Pseudobrickellia brasiliensis (Asteraceae) is a plant commonly known as arnica-do-campo and belongs to the native flora of the Brazilian Cerrado. The alcoholic extract of the plant has been used as an anti-inflammatory agent in folk medicine, but the biological mechanism of action has not been elucidated. The present study evaluated the composition of P. brasiliensis aqueous extract and its effects on pro-inflammatory cytokine production and lymphocyte proliferation. The extracts were prepared by sequential maceration of P. brasiliensis leaves in ethanol, ethyl acetate, and water. Extract cytotoxicity was evaluated by trypan blue exclusion assay, and apoptosis and necrosis were measured by staining with annexin V-FITC and propidium iodide. The ethanolic (ETA) and acetate (ACE) extracts showed cytotoxic effects. The aqueous extract (AQU) was not cytotoxic. Peripheral blood mononuclear cells stimulated with phorbol myristate acetate and ionomycin and treated with AQU (100 μg/mL) showed reduced interferon (IFN)-γ and tumor necrosis factor (TNF)-α expression. AQU also inhibited lymphocyte proliferative response after nonspecific stimulation with phytohemagglutinin. The aqueous extract was analyzed by liquid chromatography coupled with photodiode array detection and mass spectrometry. Quinic acid and its derivatives 5-caffeoylquinic acid and 3,5-dicaffeoylquinic acid, as well as the flavonoids luteolin and luteolin dihexoside, were detected. All these compounds are known to exhibit anti-inflammatory activity. Taken together, these findings demonstrate that P. brasiliensis aqueous extract can inhibit the pro-inflammatory cytokine production and proliferative response of lymphocytes. These effects may be related to the presence of chemical substances with anti-inflammatory actions previously reported in scientific literature.

Dye exclusion tests are used to determine the number of live and dead cells. These assays are based on the principle that intact plasma membranes in live cells exclude specific dyes, whereas dead cells do not. Although widely used, the trypan blue (TB) exclusion assay has limitations. The dye can be incorporated by live cells after a short exposure time, and personal reliability, related to the expertise of the analyst, can affect the results. We propose an alternative assay for evaluating cell viability that combines the TB exclusion test and the high sensitivity of the flow cytometry technique. Previous studies have demonstrated the ability of TB to emit fluorescence when complexed with proteins. According to our results, TB/bovine serum albumin and TB/cytoplasmic protein complexes emit fluorescence at 660 nm, which is detectable by flow cytometry using a 650-nm low-pass band filter. TB at 0.002% (w/v) was defined as the optimum concentration for distinguishing unstained living cells from fluorescent dead cells, and fluorescence emission was stable for 30 min after cell treatment. Although previous studies have shown that TB promotes green fluorescence quenching, TB at 0.002% did not interfere with green fluorescence in human live T-cells stained with anti-CD3/fluorescein isothiocyanate (FITC) monoclonal antibody. We observed a high correlation between the percentage of propidium iodide+CD3/FITC+ and TB+CD3/FITC+ cells, as well as similar double-stained cell profiles in flow cytometry dot-plot graphs. Taken together, the results indicate that a TB exclusion assay by flow cytometry can be employed as an alternative tool for quick and reliable cell viability analysis.

Os objetivos desta pesquisa foram caracterizar as recusas por parte da população em permitir a borrifação de seus imóveis, em quatro regiões de Belo Horizonte, no período de 2006 a 2008, e relacionar estas recusas com o surgimento de casos de leishmaniose visceral, no mesmo local e período. Utilizaram-se as localizações onde se encontraram 27 casos humanos de leishmaniose visceral obtidos do SINAN, todos referentes a quatro áreas de abrangência da região noroeste de Belo Horizonte, no período de 2006 a 2008. De um total de 33.579 residências visitadas pelo controle químico vetorial, 9636 (28,70%) aceitaram a borrifação interna e a externa do domicílio, 20741 (61,77%) concordaram com a borrifação apenas do peridomicílio, 141 (0,42%) aceitaram apenas a borrifação do intradomicílio, 909 (2,70%) se encontraram fechadas no momento da borrifação e 2152 (6,41%) recusaram qualquer tipo de borrifação no imóvel. Na maioria das residências, o controle químico foi permitido apenas no peridomicílio. A diferença entre o perfil de recusas dos quarteirões contidos em uma área de 200 metros ao redor de um caso humano de leishmaniose visceral e o mesmo perfil dos quarteirões fora desta área foi significativa (P<0,05) em sete (25,92%) dos 27 casos da doença.

The purpose of this study was to characterize the population's refusal to allow their houses to be sprayed in four regions of Belo Horizonte, in the period from 2006 to 2008, and relate these denials with the emergence of cases of visceral leishmaniasis in the same location and time. We used the location of 27 human cases of visceral leishmaniasis obtained from SINAN, all data from four regions in the West Region of the city of Belo Horizonte, from 2006 to 2008. Of a total of 33,579 houses visited by the chemical vector control, 9636 (28.70%) accepted spraying inside and outside the home, 20741 (61.77%) agreed with spraying only the areas surrounding the property, 141 (0.42%) agreed only to spray indoors, 909 (2.70%) were found closed at the time of spraying, and 2152 (6.41%) refused any kind of spray at house. A chemical control vector was allowed only in surrounding areas of most of the houses studied. The difference between the profile of denials of the blocks contained in an area of 200 meters around a human case of VL, with the same profile of the blocks out of this area was significant (P<0,05) in 07 (25,92%) of 27 cases of the disease.