Methanolic extract of Cariniana rubra Gardner ex Miers stem bark negatively regulate the leukocyte migration and TNF-α and up-regulate the annexin-A1 expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Cariniana rubra Gardner ex Miers (Lecythidaceae), is a native and endemic tree in Brazil, whose inner stem bark decoction preparation is used in folk medicine to treat various inflammatory disorders. Previous scientific reports confirmed its popular use as an anti-inflammatory, without, however, evaluating its action mechanisms. AIM: The objective of this study was to determine the cytotoxicity and anti-inflammatory mechanism of action of the methanolic extract of Cariniana rubra (MECr), using experimental models in vivo and in vitro, as well as to identify secondary metabolites present in the extract. MATERIAL AND METHODS: The MECr was prepared by maceration of inner stem bark powder in methanol (1:10 w/v). The in vitro cytotoxicity effect was evaluated in CHO-k1 cells. The Hippocratic screening test was conducted to evaluate the acute toxicity of MECr in mice. The actions of MECr on leukocyte migration, cytokine levels (IL-1ß and TNF-α) and annexin-A1 (AnxA1) expression, were carried out on lambda-type carrageenan air pouch inflammation model in Swiss mice. Additionally, the phytochemical analysis of MECr was carried out by thin-layer chromatography (TLC) and spectrometric mass analysis with electrospray ionization ESI(-)/MS and gas chromatography-mass spectrometry (GC-MS). RESULTS: Treatment of CHO-k1 cells for 24 h with MECr did not cause cytotoxicity (IC50 > 200 µg/mL), however, the MECr was shown to be cytotoxic after 72 h of cell exposure (IC50 = 19.90 ± 3.51 µg/mL). In the Hippocratic test, oral treatment of mice with 750, 1500, or 3000 mg/kg of MECr did not show any histopathological changes and mortality during the 14 days of observation. In the carrageenan air pouch inflammation model, MECr reduced (p < 0.001) polymorphonuclear migration (57.7% and 57.8%), leukocyte monocyte migration (74.5% and 61.8%) in the air pouch cavity and in the skin tissue, respectively. MECr also inhibited TNF-α concentration in the air cavity wash (3.2%, p < 0.01) and increased expression of the AnxA1 protein (26.9%, p < 0.01) in the skin tissue, particularly in neutrophils. ß-sitosterol (1.95%), gallic acid (1.24%), ß-amyrin (0.87%) and stigmasterol (0.66%) were identified as the major constituents in methanolic extract. CONCLUSION: MECr exhibits significant anti-inflammatory action at least by increasing AnxA1 expression and by inhibiting the release of TNF-α pro-inflammatory cytokine and leukocyte migration, which is probably linked to the presence of identified biologically active compounds, especially gallic acid and terpenes. We believe that the results of this study provide a pharmacological basis for the MECr to be considered as a potential therapeutic agent for the treatment of inflammatory diseases.

Analysis of the lymphocyte cell population during malaria caused by Plasmodium vivax and its correlation with parasitaemia and thrombocytopaenia.

BACKGROUND: The mechanisms of activation and regulation of T lymphocytes and their cytokines in malaria caused by Plasmodium vivax are complex and poorly understood. Previous data suggest that T cells balance protective immune responses with immune mediated pathology in malaria. This study investigates the lymphocytic profile of patients infected with P. vivax by identifying and quantifying the specific sub-populations of Th1, Th2, Th17 and Treg cells and observing the correlation between parasitaemia and the number of platelets. METHODS: A cross-sectional study was carried out in an endemic area of the state of Acre, Brazil. In order to obtain identification and quantification of lymphocyte sub-populations through flow cytometry, blood samples were collected from 50 individuals infected with P. vivax and 20 non-infected controls. To differentiate Th1 from Th2, the presence of cytokines IL-4 and TNF was examined by enzyme-linked immunosorbent assay. Utilizing the Mann-Whitney and Spearman coefficient tests, comparison and correlation analysis were rendered to test the parasitaemia and the number of platelets relationship. RESULTS: The data indicate that individuals infected with P. vivax present a significant reduction in Th1, Th2 and Th17 cell sub-populations when compared to the non-infected control group. A negative correlation exists between parasitaemia and platelet counts in individuals infected with P. vivax. There is no correlation of parasitaemia or thrombocytopaenia with any sub-population of T lymphocytes analysed. Interestingly, patients with serum Th1 cytokine profile present inversely proportional parasitaemia to the increase in the number of Th1, Th2, Th17 and Treg cells while patients with serum Th2 cytokine profile present directly proportional parasitaemia to the increase in number of Th1 and Th2 cells. Regarding the number of platelets, patients with serum Th1 cytokine profile show a correlation directly proportional to the Th17 sub-population. In contrast, platelet counts are directly proportional only to Treg and activated Treg cells in patients with serum Th2 cytokine profile. CONCLUSIONS: During the P. vivax infection patients with serum Th1 versus Th2 cytokine profile present different biological mechanisms for activating the immune system against parasite load.