Structural, thermal, electronic, vibrational, magnetic, and cytotoxic properties of chloro(glycinato-N,O)(1,10-phenanthroline-N,N')‑copper(II) trihydrate coordination complex

Brazilian Amazon Red Propolis: Leishmanicidal Activity and Chemical Composition of a New Variety of Red Propolis

Leishmaniasis is caused by protozoans of the genus Leishmania, and its treatment is highly toxic, leading to treatment discontinuation and the emergence of resistant strains. In this study, we assessed the leishmanicidal activity and chemical composition of red propolis collected from the Amazon-dominated region of northern Tocantins State, Brazil. The MTT assay was employed to determine the samples' activity against Leishmania amazonensis promastigotes and their cytotoxicity against RAW macrophages. Spectrophotometric assays were utilised to measure the concentrations of total phenolics and flavonoids, while high-performance liquid chromatography coupled to a mass spectrometer (LC-MS/MS) was used to determine the chemical composition. An in silico study was conducted to evaluate which compounds from Brazilian Amazon red propolis may correlate with this biological activity. Brazilian Amazon red propolis exhibited a high concentration of phenolic compounds and an inhibitory activity against L. amazonensis, with an IC50 ranging from 23.37 to 36.10 µg/mL. Moreover, fractionation of the propolis yielded a fraction with enhanced bioactivity (16.11 µg/mL). Interestingly, neither the propolis nor its most active fraction showed cytotoxicity towards macrophages at concentrations up to 200 µg/mL. The red colour and the presence of isoflavonoid components (isoflavones, isoflavans, and pterocarpans) confirm that the substance is Brazilian red propolis. However, the absence of polyprenylated benzophenones suggests that this is a new variety of Brazilian red propolis. The in silico study performed with two of the main leishmanicidal drug targets using all compounds identified in Amazon red propolis reported that liquiritigenin was the compound that exhibited the best electronic interaction parameters, which was confirmed in an assay with promastigotes using a standard. The findings indicate that Amazon red propolis possesses leishmanicidal activity, low toxicity, and significant biotechnological potential.

Antioxidant and Anticancer Potential of the New Cu(II) Complexes Bearing Imine-Phenolate Ligands with Pendant Amine N-Donor Groups

Cu(II) complexes bearing NNO-donor Schiff base ligands (2a, b) have been synthesized and characterized. The single crystal X-ray analysis of the 2a complex revealed that a mononuclear and a dinuclear complex co-crystallize in the solid state. The electronic structures of the complexes are optimized by Density Functional Theory (DFT) calculations. The monomeric nature of 2a and 2b species is maintained in solution. Antioxidant activities of the ligands (1a, b) and Cu(II) complexes (2a, b) were determined by in vitro assays such as 1,1-diphenyl-2-picrylhydrazyl free radicals (DPPH^.) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS⁺). Our results demonstrated that 2a showed better antioxidant activity. MTT assays were performed to assess the toxicity of ligands and Cu(II) complexes in V79 cells. The antiproliferative activity of compounds was tested against two human tumor cell lines: MCF-7 (breast adenocarcinoma) and SW620 (colorectal carcinoma) and on MRC-5 (normal lung fibroblast). All compounds showed high cytotoxicity in the all-cell lines but showed no selectivity for tumor cell lines. Antiproliferative activity by clonogenic assay 2b showed a more significant inhibitory effect on the MCF-7 cell lines than on MRC-5. DNA damage for the 2b compound at 10 µM concentration was about three times higher in MCF-7 cells than in MRC-5 cells.