RESUMO
Six new iridoid glycosides, myxosmosides A-F (1-6) were isolated from the roots of Myxopyrum smilacifolium (Wall.) Blume. Their chemical structures were determined using, 1D-, 2D-NMR, and mass spectra and chemical methods.
Assuntos
Glucosídeos Iridoides , Oleaceae , Glucosídeos Iridoides/análise , Iridoides/análise , Iridoides/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Raízes de Plantas/químicaRESUMO
Translocator protein (TSPO) expression is closely related with neuroinflammation and neuronal damage which might cause several central nervous system diseases. Herein, a series of TSPO ligands (11a-c and 13a-d) with a 2-phenylpyrazolo[1,5-a]pyrimidin-3-yl acetamide structure were prepared and evaluated via an in vitro binding assay. Most of the novel ligands exhibited a nano-molar affinity for TSPO, which was better than that of DPA-714. Particularly, 11a exhibited a subnano-molar TSPO binding affinity with suitable lipophilicity for in vivo brain studies. After radiolabeling with fluorine-18, [18F]11a was used for a dynamic positron emission tomography (PET) study in a rat LPS-induced neuroinflammation model; the inflammatory lesion was clearly visualized with a superior target-to-background ratio compared to [18F]DPA-714. An immunohistochemical examination of the dissected brains confirmed that the uptake location of [18F]11a in the PET study was consistent with a positively activated microglia region. This study proved that [18F]11a could be employed as a potential PET tracer for detecting neuroinflammation and could give possibility for diagnosis of other diseases, such as cancers related with TSPO expression.