The key role of coligands in novel ruthenium(II)-cyclopentadienyl bipyridine derivatives: Ranging from non-cytotoxic to highly cytotoxic compounds

A new family of eight ruthenium(II)-cyclopentadienyl bipyridine derivatives, bearing nitrogen, sulfur, phosphorous and carbonyl sigma bonded coligands, has been synthesized. Compounds bearing nitrogen bonded coligands were found to be unstable in aqueous solution, while the others presented appropriate stabilities for the biologic assays and pursued for determination of IC50 values in ovarian (A2780) and breast (MCF7 and MDAMB231) human cancer cell lines. These studies were also carried out for the [5: HSA] and [6: HSA] adducts (HSA = human serum albumin) and a better performance was found for the first case. Spectroscopic, electrochemical studies by cyclic voltammetry and density functional theory calculations allowed us to get some understanding on the electronic flow directions within the molecules and to find a possible clue concerning the structural features of coligands that can activate bipyridyl ligands toward an increased cytotoxic effect. X-ray structure analysis of compound [Ru(eta(5)-C5H5)(bipy)(PPh3)][PF6] (7; bipy = bipyridine) showed crystallization on C2/c space group with two enantiomers of the [Ru(eta(5)-C5H5)(bipy)(PPh3)](+) cation complex in the racemic crystal packing. (C) 2015 Elsevier Inc All rights reserved.

The key role of coligands in novel ruthenium(II)-cyclopentadienyl bipyridine derivatives: ranging from non-cytotoxic to highly cytotoxic compounds

A new family of eight ruthenium(II)-cyclopentadienyl bipyridine derivatives, bearing nitrogen, sulfur, phosphorous and carbonyl sigma bonded coligands, has been synthesized. Compounds bearing nitrogen bonded coligands were found to be unstable in aqueous solution, while the others presented appropriate stabilities for the biologic assays and pursued for determination of IC50 values in ovarian (A2780) and breast (MCF7 and MDAMB231) human cancer cell lines. These studies were also carried out for the [5: HSA] and [6: HSA] adducts (HSA=human serum albumin) and a better performance was found for the first case. Spectroscopic, electrochemical studies by cyclic voltammetry and density functional theory calculations allowed us to get some understanding on the electronic flow directions within the molecules and to find a possible clue concerning the structural features of coligands that can activate bipyridyl ligands toward an increased cytotoxic effect. X-ray structure analysis of compound [Ru(η(5)-C5H5)(bipy)(PPh3)][PF6] (7; bipy=bipyridine) showed crystallization on C2/c space group with two enantiomers of the [Ru(η(5)-C5H5)(bipy)(PPh3)](+) cation complex in the racemic crystal packing.

Cytotoxicity in L929 fibroblasts and inhibition of herpes simplex virus type 1 Kupka by estuarine cyanobacteria extracts

The cyanobacteria are known to be a rich source of metabolites with a variety of biological activities in different biological systems. In the present work, the bioactivity of aqueous and organic (methanolic and hexane) crude extracts of cyanobacteria isolated from estuarine ecosystems was studied using different bioassays. The assessment of DNA damage on the SOS gene repair region of mutant PQ37 strain of Escherichia coli was performed. Antiviral activity was evaluated against influenza virus, HRV-2, CVB3 and HSV-1 viruses using crystal violet dye uptake on HeLa, MDCK and GMK cell lines. Cytotoxicity evaluation was performed with L929 fibroblasts by MTT assay. Of a total of 18 cyanobacterial isolates studied, only the crude methanolic extract of LEGE 06078 proved to be genotoxic (IF > 1.5) in a dose-dependent manner and other four were putative candidates to induce DNA damage. Furthermore, the crude aqueous extract of LEGE 07085 showed anti- herpes type 1 activity (IC50 = 174.10 μg dry extract mL−1) while not presenting any cytotoxic activity against GMK cell lines. Of the 54 cyanobacterial extracts tested, only the crude methanolic and hexane ones showed impair on metabolic activity of L929 fibroblasts after long exposure (48–72 h). The inhibition of HSV-1 and the strong cytotoxicity against L929 cells observed emphasizes the importance of evaluating the impact of those estuarine cyanobacteria on aquatic ecosystem and on human health. The data also point out their potential application in HSV-1 treatment and pharmacological interest.

A low-cost method to test cytotoxic effects of Crotalus vegrandis (Serpentes: Viperidae) venom on kidney cell cultures

The pathogenesis of the renal lesion upon envenomation by snakebite has been related to myolysis, hemolysis, hypotension and/or direct venom nephrotoxicity caused by the venom. Both primary and continuous cell culture systems provide an in vitro alternative for quantitative evaluation of the toxicity of snake venoms. Crude Crotalus vegrandis venom was fractionated by molecular exclusion chromatography. The toxicity of C. vegrandis crude venom, hemorrhagic, and neurotoxic fractions were evaluated on mouse primary renal cells and a continuous cell line of Vero cells maintained in vitro. Cells were isolated from murine renal cortex and were grown in 96 well plates with Dulbecco's Modified Essential Medium (DMEM) and challenged with crude and venom fractions. The murine renal cortex cells exhibited epithelial morphology and the majority showed smooth muscle actin determined by immune-staining. The cytotoxicity was evaluated by the tetrazolium colorimetric method. Cell viability was less for crude venom, followed by the hemorrhagic and neurotoxic fractions with a CT50 of 4.93, 18.41 and 50.22 µg/mL, respectively. The Vero cell cultures seemed to be more sensitive with a CT50 of 2.9 and 1.4 µg/mL for crude venom and the hemorrhagic peak, respectively. The results of this study show the potential of using cell culture system to evaluate venom toxicity.

Borderline CD30+ Cutaneous Lymphoproliferative Disorder: Report of a Case with Expression of Cytotoxic Markers and Response to Clarithromycin

CD30+ cutaneous lymphoproliferative disorders (CLPDs) are usually characterized by a benign clinical course. The prognostic value of cytotoxic markers in these lymphomas has not been evaluated in large series. We describe a case of borderline CD30+ CLPD with cytotoxic phenotype, presenting in a 22-year-old male patient as an ulcer on the forearm. He reported having had similar ulcers on the buttock and thigh that spontaneously regressed over the course of 1 year. The lesion resolved with a single course of clarithromycin; a subsequent lesion, too, responded to clarithromycin, and no recurrences or systemic involvement have been documented in the 9-month follow-up. A conservative approach in the management of CD30+ CLPD is recommended. We believe that the anti-inflammatory and apoptotic effects of clarithromycin on T cells may have hastened the remission process.

Determination of permethrin and its metabolites in hearts and urines of rats by GC-ECD and GC-MS

Pyrethroids are pesticides very used in agriculture, which tend to replace organophosfate and carbamate insecticides. These pesticides have shown to exhibit cardiotoxicity. The aim of this study was to assess if cardiotoxicity is due to direct or indirect effects (metabolites) of permethrin on hearts. There were studies 8 rats; three of them were sacrificed after 24 of the end of treatment with permethrin and the other four were sacrificed after 14 days of the end of treatment. Afterwards hearts and urines were collected. The amounts of permethrin and its main metabolite (3-PBA) were evaluated on hearts and urines of female rats which were treated with permethrin and sacrificed the day after and 14 days after the treatment. Moreover has been highlighted the difference of amount of permethrin and its metabolite between rats sacrificed immediately at the end of treatment and those sacrificed after 14 days. The study of permethrin was accomplished by liquid-liquid extraction and GC-ECD. The evaluation of 3-PBA was performed by SPE procedure with 2-PBA as internal standard and gas-chromatography GC-MS. The concentration of permethrin in hearts is basically the same in 24h and 14 days. The 3-PBA concentration in urines decreased 50 times from 24h to 14 days. In hearts the 3-PBA level also decrease but only 2.24 times and a high variation of results were achieved in rats after 14 days.

EVALUATION OF ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OF PLANT EXTRACTS FROM SOUTHERN MINAS GERAIS CERRADO

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis(BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development.

DIARRHEA OUTBREAK IN PERNAMBUCO, BRAZIL, ASSOCIATED WITH A HEAT-STABLE CYTOTOXIC ENTEROTOXIN PRODUCED BY Aeromonas caviae

SUMMARY In the present study enterotoxic and cytotoxic activities of twenty Aeromonas caviaestrains were examined. They originated from fecal specimens of patients with acute diarrhea during an outbreak in Brazil in 2004. Culture supernatants of fourteen strains (70%) caused fluid accumulation in rabbit ileal intestinal loops and in suckling mice assays, and also showed a cytotoxic activity in Vero and Caco-2 cells. The enterotoxic and cytotoxic factors were heat-stable after culture supernatants treatment at 100 ºC. The results revealed that A. caviaestrains produce a putative diarrheagenic virulence factor, a heat-stable cytotoxic enterotoxin that could be linked to the diarrhea outbreak that took place in Brazil.

CHEMICAL CHARACTERIZATION AND EVALUATION OF ANTIBACTERIAL, ANTIFUNGAL, ANTIMYCOBACTERIAL, AND CYTOTOXIC ACTIVITIES OF Talinum paniculatum

SUMMARY In this study, the bioactivity of Talinum paniculatum was evaluated, a plant widely used in folk medicine. The extract from the T. paniculatum leaves (LE) was obtained by percolation with ethanol-water and then subjecting it to liquid-liquid partitions, yielding hexane (HX), ethyl acetate (EtOAc), butanol (BuOH), and aqueous (Aq) fractions. Screening for antimicrobial activity of the LE and its fractions was evaluated in vitro through broth microdilution method, against thirteen pathogenic and non-pathogenic microorganisms, and the antimycobacterial activity was performed through agar diffusion assay. The cytotoxic concentrations (CC90) for LE, HX, and EtOAc were obtained on BHK-21 cells by using MTT reduction assay. The LE showed activity against Serratia marcescens and Staphylococcus aureus, with Minimum Inhibitory Concentration (MIC) values of 250 and 500 µg/mL, respectively. Furthermore, HX demonstrated outstanding activity against Micrococcus luteus and Candida albicans with a MIC of 31.2 µg/mL in both cases. The MIC for EtOAc also was 31.2 µg/mL against Escherichia coli. Conversely, BuOH and Aq were inactive against all tested microorganisms and LE proved inactive against Mycobacterium tuberculosisand Mycobacterium bovisas well. Campesterol, stigmasterol, and sitosterol were the proposed structures as main compounds present in the EF and HX/EtOAc fractions, evidenced by mass spectrometry. Therefore, LE, HX, and EtOAc from T. paniculatumshowed potential as possible sources of antimicrobial compounds, mainly HX, for presenting low toxicity on BHK-21 cells with excellent Selectivity Index (SI = CC90/MIC) of 17.72 against C. albicans.

Inhibition of SNF1-related protein kinase1 by trehalose 6-phosphate and other metabolites and the interrelation with plant gorwth

All life forms need to monitor carbon and energy availability to survive and this is especially true for plants which must integrate unavoidable environmental conditions with metabolism for cellular homeostasis maintenance. Sugars, in the heart of metabolism, are now recognized as crucial signaling molecules that translate those conditions. One such signal is trehalose 6- phosphate (T6P), a phosphorylated dimer of glucose molecules which levels correlate well with those of sucrose (Suc). Central integrators of stress and energy regulation include the conserved plant Snf1-related kinase1 (SnRK1) which respond to low cellular energy levels by up-regulating energy conserving and catabolic metabolism and down-regulating energy consuming processes. In 2009 T6P was shown to inhibit SnRK1. The in vitro inhibition of SnRK1 by T6P was confirmed in vivo through the observation that genes normally induced by SnRK1 were repressed by T6P and vice-versa, promoting growth processes. These observations provided a model for the regulation of growth by sugar.(...)

Monoterpene isolated from the essential oil of Trachyspermum ammi is cytotoxic to multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus strains

Abstract INTRODUCTION: The aim of this study was to determine whether an herbal extract containing monoterpene exhibited activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinical infection samples. METHODS: The essential oil of Trachyspermum ammi (L.) Sprague ex Turrill (Apiaceae) fruit was extracted by hydrodistillation. Fruit residues were treated with hydrochloric acid and re-hydrodistilled to obtain volatile compounds. Compounds in the distilled oil were identified using gas-chromatography (GC) and GC-mass spectrometry (MS). The antibiotic susceptibility of all bacterial isolates was analyzed using both the disc diffusion method and determination of the minimum inhibitory concentration (MIC). The sensitivity of antibiotic-resistant isolates to essential oil was also determined by using the disc diffusion method and MIC determination. RESULTS: Of 26 clinical isolates, 92% were multidrug-resistant (MDR). Aromatic monoterpenes (thymol, paracymene, and gamma-terpinene) were the major (90%) components of the oil. Growth of S. aureus strains was successfully inhibited by the oil, with an inhibitory zone diameter (IZD) between 30-60mm and MIC <0.02μL/mL. The oil had no antimicrobial activity against clinical isolates of P. aeruginosa; rather, it prevented pigment production in these isolates. CONCLUSIONS: This study revealed that the essential oil of Trachyspermum ammi, which contains monoterpene, has good antibacterial potency. Monoterpenes could thus be incorporated into antimicrobial ointment formulas in order to treat highly drug-resistant S. aureus infections. Our findings also underscore the utility of research on natural products in order to combat bacterial multidrug resistance.

Antioxidant, cytotoxic and UVB-absorbing activity of Maytenus guyanensis Klotzch. (Celastraceae) bark extracts

Maytenus guyanensis Klotzch. is an Amazonian medicinal tree species known in Brazil by the common name chichuá and in Peru and Colombia by the name chuchuhuasi. It is used in traditional medicine as stimulant, tonic, and muscle relaxant, for the relief of arthritis, rheumatism, hemorrhoids, swollen kidney, skin eruptions, and skin cancer prevention, among others. Initially, different extraction solvents and methods were applied to dried, ground bark which made possible the preparation of extracts having both significant lethality to brine shrimp larvae (Artemia franciscana Leach) as well as antioxidant activity in vitro based on tests involving reactions with 2,2,-diphenyl-1-picrylhydrazyl (DPPH). Analysis of fractions from serial extractions with solvents of increasing polarity supports the notion that antioxidant activity is associated with compounds of intermediate polarity and cytotoxicity is associated with compounds of low to intermediate polarity. Variation of extraction time and conditions revealed that hot, continuous ethanol extraction provided good yields of bark extract in several hours. Hot extraction also provided ethanol extracts having greater lethality to brine shrimp and antioxidant activity (compared to the flavonoid rutin in semi-quantitative methods based on DPPH) than extracts obtained from maceration at room temperature. Freeze-dried ethanol extracts were prepared by: 1) maceration at room temperature and 2) hot extraction (eight hours) on several hundred gram scales and the latter extract was shown to have partial screening effects on UVB light. In this work, cytotoxic, antioxidant and potential sun-screening activity are shown for the first time in M. guyanensis.

Cytotoxic evaluation of essential oil from Zanthoxylum rhoifolium Lam. leaves

Zanthoxylum rhoifolium Lam is a plant popularly used as antimicrobial, for malaria and inflammatory treatment. The essential oil of Z. rhoifolium was extracted and its cytotoxic effects against HeLa (human cervical carcinoma), A-549 (human lung carcinoma), HT-29 (human colon adenocarcinoma), Vero (monkey kidney) cell lines and mice macrophages were evaluated. Some of the terpenes of its essential oil (ß-caryophyllene, alpha-humulene, alpha -pinene, myrcene and linalool) were also tested to verify their possible influence in the oil cytotoxic activity. The results obtained permitted to confirm that the essential oil is cytotoxic against tumoral cells (CD50 = 82.3, 90.7 and 113.6 µg/ml for A-549, HeLa e HT-29 cell lines, respectively), while it did not show cytotoxicity against non-tumoral cells (Vero and mice macrophages). Thus, the essential oil from Z. rhoifolium leaves seems to present a possible therapeuthic role due to its selective cytotoxic activity against tumoral cell lines.

Cytotoxic evaluation of essential oil from Casearia sylvestris Sw on human cancer cells and erythrocytes

A Casearia sylvestris (Flacourtiaceae) é uma planta popularmente conhecida como "guaçatonga" e é usada por povos indígenas da América do sul (Brasil, Peru e Bolivia) no tratamento de muitas doenças, incluindo câncer. Estudos citotóxicos mostraram que esta planta apresenta um possível e interessante potencial antitumoral devido à presença de moléculas chamadas casearinas. Além disso, a composição do óleo essencial mostrou uma alta concentração de sesquiterpenos de alto potencial citotóxico. Neste trabalho, nós verificamos que o óleo essencial da C. sylvestris apresentou uma boa citotoxicidade seletiva contra as linhagens de células tumorais HeLa, A-549 and HT-29 (CD50 63,3, 60,7 e 90,6 µg.ml-1, respectivamente) quando comparada às células não-tumorais Vero (CD50 210,1 µg.ml-1) e macrófagos de camundongos (CD50 234,0 µg.ml-1). Além disso, o óleo causou hemólise em sete diferentes tipos de eritrócitos, indicando que a C. sylvestris precisa ser usada com cuidado. Também foram testados padrões de β-cariofileno e α-humuleno que mostraram citotoxicidade similar àquelas apresentadas pelo óleo, indicando que estes compostos podem ser os responsáveis pelos efeitos tóxicos que foram observados neste estudo.

A review of mycotoxins in food and feed products in Portugal and estimation of probable daily intakes

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that occur naturally in agricultural commodities worldwide. Aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone, trichothecenes and ergot alkaloids are presently the most important for food and feed safety. These compounds are produced by several species that belong to the Aspergillus, Penicillium, Fusarium and Claviceps genera and can be carcinogenic, mutagenic, teratogenic, cytotoxic, neurotoxic, nephrotoxic, estrogenic and immunosuppressant. Human and animal exposure to mycotoxins is generally assessed by taking into account data on the occurrence of mycotoxins in food and feed as well as data on the consumption patterns of the concerned population. This evaluation is crucial to support measures to reduce consumer exposure to mycotoxins. This work reviews the occurrence and levels of mycotoxins in Portuguese food and feed to provide a global overview of this issue in Portugal. With the information collected, the exposure of the Portuguese population to those mycotoxins is assessed, and the estimated dietary intakes are presented.