In vitro leishmanicidal activity and theoretical insights into biological action of ruthenium(II) organometallic complexes containing anti-inflammatories.

Leishmaniasis, a neglected tropical disease caused by protozoans of the genus Leishmania, kills around 20-30 thousand people in Africa, Asia, and Latin America annually and, despite its potential lethality, it can be treated and eventually cured. However, the current treatments are limited owing to severe side effects and resistance development by some Leishmania. These factors make it urgent to develop new leishmanicidal drugs. In the present study, three ruthenium(II) organometallic complexes containing as ligands the commercially available anti-inflammatories diclofenac (dic), ibuprofen (ibu), and naproxen (nap) were synthesized, characterized, and subjected to in vitro leishmanicidal activity. The in vitro cytotoxicity assays against Leishmania (L.) amazonensis and Leishmania (L.) infantum promastigotes have shown that complexes [RuCl(dic)(η6-p-cymene)] (1) and [RuCl(nap)(η6-p-cymene)] (3) were active against both Leishmania species. Complex [RuCl(ibu)(η6-p-cymene)] (2) has exhibited no activity. The IC50 values for the two active complexes were respectively 7.42 and 23.55 µM, for L. (L.) amazonensis, and 8.57 and 42.25 µM, for L. (L.) infantum. Based on the toxicological results and computational analysis, we proposed a correlation between the complexes and their activity. Our results suggest both complexation to ruthenium(II) and ligands structure are key elements to leishmanicidal activity.

Alkaline pre-treatment (NAOH) as a strategy to increase the performance and feasibility of the anaerobic digestion of cattle slurry.

Dairy cattle manure with bedding (CB), including manure, urine, water, and shavings, is lignocellulosic biomass and needs to be pre-treated in anaerobic reactors to enhance biomass digestibility. This study analyzed the technical and economic feasibility of physical treatment (milling) and alkaline treatment of CB for biogas production. Pre-treatment included drying, milling, and alkaline hydrolysis at room temperature for 24 h. Maximum biogas production was determined using the biochemical methane potential (BMP) test. Physicochemical analyses were performed to characterise CB before and after pre-treatment and the BMP test. The characteristics of the lignocellulosic material were examined by scanning electron microscopy. The economic feasibility (return on investment) of each treatment (USD per ton of CB) was determined. Treatment with 3% NaOH achieved the highest biogas production (771 mL per kg of volatile solids) and was 104.5% higher than that of milling and 124.7% higher than that of chemical pre-treatment with 4% NaOH. The analysis of economic feasibility showed that the payback period of treatment with 3% NaOH was 1.4 years for scenario 1 (continuous stirred tank reactor - CSTR) and 3 years for scenario 2 (covered lagoon digester). These results demonstrate the feasibility of producing biogas as a renewable energy source via the anaerobic digestion of CB.

New ruthenium(II) complexes with cyclic thio- and semicarbazone: evaluation of cytotoxicity and effects on cell migration and apoptosis of lung cancer cells.

We describe the synthesis, physicochemical characterization, and in vitro antitumor assays of four novel analogous ruthenium(II) complexes with general formula cis-[RuII(N-L)(P-P)2]PF6, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with cis arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through N,S and N,O, respectively. Single-crystal X-ray diffraction showed that complex 1 crystallized in the monoclinic system, space group P21/c. Determination of the cytotoxicity profiles of complexes 1-4 gave SI values ranging from 1.19 to 3.50 against the human lung adenocarcinoma cell line A549 and the non-tumor lung cell line MRC-5. Although the molecular docking studies suggested that the interaction between DNA and complex 4 was energetically favorable, the experimental results showed that they interacted weakly. Overall, our results demonstrated that these novel ruthenium(II) complexes have interesting in vitro antitumor potential and this study may contribute to further studies in medicinal inorganic chemistry.

Anti-Leishmania activity of new ruthenium(II) complexes: Effect on parasite-host interaction.

Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis­[RuII(η2-O2CR)(dppm)2]PF6, with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction. The cytotoxicity of complexes was analyzed by MTT assay against Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, Leishmania (Leishmania) infantum promastigotes and the murine macrophage (RAW 264.7). The effect of complexes on parasite-host interaction was evaluated by in vitro infectivity assay performed in the presence of two different concentrations of each complex: the promastigote IC50 value and the concentration nontoxic to 90% of RAW 264.7 macrophages. Complexes 1-3 exhibited potent cytotoxic activity against all Leishmania species assayed. The IC50 values ranged from 7.52-12.59µM (complex 1); 0.70-3.28µM (complex 2) and 0.52-1.75µM (complex 3). All complexes significantly inhibited the infectivity index at both tested concentrations. The infectivity inhibitions ranged from 37 to 85%. Interestingly, the infectivity inhibitions due to complex action did not differ significantly at either of the tested concentrations, except for the complex 1 against Leishmania (Leishmania) infantum. The infectivity inhibitions resulted from reductions in both percentage of infected macrophages and number of parasites per macrophage. Taken together the results suggest remarkable leishmanicidal activity in vitro by these new ruthenium(II) complexes.

Comparison of five agro-industrial waste-based composts as growing media for lettuce: Effect on yield, phenolic compounds and vitamin C.

Overall phenolic content in plants is on average higher in organic farming, including when renewable resources such as composts are used as soil amendments. In most cases, however, the composting process needs to be optimized to reach the desired outcome. Using composts obtained from chestnut, red and white grapes, olive and broccoli wastes, the relative antioxidative abilities of lettuces cultivated in greenhouse were examined. Results clearly coupled high phenolic levels with high yield in lettuce grown on the chestnut-based compost. A huge accumulation of phenolics was observed with the white grape-based compost, but this coincided with low yield. Three compounds were identified as discriminating factors between treated samples, namely quercetin 3-O-glucoside, luteolin 7-O-glucoside, and cyanidin 3-O-(6″-malonyl)-ß-d-glucoside; these are also some of the compounds receiving health claims on lettuce consumption. On a negative note, all composts led to decreased vitamin C levels. Collectively, the data suggest that compost amendments can help add value to lettuce by increasing its antioxidant activity as compared to other organic resources.