Bis-azo-linkage Schiff bases—Part(II): Synthesis, characterization, photoluminescence and DPPH radical scavenging properties of their novel luminescent mononuclear Zn(II) complexes

A Novel Naphthylidene-diimine Chemosensor for Selective Colorimetric and Fluorometric Detection of Al3+ and CN- Ions

A naphthylidene-diimine L2 was newly designed, and its structure was identified by elemental analysis and spectroscopic methods. The effect of temperature, acid-base and light on enol-keto tautomerism in this Schiff base was evaluated by colorimetry, UV-Vis and fluorescence spectroscopy. Under irradiation 365 nm, L2 emitted yellow, orange and strong green emission in pure, basic and aqueous DMSO media (v/v, 1/1), respectively. Its ionochromic behavior against various cations (Fe3+, Al3+, Cr3+, Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, Ba2+ and Ag+) and anions (F-, Cl-, CH3COO-, SO32-, S2O32-, HSO4-, H2PO4-, NO3-, CN-, and OH-) was investigated in aqueous DMSO media (v/v, 1/1) by UV-Vis and fluorescence experiments. Dark yellow color of L2 changed to colorless for Fe3+, Cr3+ and HSO4- ions, and turned to light yellow for Al3+ and Cu2+ ions, and to orange for CN- and OH- ions. According to UV-Vis data, the chemosensor displayed selective recognition towards Fe3+, Al3+, Cu2+, HSO4-, CN- and OH- with a 1:1 stoichiometric ratio. At the excitation wavelength of 365 nm, L2 gave strong yellowish white emission (λem = 445 and 539 nm) in the presence of Al3+, and the intensity increased about 12.5 times. On the other hand, the chemosensor displayed one emission band at 452 nm and 450 nm in the presence of CN- and OH- with 1.9 fold and 2.3 fold fluorescence enhancement, respectively.

Synthesis, characterization, antioxidant and anticancer activities of a new Schiff base and its M(II) complexes derived from 5-fluorouracil

In this study, Schiff base ligand was obtained from the condensation reaction of benzene-1,2-diamine and 5-fluoropyrimidine-2,4(1H,3H)-dione (5-FU). Metal(II) complexes were synthesized with Fe(II), Co(II) and Ni(II) chloride salts. The synthesized ligand and metal complexes were characterized by FT-IR, UV-vis, ¹H-¹³C NMR, elemental analyses, mass spectroscopy, magnetic moments, molar conductivity and thermogravimetric analysis studies. With the help of different techniques reveal Fe(II), Co(II) and Ni(II) complexes have exhibited tetrahedral and octahedral geometry. Ligand acted as bidentate and it binds metal(II) ions through deprotonated-NH, imine-N atom and carbonyl-O atom, respectively. DPPH, ABTS, FRAP, CUPRAC and total antioxidant activity methods were used to determine the antioxidant properties of ligand and metal complexes. According to the results, the synthesized compounds showed very high antioxidant activity compared to 5-FU. The cytotoxicities of the synthesized compounds were performed on MCF-7 (human breast cancer) and L-929 (fibroblast) cell lines using the MTT assay. In addition, the effect of electroporation (EP) on the cytotoxicity of the compounds was investigated. Our results demonstrated that novel Co(II) and Ni(II) complexes show potential as new anticancer agents and ECT may be a viable treatment option for breast cancer.

An Iron(III)-S-methylthiosemicarbazone Complex: Synthesis, Spectral Characterization, and Antioxidant Potency Measured by CUPRAC and DPPH Methods

An iron(III) complex, [Fe(L1)Cl].H2O, was synthesized by template condensation reaction of 1,1,1-Trifluoroacetylacetone-S-methylthiosemicarbazone hydrogen iodide (L) and 2,3-dihydroxybenzaldehyde in the presence of iron(III) ions. The complex was characterized by IR, ESI MS and X-ray diffraction techniques. Free radical scavenging (FRS) ability and antioxidant capacity of the S-methylthiosemicarbazone and the iron(III) complex were evaluated through DPPH and CUPRAC methods, respectively. The complex exerted better than the S-methylthiosemicarbazone in both TEAC and FRS% values. In addition, iron(III) complex was found to be 3.1 times more antioxidant than the reference ascorbic acid according to the CUPRAC method.

Hepatoprotective and Antioxidant Potential of Phenolics-Enriched Fraction of Anogeissus acuminata Leaf against Alcohol-Induced Hepatotoxicity in Rats

Anogeissus acuminata is used to treat wounds, diarrhoea, dysentery, and skin ailments. However, its hepatoprotective effect against ethanol-induced liver damage is yet to be reported. The phenolic-enriched ethyl acetate fraction of Anogeissus acuminata (AAE) was evaluated for hepatoprotective activity against ethanol-induced liver toxicity in rats. The intoxicated animals were treated with a phenolic-rich fraction of Anogeissus acuminata (AAE) (100 and 200 mg/kg) and silymarin (100 mg/kg). The antioxidant activity of AAE was analysed. Biochemical markers (ALT, AST, ALP, GGT, and TBL) for liver injury in ethanol-administered animals resulted in higher levels of key serum biochemical injury markers, as evidenced by increased levels of ALT (127.24 ± 3.95), AST (189.54 ± 7.56), ALP (263.88 ± 12.96), GGT (91.65 ± 3.96), and TBL (2.85 ± 0.12) compared to Group I ALT (38.67 ± 3.84), AST (64.45 ± 5.97), GGT (38.67 ± 3.84), and TBL (0.53 ± 064) (p < 0.05). AAE administration decreased serum biochemical liver injury markers as manifested in Group III animals’ ALT (79.56 ± 5.16), AST (151.76 ± 6.16), ALP (184.67 ± 10.12), GGT (68.24 ± 4.05), TBL (1.66 ± 0.082) (p < 0.05), and Group IV ALT (55.54 ± 4.35), AST (78.79 ± 4.88), ALP (81.96 ± 9.43), GGT (47.32 ± 2.95), TBL (0.74 ± 0.075) (p < 0.05). Group IV exhibited the most significant reduction in serum biochemical markers as compared to Group III (p < 0.05) and close to silymarin-treated Group V ALT (44.42 ± 3.15), AST (74.45 ± 5.75), ALP (67.32 ± 9.14), GGT (42.43 ± 2.54), TBL (0.634 ± 0.077). Gene expression indices and histoarchitecture were evaluated to demonstrate the potential of AAE. The bioactive fraction of Anogeissus acuminata was rich in phenolics and flavonoid content. GC−MS analysis identified gallic acid, palmitic acid, cis-10-heptadecenoic acid, 9-octadecenoic acid, epigallocatechin, 2,5-dihydroxyacetophenone, and catechin. Oral administration of AAE (100 and 200 mg/kg) lowered the elevated levels of the biochemical markers and interleukin, and enhanced the level of enzymatic antioxidant. It also downregulated the expression level of proapoptotic genes and upregulated the expression level of the antiapoptotic gene along with improved liver histopathology.

In vitro and in silico assessment of antitumor properties and biomolecular binding studies for two new complexes based on NiII bearing k2N,S-donor ligands

This work deals with two new molecule-based materials, namely Ni^II-complexes of general formulae [Ni(L1)₂] (Ni1) and [Ni(L2)₂] (Ni2), where L1 = trans-cinnamaldehyde-N(4)-methyl thiosemicarbazone and L2 = trans-cinnamaldehyde-N(4)-ethyl thiosemicarbazone, as potential antitumor agents. Both compounds were characterized by elemental analysis, molar conductivity and spectroscopic techniques (FTIR and NMR). Their molecular structures were obtained by single-crystal X-ray diffraction analysis. Each one crystallizes in a monoclinic space group P 2₁/c, also the asymmetric unit comprises of one Ni^II ion located on an inversion centre and one anionic ligand, which acts as a κ²N,S-donor affording a five-membered metallaring. The compounds were screened against two selected tumour cell lines (MCF-7 and A549) and non-tumour fibroblasts cell line (MRC-5) via MTT assays. In both tumour cells, all compounds exhibited higher cytotoxicity than the control drug (cisplatin). The IC₅₀ values ranges of 3.70 - 41.37 μM and 1.06 - 14.91 μM were found for MCF-7 and A549, respectively. Importantly, all of them were less toxicity than cisplatin in MRC-5 with SI values ranged at 11.80 - 86.60. The red blood cell (RBC) assay revealed Ni2 as non-toxic due to its reduced haemolytic effect (0--9% at 1--10 μM). The DNA binding was investigated through a combination of spectrophotometric absorption and emission titrations, electrophoresis, and circular dichroism experiments. As a result, these metal complexes were not able to strongly binding to DNA (K_b values ~10⁴ mol L^--1) but suggesting groove-binding interactions. The scavenging ability of them towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical was also evaluated in this work, but no important antioxidant behaviour was detected. Further, the interaction of Ni1 and Ni2 to human serum albumin (HSA) was explored by quenching of tryptophan emission, warfarin competitive assay, and molecular docking protocols. The HSA binding analyses indicated good affinity of both complexes to Sudlow site I (K_b values ⁓10³ mol L^-1).