents within chloroform soluble portions. Investigation in the pure constituents on the chloroform portions of A. persica accomplished by column chromatography, NMR and MS analysis. The bioguided isolation yields four chemical constituents of coumaronochromone family, namely aervin (1-4). These pure chemical entities (1-4) showed significant antibacterial activity in the range of 60.05–79.21 µg/ml against various bacterial strains using ampicillin and ciprofloxacin as standard drugs. The compounds 1-4 showed promising carbonic anhydrase inhibition with IC50 values of 19.01, 18.24, 18.65 and 12.92 µM, respectively, using standard inhibitor acetazolamide. First-principles calculations revealed comprehensive intramolecular charge transfer in the studied compounds 1-4. The spatial distribution of highest occupied and lowest unoccupied molecular orbitals, ionization potential, molecular electrostatic potential and Hirshfeld analysis revealed that these coumaronochromone compounds would be proficient biological active compounds. These pure constituents may be used as a new pharmacophore to treat leaukomia, epilepsy, glaucoma and cystic fibrosis.

A new series of 5-chloroindoline-2,3-dione (isatin) derived ligands (L1 )-(L4 ) were prepared by reacting isatin with various diamines such as ethane-1,2-diamine, propane-1,3-diamine, butane-1,4-diamine, and benzene-1,2-diamine in an equimolar ratio to give 3-[(2-aminoethyl)imino]-5-chloro-1,3-dihydro-2H-indol-2-one (L1 ), 3-[(3-aminopropyl) imino]-5-chloro-1,3-dihydro-2H-indol-2-one (L2 ), 3-[(4-aminobutyl)imino]-5-chloro-1,3-dihydro-2H-indol-2-one (L3 ) and 3-[(2-aminophenyl)imino]-5-chloro-1,3-dihydro-2H-indol-2-one (L4 ). All ligands acted as tridentate possessing three active sites, isatin-O, azomethine-N, and amino-N for binding with the metal atoms. The structures of the isatin based Schiff bases were elucidated through their spectral (infrared, ultraviolet, nuclear magnetic resonance, and mass spectra), physical (melting point and solubility) and analytical (C, N, H %) data. The prepared ligands were reacted with Co(II), Ni(II), Cu(II), and Zn(II) transition metals in 1:2 molar ratio (metal:ligand) to form their complexes. IR, UV, NMR, conductance, magnetic moment, and elemental analysis was used to characterize the metal complexes. Metals based isatins were evaluated for their in-vitro antimicrobial properties against selected fungal and bacterial species. The anti-bacterial and anti-fungal results showed the metal chelates to be more biologically active than their parent uncomplexed ligands.

In the present research, novel unsymmetrically substituted triazole-derived Schiff base ligand 2-[[[5-[[1-(5-methylfuran-2-yl)ethylidene]amino]-1H-1,2,4-triazol-3-yl]imino]methyl]phenol (L) has been synthesized by the reaction of 1,2,4-triazole-3,5-diamine with 2-hydroxybenzaldehyde and with 5-methyl-2-acetylfuran in an equimolar ratio. The synthesized ligand L was characterized by physical methods (melting point, solubility, color) as well as by spectral techniques (IR, UV–Vis, 1H NMR, 13C NMR, and MS), elemental analysis, and computational studies. Computational analysis further elucidated the structure, polarity, stability, and nature of the ligand. The bivalent(II), trivalent(III), and tetravalent(IV) transition metal complexes were formed by reacting Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cr(III) metals as chloride and, VO(IV) as sulfate with Schiff base ligand L in 1:2 (M:L) molar ratio. Ligand was coordinated with the metal ions, VO via benzaldehyde-O and azomethine-N and with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cr(III) via benzaldehyde-O, azomethine-N, and triazole-N. The structure of the metal complexes was deduced by IR, conductance, magnetic moments, and elemental analysis. Biological evaluation of triazole-derived Schiff base ligand and its metal complexes was carried out against bacterial strains, Escherichia coli, Staphylococcus aureus, Neisseria gonorrhea, and Pseudomonas syringae. Copper complex showed the highest inhibition against all bacterial strains as compared to the free ligand and amongst other metal complexes. In vitro antibacterial studies thus concluded that the prepared ligand showed bioactivity which was enhanced upon chelation/coordination with the metal ions.

Microemulsions (μEs)-based drug delivery is known to be superior as well as effective due to customizable and easy management, efficiency and capability, and quick drug absorption over a wide range of targets. Herein, two μE formulations were established comprising of clove oil (as oil phase), water (as aqueous phase), Tween-80 (as surfactant), isopropanol, and methanol (as cosurfactant) for formulation A (μE-A) and formulation B (μE-B), respectively, and further used for the encapsulation of an antimuscarinic drug, mirabegron (MBG). Multiple complementary measurements, namely, electrical conductivity (σ), viscosity (η), and optical microscopy, show the existence of phase transition from W/O to O/W μE via intermediate bicontinuous channels. MBG showed long storage stability as well as good solubility i.e. 3.0 and 2.5 wt% at pH 6.4 in optimum μE-A and μE-B, respectively. Furthermore, no apparent aggregation of MBG was observed, as revealed by scanning transmission electron microscopy and peak correlations of IR analysis, suggesting the stability of MBG inside the formulations. Likewise, fluorescence detection senses the interfacial environment of MBG molecules in the examined formulations that could be vital for understanding the mechanism of controlled drug release.

Capped silver nanoparticles (AgNPs) are used in many applications in the biomedical field because of their unique structural flexibility. Herein, a viable chemical reduction synthesis method for AgNPs is described employing ionic surfactants as stabilizing as well as capping agents. Stabilized AgNPs of a quasi-spherical shape were obtained using silver nitrate (AgNO3) as a precursor and sodium borohydride (NaBH4) as a reducing agent under multiple ionic micellar hierarchical approaches. UV-Visible spectroscopy studies showed characteristic single and sharp absorbance peaks in the range 400 to 420 nm, which indicates the absence of the self-aggregation of AgNPs, whereas the FTIR results indicated the surfactant functionalities responsible for the stability of the AgNPs. Micrographs of the as-obtained AgNPs, obtained via electron microscopy (SEM, STEM), demonstrated a fine monomodal collection of spherical nanoparticles of

From the apocalyptic era of antibiotic resistance, the scientific community around the world is engaged in designing and developing metal-based compounds to inhibit and control continuously rising microbial infections. Metal based triazole-derived compounds are being explored for antimicrobial actions and potentially applicable to provide effective and nontoxic drug candidates having preferred and improved pharmacological activity. Updating the existing literature supporting such details, this review combines the chemistry, synthetic aspects of formation of triazole Schiff bases, mechanism of bioactivity of metal complexes accompanied by the assessment of the biological efficacy including antibacterial, antifungal, enzyme inhibition and antioxidant activity. This review covers bioactive symmetrical and assymmetrical mono and bis-Schiff bases synthesized from condensation involving the amine group of 3-amino-1,2,4-triazole and 3,5-diamino-1,2,4-triazole with the carbonyl group of several aromatic aldehydes and ketones along with their transition metal complexes which were characterized by physical, spectral and chemical properties. In most of the studies highlighting the biomedical assessment of imine functionalized compounds, metal complexes showed outstanding results in comparison to free ligands.

Plastics are high molecular mass organic polymers obtained mostly from various hydrocarbons of petrochemicals. Over the past 50 years, plastic materials have been used as a substitution of metal, wood, and paper for many applications because of their excellent features in terms of stability, lightness, low cost, and durability. These polymers are basically nonbiodegradable with only a few exceptions. Poor behavior in communities toward the proper disposal of plastic wastes poses significant threats to the environment. Plastic waste consists of polypropylene, low and high-density polyethylene, polystyrene, polyethylene tetrachloride, polyvinyl chloride, and so forth. Plastic additives of concerns to health and environment include bisphenol A, organotin, triclosan, phthalates, and brominated flame retardants. The current methods used for plastic waste management include incineration, landfilling, chemical, and mechanical recycling. Because plastics are quite recalcitrant type materials, the combined approach using photochemical or thermochemical processes, followed by bioprocessing, is an excellent example of plastic waste management. Biodegradation of plastics is a biochemical process in which a particular compound ultimately breaks into very simpler molecules by the action of enzymes. Plastics are usually biodegraded partly aerobically in soil and compost and anaerobically in landfills and sediments. Aerobic biodegradation produces water and carbon dioxide, while water, carbon dioxide, and methane are produced during anaerobic biodegradation. Biodegradation of plastic waste materials may result in the formation of nanoplastics.

Bioassay guided fractionation of Pistacia integerrima crude methanolic extract gave Pistacide-A (1) and Pistacide-B (2), along with ten known phytochemicals (3–12). Biochemical analysis of crude plant extract, in-vitro and in-silico carbonic anhydrase inhibitory potential of newly isolated compounds Pistacide-A (1) and Pistacide-B (2) were performed. The cytotoxicity of extract in methanol, ethylacetate and n-butanol against Artemia salina brine-shrimp was 34.98 g/ml, 160.81 g/ml, and 135.77 g/ml, respectively. The significant antimicrobial activity was exhibited by crude, ethyl acetate, and n-butanol fractions. Compounds 1 (IC50 = 6.51 ± 0.42 mM) and 2 (IC50 = 2.85 ± 0.09 mM) showed good carbonic anhydrase inhibition compared with standard zonisamide drug (IC50 = 1.87 ± 0.003 mM). In addition, we have also clarified the electronic properties, absorption wavelengths, molecular electrostatic potential and Hirshfeld analysis by first-principles studies. The coherent intra-molecular charge transfer was seen from occupied to unoccupied molecular orbitals. The absorption wavelengths calculated at time dependent B3LYP/6-31G** level in methanol provided excellent accord with the experimental evidence. Molecular docking score revealed that Pistacide-B would be an efficient drug than its other counterpart that is rational to the experimental data.

The scientific interest in developing the advanced metal based compounds to inhibit and control bacterial infections is continuously rising. Keeping in view their pharmacological significance, two new bioactive symmetrical phenylenediamine mono- and bis-Schiff bases, 2-{[(4-aminophenyl)imino]methyl}-6-methoxyphenol (L1) and 2,2'-{benzene-1,2-diylbis[nitrilomethylylidene]}bis(6-methoxyphenol) (L2) have been synthesized and characterized by using physical techniques, spectral methods, elemental and DFT based computational analysis with B3LYP/6-311++G(d, p) basis set. Furthermore, the synthesized ligands were complexed with VO, Mn, Co, Ni, Cu and Zn ions in ratio [M:L,1:2 and 1:1], respectively. All the complexes exhibited significant antibacterial action against all tested bacterial strains. But overall, the zinc complexes possessed higher antibacterial activity. These results concluded that metal complexes might be promising induction in the upcoming time for medical purposes.

The present study advocates the combined experimental and computational study of metal-based aminothiazole-derived Schiff base ligands. The structure and electronic properties of ligands have been experimentally studied by spectroscopic methods (UV-Vis, FT-IR, 1 H-NMR and 13 C-NMR), mass spectrometry, elemental analysis and theoretically by density function theory (DFT). Computational calculations employing the B3LYP/6-31 + G(d,p) functional of DFT were executed to explore the optimized geometrical structures of ligands along with geometric parameters, molecular electrostatic potential (MEP) surfaces and frontier molecular orbital (FMO) energies. Global reactivity parameters estimated from FMO energy gaps signified the bioactive nature of ligands. The synthesized ligands were used for chelation with 3 d -transition metals [VO(IV), Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 1 : 2 (metal : ligand) molar ratio. The spectral and magnetic results confirmed the formation of octahedral geometry around all the divalent and trivalent metal centres, whereas the tetravalent vanadyl centres were confirmed to have square-pyramidal geometry. All the as-synthesized compounds were investigated for in vitro antibacterial potential against two Gram-negative ( Salmonella typhimurium and Escherichia coli ) and two Gram-positive ( Bacillus subtilis and Staphylococcus aureus ) bacteria. Antibacterial assay results displayed pronounced activity, and their activity is comparable to that of a standard drug (streptomycin). The antioxidant potential of these compounds was assessed by employing diphenyl picryl hydrazide radical scavenging activity. The results displayed that all the metal chelates have exhibited more bioactivity in contrast with free ligands. The chelation was the main reason for their enhanced bioactivity. These results indicated that the thiazole metal-based compounds could be exploited as antioxidant and antimicrobial candidates.

In this study, Trapa bispinosa's peel (TBP) biomass is exploited as an effective, low cost and new adsorbent to remove Pb(II) from aqueous solution. TBP is pretreated and modified with HNO3, HClO4 and H2O2 to enhance the Pb(II) removal and it is perceived that chemical modifications enhance the adsorption capacity of TBP. The adsorption behavior of Pb(II) is studied under different conditions, including pH (3-6), TBP dose (0.050.8 g), stirring speed (100-200 rpm), initial Pb(II) ion concentration (25-400 mg L-1) and contact time (0-1440 min). Kinetic study reveals sorption is fast in first 15 to 30 min achieving equilibrium in 60 min with qmax (mg g-1) are 77.09, 105.40 and 123.82 for NT-TBP, NA-TBP and HCA-TBP respectively. The Langmuir model successfully defines the sorption data having higher R2 and good agreement between theoretical and experimental uptake capacity of Pb(II). The kinetic study exhibits that the pseudo-second order rate equation is better portrayed sorption process. TBP modified with HClO4 shows the highest metal uptake in comparison to HNO3, H2O2 modified TBP and native TBP.

The present study describes the discovery of novel inhibitors of mushroom tyrosinase enzyme. For that purpose, a series of varyingly substituted 2-phenylchromone analogues 1–28 were synthesized and characterized in detail by various spectroscopic techniques (UV–Vis, FTIR, 1H NMR, 13C NMR) and mass spectrometry. All the derivatives (1–28) were screened in vitro for their inhibitory potential against mushroom tyrosinase enzyme. Interestingly, all the synthetic compounds displayed good to excellent inhibitory activity with IC50 values ranging from 0.093 ± 0.003 μg/ml to 23.58 ± 0.94 μg/ml for brominated 3-hydroxy-2-phenylchromones and 0.22 ± 0.017 μg/ml to 22.22 ± 1.1 μg/ml for brominated 2-phenylchromones against tyrosinase in comparison to the standard kojic acid (IC50 = 1.79 ± 0.64 μg/ml). Remarkably, the bromine atoms attached on ring A attribute to increases the inhibitory potential of 2-phenylchromone moiety and anti-tyrosinase assay demonstrated that compound 10 (IC50 = 0.093 ± 0.003 µg/ml) was found almost nineteenfold, 11 (IC50 = 0.126 ± 0.015 µg/ml) fourteenfold and 26 (IC50 = 0.22 ± 0.017 µg/ml) about eightfold more active than the positive control. Notably, among the already literature reported tyrosinase inhibitors, these analogues have been found the most active inhibitors of mushroom tyrosinase with the lowest possible IC50 values. To design and develop novel tyrosinase inhibitors using 2-phenylchromone as a structural motif in the future, a limited structure-activity relationship was established. Moreover, in silico studies were carried out to rationalize the binding mode of interactions of all the targeted compounds (1–28) with the active site of enzymes. The experimental and theoretical results are in parallel with one another. In addition, molecular description was performed with the drug-likeness and bioactivity scores. Computational analysis predicted that few compounds are in a linear correlation with Lipinski’s RO5 indicating superb drug-likeness and bioactivity score for drug targets.

By condensing ethylene-1,2-diamine with different aldehydes such as benzaldehyde, 4-chloroacetophenone and 2-chlorobenzaldeyhde within 1:2 molar ratio, resulted new series of Schiff base ligands (L1)-(L3) containing bidentate nitrogen atom. Their metal complexes were synthesized by coordinating the ligands with transition metals as Co(II), Cu(II), Ni(II) and Zn(II) and exhibited octahedral geometry. Their characterization was done with the help of spectral, physical and analytical analysis. Spectral and elemental analysis of all bidentate ligands and their corresponding 3d-metal chelates was consistent with their proposed structures, signifying the high purity of these compounds. For in-vitro studies, these metal complexes along their ligands were screened against the six bacterial strains; Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus and Streptococcus faecalis. Six fungal strains; Aspergillus niger, Trichophyton mentogrophytes, Epidermophyton floccosum, Trichophyton schoenleinii, Microscopum canis and Fusarium culmorum were used to study antifungal activity of the compounds. Bioactivity results exhibited that metal complexes showed higher antimicrobial potential as compared with their corresponding ligands. The enhanced activity resulted due to chelation that decreases the polarity of metal ions by complexing with bidentate ligands.

Targeting tyrosinase (TYR), a key enzyme responsible for melanogenesis disorders, is a well-known approach utilized for the development of melanogenesis inhibitor. A variety of dermatological disorders and microbial skin infections can cause hyperpigmentation. Hence, exploring new scaffolds for the treatment of melanogenesis disease is an inspiring goal. In this context, a series of varyingly substituted flavone-based hydrazones have been designed, synthesized and characterized successfully. The present study describes the discovery of novel mushroom tyrosinase inhibitors (TIs) for treating hyperpigmentation. In due course, flavone scaffold has been incorporated into the novel chemotypes that exhibit in vitro inhibitory effects against mushroom tyrosinase for the purpose of discovering anti‐melanogenic agents. Biological investigations of prepared analogs herein demonstrated moderate to excellent activity against most of the fungal-bacterial strains and their activity is comparable to those of commercially available antibiotics i.e., Ciprofloxacin and Ketoconazole. Based on in vitro tyrosinase inhibitory assay, some compounds exhibited potent inhibition particularly, 3g (IC50 = 1.40 ± 0.16 µM), 3j (IC50 = 0.95 ± 0.07 µM), 3o (IC50 = 1.13 ± 0.11 µM), and 3q (IC50 = 1.01 ± 0.1 µM) showed best inhibition i.e., 0.7, 0.5, 0.6 and 0.5 folds, respectively, than kojic acid (IC50 = 1.79 ± 0.6 µM). Lineweaver-Burk plots demonstrated that the most potential derivative 3j tyrosinase inhibition proceeds via non-competitive pathway and the Michaelis-Menton constant (Km) value is 0.0265. Molecular modeling was performed for all tested analogs (3a–3q) using a model of mushroom tyrosinase to find crucial binding modes liable for inhibitory activity. The SARs were preliminarily examined, and the docking study revealed that analogs 3j, 3o and 3p had a strong binding association to tyrosinase (2Y9X). Furthermore, a drug-likeness study was employed and confirmed the favorable activity of the new analogs as a new anti-tyrosinase agent.

In this report, new sulfonamide based ligands (L1)-(L3) from 4-amino-N-(pyrimidin-2-yl)benzene-1-sulfonamide are synthesized and branded on the basis of their physical, analytical and spectral (1H & 13C-NMR, MS, FT-IR, UV–Vis) grounds. The ligands reacted with the transition metals (VO2+, Fe2+, Co2+, Ni2+, Cu2+ & Zn2+) to synthesize their complexes (1)-(18). Their structure was considered by their elemental, conductance, magnetic, physical, and spectral (UV–Vis, FT-IR & MS) analysis. The geometry optimization of the compounds was achieved at M06/6-311+G(d,p). The natural bond orbital (NBO) analysis with a WB97XD/6-311+G(d,p) function demonstrated that the inter-molecular charges and the hyper conjugation play a significant role in stabilizing the molecular systems. The orbital band gap explained chemical interactions and the phenomena of charge transfer. The lowest band gap of HOMO/LUMO (0.78 eV) is shown for compound (l3), while the highest gap of 1.47 eV is found for ligand (L3). The global parameters of reactivity (GRP) have been investigated with (L2) having higher hardness (2.384 eV) and (17) with higher (2.27 eV) softness (S). The in vitro screening results for their antibacterial activity revealed the compound (5) with the highest activity (31 mm) against Streptococcus aureus while the antifungal activity ranged between 11-28 mm with the compound (12) having the highest one for Aspergillus niger. The enzyme inhibition activity (%) against α-Amylase, Protease, Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) with highest (75±0.11; IC50: 66±0.11µL, 73±0.11; IC50: 68±0.10 µL, 75±0.12; IC50: 66±0.11 µL and 71±0.12; IC50: 70±0.08 µL) activity for compounds (16), (18), (17), respectively. The antioxidant action was explored by operating several in vitro assays: scavenging activity against DPPH radical, reducing power against ferric oxidation and total phenols as Gallic acid equivalents. Results indicated that the compound (7) has offered the highest (67.02 ± 0.09) DPPH activity. The results revealed all the compounds to be more biologically active than free ligands. These results also indicated that the meal complexes may be considered for further drug design endeavors.

During the present investigation, two new sulfonamide-based Schiff base ligands, 4-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}-N-(1,3-thiazol-2-yl)benzene-1-sulfonamide (L

In this protocol, a series of 3-benzyloxyflavone derivatives have been designed, synthesized, characterized and investigated in vitro as cholinesterase inhibitors. The findings showed that all the ...