The present study aimed to examine the immunomodulatory properties of the methanolic (MeOH) extract from Pouteria. campechiana leaves in peritoneal macrophages of Balb/c mice. Peritoneal macrophages isolated from mice and Vero cells were treated with the MeOH extract from leaves. Cell viability of the macrophages and Vero cells were evaluated by the 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. The phagocytic activity, as nitric oxide (NO), hydrogen peroxide (H 2 O 2 ), interleukin 6 (IL-6) and tumour necrosis factor α (TNF-α) production were evaluated on peritoneal macrophages. Results showed that the MeOH extract from leaves was able to stimulate the phagocytic activity and increase NO, H 2 O 2 and cytokines production. The viability assays do not show cytotoxic effect on cell viability and cause a significative proliferative effect in the macrophages of a concentration-dependent manner. These results conclude that the MeOH extract from P. campechiana leaves possessed a stronger immunostimulatory effect in a concentration-dependent manner without affect the cell viability.
The leishmanicidal activity of 15 extracts and 4 pure metabolites obtained from Urechites andrieuxii, Colubrina greggii, Dorstenia contrajerva, and Tridax procumbens was evaluated using the newly developed MTS ({3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) assay, optimized for promastigotes of Leishmania major, Leishmania tropica, and Leishmania aethiopica, as well as for L. aethiopica axenic amastigotes. The assay was then used for calculating the percentage of viable stationary phase parasites after a 24-hr treatment with each plant extract or pure metabolite. The 3 most active samples, 2 from C. greggii (NCG-5C and DCG-3A) and 1 from T. procumbens (TPZ-2A), showed LD50 values of 62.4, 7.2, and 18.5 microg/ml, respectively, on stationary promastigotes, and of 94.2, 27.1, and 95.2 microg/ml, on amastigotes of L. aethiopica. Moreover, TPZ-2A and DCG-3A significantly reduced the percentage of infected monocyte-derived macrophages (THP-I). The percentage of infected cells decreased from 69.9% +/- 2.5% to 20.8% +/- 2% when the cells were treated with the DCG-3A fraction and to 14.9% +/- 0.5% when treated with TPZ-2A, without significantly decreasing the number of human cells. These findings indicate the presence of potentially bioactive metabolites in the roots of C. greggii and in T. procumbens and reflect the importance of pursuing the bioassay-guided purification of these metabolites.
The in vitro leishmanicidal effect of (3S)-16,17-didehydrofalcarinol (1) isolated from Tridax procumbens whole plant against Leishmania mexicana, the causative agent of cutaneous leishmaniasis (chiclero's ulcer) in the New World, was investigated. This oxylipin showed significant in vitro activity against promastigotes and intracellular amastigotes of L. mexicana. Its inhibitory effect on amastigotes was not due to activation of NO in recombinant gamma-interferon-stimulated macrophages, since the production of NO was decreased in presence of the oxylipin. This is the first report on the leishmanicidal activity against the intracellular stage (amastigote) of the oxylipin (3S)-16,17-didehydrofalcarinol.
This paper describes the seasonal phytochemical variation and the antimicrobial potential of V. zizanioides roots collected in Brazil. Considering the high levels of chemical constituents and their biological activity in dichloromethane fraction, the plants were grown in different seasons and the respective dichloromethane fractions were analyzed by gas chromatography-mass spectrometry. The antimicrobial activity was evaluated against several pathogenic microorganisms by determining the minimum inhibitory concentration (MIC) using the agar dilution method. Yields of dichloromethane fractions from plants collected in the autumn and spring occurred in a higher proportion than in other seasons. Khusimol (2) was isolated by column chromatography and identified by NMR and CG-MS, along with other sesquiterpenes, including β-vetivenene (1), vetiselinenol (3), isovalencenol (4), vetivenic acid (5), α-vetivone (6) and β-vetivone (7). Some extracts showed promising antimicrobial effects, with MICs ranging from 31.25 to 500 μg mL -1. Kushimol was slightly active against the tested microorganisms.
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