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A novel 1,2,4-triazole intermediate 5-pyridin-2-yl-1H-[1,2,4]triazole-3-carboxylic acid ethyl ester was prepared by the reaction of N'-aminopiridyne-2-carboximidamine and an excess monoethyl oxalyl chloride and screened for biological activities. The compound was structurally characterized by nuclear magnetic resonance spectroscopy, elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction. Bioassays indicated that the compound exhibits potent anti-inflammation activity in vitro. An egg albumin denaturation assay to assess the anti-inflammatory effect of the synthesized compound showed a significant inhibition of protein with a maximum inhibition of 71.1% at the highest tested concentration (1000 µg/mL) compared to 81.3% for Aspirin as standard drug. The antimalarial activity on the 3D7 P. falciparum strain was determined to be IC50 176 µM and was obtained prior to connection with pharmacophoric groups. [ABSTRACT FROM AUTHOR]

The development of drug-resistant strains is rising and the search for new and novel ways of fighting new or reemerging microbes goes on. A hope of treating such multidrug-resistant infections came from plants mediated nanoparticles since nature is a generous source which provides a variety of chemical compounds that can be used for new drug discovery. Silver nanoparticles are reported to possess antiviral, antibacterial, antifungal, antiparasitic, larvicidal activity and anticancer properties. We reported green synthesis of silver nanoparticles mediated food plants Megaphrynium macrostachyum, Corchorus olitorus, Ricinodendron heudelotii, Gnetum bucholzianum, and Ipomoea batatas and their antibacterial efficacy against the Enterobacteriaceae Escherichia coli. The nature and size of the obtained nanoparticles are discussed as well as their Minimum Inhibitory Concentration (MIC) and the Minimum Bactericide Concentration (MBC) values considering their application in medical industry. [ABSTRACT FROM AUTHOR]

• A systematic review on the toxicity of green nanoparticles on non-target organisms was carried out • In general, green NPs were safe to non-target organisms • The predatory efficiency of these organisms is boosted in NP-treated milieu • In some studies, green NPs were found induce side effects on non-target organisms • There are still some obstacles to commercial development of NPs as bioinsecticides Studies capturing the high efficiency of green-synthesized metal nanoparticles (NPs) in targeting mosquito vectors of the world's main infectious diseases suggest the NPs' possible utilization as bio-insecticides. However, it is necessary to confirm that these potential bio-insecticides are not harmful to non-target organisms that are often sympatric and natural enemies of the vectors of these diseases. In this systematic review, we comprehensively analyse the content of 56 publications focused on the potentially deleterious effects of NPs on these non-target organisms. Current research on biosynthesised NPs, characterization, and impact on mosquito vectors and non-target larvivorous organisms is reviewed and critically discussed. Finally, we pinpoint some major challenges that merit future investigation. Plants (87.5%) were mainly used for synthesizing NPs in the studies. NPs were found to be spherical or mainly spherical in shape with a large distribution size. In most of the included studies, NPs showed interesting mosquitocidal activity (LC 50 < 50 ppm). Some plant families (e.g., Meliaceae, Poaceae, Lamiaceae) have produced NPs with a particularly high larvicidal and pupicidal activity (LC 50 < 10 ppm). Regarding non-target organisms, most of the studies concluded that NPs were safe to them, with boosted predatory activity in NP-treated milieu. In contrast, some studies reported NP-elicited adverse effects (i.e., genotoxic, nuclear, and enzymatic effects) on these non-target organisms. This review outlines the promising mosquitocidal effects of biosynthesized NPs, recognizing that NPs' potential usage is currently limited by the harm NPs are thought pose to non-target organism. It is of utmost importance to investigate green NPs to determine whether laboratory findings have applications in the real world. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Fe3+, Co2+, and Zn2+ complexes with the ligand N′-{[1-(pyridin-2-yl)ethylidene]amino}pyridine-2-carboximidamide (pmhpa) have been synthesised and characterized. • [Fe(pmhap) 2 [FeCl 4 , [Co 2 (pmhap) 2 Cl 3 2 [CoCl 4.4MeOH. and [Zn 2 (pmhpa) 3 (NO 3) 4.2.75MeOH (3) contain the ligand coordinated through the azide bridge. • The Fe3+and Co2+ complexes are paramagnetic between 5 and 300 K. Mössbauer spectroscopic data confirm the presence of octahedral and tetrahedral iron environments. Coordination complexes of iron(III), cobalt(II) and zinc(II) with the ligand N′-{[1-(pyridin-2-yl)ethylidene]amino}pyridine-2-carboximidamide (pmhpa) have been synthesised and were structurally characterized by elemental analysis, mass spectrometry, X-ray diffraction and infrared spectroscopy. The mononuclear iron(III) complex, [Fe(pmhap) 2 [FeCl 4 , (1), adopts the orthorhombic non-centric space group P2 1 2 1 2 1. The iron is present in an octahedral environment in the ion [Fe(pmhap) 2 +. The crystallographically-determined formula of the cobalt(II) complex (2) is [Co 2 (pmhap) 2 Cl 3 2 [CoCl 4.4MeOH. The compound crystallizes in the non-centric space group P 4 ̄ 2 1 c with a single cobalt ion in the asymmetric unit. The complex is dinuclear, with two cobalt ions bridged by chloride and the two nitrogen atoms of N=N of the pmhap ligand. The zinc(II) complex; [Zn 2 (pmhpa) 3 (NO 3) 4.2.75MeOH (3) crystallizes in the cubic space group Pa 3 ̄ with disordered methanol molecules present. This is dinuclear with the two zinc atoms being bridged by three N=N links from the ligand to form a threefold symmetric rotor. Infrared spectroscopy confirms that coordination occurs through the azide bridge. Measurements of magnetic susceptibility for the iron(III) and cobalt(II) complexes show that they are paramagnetic between 5 and 300 K. Mössbauer spectroscopic data supports the structure of the iron(III) complex being composed of an octahedral and a tetrahedral iron atom. [ABSTRACT FROM AUTHOR]

Background: The recent emergence in Southeast Asia of artemisinin resistance poses major threats to malaria control and elimination globally. Green nanotechnologies can constitute interesting tools for discovering anti-malarial medicines. This systematic review focused on the green synthesis of metal nanoparticles as potential source of new antiplasmodial drugs. Methods: Seven electronic database were used following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 17 papers were included in the systematic review. 82.4% of the studies used plant leaves to produce nanoparticles (NPs) while three studies used microorganisms, including bacteria and fungi. Silver was the main metal precursor for the synthesis of NPs. The majority of studies obtained nanoparticles spherical in shape, with sizes ranging between 4 and 65 nm, and reported no or little cytotoxic effect of the NPs. Results based on 50% inhibitory concentration (IC50) varied between studies but, in general, could be divided into three NP categories; (i) those more effective than positive controls, (ii) those more effective than corresponding plant extracts and, (iii) those less effective than the positive controls or plant extracts. Conclusions: This study highlights the high antiplasmodial potential of green-synthesized metal nanoparticles thereby underscoring the possibility to find and develop new anti-malarial drugs based on green synthesis approaches. However, the review also highlights the need for extensive in vitro and in vivo studies to confirm their safety in humans and the elucidation of the mechanism of action. [ABSTRACT FROM AUTHOR]

Many infectious diseases including malaria, lymphatic filariasis, chikungunya and dengue are transmitted by mosquitoes. Understanding the entomological diversity in a given area is critical for defining health risks, but also to design and evaluate control measures. Our study aimed to establish an entomological database of the Culicidae fauna in two clusters (Nyalla and Kambo) in the city of Douala in Cameroon. A longitudinal study was conducted from August to December in the Nyalla and Kambo neighbourhoods in the city of Douala. Culicidae larvae were weekly collected and reared until adult emergence. Adults were then morphologically identified using reference identification keys. A total of 20 breeding sites were productive out of an approximately 90 sites prospected. Water collections, pits, swamps and cinder blocks were main categories of larval habitats. In total, 2125 mosquito larvae were collected and reared during the survey. A total of 1790 mosquito adults emerged and were further identified and distributed among three genera: Culex (73.3%); Anopheles (22.6%) and Aedes (4.1%). Eleven Culicidae species were identified: Culex duttoni, Cx. descens, Cx. poicilipes, Cx. univittatus, Cx tigripes, Cx. antennatus, Cx. simpsoni, Cx. pipiens, Anopheles gambiae sl, Aedes aegypti and Ae. albopictus. Culex duttoni (39%) and An. gambiae s.l. (22.6%) were the main species recorded. The equitability, species richness and abundance of these genera was influenced by the nature of breeding sites and physical parameters including rainfall and temperature. The present study provides insights on the entomological diversity of the Culicidae fauna in the study area. Such information will help to orientate the fight against mosquito vectors in conjunction with the species and the types of breeding sites. [ABSTRACT FROM AUTHOR]

This work reports the first example of the spectroscopic measurements of the Magneto-Optical Kerr Effect (MOKE) of films being composed of trinuclear transition metal complexes on a non-transparent substrate at room temperature. The thin films of the tailor-made trinuclear bis(oxamidato) type complex 5 ([Cu 3 (opbo n Pr 2 )(tmcd) 2 (NO 3 ) 2 ], opbo n Pr 2 = o - p henylene b is( N ’- n propyl o xamido, tmcd= trans -(1 R ,2 R )- N , N , N ′, N ′-tetramethyl-cyclohexane d iamine) and of the bis(oxamato) type complexes 11 ([Cu 2 Ni(opbaCF 3 )(pmdta) 2 (NO 3 ) 2 ], opbaCF 3 = 4-trifluoromethyl- o - p henylene b is(ox a mato), pmdta = N , N , N ,′ N ″, N ″- p enta m ethyl d iethylene t ri a mine) and 12 ([Cu 3 (opba)(bppe) 2 (NO 3 ) 2 ] (opba = o - p henylene b is(ox a mato), bppe = S-N , N - b is(2- p icolyl)−1- p henyl e thylamine) were fabricated by spin-coating and their thicknesses in the range between 0.5 µm and 2 µm was determined by spectroscopic ellipsometry. Based on the spectroscopic ellipsometry results it was also possible to determine the optical constants of the film and compare them with the absorption of the complexes in solution in order to confirm the complex integrity after the film deposition. The fabrication of high-quality films which exhibit Kerr rotation up to 0.2 mrad (11.5 mdeg) was only possible due to tailor-made synthesis, which allows circumventing intermolecular interactions of the trinuclear complexes during the film formation. [ABSTRACT FROM AUTHOR]

The diethyl ester of o-phenylenebis(oxamic acid) (opbaH2Et2) was treated with an excess of RNH2 in MeOH to cause the exclusive formation of the respective o-phenylenebis(N(R)-oxamides) (opboH4R2, R = Me 1, Et 2, nPr 3) in good yields. Treatment of 1–3 with half an equivalent of [Cu2(AcO)4(H2O)2] or one equivalent of [Ni(AcO)2(H2O)4] followed by the addition of four equivalents of [nBu4N]OH resulted in the formation of mononuclear bis(oxamidato) type complexes [nBu4N]2[M(opboR2)] (M = Ni, R = Me 4, Et 5, nPr 6; M = Cu, R = Me 7, Et 8, nPr 9). By addition of two equivalents of [Cu(pmdta)(NO3)2] to MeCN solutions of 7–9, novel trinuclear complexes [Cu3(opboR2)(L)2](NO3)2 (L = pmdta, R = Me 10, Et 11, nPr 12) could be obtained. Compounds 4–12 have been characterized by elemental analysis and NMR/IR spectroscopy. Furthermore, the solid state structures of 4–10 and 12 have been determined by single-crystal X-ray diffraction studies. By controlled cocrystallization, diamagnetically diluted 8 and 9 (1%) in the host lattice of 5 and 6 (99%) (8@5 and 9@6), respectively, in the form of single crystals have been made available, allowing single crystal ESR studies to extract all components of the g-factor and the tensors of onsite CuA and transferred NA hyperfine (HF) interaction. From these studies, the spin density distribution of the [Cu(opboEt2)]2− and [Cu(opbonPr2)]2− complex fragments of 8 and 9, respectively, could be determined. Additionally, as a single crystal ENDOR measurement of 8@5 revealed the individual HF tensors of the N donor atoms to be unequal, individual estimates of the spin densities on each N donor atom were made. The magnetic properties of 10–12 were studied by susceptibility measurements versus temperature to give J values varying from −96 cm−1 (10) over −104 cm−1 (11) to −132 cm−1 (12). These three trinuclear CuII-containing bis(oxamidato) type complexes exhibit J values which are comparable to and slightly larger in magnitude than those of related bis(oxamato) type complexes. In a summarizing discussion involving experimentally obtained ESR results (spin density distribution) of 8 and 9, the geometries of the terminal [Cu(pmdta)]2+ fragments of 12 determined by crystallographic studies, together with accompanying quantum chemical calculations, an approach is derived to explain these phenomena and to conclude if the spin density distribution of mononuclear bis(oxamato)/bis(oxamidato) type complexes could be a measure of the J couplings of corresponding trinuclear complexes. [ABSTRACT FROM AUTHOR]