Synthesis, structural characterization, and biological studies of ATBS-M complexes (M(II) = Cu, Co, Ni, and Mn): Access for promising antibiotics and anticancer agents

Three metal complexes with a pyridyl Schiff base: cytotoxicity, migration and mechanism of apoptosis

Three metal complexes [CuL(NO₃)]_n (1), [Cd(HL)(NO₃)₂]_n (2) and [EuL(HCOOH)(H₂O)(NO₃)₂] (3) were synthesized with a pyridyl Schiff ligand L (N'-[(1E)-pyridin-2-ylmethylidene]pyridine-4-carbohydrazide). A crystallographic study revealed that complexes 1 and 2 have a chain structure, and complex 3 is a zero-dimensional monomer. In vitro cytotoxicity studies showed that complex 2 had the best antiproliferative activity against SMMC-7721 cells and complex 3 had the best antiproliferative activity against MDA-MB-231 cells with single-digit IC₅₀ values, both exceeding those of the control drug cisplatin by far. The cell invasion and migration ability through the transwell assay and wound-healing assay showed that the selected complexes could inhibit the invasion and migration of cancer cells. The Hoechst staining assay and ROS generation assay with SMMC-7721 cells indicated that the cytotoxic effects of complex 2 involved apoptosis induction through ROS accumulation. The apoptosis-inducing and cell cycle arrest effects of complex 2 on SMMC-7721 cells indicated that the antitumor effect was achieved through apoptosis induction and inhibition of DNA synthesis by blocking the G₀/G₁ phase of the cell cycle. In addition, complex 2 showed significant inhibition against B. dysentery with an inhibition circle diameter of 24 mm.

Enhanced In Vivo Wound Healing Efficacy of a Novel Hydrogel Loaded with Copper (II) Schiff Base Quinoline Complex (CuSQ) Solid Lipid Nanoparticles

Wound dressings created using nanotechnology are known as suitable substrates to speed up the healing of both acute and chronic wounds. Therapeutic substances can be delivered using these materials. In this study, a hydrogel loaded with Cu (II) Schiff base 8-hydroxy quinoline complex (CuSQ) solid lipid nanoparticles (SLN) was formulated to investigate its wound healing potential in an excision wound healing model in rats. The CuSQ SLN were spherical shaped with sizes ranging from 111 to 202 nm and a polydispersity index (PDI) ranging from 0.43 to 0.76, encapsulation efficiency (EE) % between 85 and 88, and zeta potential (ZP) of −11.8 to −40 mV. The formulated hydrogel showed good homogeneity, good stability, and a pH of 6.4 which indicates no skin irritation and had no cytotoxicity on the human skin fibroblast (HSF) cell line. In the in vivo study, animals were placed in five groups: control, standard, plain hydrogel, low dose, and high dose of CuSQ hydrogel. Both doses of CuSQ showed significantly faster healing rates compared to standard and control rats. In addition, the histopathology study showed more collagen, improved angiogenesis, and intact re-epithelization with less inflammation. A significant increase in transforming growth factor-beta1 (TGF-β1) level and increased immune expression of vascular endothelial growth factor (VEGF) by CuSQ treatment validates its role in collagen synthesis, proliferation of fibroblasts and enhancement of angiogenesis. Matrix metalloproteinase-9 (MMP-9) was found to be significantly reduced after CuSQ treatment. Immunohistochemistry of tumor necrosis factor alpha (TNF-α) revealed a marked decrease in inflammation. Thus, we concluded that CuSQ would be a beneficial drug for cutaneous wound healing since it effectively accelerated wound healing through regulation of various cytokines and growth factors.