RESUMO
This work reports isolation of an unusual lignan with a bicyclic [2.2.2] octene skeleton, named rufescenolide (1), from stems of Cordia rufescens, along with ß-sitosterol, stigmasterol, syringaldehyde, 3-ß-O-D-glucopyranosyl-sitosterol, methyl caffeate, 4-methoxy-protocatechuic acid and methyl rosmarinate. Structural characterizations employed IR spectroscopic, ESIHRMS and mono and dimensional NMR spectroscopy.
Assuntos
Compostos Bicíclicos com Pontes/isolamento & purificação , Ácidos Cafeicos/química , Cordia/química , Lignanas/química , Octanos/química , Compostos Bicíclicos com Pontes/química , Hidroxibenzoatos/química , Lignanas/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Octanos/isolamento & purificação , Caules de Planta/química , Sitosteroides/química , Sitosteroides/isolamento & purificação , Estigmasterol/química , Estigmasterol/isolamento & purificaçãoRESUMO
Flavonoids have key functions in the regulation of multiple cellular processes; however, their effects have been poorly examined in pluripotent stem cells. Here, we tested the hypothesis that neurogenesis induced by all-trans retinoic acid (RA) is enhanced by agathisflavone (FAB, Caesalpinia pyramidalis Tull). Mouse embryonic stem (mES) cells and induced pluripotent stem (miPS) cells growing as embryoid bodies (EBs) for 4 days were treated with FAB (60 µM) and/or RA (2 µM) for additional 4 days. FAB did not interfere with the EB mitotic rate of mES cells, as evidenced by similar percentages of mitotic figures labeled by phospho-histone H3 in control (3.4% ± 0.4%) and FAB-treated groups (3.5% ± 1.1%). Nevertheless, the biflavonoid reduced cell death in both control and RA-treated EBs from mES cells by almost 2-fold compared with untreated EBs. FAB was unable, by itself, to induce neuronal differentiation in EBs after 4 days of treatment. On the other hand, FAB enhanced neuronal differentiation induced by RA in both EBs of mES and miPS. FAB increased the percentage of nestin-labeled cells by 2.7-fold (mES) and 2.4 (miPS) and ß-tubulin III-positive cells by 2-fold (mES) and 2.7 (miPS) in comparison to RA-treated EBs only. FAB increased the expression of RA receptors α and ß in mES EBs, suggesting that the availability of RA receptors is limiting RA-induced neurogenesis in pluripotent stem cells. This is the first report to describe that naturally occurring biflavonoids regulate apoptosis and neuronal differentiation in pluripotent stem cells.
