Synthetic Mn(III) porphyrins as biomimetic catalysts of CYP450: Degradation of antibiotic norfloxacin in aqueous medium

Combined toxic effects of nanoplastics and norfloxacin on mussel: Leveraging biochemical parameters and gut microbiota

Antibiotics and nanoplastics (NPs) are among the two most concerned and studied marine emerging contaminants in recent years. Given the large number of different types of antibiotics and NPs, there is a need to apply efficient tools to evaluate their combined toxic effects. Using the thick-shelled mussel (Mytilus coruscus) as a marine ecotoxicological model, we applied a battery of fast enzymatic activity assays and 16S rRNA sequencing to investigate the biochemical and gut microbial response of mussels exposed to antibiotic norfloxacin (NOR) and NPs (80 nm polystyrene beads) alone and in combination at environmentally relevant concentrations. After 15 days of exposure, NPs alone significantly inhibited superoxide dismutase (SOD) and amylase (AMS) activities, while catalase (CAT) was affected by both NOR and NPs. The changes in lysozyme (LZM) and lipase (LPS) were increased over time during the treatments. Co-exposure to NPs and NOR significantly affected glutathione (GSH) and trypsin (Typ), which might be explained by the increased bioavailable NOR carried by NPs. The richness and diversity of the gut microbiota of mussels were both decreased by exposures to NOR and NPs, and the top functions of gut microbiota that were affected by the exposures were predicted. The data fast generated by enzymatic test and 16S sequencing allowed further variance and correlation analysis to understand the plausible driving factors and toxicity mechanisms. Despite the toxic effects of only one type of antibiotics and NPs being evaluated, the validated assays on mussels are readily applicable to other antibiotics, NPs, and their mixture.

Bacterium-Sculpted Porphyrin-Protein-Iron Sulfide Clusters for Distinction and Inhibition of Staphylococcus aureus

Microbe-catalyzed surface modification is a promising method for the production of special targeting nanomaterials. A bacterium-selective material can be obtained by investigating the microbe-catalyzed mineralization of proteins. Herein, a novel method was fabricated for the biosynthesis of FeS-decorated porphyrin-protein clusters (P-CA@BE) via E. coli (Escherichia coli)-catalyzed bio-Fe(III) reduction and bio-sulfidation of porphyrin (P), caffeic acid (CA), and protein [bovine serum albumin (BSA)] assemblies. The assembly (P-CA@BSA) was identified by spectroscopic methods. Next, the P-CA@BSA assembly was transferred into FeS-decorated porphyrin-protein clusters (P-CA@BE) catalyzed by E. coli. There are partial β-folding proteins in P-CA@BE, which selectively recognize S. aureus (Staphylococcus aureus) and show different antibacterial properties against E. coli and S. aureus. Results demonstrate that the E. coli-catalyzed mineralization of the porphyrin-protein assembly is an effective method for the biosynthesis of S. aureus-sensitive metal-protein clusters.

Norfloxacin and gentamicin degradation catalyzed by manganese porphyrins under mild conditions: the importance of toxicity assessment

The current work assessed the degradation degree and the degradation products derived from norfloxacin (NOR) and gentamicin (GEN) using iodosylbenzene and iodobenzene diacetate, in the presence of manganese porphyrin as catalysts. Better results for NOR degradation (> 80%) were obtained when more hydrophobic porphyrins were employed. β-brominated manganese porphyrins showed a lower GEN degradation (~ 25%) than the non-brominated ones (~ 35%), probably due to their steric hindrance. In any case, complete mineralization was achieved neither for NOR nor for GEN, and the assignment of the generated products, complemented by the study of their toxicity, was an important step performed. From the obtained results, no correlation was found between the number of identified products and the reported toxicity value (r_Spearman,NOR = 0.006; p value = 0.986 and r_Spearman,GEN =  - 0,198; p value = 0.583), which reinforces the idea of synergism and antagonistic phenomena. The higher degradation degree could have led to products of lower steric hindrance and easier penetration into the A. fischeri cells, which subsequently led to an increase in toxicity for these experiments. In most cases, the products presented higher toxicity than the original compound, which raises a concern about their occurrence in environmental matrices.

Oxidative Degradation of Pharmaceuticals: The Role of Tetrapyrrole-Based Catalysts

Nowadays, society’s widespread consumption of pharmaceutical drugs and the consequent accumulation of such compounds or their metabolites in effluents requires the development of efficient strategies and systems that lead to their effective degradation. This can be done through oxidative processes, in which tetrapyrrolic macrocycles (porphyrins, phthalocyanines) deserve special attention since they are among the most promising degradation catalysts. This paper presents a review of the literature over the past ten years on the major advances made in the development of oxidation processes of pharmaceuticals in aqueous solutions using tetrapyrrole-based catalysts. The review presents a brief discussion of the mechanisms involved in these oxidative processes and is organized by the degradation of families of pharmaceutical compounds, namely antibiotics, analgesics and neurological drugs, among others. For each family, a critical analysis and discussion of the fundamental roles of tetrapyrrolic macrocycles are presented, regarding both photochemical degradative processes and direct oxidative chemical degradation.

Water-soluble manganese porphyrins as good catalysts for cipro- and levofloxacin degradation: Solvent effect, degradation products and DFT insights

Synthetic manganese porphyrins (MnPs), in the presence of oxidants, were employed for the degradation of fluoroquinolone antibiotics. Ciprofloxacin (CIP) and levofloxacin (LEV) degradation by iodosylbenzene, iodobenzene diacetate, H₂O₂ and meta-chloroperbenzoic acid using water-soluble MnP catalysts yielded thirteen and nine products, respectively, seven of which have been proposed for the first time. The MnP catalysts have demonstrated the ability to degrade these antibiotics to a high degree (up to 100% degradation). The structures of the degradation products were proposed based on mass spectrometry analysis, and density functional theory calculations could confirm how the substituent moieties attached to the basic chemical structure of the fluoroquinolones influence the degradation reactions. CIP has been shown to be a more reactive substrate towards the porphyrinic catalysts tested because of its three-membered ring. However, the catalysts could almost completely degrade LEV, highlighting the ability of these porphyrins to act as catalysts to degrade environmental pollutants.

Rhodamine B oxidation promoted by P450-bioinspired Jacobsen catalysts/cellulose systems

P450-bioinspired Jacobsen/Cell(NEt2) catalysts have been applied in RhB dye oxidation, which is used illegally in food industries of some countries.

Magnetic Nanoparticles with Dual Surface Functions-Efficient Carriers for Metalloporphyrin-Catalyzed Drug Metabolite Synthesis in Batch and Continuous-Flow Reactors

The dual functionalization of magnetic nanoparticles with inert (methyl) and reactive (aminopropyl) groups enables efficient immobilization of synthetic metalloporphyrins (such as 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)iron(II) porphyrin and 5,10,15,20-tetrakis-(4-sulfonatophenyl)iron(II) porphyrin) via covalent or ionic interactions. The proportion of reactive function on the surface has significant effect on the biomimetic activity of metalloporphyrins. The optimized magnetic nanocatalyst containing porphyrin was successfully applied for biomimetic oxidation of antihypertensive drug Amlodipine in batch and continuous-flow reactors as well.

Multifunctional magnetic MgMn-oxide composite for efficient purification of Cd2+ and paracetamol pollution: Synergetic effect and stability

A multifunctional magnetic composite (0.3Ma-MgMnLDO-a) with the function of Cd²⁺ adsorption and paracetamol (PAM) degradation was successfully fabricated. Surface morphology showed that Fe₃O₄ agglomeration was overcome on composite. The composite had high specific surface area of 105.32 m² g^-1 and saturation magnetization of 40 emu∙g^-1. 0.3Ma-MgMnLDO-a could reach Cd²⁺ adsorption equilibrium within 5 min with 99 % removal rate. The maximum adsorption capacity was 3.76 mmol·g^-1 (422.62 mg g^-1), which apparently higher than that of Fe₃O₄-a and MgMnLDO-a, indicating that the Fe/Mn synergism results in excellent ability for Cd²⁺ adsorption. Moreover, the composite could efficiently activate peroxymonosulfate (PMS) to rapid degrade PAM with the highest first-order rate constants (k_obs = 0.116 min^-1) and total organic carbon (TOC) removal rate (67.7 %), which also due to the contribution of Fe/Mn synergism in PMS activation. The cycling of Mn^III/Mn^IV and Fe^II/Fe^III played an important role in activating PMS to generateO₂^-•, ¹O₂ and OH for degradation. The composite exhibited both stable adsorption and catalytic performance on wide pH (3-9) and five reuse cycles. Notably, there was mutual promotion between Cd²⁺ and PAM adsorption, while the coexistence of Cd²⁺ had slight inhibition on PAM degradation. Overall, the magnetic composite had promising application for purifying heavy metals and pharmaceuticals.

Experimental data on synthesis and characterization of chiral dinuclear manganese (II-II) compounds as biomimetic models of the active center of catalase

Dinuclear manganese (II– III) compounds, which are potential models of the active center of catalase, were synthetized. This type of metalloenzymes presents biological importance due to three factors: they are redox catalyst centres, they are able to carry out hydrolytic reactions and they participate in activated processes via Lewis acids. Structurally, their active centre is composed by dinuclear manganese compounds, linked to nitrogen and oxygen donor atoms. An octahedral geometry around the metal ions were found, with acetate, hydroxy and aquo ligands; which can work as molecule bridges between them. The acid medium favours the electronic transfer between Mn³⁺ - Mn²⁺ as redox centre at 1.559 V and the consequent oxidation of hydrogen peroxide or organic molecules. The work also reports the data of two chiral novel compounds, [Mn₂(S,S(+)Hcpse)₄(NaClO₄)₂(NaOH)(CH₄O)]_n·[(C₂H₆O)₂]_n·[(CH₄O)₂]_n and its respective enantioisomer, in which μ-oxo being as bridge metal centre. The X-ray structural was obtained as well as the optical and magnetic properties using Circular Dichroism, Electronic Paramagnetic Resonance, Magnetic Susceptibility and X-ray photoelectron spectroscopy.