Screening of anti-dengue activity in methanolic extracts of medicinal plants

<p>Abstract</p> <p>Background</p> <p>Dengue fever regardless of its serotypes has been the most prevalent arthropod-borne viral diseases among the world population. The development of a dengue vaccine is complicated by the antibody-dependent enhancement effect. Thus, the development of a plant-based antiviral preparation promises a more potential alternative in combating dengue disease.</p> <p>Methods</p> <p>Present studies investigated the antiviral effects of standardised methanolic extracts of <it>Andrographis paniculata, Citrus limon, Cymbopogon citratus, Momordica charantia, Ocimum sanctum </it>and <it>Pelargonium citrosum </it>on dengue virus serotype 1 (DENV-1).</p> <p>Results</p> <p><it>O. sanctum </it>contained 88.6% of total flavonoids content, an amount that was the highest among all the six plants tested while the least was detected in <it>M. charantia</it>. In this study, the maximum non-toxic dose (MNTD) of the six medicinal plants was determined by testing the methanolic extracts against Vero E6 cells <it>in vitro</it>. Studies also determined that the MNTD of methanolic extract was in the decreasing order of <it>M. charantia </it>><it>C. limon </it>><it>P. citrosum, O. sanctum </it>><it>A. paniculata </it>><it>C. citratus</it>. Antiviral assay based on cytopathic effects (CPE) denoted by degree of inhibition upon treating DENV1-infected Vero E6 cells with MNTD of six medicinal plants showed that <it>A. paniculata </it>has the most antiviral inhibitory effects followed by <it>M. charantia</it>. These results were further verified with an <it>in vitro </it>inhibition assay using MTT, in which 113.0% and 98.0% of cell viability were recorded as opposed to 44.6% in DENV-1 infected cells. Although methanolic extracts of <it>O. sanctum </it>and <it>C. citratus </it>showed slight inhibition effect based on CPE, a significant inhibition was not reflected in MTT assay. Methanolic extracts of <it>C. limon </it>and <it>P. citrosum </it>did not prevent cytopathic effects or cell death from DENV-1.</p> <p>Conclusions</p> <p>The methanol extracts of <it>A. paniculata </it>and <it>M. charantia </it>possess the ability of inhibiting the activity of DENV-1 in <it>in vitro </it>assays. Both of these plants are worth to be further investigated and might be advantageous as an alternative for dengue treatment.</p

Il genocidio in Rwanda. Da guerra civile a guerra regionale

Since the time of independence Rwanda has had a number of so-called ethnic violence episodes. In most of the cases an instrumental use of violence from the central government to keep power through perpetuation of social divisions. Although historically ethnic violence was always kept inside the state, these episodes of violence pushed over the decades a large number of refugees out of Rwanda. The systematic genocide in 1994 caused a war that was spread into the Great Lakes Region due to the flow of refugees, particularly in former Zaire, starting a regional war that has not ended yet