In vitro antibacterial and time kill evaluation of mononuclear phosphanegold(I) dithiocarbamates

Unraveling the antibacterial mechanism of 3-carene against Pseudomonas fragi by integrated proteomics and metabolomics analyses and its application in pork

Pseudomonas fragi is primarily responsible for the spoilage of various foods, especially meat. The aim of this study was to investigate the antibacterial mechanism of 3-carene against P. fragi. 3-Carene treatment decreased the phospholipid content and the fluidity of the cell membrane, induced reactive oxygen species (ROS) generation and affected respiratory chain dehydrogenase, oxoglutarate dehydrogenase and citrate synthase in P. fragi. Metabolomics and proteomics analyses further showed that in the presence of 3-carene, 519 proteins, 136 metabolites in positive ion mode and 100 metabolites in negative ion mode were differentially expressed. These proteins and metabolites were primarily involved in amino acid metabolism, fatty acid degradation, the tricarboxylic acid cycle (TCA cycle) and other processes. Consequently, the stimulation of 3-carene altered cell membrane properties, disturbed important amino acid and energy metabolism, and even caused oxidative stress. Additionally, the results of total viable counts and the total volatile base nitrogen indicated that 3-carene could significantly improve the preservation of refrigerated pork. This study suggested that 3-carene has promising potential to be developed as a food preservative.

Antibacterial Mechanism of 3-Carene against the Meat Spoilage Bacterium Pseudomonas lundensis and Its Application in Pork during Refrigerated Storage

Pseudomonas lundensis is the main bacterium responsible for meat spoilage and its control is of great significance. 3-Carene, a natural monoterpene, has been proved to possess antimicrobial activities. This study aimed to investigate the antibacterial activity and mechanism of 3-carene against the meat spoilage bacterium P. lundensis, and explore its application on pork. After 3-carene treatment, cellular structural changes were observed. Cell walls and membranes were destroyed, resulting in the leakage of alkaline phosphatase and cellular contents. The decreased activity of Ca²⁺-Mg²⁺-ATPase and Na⁺-K⁺-ATPase showed the imbalance of intracellular ions. Subsequently, adenosine triphosphate (ATP) content and oxidative respiratory metabolism characteristics indicated that 3-carene inhibited the metabolism of the tricarboxylic acid cycle in P. lundensis. The results of binding 3-carene with the vital proteins (MurA, OmpW, and AtpD) related to the formation of the cell wall, the composition of the cell membrane, and the synthesis of ATP further suggested that 3-carene possibly affected the normal function of those proteins. In addition, the growth of P. lundensis and increase in pH were inhibited in pork during the 5 days of cold storage after the samples were pre-treated with 3-carene. These results show the anti-P. lundensis activity and mechanism of 3-carene, and its potential use in meat preservation under refrigerated conditions.

Insights into the Antimicrobial Potential of Dithiocarbamate Anions and Metal-Based Species

Bacterial infection remains a worldwide problem that requires urgent addressing. Overuse and poor disposal of antibacterial agents abet the emergence of bacterial resistance mechanisms. There is a clear need for new approaches for the development of antibacterial therapeutics. Herein, the antibacterial potential of molecules based on dithiocarbamate anions, of general formula R(R’)NCS2(−), and metal salts of transition metals and main group elements, is summarized. Preclinical studies show a broad range of antibacterial potential, and these investigations are supported by appraisals of possible biological targets and mechanisms of action to guide chemical syntheses. This bibliographic review of the literature points to the exciting potential of dithiocarbamate-based therapeutics in the crucial battle against bacteria. Additionally, included in this overview, for the sake of completeness, is mention of the far fewer studies on the antifungal potential of dithiocarbamates and even less work conducted on antiparasitic behavior.

Crystal structure of bis[μ2-(N,N-diethylcarbamodithioato-κS:κS,κS′)]-bis(triethylphosphine-P)-di-silver(I), C22H50Ag2N2P2S4

C22H50Ag2N2P2S4, triclinic, P1̄ (no. 2), a = 9.0672(2) Å, b = 11.2091(3) Å, c = 16.6853(4) Å, α = 91.097(2)°, β = 90.363(2)°, γ = 110.989(2)°, V = 1582.85(7) Å3, Z = 2, R gt(F) = 0.0241, wR ref(F 2) = 0.0653, T = 100(2) K.

Crystal structure of N-methyl-N-phenyl(methylsulfanyl)carbothioamide, C9H11NS2

C9H11NS2, monoclinic, P21/n (no. 14), a = 5.6183(1) Å, b = 18.2426(3) Å, c = 9.5185(2) Å, β = 96.835(2)°, V = 968.64(3) Å3, Z = 4, Rgt(F) = 0.0303, wRref(F2) = 0.0826, T = 100(2) K.

Crystal structure of 4-phenylpiperazin-1-ium (4-phenylpiperazin-1-yl)carbothioylsulfanide, [C10H15N2][C11H13N2S2]

[C21H28N4S2], monoclinic, P21/c (no. 14), a = 16.1880(2) Å, b = 6.8168(1) Å, c = 19.7605(2) Å, β = 106.412(1)°, V = 2091.73(5) Å3, Z = 4, Rgt(F) = 0.0281, wRref(F2) = 0.0740, T = 100(2) K.

Multifunctional CuO nanoparticles with cytotoxic effects on KYSE30 esophageal cancer cells, antimicrobial and heavy metal sensing activities

In this work, fluorescent copper oxide nanoparticles (CuO NPs) were green synthesized using viable cells, cell lysate supernatant (CLS) and protein extracts of luminescent Vibrio sp. VLC. Biogenic CuO NPs were then characterized by XRD, FTIR, UV/Vis spectroscopy, TEM, DLS, and PL spectroscopy. Results showed that CLS method was more efficient for CuO NPs production, therefore CuO NPs synthesized by this method from copper sulfate (CuO NPs-1) and/or copper nitrate (CuO NPs-2) were used for further studies. The crystallite size of polydispersed CuO NPs-1 and CuO NPs-2 were about 8.83 and 8.77 nm, respectively indicating their suitability for biological applications. Antibacterial activity of CuO NPs was determined using broth microdilution, well diffusion agar, and time-kill curves methods. Both CuO NP-1 and CuO NP-2 inhibited bacterial growth at the minimum inhibitory concentration (MIC) of 625 mg/L except St. mutants (MIC = 1250 mg/L). Emission of fluorescent light from the surface of NPs was increased when exposed to Cd²⁺, As²⁺ and Hg²⁺ ions but decreased by Pb²⁺ ions. Results showed that CuO NP-1 had anticancer properties against KYSE30 esophageal cancer cell line (IC₅₀ = 13.96 mg/L) while no higher cytotoxic effects were observed on Human Dermal Fibroblasts (HDF) (IC₅₀ = 48.88 mg/L).

Properties of Poly-γ-Glutamic Acid Producing-Bacillus Species Isolated From Ogi Liquor and Lemon-Ogi Liquor

Poly-γ-glutamic acid (γPGA) is a natural and promising biopolymer synthesized by Bacillus spp. during fermentation. This study isolated Bacillus spp. from ogi steep liquor (OSL) and lemon-ogi steep liquor (LOSL) using standard methods and determined the γPGA-producing ability. The antimicrobial and angiotensin-converting enzyme (ACE) inhibitory activities of γPGA polymer were evaluated and isolates were sequenced. Four isolates (TA004, TA006, TA011, TA012) selected based on phenotypic characterization and stickiness (<15 cm) showed antibacterial activity against different pathogens with the highest activity found in TA004 (22.5 mm) and least in TA011 (16.6 mm). Furthermore, time-kill assay showed that the combined γPGA polymer was more effective and demonstrated bactericidal activity over individual γPGA which are bacteriostatic in nature. All γPGA polymer exhibited ACE properties except TA011. The highest IC50 was observed in TA006 (0.11 mg/ml) and least in TA004 (0.35 mg/ml). TA004 had the highest molecular weight (261 kDa) while TA011 had the least (194.97 kDa). In addition, all γPGA exhibited characteristic peaks at 3413-3268 cm-1 and 1722-1664 cm-1 that corresponded to amine N-H stretching intensities and C = O stretching in COOH. Bacillus isolates were identified as TA004 (B. subtilis-GenBank: MH782061), TA006 (B. amyloliquefaciens- GenBank: MH782075), TA011 (B. subtilis- GenBank: MH782088), TA012 (B. subtilis- GenBank: MH782083). OSL and LOSL have the potential for developing functional foods with a valuable effect on health.

In vitro anti-bacterial and time kill evaluation of binuclear tricyclohexylphosphanesilver(I) dithiocarbamates, {Cy3PAg(S2CNRR')}2

Four binuclear phosphanesilver(I) dithiocarbamates, {cyclohexyl₃PAg(S₂CNRR')}₂ for R = R' = Et (1), CH₂CH₂ (2), CH₂CH₂OH (3) and R = Me, R' = CH₂CH₂OH (4) have been synthesised and characterised by spectroscopy and crystallography, and feature tri-connective, μ₂-bridging dithiocarbamate ligands and distorted tetrahedral geometries based on PS₃ donor sets. The compounds were evaluated for anti-bacterial activity against a total of 12 clinically important pathogens. Based on minimum inhibitory concentration (MIC) and cell viability tests (human embryonic kidney cells, HEK 293), 1-4 are specifically active against Gram-positive bacteria while demonstrating low toxicity; 3 and 4 are active against methicillin resistant S. aureus (MRSA). Across the series, 4 was most effective and was more active than the standard anti-biotic chloramphenicol. Time kill assays reveal 1-4 to exhibit both time- and concentration-dependent pharmacokinetics against susceptible bacteria. Compound 4 demonstrates rapid (within 2 h) bactericidal activity at 1 and 2 × MIC to reach a maximum decrease of 5.2 log₁₀ CFU/mL against S. aureus (MRSA).

1-(2-Hydroxyethyl)imidazolidine-2-thione

1-(2-Hydroxyethyl)imidazolidine-2-thione (1) was obtained as a product from an in situ reaction between N-(2-hydroxyethyl)ethylenediamine, carbon disulfide, potassium hydroxide, and di(4-fluorobenzyl)tin dichloride. Compound 1 was characterized by IR, UV, 1H, 13C{1H}, and 2D (COSY, NOESY, HSQC, and HMBC) NMR spectroscopies. The cyclic molecular structure was confirmed by single crystal X-ray crystallography which showed the five-membered ring to be non-planar and the π-electron density to be localized over the CN2S chromophore. In the crystal, thioamide–N–H…O(hydroxy) and hydroxy–O–H…S(thione) hydrogen bonds lead to supramolecular layers in the bc-plane.

Crystal structure of bis(μ2-di-n-butyldithiocarbamato-κ3 S,S′:S;κ3 S:S:S′)-hexacarbonyl-di-rhenium(I), C24H36N2O6Re2

C24H36N2O6Re2, triclinic, P1̅ (no. 2), a = 10.3013(2) Å, b = 11.3471(2) Å, c = 14.5967(3) Å, α = 72.540(2)°, β = 73.074(2)°, γ = 85.369(2)°, V = 1557.05(6) Å3, Z = 2, R gt(F) = 0.0214, wR ref(F 2) = 0.0466, T = 100(2) K.

μ3-Chlorido-μ2-chlorido-(μ3-pyrrolidine-1-carbo-dithio-ato-κ4S:S,S':S')tris-[(tri-ethyl-phosphane-κP)copper(I)]: crystal structure and Hirshfeld surface analysis

The title trinuclear compound, [Cu3(C5H8NS2)Cl2(C6H15P)3], has the di-thio-carbamate ligand symmetrically chelating one CuI atom and each of the S atoms bridging to another CuI atom. Both chloride ligands are bridging, one being μ3- and the other μ2-bridging. Each Et3P ligand occupies a terminal position. Two of the CuI atoms exist within Cl2PS donor sets and the third is based on a ClPS2 donor set, with each coordination geometry based on a distorted tetra-hedron. The constituents defining the core of the mol-ecule, i.e. Cu3Cl2S2, occupy seven corners of a distorted cube. In the crystal, linear supra-molecular chains along the c axis are formed via phosphane-methyl-ene-C-H⋯Cl and pyrrolidine-methyl-ene-C-H⋯π(chelate) inter-actions, and these chains pack without directional inter-actions between them. An analysis of the Hirshfeld surface points to the predominance of H atoms at the surface, i.e. contributing 86.6% to the surface, and also highlights the presence of C-H⋯π(chelate) inter-actions.

A triclinic polymorph of tri-cyclo-hexyl-phosphane sulfide: crystal structure and Hirshfeld surface analysis

The title compound, (C6H11)3PS (systematic name: tri-cyclo-hexyl-λ5-phosphane-thione), is a triclinic (P-1, Z' = 1) polymorph of the previously reported ortho-rhom-bic form (Pnma, Z' = 1/2) [Kerr et al. (1977 ▸). Can. J. Chem. 55, 3081-3085; Reibenspies et al. (1996 ▸). Z. Kristallogr. 211, 400]. While conformational differences exist between the non-symmetric mol-ecule in the triclinic polymorph, cf. the mirror-symmetric mol-ecule in the ortho-rhom-bic form, these differences are not chemically significant. The major feature of the mol-ecular packing in the triclinic polymorph is the formation of linear chains along the a axis sustained by methine-C-H⋯S(thione) inter-actions. The chains pack with no directional inter-actions between them. The analysis of the Hirshfeld surface for both polymorphs indicates a high degree of similarity, being dominated by H⋯H (ca 90%) and S⋯H/H⋯S contacts.

[N,N-Bis(2-hy-droxy-eth-yl)di-thio-carbamato-κ2S,S']bis-(tri-phenyl-phosphane-κP)copper(I) chloro-form monosolvate: crystal structure, Hirshfeld surface analysis and solution NMR measurements

The title compound, [Cu(C5H5NO2S2)(C18H15P)2]·CHCl3, features a tetra-hedrally coordinated CuI atom within a P2S2 donor set defined by two phosphane P atoms and by two S atoms derived from a symmetrically coordinating di-thio-carbamate ligand. Both intra- and inter-molecular hy-droxy-O-H⋯O(hydroxy) hydrogen bonding is observed: the former closes an eight-membered {⋯HOC2NC2O} ring, whereas the latter connects centrosymmetrically related mol-ecules into dimeric aggregates via eight-membered {⋯H-O⋯H-O}2 synthons. The complex mol-ecules are arranged to form channels along the c axis in which reside the chloro-form mol-ecules, being connected by Cl⋯π(arene) and short S⋯Cl [3.3488 (9) Å] inter-actions. The inter-molecular inter-actions have been investigated further by Hirshfeld surface analysis, which shows the conventional hydrogen bonding to be very localized with the main contributors to the surface, at nearly 60%, being H⋯H contacts. Solution NMR studies indicate that whilst the same basic mol-ecular structure is retained in solution, the tri-phenyl-phosphane ligands are highly labile, exchanging rapidly with free Ph3P at room temperature.