RESUMO
A methanol extract of the soft coral Sinularia microspiculata revealed five sterols, including two new compounds. Using combined chromatographic and spectroscopic experiments, the new compounds were found to be 7-oxogorgosterol (1) and 16α-hydroxysarcosterol (2). Their structures were determined on the basis of spectroscopic data ((1)H and (13)C NMR, HSQC, HMBC, (1)H-(1)H COSY, NOESY, and FT-ICR-MS) and by comparing obtained results to the values indicated in previous studies. Among the isolated compounds, 3 showed weak cytotoxic effects against HL-60 (IC50 = 89.02 ± 9.93 µM) cell line, whereas 5 was weakly active against HL-60 (IC50 = 82.80 ± 13.65 µM) and SK-Mel2 (IC50 = 72.32 ± 1.30 µM) cell lines.
Assuntos
Antozoários/química , Antineoplásicos/isolamento & purificação , Colesterol/análogos & derivados , Desidrocolesteróis/isolamento & purificação , Esteroides/administração & dosagem , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Colesterol/química , Colesterol/isolamento & purificação , Colesterol/farmacologia , Desidrocolesteróis/química , Desidrocolesteróis/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60 , Humanos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Esteroides/química , VietnãRESUMO
The level of 7-dehydrocholesterol (7-DHC) is elevated in tissues and fluids of Smith-Lemli-Opitz syndrome (SLOS) patients due to defective 7-DHC reductase. Although over a dozen oxysterols have been identified from 7-DHC free radical oxidation in solution, oxysterol profiles in SLOS cells and tissues have never been studied. We report here the identification and complete characterization of a novel oxysterol, 3ß,5α-dihydroxycholest-7-en-6-one (DHCEO), as a biomarker for 7-DHC oxidation in fibroblasts from SLOS patients and brain tissue from a SLOS mouse model. Deuterated (d7)-standards of 7-DHC and DHCEO were synthesized from d7-cholesterol. The presence of DHCEO in SLOS samples was supported by chemical derivatization in the presence of d7-DHCEO standard followed by HPLC-MS or GC-MS analysis. Quantification of cholesterol, 7-DHC, and DHCEO was carried out by isotope dilution MS with the d7-standards. The level of DHCEO was high and correlated well with the level of 7-DHC in all samples examined (R = 0.9851). Based on our in vitro studies in two different cell lines, the mechanism of formation of DHCEO that involves 5α,6α-epoxycholest-7-en-3ß-ol, a primary free radical oxidation product of 7-DHC, and 7-cholesten-3ß,5α,6ß-triol is proposed. In a preliminary test, a pyrimidinol antioxidant was found to effectively suppress the formation of DHCEO in SLOS fibroblasts.