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Antibiotic resistance, particularly against fluoroquinolones and macrolides, has emerged globally among thermophilic Campylobacters (Campylobacter jejuni and Campylobacter coli), giving rise to concerns about the efficacy of antibiotic treatment of these bacteria. Thus, developing new antibacterials with excellent activity is important. Isatin (IST) and its derivatives have exhibited promising antibacterial activities in several pathogenic bacteria. However, its activity against Campylobacter is unknown. Therefore, this study was conducted to evaluate the antibacterial activity of isatin against 29-Campylobacter strains (C. jejuni-17 and C. coli-12) and investigate the effects at the cellular level. The minimal inhibitory concentrations (MICs) of isatin were between <1.0 and 16.0 µg/mL in Campylobacter strains. Most strains presented with MIC = 8.0 µg/mL (76%). The minimal bactericidal concentration (MBC) was determined to be 16.0 µg/mL for 72% of the Campylobacter strains tested. The 50% inhibitory concentration (IC50) value for isatin was 125.63 µg/mL on the MRC-5 normal cell line, suggesting that isatin can be considered a safe substance in terms of cytotoxicity. In this study, we demonstrated the potential of isatin based on its low toxicity and effectiveness in vitro against antibiotic-resistant Campylobacter strains, which indicates that this compound could be an attractive candidate for future use in multidrug-resistant Campylobacter treatment. [ABSTRACT FROM AUTHOR]

The anti-corrosive effect of the extract in ethanol of Justicia brandegeeana (Acanthaceae) against carbon steel AISI 1020 in sulfuric acid medium 1 mol L-1 was investigated. In addition to the effect of seasonality, several techniques were used to investigate the anti-corrosive activity, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), linear polarization resistance (LPR), and weight loss. The chelating effect was analyzed by UV-Vis spectrophotometry and the surface was analyzed by scanning electron microscopy (SEM). The results showed that the inhibition efficiency is dependent on the concentration of the extract, reaching its maximum at 1500 ppm and despite having good thermal stability (82.41% inhibition at 70°C), it decreases with increasing temperature, indicating a physisorption behavior. The extract obeyed the Langmuir isotherm and the Tafel curves characterized it as a mixed inhibitor, with a tendency to cathodic region. It also presented a 52% chelating effect against Fe+2 ions, and the SEM analysis indicated a protection with the presence of plant extract, thus minimizing surface roughness. These results indicated the J. brangeeana ethanol extract as a green anti-corrosive agent. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis comprises several infectious diseases caused by protozoa parasites of Leishmania genus. In recent years, there has been a growing interest in the therapeutic use of natural products to treat parasitic diseases. Among them Croton cajucara Benth. (Euphorbiaceae) is a plant found in the Amazonian region with a history of safe use in folk medicine. Purpose: The purpose of this study was to investigate the effects of derodane diterpenes, trans dehydrocrotonin (DCTN), trans-crotonin (CTN) and acetylaleuritolic acid (AAA) obtained from powdered bark of C. cajucara against promastigotes, axenic and intracellular amastigotes of Leishmania amazonensis. Furthermore, the effects of DCTN and CTN on the trypanotiona reductase enzyme were also investigated. The extraction of the terpenes was carried out as previously reported (Maciel et al., 1998; 2003). Methods: The effect of the isolated compounds (DCTN, CTN and AAA) from the bark of C. cajucara was assessed in vitro against promastigotes, axenic amastigotes and intracellular amastigotes of L. amazonensis by counting of remaining parasites in a Neubauer chamber in comparison to pentamidine used as standard drug. The action of natural products on trypanothione reductase was assessed using soluble protein fraction of promastigotes. The assays were performed by incubation with HEPES, EDTA, NADPH and trypanothione disulfide to quantify the NAPH consumption by TryR. Results: The results showed very high efficacy, especially of the diterpene DCTN, against promastigotes (ICS0 = 6.30 ± 0.06 µg/ml) and axenic amastigotes ([IC.sub.50] = 19.98 ± 0.05 µg/ml) of L amazonenesis. The cytotoxic effect of the best active natural product was evaluated on mouse peritoneal infected macrophages ([IC.sub.50] = 0.47 [+ or -] 0.03 µg/ml in 24 h of culture), and the treatment revealed that DCTN never reaches toxic concentrations while reducing the infection and, most importantly, with no toxicity (>100 µg/ml with 0% of macrophage kill) when compared to pentamidine (37.5 µg/ml with 100% of macrophage kill). Furthermore, all of the natural products assayed on the trypanothione reductase enzyme inhibited the enzyme activity compared to the control. Conclusion: Clerodane diterpenes from C. cajucara showed promising in vitro antileishmanial effects against L amazonensis, specially the DCTN with no macrophage toxicity up to the assayed concentration. In addition, the action on trypanothione reductase enzyme revealed a possible mechanism of action. Keywords: Leishmania amazonensis Terpenes trans-Deydrocrotonin Croton cajucara Macrophage Antiprotozoal activity, Introduction Leishmaniasis comprises several diseases caused by protozoan parasites of the Leishmania genus, which are transmitted by sand-flies. This parasite has been endemic in 88 countries of four continents (Paloque [...]

Novel derivatives of lapachol 2, nor-lapachol 3 and lawsone 4 have been synthesized by nucleophilic displacement of the methoxynaphthoquinones 2a, 3a and 4a with the polyamine (PA) N¹-Boc-N5-Bn-spermidine 1a. The respective products 2b-4b were obtained in good yields and characterized by spectroscopic and analytical methods. The inhibitory action of these naphthoquinone-PA conjugates on DNA-topoisomerases (topo) I and II-alpha was evaluated by relaxation assay of supercoiled DNA plasmid. All compounds (1a 2b, 3b and 4b) presented significant inhibition of topo II-alpha catalytic activity at the 2 µM dose. Considering that only PA 1a did not inhibit the enzyme catalytic activity at the 0.2 µM dose, the appended naphthoquinone moiety acts as a "value added" fragment. Compounds 1a 2b, 3b and 4b did not inhibit the enzyme DNA-topo I at the 200 µM dose.

A series of seven Schiff bases have been synthesized from 3,3-diphenylpropilamine and substituted benzaldehydes. These imines were treated with NaBH4 in ethanol affording the corresponding amines in 98-55% yields. A molecular modeling study was performed with the Schiff bases in order to compare the theoretical parameters with the experimental results. The theoretical parameters were obtained by AM1 and PM3 semi-empirical methods. The analysis of charge, electron densities and LUMO coefficients suggested that the most favorable interactions should occur with Schiff bases containing electron-donating groups, in accordance with experimental yields, showing that the higher reactivity is due to higher electrophilic character of imine carbons.

Steroidal alkaloids, flavonoids and their glycosides occurring in numerous species of Solanum genus are known to possess a variety of biological activities. The flavonoid tiriloside (1), a rich in glycoalkaloids total fraction named GB and the glycoalkaloid solasonine (2) isolated from thricomes of young branches and fruits from Solanum crinitum Lam, and the aglycone solasodine (3) isolated from Solanum jabrense Agra & M. Nee, were assayed against murine Ehrlich carcinoma and human K562 leukaemia cultured cells. The exposure in vitro of these cancer cells to these products resulted in a dose-dependent growth inhibition evaluated by the MTT method. The results indicated significant cytotoxic activities with IC50 = 69.50 muM, 19.5 mug mL-1, and 74.20 muM for 1, GB and 2, respectively, against Ehrlich carcinoma, and IC50 = 186.50 muM, 13.65 mug mL-1 and 76.92 muM, for 1, GB, 2 and 2a, respectively, against K562 leukaemia cells. The low activity of the aglycone 3 indicates that the role of the sugar moiety is very important in the cytotoxic activity of glycoalkaloid solsonine. The cytotoxic activity revealed by the GB fraction may be attributed to the presence of 2. Additionally, these results show the viability of the MTT assay for monitoring phytochemical bioactive compounds.

This paper presents a program emphasizing ethnopharmacological approaches that could allow great success in the study of medicinal plants. The minimum ethnopharmacological research team should consist of a botanist, a chemist and a pharmacologist with each carrying the responsibility for answering in sequential fashion critical questions. The chemical composition and pharmacological properties of the very efficient medicinal plant Croton cajucara were investigated according to ethnopharmacological approaches. The study with this Croton proved to be both efficient and successful. This happy situation was only possible because a multidisciplinary team was involved getting the research done correctly. The ethnopharmacological study involving one other especies Copaifera will be cited.

A series of eleven Schiff Bases have been synthesized. They were obtained by condensation of piperonal (3,4-methylenedioxybenzaldehyde) with the corresponding aromatic primary amines. Their ¹H and 13C-NMR spectra have been obtained and the Hammett correlations including chemical shifts and the subsitutent constants (sigmap, sigmaR e sigmaI) were studied. Linear and bilinear significant correlations were observed for iminic carbon (C-alpha) and C-1?, showing a more significant ressonance effect on chemical shifts. The chemical shifts for C-4? were highly affected by substituent effects, especially for halogens in the expected direction. Their biological activity against microorganisms has also been measured and significant activity was showed against Epidermophyton floccosum. The biological activity did not give a reasonable relationship with electronic effects.

Hydrogen-bond structure and dynamics of pyrazole-4-carboxylic acid chains were studied using solid-state NMR, x-ray diffraction and ab initio computations.

The synthesis of the ligands 2,4,6-tris(4-methylpyrazol-1-yl)-1,3,5-triazine (Me-TPzT), 2,4,6(4-bromopyrazol-1-yl)-1,3,5-triazine (Br-TPzT) and 2-methoxy-4,6-bis(4-methylpyrazol-1-yl)-1,3,5-triazine (Me-BPzTOMe) was described. In addition, the reactions of the ligands with some palladium analogues were investigated. Experimental results revealed two simultaneous fluxional processes with different energy barriers, and this difference is attributed to the Pd-N bond strength.