Biological effects of vanillic acid, iso-vanillic acid, and orto-vanillic acid as environmental pollutants.

Vanillic acid (4-hydroxy-3-methoxybenzoic acid) (VA) is a natural benzoic acid derivative commonly found in herbs, rice, maize, and some fruits and vegetables. However, due to the wide use of VA in various industrial sectors, its presence in the environment might harm living organisms. This study evaluated the toxicity of VA and its isomers, iso-VA and orto-VA. Firstly, the antimicrobial effect of VA and its isomers iso-VA and orto-VA (in doses of 1000; 100, 10, 1; 0.1; 0.01 mg/L) against Escherichia coli, Sarcina spp., Enterobacter homaechei, Staphylococcus aureus and Candida albicans were identified. The toxic effect and protein degradation potential of VA and its isomers were determined using E. coli grpE:luxCDABE and lac:luxCDABE biosensor strains. However, the genotoxicity and oxidative stress generation were assessed with the E. coli recA:luxCDABE biosensor and E. coli strain. The results showed that VA, iso-VA, and orto-VA exhibited antimicrobial activity against all tested bacterial strains. However, VA's antimicrobial effect differed from iso-VA and orto-VA. Similar toxic, genotoxic, and oxidative stress-inducing effects were observed for VA and its isomers. Each compound exhibited toxicity, cellular protein degradation, and genotoxic activity against E. coli grpE:luxCDABE, E. coli lac:luxCDABE, and E. coli recA:luxCDABE strains. Analysis of reactive oxygen species (ROS) generation within E. coli cells highlighted oxidative stress as a contributing factor to the toxicity and genotoxicity of VA and its isomers. While the findings suggest potential applications of VA compounds as food preservatives, their presence in the environment raises concerns regarding the risks posed to living organisms due to their toxic and genotoxic characteristics.

Apigenin's Modulation of Doxorubicin Efficacy in Breast Cancer.

Apigenin, a naturally derived flavonoid, is increasingly being acknowledged for its potential therapeutic applications, especially in oncology. This research explores apigenin's capacity to modulate cancer cell viability, emphasizing its roles beyond its minimal antioxidant activity attributed to its basic molecular structure devoid of hydroxyl groups. We investigated apigenin's effects on two breast cancer cell lines, estrogen-dependent MCF-7 and non-estrogen-dependent MDA-MB-231 cells. Our findings reveal that apigenin exerts a dose-dependent cytotoxic and anti-migratory impact on these cells. Interestingly, both apigenin and doxorubicin-a standard chemotherapeutic agent-induced lipid droplet accumulation in a dose-dependent manner in MDA-MB-231 cells. This phenomenon was absent in MCF-7 cells and not evident when doxorubicin and apigenin were used concurrently, suggesting distinct cellular responses to these treatments that imply that their synergistic effects might be mediated through mechanisms unrelated to lipid metabolism. A further chemoinformatics analysis indicated that apigenin and doxorubicin might interact primarily at the level of ATP-binding cassette (ABC) transporter proteins, with potential indirect influences from the AKT and MYC signaling pathways. These results highlight the importance of understanding the nuanced interactions between apigenin and conventional chemotherapeutic drugs, as they could lead to more effective strategies for cancer treatment. This study underscores apigenin's potential as a modulator of cancer cell dynamics through mechanisms independent of its direct antioxidant effects, thereby contributing to the development of flavonoid-based adjunct therapies in cancer management.

Research on the Electron Structure and Antimicrobial Properties of Mandelic Acid and Its Alkali Metal Salts.

This article investigated the structure, and the spectroscopic and antimicrobial properties of mandelic acid and its alkali metal salts. The electron charge distribution and aromaticity in the analyzed molecules were investigated using molecular spectroscopy methods (FT-IR, FT-Raman, 1H NMR, and 13C NMR) and theoretical calculations (structure, NBO, HOMO, LUMO, energy descriptors, and theoretical IR and NMR spectra). The B3LYP/6-311++G(d,p) method was used in the calculations. The antimicrobial activities of mandelic acid and its salt were tested against six bacteria: Gram-positive Listeria monocytogenes ATCC 13932, Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, and Loigolactobacillus backii KKP 3566; Gram-negative Escherichia coli ATCC 25922 and Salmonella Typhimurium ATCC 14028, as well as two yeast species, Rhodotorulla mucilaginosa KKP 3560 and Candida albicans ATCC 10231.

Structures, Antioxidant Properties, and Antimicrobial Properties of Eu(III), Gd(III), and Dy(III) Caffeinates and p-Coumarates.

In this study, we investigated the structures of lanthanide (Eu(III), Dy(III), and Gd(III)) complexes with p-coumaric (p-CAH2) and caffeic (CFAH3) acids using the FTIRKBr, FTIRATR, and Raman spectroscopic methods. The compositions of the solid phase caffeinates and p-coumarates were obtained on the basis of the amounts of hydrogen and carbon determined using an elemental analysis. The degree of hydration and the thermal decomposition of each compound were examined via a thermal analysis of TG, DTG, and DSC. Antioxidant spectroscopic tests were performed using the DPPH (1,1-diphenyl-2-picrylhydrazyl radical), FRAP (ferric reducing antioxidant activity), and ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (diammonium salt radical cation) methods. The antimicrobial activity of each compound against Escherichia coli, Bacillus subtilis, and Candida albicans was investigated. The electrical properties of the liposomes which mimicked the microbial surfaces formed in the electrolyte containing the tested compounds were also investigated. The above biological properties of the obtained complexes were compared with the activities of p-CAH2 and CFAH3. The obtained data suggest that lanthanide complexes are much more thermally stable and have higher antimicrobial and antioxidant properties than the ligands (with the exception of CFAH3 in the case of antioxidant activity tests). The Gd(III) complexes revealed the highest biological activity among the studied lanthanide complexes.

The study of biological activity of mandelic acid and its alkali metal salts in wastewaters.

In the present work we compared the biological activity of mandelic acid (MA) and its Li, Na, K, Rb and Cs salts. The study also investigated the effect of raw wastewaters (RW) and treated wastewaters (TW), comparable to microbial medium (MM) on the biological activity of the tested chemical compounds used in concentrations of 5; 2.5; 1.25; 0.625; 0.3125 mg/ml. In the present experiment the evaluation of the following parameters was performed: E. coli (ATCC 25922) cells viability, growth inhibition of E. coli (ATCC 25922), the inhibition of GFP protein, genotoxicity and ROS generation. Our results showed that three main factors differentiated the antibacterial activity of MA and its Li, Na, K, Rb and Cs salts: study environment (MM, RW, TW), metal forming salt of mandelic acid and concentration of tested compounds. Additionally, raw and treated wastewater, compared to microbial medium, changes the antimicrobial activity of MA and its salts in relation to the E. coli strain. We also detected that both MA and its salts affect the GFP protein and the induction of the recA promoter (genotoxicity test). The activity of the tested salts in relation to these two parameters is strictly dependent on the type of salt-forming metal and the concentration used. The analysis of ROS synthesis suggests that in the majority of the studied mandelic acid salts, oxidative stress is the dominant mechanism of cytotoxicity and genotoxicity. We also showed that both raw wastewaters (RW) and treated wastewaters (TW), compared to microbial medium (MM), change significantly the activity of MA and its salts.

Why Do Dietary Flavonoids Have a Promising Effect as Enhancers of Anthracyclines? Hydroxyl Substituents, Bioavailability and Biological Activity.

Anthracyclines currently play a key role in the treatment of many cancers, but the limiting factor of their use is the widespread phenomenon of drug resistance and untargeted toxicity. Flavonoids have pleiotropic, beneficial effects on human health that, apart from antioxidant activity, are currently considered small molecules-starting structures for drug development and enhancers of conventional therapeutics. This paper is a review of the current and most important data on the participation of a selected series of flavonoids: chrysin, apigenin, kaempferol, quercetin and myricetin, which differ in the presence of an additional hydroxyl group, in the formation of a synergistic effect with anthracycline antibiotics. The review includes a characterization of the mechanism of action of flavonoids, as well as insight into the physicochemical parameters determining their bioavailability in vitro. The crosstalk between flavonoids and the molecular activity of anthracyclines discussed in the article covers the most important common areas of action, such as (1) disruption of DNA integrity (genotoxic effect), (2) modulation of antioxidant response pathways, and (3) inhibition of the activity of membrane proteins responsible for the active transport of drugs and xenobiotics. The increase in knowledge about the relationship between the molecular structure of flavonoids and their biological effect makes it possible to more effectively search for derivatives with a synergistic effect with anthracyclines and to develop better therapeutic strategies in the treatment of cancer.

Caffeic Acid/Eu(III) Complexes: Solution Equilibrium Studies, Structure Characterization and Biological Activity.

Caffeic acid (CFA) is one of the various natural antioxidants and chemoprotective agents occurring in the human diet. In addition, its metal complexes play fundamental roles in biological systems. Nevertheless, research on the properties of CFA with lanthanide metals is very scarce, and little to no chemical or biological information is known about these particular systems. Most of their properties, including their biological activity and environmental impact, strictly depend on their structure, stability, and solution behaviour. In this work, a multi-analytical-technique approach was used to study these relationships for the Eu(III)/CFA complex. The synthesized metal complex was studied by FT-IR, FT-Raman, elemental, and thermal (TGA) analysis. In order to examine the chemical speciation of the Eu(III)/CFA system in an aqueous solution, several independent potentiometric and spectrophotometric UV-Vis titrations were performed at different M:L (metal:ligand) and pH ratios. The general molecular formula of the synthesized metal complex in the solid state was [Eu(CFA)3(H2O)3]∙2H2O (M:L ratio 1:3), while in aqueous solution the 1:1 species were observed at the optimum pH of 6 ≤ pH ≤ 10, ([Eu(CFA)] and [Eu(CFA)(OH)]-). These results were confirmed by 1H-NMR experiments and electrospray-ionization mass spectrometry (ESI-MS). To evaluate the interaction of Eu(III)/CFA and CFA alone with cell membranes, electrophoretic mobility assays were used. Various antioxidant tests have shown that Eu(III)/CFA exhibits lower antioxidant activity than the free CFA ligand. In addition, the antimicrobial properties of Eu(III)/CFA and CFA against Escherichia coli, Bacillus subtilis and Candida albicans were investigated by evaluation of the minimum inhibitory concentration (MIC). Eu(III)/CFA shows higher antibacterial activity against bacteria compared to CFA, which can be explained by the highly probable increased lipophilicity of the Eu(III) complex.

Synergistic interaction of diclofenac and its metabolites with selected antibiotics and amygdalin in wastewaters.

Diclofenac (DCF), a non-steroidal anti-inflammatory drug (NSAID) belongs to one of the most frequently detected pharmaceutical residues in the environment. Little is known on the interactions of DCF as well as its major biodegradation metabolites 4'-OHDCF and 5-OHDCF with chemical compounds found in wastewater, including antibiotics such as ampicillin and kanamycin. In the present work we examined the potential interactions between DCF, its metabolites 4'-OHDCF and 5-OHDCF and ampicyllin and kanamycin. We also measured the effect of the mixture of DCF with natural compound - amygdalin. We evaluated the following parameters: E. coli K-12 cells viability, growth inhibition of E. coli K-12 culture, genotoxicity, oxidative stress parameters: sodA promoter induction and ROS generation. The reactivity of E. coli SM recA:luxCDABE biosensor strain in wastewaters matrices contaminated with DCF and kanamycin was also monitored. Obtained results indicated that used antibiotics (ampicyllin, kanamycin) enhanced the toxic effect of DCF used individually and in the mixtures with its metabolites 4'-OHDCF and 5-OHDCF toward E. coli. Similar effect was also obtained in genotoxicity assay. The oxidative stress assays revealed that the highest level of ROS generation and sodA promoter induction were obtained also for the mixtures of DCF, its metabolites with antibiotics. It was also showed that amygdalin influenced the activity of DCF and its biodegradation metabolites. The strongest luminescence response of E. coli SM biosensor strain with recA:luxCDABE genetic construct in filtered treated wastewaters, comparable to control sample was noticed. Obtained results showed that DCF and its biodegradation metabolites 4'-OHDCF and 5-OHDCF can interact with tested antibiotics and compounds of natural origin, i.e. amygdalin to form mixtures showing stronger antimicrobial activity against E. coli than parent chemicals. Moreover the assays in wastewater matrices revealed that E. coli SM recA:luxCDABE biosensor strains is a good tool for bacteria monitoring in wastewater environments.

The study of biological activity of transformation products of diclofenac and its interaction with chlorogenic acid.

In the present work we compared the biological activity of DCF, 4'-OHDCF and 5-OHDCF as molecules of most biodegradation pathways of DCF and selected transformation products (2-hydroxyphenylacetic acid; 2,5-dihydroxyphenylacetic acid and 2,6-dichloroaniline) which are produced during AOPs, such as ozonation and UV/H2O2. We also examined the interaction of DCF with chlorogenic acid (CGA). CGA is commonly used in human diet and entering the environment along with waste mainly from the processing and brewing of coffee and it can be toxic for microorganisms included in activated sludge. In the present experiment the evaluation of following parameters was performed: E. coli K-12 cells viability, growth inhibition of E. coli K-12 culture, LC50 and mortality of Chironomus aprilinus, genotoxicity, sodA promoter induction and ROS generation. In addition the reactivity of E. coli SM recA:luxCDABE biosensor strain in wastewater matrices was measured. The results showed the influence of DCF, 4'-OHDCF and 5-OHDCF on E. coli K-12 cells viability and bacteria growth, comparable to AOPs by-products. The highest toxicity was observed for selected, tested AOPs by-products, in comparison to the DCF, 4'-OHDCF and 5-OHDCF. Genotoxicity assay indicated that 2,6-dichloroaniline (AOPs by-product) had the highest toxic effect. The oxidative stress assays revealed that the highest level of ROS generation and sodA promoter induction were obtained for DCF, 4'-OHDCF and 5-OHDCF, compared to other tested compounds. We have also found that there is an interaction between chlorogenic acid and DCF, which resulted in increased toxicity of the mixture of the both compounds to E. coli K-12, comparable to parent chemicals. The strongest response of E. coli SM biosensor strain with recA:luxCDABE genetic construct in filtered treated wastewaters, comparable to control sample was noticed. It indicates, that E. coli SM recA:luxCDABE biosensor strains is a good tool for bacteria monitoring in wastewater environment. Due to toxicity and biological activity of tested DCF transformation products, there is a need to use additional wastewater treatment systems for wastewater contaminated with pharmaceutical residues.

Molecular Structure and Antioxidant Properties of Alkali Metal Salts of Rosmarinic Acid. Experimental and DFT Studies.

The molecular structure of alkali metal rosmarinates was studied in comparison to rosmarinic acid using FT-IR, FT-Raman, 1H and 13C NMR spectroscopy, as well as density functional theory (DFT) calculations. The B3LYP/6-311+G(d,p) method was used to calculate optimized geometrical structures of studied compounds, atomic charges, dipole moments, energies, as well as the wavenumbers and intensities of the bands in vibrational and NMR spectra. Theoretical parameters were compared to experimental data. Antioxidant activity was determined using two spectrophotometric methods: (i) Assessing the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable radical and (ii) assay of antioxidant power of ferric ions reducing (FRAP). The linear correlations were found between HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) energy gap and the reducing power expressed as FRAP (R = 0.77) as well as between IC50 values (the ability of quenching DPPH radicals) and Δνas-s(COO) in IR spectra (differences between asymmetric and symmetric stretching vibrations bands) (R = 0.99). Photochemical properties of studied compounds were also evaluated. The influence of alkali metal on the electronic system of the rosmarinic acid molecule was discussed.

MONITORING OF SYNERGISTIC ENHANCEMENT OF CAFFEIC ACID ON ESCHERICHIA COLI K-12 RECA::GFP STRAIN TREATED WITH DACARBAZINE.

Caffeic acid and its derivatives because of its biological activities, including antioxidants, antithrombosis, antihypertensive, antifibrosis, antiviral, and anti-tumor properties are good candidates as adjuvants in anticancer therapy. The aim of this study was the examination of cyto- and genotoxic effect of caffeic acid on Escherichia coli K-12 recA::gfp strain treated with dacarbazine. Obtained results indicate that dacarbazine and caffeic acid influenced the reactivity of recA promoter and modulate the level of gfp expression in genetic construct rrcA::gfpmut2 in E. coli K-12. Simultaneuos administration of dacarbazine with caffeic acid caused the stronger inhibition of the bacteria growth than the dacarbazine and caffeic acid separated administration to bacteria cells. The simultaneous effect of the both tested chemicals - dacarbazine and caffeic acid indicated (cytostatic effect) anticancer activity in relation to bacteria cells. It suggests, that combination of known anticancer drug - dacarbazine w ith caffeic acid exerted synergistic cytotoxic and genotoxic effects toward E. coli K- 12 cells and indicated the possibility of usefulness of caffeic acid as a natural adjuvant in anticancer therapy.

IN VITRO EVALUATION OF BIOLOGICAL ACTIVITY OF CINNAMIC, CAFFEIC, FERULIC AND CHLOROGENIC ACIDS WITH USE OF ESCHERICHIA COLI K-12 RECA::GFP BIOSENSOR STRAIN.

Cinnamic acid and its derivatives are important and promising compounds in cancer therapy, because of its broad spectrum of anicancer and antioxidative ability, and with high potential for development into new generation drugs. The aim of this study was to compare the cyto- and genotoxic effects of cinnamic acid and its derivatives with the use of4Escherichia coli K-12 recA::gfp microbial biosensor strain with plasmid fusion of recA promoter and gfp gene as reporter. Obtained results indicate that recA::gfpmut2 genetic system was a sensitive biosensor to the most chemicals tested in our experiments. The cinnamic acid and its derivatives modulated the reactivity of wcA promoter in relation to control sample and significantly inhibited bacteria cells growth. In the light of our results only chlorogenic and ferulic acids at higher concentrations demonstrated cyto and genotoxic activity toward to E. coli K-12 mcA::gfp cells.

Spectroscopic (FT-IR, FT-Raman, 1H- and 13C-NMR), theoretical and microbiological study of trans o-coumaric acid and alkali metal o-coumarates.

This work is a continuation of research on a correlation between the molecular structure and electronic charge distribution of phenolic compounds and their biological activity. The influence of lithium, sodium, potassium, rubidium and cesium cations on the electronic system of trans o-coumaric (2-hydroxy-cinnamic) acid was studied. We investigated the relationship between the molecular structure of the tested compounds and their antimicrobial activity. Complementary molecular spectroscopic techniques such as infrared (FT-IR), Raman (FT-Raman), ultraviolet-visible (UV-VIS) and nuclear magnetic resonance (1H- and 13C-NMR) were applied. Structures of the molecules were optimized and their structural characteristics were calculated by the density functional theory (DFT) using the B3LYP method with 6-311++G** as a basis set. Geometric and magnetic aromaticity indices, atomic charges, dipole moments and energies were also calculated. Theoretical parameters were compared to the experimental characteristics of investigated compounds. Correlations between certain vibrational bands and some metal parameters, such as electronegativity, ionization energy, atomic and ionic radius, were found. The microbial activity of studied compounds was tested against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris and Candida albicans.

Biomaterials in Cancer Therapy: Investigating the Interaction between Kaempferol and Zinc Ions through Computational, Spectroscopic and Biological Analyses.

A complex of the natural flavonoid kaempferol with zinc (Kam-Zn) was synthesized, and its physicochemical properties were investigated using spectroscopic methods such as Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy and theoretical chemistry. Biological studies were conducted to evaluate the cytotoxic and antiproliferative effects of these complexes on MCF-7 breast cancer cells. Treatment with Kam 100 µM (84.86 ± 7.79%; 64.37 ± 8.24%) and Kam-Zn 100 µM (91.87 ± 3.80%; 87.04 ± 13.0%) showed no significant difference in proliferation between 16 h and 32 h, with the gap width remaining stable. Both Kam-Zn 100 µM and 200 µM demonstrated effective antiproliferative and cytotoxic activity, significantly decreasing cell viability and causing cell death and morphology changes. Antioxidant assays revealed that Kam (IC50 = 5.63 ± 0.06) exhibited higher antioxidant potential compared to Kam-Zn (IC50 = 6.80 ± 0.075), suggesting that zinc coordination impacts the flavonoid's radical scavenging activity by the coordination of metal ion to hydroxyl groups. Computational studies revealed significant modifications in the electronic structure and properties of Kam upon forming 1:1 complexes with Zn2+ ions. Spectroscopy analyses confirmed structural changes, highlighting shifts in absorption peaks and alterations in functional group vibrations indicative of metal-ligand interactions. FT-IR and UV-Vis spectra analysis suggested that Zn coordinates with the 3-OH and 4C=O groups of ligand. These findings suggest that the Kam-Zn complex exhibits interesting antiproliferative, cytotoxic and modified antioxidant effects on MCF-7 cells, providing valuable insights into their structural and anticancer properties.

Comparison of Physicochemical, Antioxidant, and Cytotoxic Properties of Caffeic Acid Conjugates.

Spectroscopic studies (FT-IR, Raman, 1H, and 13C NMR, UV-VIS) of caffeic acid (CFA) and its conjugates, i.e., caftaric acid (CTA), cichoric acid (CA), and cynarin (CY), were carried out. The antioxidant activity of these compounds was determined by a superoxide dismutase (SOD) activity assay and the hydroxyl radical (HO•) inhibition assay. The cytotoxicity of these compounds was performed on DLD-1 cell lines. The molecules were theoretically modeled using the B3LYP-6-311++G(d,p) method. Aromaticity indexes (HOMA, I6, BAC, Aj), HOMO and LUMO orbital energies and reactivity descriptors, NBO electron charge distribution, EPS electrostatic potential maps, and theoretical IR and NMR spectra were calculated for the optimized model systems. The structural features of these compounds were discussed in terms of their biological activities.

Dietary factors and their influence on immunotherapy strategies in oncology: a comprehensive review.

Immunotherapy is emerging as a promising avenue in oncology, gaining increasing importance and offering substantial advantages when compared to chemotherapy or radiotherapy. However, in the context of immunotherapy, there is the potential for the immune system to either support or hinder the administered treatment. This review encompasses recent and pivotal studies that assess the influence of dietary elements, including vitamins, fatty acids, nutrients, small dietary molecules, dietary patterns, and caloric restriction, on the ability to modulate immune responses. Furthermore, the article underscores how these dietary factors have the potential to modify and enhance the effectiveness of anticancer immunotherapy. It emphasizes the necessity for additional research to comprehend the underlying mechanisms for optimizing the efficacy of anticancer therapy and defining dietary strategies that may reduce cancer-related morbidity and mortality. Persistent investigation in this field holds significant promise for improving cancer treatment outcomes and maximizing the benefits of immunotherapy.

Structural characterization and evaluation of antimicrobial and cytotoxic activity of six plant phenolic acids.

Phenolic acids still gain significant attention due to their potential antimicrobial and cytotoxic properties. In this study, we have investigated the antimicrobial of six phenolic acids, namely chlorogenic, caffeic, p-coumaric, rosmarinic, gallic and tannic acids in the concentration range 0.5-500 µM, against Escherichia coli and Lactobacillus rhamnosus. The antimicrobial activity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. Additionally, the cytotoxic effects of these phenolic acids on two cancer cell lines, the colorectal adenocarcinoma Caco-2 cell line and Dukes' type C colorectal adenocarcinoma DLD-1 cell line was examined. To further understand the molecular properties of these phenolic acids, quantum chemical calculations were performed using the Gaussian 09W program. Parameters such as ionization potential, electron affinity, electronegativity, chemical hardness, chemical softness, dipole moment, and electrophilicity index were obtained. The lipophilicity properties represented by logP parameter was also discussed. This study provides a comprehensive evaluation of the antimicrobial and cytotoxic activity of six phenolic acids, compounds deliberately selected due to their chemical structure. They are derivatives of benzoic or cinnamic acids with the increasing number of hydroxyl groups in the aromatic ring. The integration of experimental and computational methodologies provides a knowledge of the molecular characteristics of bioactive compounds and partial explanation of the relationship between the molecular structure and biological properties. This knowledge aids in guiding the development of bioactive components for use in dietary supplements, functional foods and pharmaceutical drugs.

Structure, Antioxidant Activity and Antimicrobial Study of Light Lanthanide Complexes with p-Coumaric Acid.

This paper presents the results of a study of the effects of the lanthanide ions Ce3+, Pr3+, Nd3+ and Sm3+ on the electronic structure and antioxidant and biological (antimicrobial and cytotoxic) properties of p-coumaric acid (p-CAH2). Structural studies were conducted via spectroscopic methods (FTIR, ATR, UV). Thermal degradation studies of the complexes were performed. The results are presented in the form of TG, DTG and DSC curves. Antioxidant properties were determined via activity tests against DPPH, ABTS and OH radicals. The reducing ability was tested via CUPRAC assays. Minimum inhibitory concentrations (MICs) of the ligand and lanthanide complexes were determined on E. coli, B. subtilis and C. albicans microorganisms. The antimicrobial activity was also determined using the MTT assay. The results were presented as the relative cell viability of C. albicans, P. aeruginosa, E. coli and S. aureus compared to controls and expressed as percentages. In the obtained complexes in the solid phase, lanthanide ions coordinate three ligands in a bidentate chelating coordination mode through the carboxyl group of the acid. Spectroscopic analysis showed that lanthanide ions increase the aromaticity of the pi electron system of the ligand. Thermal analysis showed that the complexes are hydrated and have a higher thermal stability than the ligand. The products of thermal decomposition of the complexes are lanthanide oxides. In the aqueous phase, the metal combines with the ligand in a 1:1 molar ratio. Antioxidant activity tests showed that the complexes have a similar ability to remove free radicals. ABTS and DPPH tests showed that the complexes have twice the ability to neutralise radicals than the ligand, and a much higher ability to remove the hydroxyl radical. The abilities of the complexes and the free ligand to reduce Cu2+ ions in the CUPRAC test are at a similar level. Lanthanide complexes of p-coumaric acid are characterised by a higher antimicrobial capacity than the free ligand against Escherichia coli bacteria, Bacillus subtilis and Candida albicans fungi.

Determination of the Effect of Wastewater on the Biological Activity of Mixtures of Fluoxetine and Its Metabolite Norfluoxetine with Nalidixic and Caffeic Acids with Use of E. coli Microbial Bioindicator Strains.

In the present work, the conducted research concerned the determination of the toxicity and oxidative stress generation of the antidepressant fluoxetine (FLU), its metabolite nor-fluoxetine (Nor-FLU), the antibiotic nalidixic acid (NA), caffeic acid (CA) and their mixtures in three different environments: microbial medium (MM), raw wastewaters (RW) and treated wastewaters (TW). We evaluated the following parameters: E. coli cell viability, toxicity and protein damage, sodA promoter induction and ROS generation. It was found that FLU, Nor-FLU, NA, CA and their mixtures are toxic and they have the potency to generate oxidative stress in E. coli strains. We also detected that the wastewater, in comparison to the microbial medium, had an influence on the toxic activity and oxidative stress synthesis of the tested chemicals and their mixtures. Regardless of the environment under study, the strongest toxic activity and oxidative stress generation were detected after bacterial incubation with NA at a concentration of 1 mg/dm3 and the mixture of FLU (1 mg/dm3) with Nor-FLU (0.1 mg/dm3) and with NA (0.1 mg/dm3). The ROS synthesis and sodA promoter induction suggest that, in the case of the examined compounds and their mixtures, oxidative stress is the mechanism of toxicity. The analysis of the types of interactions among the substances constituting the mixtures in the wastewater revealed synergism, potentiation and antagonism.

Spectroscopic Characterization and Antioxidant Properties of Mandelic Acid and Its Derivatives in a Theoretical and Experimental Approach.

The following article discusses the antioxidant properties of mandelic acid and its hydroxy and methoxy derivatives. The antioxidant capacity of these compounds is determined by DPPH, FRAP, CUPRAC and ABTS. The mechanisms underlying the antioxidant properties are described by BDE, IP, PDE, ETE and PA calculation method values and referenced to experimental data. Thermochemistry, HOMO/LUMO energies, dipole moments, charge distribution, IR, RAMAN, NMR frequencies, binding lengths and angles were calculated using the B3LYP method and the 6-311++G(d,p) basis set. The structure of mandelic acid and its derivatives was determined experimentally using IR and RAMAN spectroscopy.