Synthesis of precursors of iodine-labeled multifunctional ligands containing 2-nitroimidazole for the detection of hypoxic tissues and/or tumors

International audienc

Stereoelectronic control of oxazolidine ring-opening: structural and chemical evidences

International audienc

Anomeric effects in non-carbohydrate compounds: conformational differences between the oxazolidine rings of a cis-fused bicyclic system

International audienc

Anti-Alphaviral Alkaloids: Focus on Some Isoquinolines, Indoles and Quinolizidines

The discovery and the development of safe and efficient therapeutics against arthritogenic alphaviruses (e.g., chikungunya virus) remain a continuous challenge. Alkaloids are structurally diverse and naturally occurring compounds in plants, with a wide range of biological activities including beneficial effects against prominent pathogenic viruses and inflammation. In this short review, we discuss the effects of some alkaloids of three biologically relevant structural classes (isoquinolines, indoles and quinolizidines). Based on various experimental models (viral infections and chronic diseases), we highlight the immunomodulatory effects of these alkaloids. The data established the capacity of these alkaloids to interfere in host antiviral and inflammatory responses through key components (antiviral interferon response, ROS production, inflammatory signaling pathways and pro- and anti-inflammatory cytokines production) also involved in alphavirus infection and resulting inflammation. Thus, these data may provide a convincing perspective of research for the use of alkaloids as immunomodulators against arthritogenic alphavirus infection and induced inflammation

<i>Artemisia annua</i>, a Traditional Plant Brought to Light

International audienceTraditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria

<i>In vitro</i> comparison of three common essential oils mosquito repellents as inhibitors of the Ross River virus

<div><p>Background</p><p>The essential oils of <i>Cymbopogon citratus</i> (CC), <i>Pelargonium graveolens</i> (PG) and <i>Vetiveria zizanioides</i> (VZ) are commonly used topically to prevent mosquito bites and thus the risk of infection by their vectored pathogens such as arboviruses. However, since mosquito bites are not fully prevented, the effect of these products on the level of viral infection remains unknown.</p><p>Objectives</p><p>To evaluate <i>in vitro</i> the essentials oils from Reunion Island against one archetypal arbovirus, the Ross River virus (RRV), and investigate the viral cycle step that was impaired by these oils.</p><p>Methods</p><p>The essential oils were extracted by hydrodistillation and analyzed by a combination of GC-FID and GC×GC-TOF MS techniques. <i>In vitro</i> studies were performed on HEK293T cells to determine their cytotoxicity, their cytoprotective and virucidal capacities on RRV-T48 strain, and the level of their inhibitory effect on the viral replication and residual infectivity prior, during or following viral adsorption using the reporter virus RRV-<i>ren</i>Luc.</p><p>Results</p><p>Each essential oil was characterized by an accurate quantification of their terpenoid content. PG yielded the least-toxic extract (CC₅₀ > 1000 μg.mL^-1). For the RRV-T48 strain, the monoterpene-rich CC and PG essential oils reduced the cytopathic effect but did not display virucidal activity. The time-of-addition assay using the gene reporter RRV-<i>ren</i>Luc showed that the CC and PG essential oils significantly reduced viral replication and infectivity when applied prior, during and early after viral adsorption. Overall, no significant effect was observed for the low monoterpene-containing VZ essential oil.</p><p>Conclusion</p><p>The inhibitory profiles of the three essential oils suggest the high value of the monoterpene-rich essential oils from CC and PG against RRV infection. Combined with their repellent activity, the antiviral activity of the essential oils of CC and PG may provide a new option to control arboviral infection.</p></div

<i>In vitro</i> comparison of three common essential oils mosquito repellents as inhibitors of the Ross River virus - Fig 2

<p><b>Infectious capacity of RRV-T48</b> determined by plaque assay on infected Vero cells after pre-treatment of the viruses (1×10⁵ PFU) with the essential oils: <b>A:</b> residual infectivity; pre-treatment of the cells with the essential oils <b>B</b>: entry inhibition. Controls are infected cells and virus without treatment by the essential oils and values are expressed as mean ± SEM (n = 5).</p