Three VO 2+ complexes of the pyridoxal-derived Schiff bases: Synthesis, experimental and theoretical characterizations, and catalytic activity in a cyclocondensation reaction

The anticancer impact of folate-linked ZnO-decorated bovine serum albumin/silibinin nanoparticles on human pancreatic, breast, lung, and colon cancers

In the current study, we aimed to design an individual hybrid silibinin nano-delivery system consisting of ZnO and BSA components to study its antioxidant activity and apoptotic potential on human pancreatic, breast, lung, and colon cancer cell lines. The folate-linked ZnO-decorated bovine serum albumin/silibinin nanoparticles (FZBS-NP) were synthesized and characterized by FTIR, FESEM, DLS, and zeta potential analysis. The FZBS-NP's cytotoxicity was evaluated by measuring the cancer cells' (MCF-7, A549, HT-29, and Panc) viability. Moreover, the apoptotic potential of the nanoparticles was studied by conducting several analyses including AO/PI and DAPI cell staining analysis, apoptotic gene expression profile (BAX, BCL2, and Caspase-8) preparation, and FITC Annexin V/PI flow cytometry. Finally, both antioxidant assays (ABTS and DPPH) were utilized to analyze the FZBS-NPs' antioxidant activities. The 152-nm FZBS-NP significantly induced the selective apoptotic death on the MCF-7, A549, HT-29, Panc, and Huvec cancer cells by increasing the SubG1 cell population following the increased treatment concentrations of FZBS-NP. Moreover, the FZBS-NPs exhibited powerful antioxidant activity. The BSA component of the FZBS-NPs delivery system improves the ability of the nanoparticles to gradually release silibinin and ZnO near the cancer cells. On the other hand, considering the powerful antioxidant activity of FZBS-NP, they have the potential to selectively induce apoptosis in human colon and breast cancer cells and protect normal types, which makes it an efficient safe anticancer compound. However, to verify the FZBS-NP anti-cancer efficiency further cancer and normal cell lines are required to measure several types of apoptotic gene expression.

Anti-proliferative activity of chitosan-coated oxypeucedanin nano-chitosomes (COPD-NCs) against human HT-29 colon cancer cells: in vitro study

Oxypeucedanin (OPD) as a powerful anti-proliferative agent found in the Angelicae dahuricae has been used to suppress cancer cell growth. However, the hydrophobic chemical structure has limited its solubility and bio-accessibility. This is the first time OPD is encapsulated into a nano-liposomal structure and coated with poly-cationic chitosan polymer as the oxypeucedanin drug delivery system to evaluate its antioxidant and anti-colon cancer potential. The chitosan-coated oxypeucedanin nano-chitosomes (COPD-NCs) were synthesized utilizing the thin-layer hydration method and characterized by FESEM, DLS, FTIR, and zeta potential analysis. The anti-cancer potential of COPD-NC was analyzed by measuring the cell survival rate (MTT assay) and studying the cellular death type (AO/PI staining) following the increased treatment concentrations of COPD-NC on the HT-29 colon cancer cell line. Moreover, the COPD-NCs' apoptotic activity was verified by analyzing Cas-3 and Cas-9 gene expression profiles. Finally, the COPD-NCs' antioxidant activity was evaluated by applying ABTS, DPPH, and FRAP antioxidant assays. The 258.26-nm COPD-NCs significantly inhibited the HT-29 colon cancer cells compared with the normal fibroblast HFF cells. The up-regulated Cas-3 and Cas-9 gene expression exhibited the COPD-NCs' apoptotic activity. Also, the COPD-NCs' apoptotic activity was verified by detecting the increased apoptotic bodies following the AO/PI fluorescent staining in the increased exposure doses of COPD-NCs. Ultimately, the COPD-NCs meaningfully inhibited the ABTS-DPPH radicals and exhibited an appropriate FRAP-reductive potential. The designed nanostructure for COPD-NCs significantly improved its antioxidant potential and selective cytotoxicity on human HT-29 human cancer cells, which makes them a safe selective natural drug delivery system. Therefore, the COPD-NCs can selectively induce apoptotic death in human HT-29 cancer cells and have the potential to be studied as an anti-colon cancer compound. However, further cancer and normal cell lines are required to verify their selective cytotoxicity.

Evaluation of the effect of designed PLGA-arctiin nanoparticles modified with folic acid and chitosan on colon cancer cells

In this study, we designed nanoparticles (NPs) based on polylactic acid glycolic acid modified with chitosan and folic acid to optimize the anti-cancer, anti-inflammatory, and antioxidant effects of arctiin (ARC), and we measured its effects on cancer cells, including colon cancer. NPs were synthesized using the W1/O/W2 double-emulsion solvent evaporation method. Physicochemical characteristics of synthesized NPs (ARC-PCF-NPs), including average particle size, dispersity index (PDI), zeta potential (ZP), field emission scanning electron microscope figures, and encapsulation efficiency (EE), were evaluated. 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) methods were carried out to determine the antioxidant properties of NPs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay was performed to investigate cytotoxicity effects on cancer cells and normal fibroblasts. Quantitative polymerase chain reaction was also performed on inflammatory and antioxidant genes. The obtained results indicated that the synthesized NPs have a size of 100 nm, a DPI of 0.36, a ZP of 26.30 mV, and EE was calculated at about 87.5%. The antioxidant influence of ARC-PCF-NPs was confirmed by inhibiting ABTS and DPPH free radicals and ferrous reduction in the FRAP method. Moreover, the reduction of inflammatory and antioxidant genes confirmed the anti-inflammatory and antioxidant properties of NPs. These results indicate the modification of the surface of NPs in order to increase the bioavailability, stability, and effectiveness of medicinal compounds in therapeutic applications.

Brønsted acid catalyzed mechanochemical domino multicomponent reactions by employing liquid assisted grindstone chemistry

Here, we have demonstrated a metal-free energy-efficient mechanochemical approach for expedient access to a diverse set of 2-amino-3-cyano-aryl/heteroaryl-4H-chromenes, tetrahydrospiro[chromene-3,4'-indoline], 2,2'-aryl/heteroarylmethylene-bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) as well as tetrahydro-1H-xanthen-1-one by employing the reactivity of 5,5-dimethylcyclohexane-1,3-dione/cyclohexane-1,3-dione with TsOH⋅H₂O as Brønsted acid catalyst under water-assisted grinding conditions at ambient temperature. The ability to accomplish multiple C-C, C=C, C-O, and C-N bonds from readily available starting materials via a domino multicomponent strategy in the absence of metal-catalyst as well as volatile organic solvents with an immediate reduction in the cost of the transformation without necessitates complex operational procedures, features the significant highlights of this approach. The excellent yield of the products, broad functional group tolerances, easy set-up, column-free, scalable synthesis with ultralow catalyst loading, short reaction time, waste-free, ligand-free, and toxic-free, are other notable advantages of this approach. The greenness and sustainability of the protocol were also established by demonstrating several green metrics parameters.

Novel chiral Schiff base Palladium(II), Nickel(II), Copper(II) and Iron(II) complexes: Synthesis, characterization, anticancer activity and molecular docking studies

In this study, two chiral Schiff base ligands (L1 and L2) were synthesized from the condensation reaction of (S)-2-amino-3-phenyl-1-propanol with 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde as metal precursors for the preparation of transition metal complexes with Pd(II), Fe(II), Ni(II) and Cu(II). The compounds were characterized by using X-ray (for L1-Pd(II)), NMR, FT-IR, UV-Vis, magnetic susceptibility, molar conductivity, and elemental analysis. The in vitro cytotoxic effects of ligands (L1 and L2) and their metal complexes on colon cancer cells (DLD-1), breast cancer cells (MDA-MB-231) and healthy lung human cell lines were investigated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5‑diphenyl tetrazolium bromide (MTT) assay. Among the synthesized compounds, L1-Pd(II) was particularly found to be the most potent anticancer drug candidate in this series with IC50 values of 4.07, and 9.97 µM in DLD-1 and MDA-MB-231 cell lines, respectively. In addition, molecular docking results indicate that Glu122, Asn103, Ala104, Lys126, Phe114, Leu123, and Lys126 amino acids are the binding site of the colon cancer antigen protein, in which the most active complex, L1-Pd(II) can inhibit the current target.

Functionalization of magnetic nanoparticles by creatine as a novel and efficient catalyst for the green synthesis of 2-amino-4H-chromene derivatives

By employing the naturally-originated molecule of creatine, Fe₃O₄@SiO₂-creatine as an environmentally benign magnetic organometallic nanobiocatalyst was successfully prepared via a convenient and green route. Then to acquire an inclusive comprehension of different properties of the catalyst, it was studied by various characterization techniques such as FT‐IR, FE-SEM, TEM, EDX, XRD, and VSM analyses. It was found that the size distribution of nanoparticles was an average diameter size of 70 nm. To examine the catalytic activity, it was applied in sequential knoevenagel condensation-Michael addition room temperature reaction of dimedone, malononitrile, and different substituted aromatic aldehydes to produce a variety of 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives in a single step. Among the multiple outstanding advantages that can be mentioned for this work, some of the most noticeable ones include: affording the products in short reaction times with high yields, operating the reaction at ambient conditions and ease of catalyst separation.

Recent reports on Pyridoxal derived Schiff base complexes

Pyridoxal and Pyridoxal 5-phosphate are two among the six aqua soluble vitamers of vitamin B6. They can form Schiff bases readily due to the presence of aldehyde group. Schiff bases can offer diverse coordination possibilities for many transition metals as has been found in a large volume of research till now. The coordination complexes thus formed gives insight into the active core structure and enzymatic activities of vit B6 containing enzymes. Apart from that, these complexes have been found useful as catalysts for synthesis of fine chemicals, as sensors and for their diverse biological activities.

Surface functionalization of chitosan with 5-nitroisatin

Several possible configurations (CS/NI1-10) for the surface adsorption of 5-nitroisatin (NI) on the chitosan polymer (CS) were investigated using quantum mechanical methods in the gas and solution phases. The values of the binding energies indicate the energetic stability of these configurations. The solvation energies demonstrate that the solubility of NI and CS increases in the presence of each other. The role of hydrogen bonds in noncovalent surface functionalization was determined by AIM analysis. The mechanism of covalent surface functionalization and the explicit solvent effects (methanol) in this mechanism were investigated and it was determined that the covalent functionalization through Schiff base formation is possible. These findings, in addition to the biological applications of the chitosan Schiff bases and their complexes, led us to synthesize a new Schiff base from condensation reaction of CS and NI (CSB) together with its Ni(II) and Cu(II) complexes. The synthesized compounds were characterized by the elemental analysis, infrared spectroscopy (IR), thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Also, optimized geometries, assignment of the IR vibrational bands as well as exploring of the frontier orbitals of the synthesized compounds have been calculated using density functional levels of theory.

Mn(II) complex of a vitamin B6 Schiff base as an exclusive apoptosis inducer in human MCF7 and HepG2 cancer cells: Synthesis, characterization, and biological studies

Herein, a Mn(II) complex of the N,N'-dipyridoxyl(1,4-butanediamine) (═H₂ L) Schiff base has been newly synthesized. The synthesized complex was characterized by several experimental methods. In addition, the density functional theory approaches were used for theoretical identification of the complex. A good agreement between the computed and experimental infrared frequencies demonstrates validity of the optimized geometry for the synthesized complex. In a N₂ O₂ manner, two azomethine nitrogens and two phenolate oxygens of the L^2- ligand are coordinated to the Mn²⁺ metal ion. The biological studies indicate an efficient apoptotic and antioxidant activities of the synthesized [MnL(CH₃ OH)₂ ] complex on both of the HepG2 and MCF7 cancer cells. Since it has been suggested that the complex is an exclusive potent antitumor for treatment of the human breast and liver cancers.