Decrease in Dengue virus-2 infection and reduction of cytokine/chemokine production by Uncaria guianensis in human hepatocyte cell line Huh-7

ABSTRACT BACKGROUND Dengue fever may present hemorrhages and cavitary effusions as result of exacerbated immune responses. We investigated hydro-alcoholic extracts from leaves (UGL) and bark (UGB) of the medicinal species Uncaria guinanensis with respect to antiviral effects in Dengue virus (DENV) infection and in immunological parameters associated with in vivo physiopathological features. METHODS Chemical profiles from UGB or UGL were compared in thin layer chromatography and 1H nuclear magnetic resonance using flavonoid compounds and a pentacyclic oxindole alkaloid-enriched fraction as references. DENV-2-infected hepatocytes (Huh-7) were treated with extracts. Cell viability, DENV antigens and immunological factors were detected by enzyme-linked immunosorbent assay (ELISA) or flow cytometry. FINDINGS The UGL mainly differed from UGB by selectively containing the flavonoid kaempferitrin. UGB and UGL improved hepatocyte viability. Both extracts reduced intracellular viral antigen and inhibited the secretion of viral non-structural protein (NS1), which is indicative of viral replication. Reduction in secretion of macrophage migration inhibitory factor was achieved by UGB, of interleukin-6 by UGL, and of interleukin-8 by both UGB and UGL. MAIN CONCLUSIONS The U. guianensis extracts presented, antiviral and immunomodulatory effects for DENV and possibly a hepatocyte-protective activity. Further studies may be performed to consider these products as potential candidates for the development of an herbal product for the future treatment of dengue.

In Vitro study of Vellozia pusilla pohl (Velloziaceae), a Brazilian plant species: antitumoral activity and labeling of blood elements

Vellozia pusilla Pohl is a species of the botanic family Velloziaceae that occurs in the subtropical regions of South America and, although it lives under conditions of high solar irradiation and low water availability, shows great longevity. The methanol extract of roots, stem and leaf sheaths of this species showed an antitumoral activity through the inhibition of the enzyme Topoisomerase I when analyzed by an in vitro bioassay employing DNA repair or recombination deficient mutants of the yeast Saccharomyces cerevisiae. In the evaluation of the effect of Vellozia pusilla methanol extract on the labeling of RBC, blood of mice was treated with 99mTc tracer solutions. The percentage of radioactivity ( percentATI) bound to plasma (P) and blood cells (BC) was determined. The percentATI in the insoluble fraction of plasma (IF) was also evaluate, and the results showed that there was a decrease in percentATI in this fraction that represents the plasmatic proteins.

Vellozia pusilla Pohl é uma espécie de planta da família Velloziaceae que ocorre em regiões subtropicais da América do Sul e, apesar de viver sob condições de alta incidência solar e baixa disponibilidade de água, apresenta grande longevidade. O extrato metanólico das raízes, caule e folhas desta espécie apresentou atividade antitumoral através da inibição da enzima Topoisomerase I quando utilizado o bioensaio in vitro que emprega cepas mutantes Saccharomyces cerevisiae que apresentam deficiência na reparação ou recombinação do DNA. Na avaliação do efeito do extrato metanólico de Vellozia pusilla na marcação dos elementos sangüíneos com tecnécio 99m, sangue de rato foi tratado com solução de 99mTc como traçador sendo determinado o percentual de radioatividade ( por centoATI) no plasma (P) e nas células vermelhas (BC). As frações solúvel e insolúvel do plasma também foram avaliadas. Os resultados mostraram que houve um decréscimo de por centoATI na fração insolúvel do plasma que é representada pelas proteínas plasmáticas.