RESUMEN
Phytochemical study on the flowers of Hypericum formosanum Maxim. (Hypericaceae) led to the isolation of formohyperins G-L (1-6), whose structures were assigned by detailed spectroscopic analysis. Formohyperins G-L (1-6) are new benzoylphloroglucinols substituted by a C10 unit, a prenyl group, and a methyl group. Formohyperins G-J (1-4) possess a 6/6/6-tricyclic structure, while formohyperins K (5) and L (6) have a unique 6/6/5/4-tetracyclic structure consisting of cyclohexadienone, dihydropyrane, cyclopentane, and cyclobutane rings. The absolute configurations of 1-6 were deduced by analysis of the ECD spectra. Formohyperins G-J (1-4) and L (6) were found to show potent inhibitory activities against IL-1ß release from LPS-treated murine microglial cells with EC50 values of 5.0, 10.9, 6.3, 10.8, and 13.7 µM, respectively, without cytotoxicity. 6-O-Methylformohyperins G (1a) and I (3a) also exhibited the inhibitory activities with EC50 values of 4.7 and 2.7 µM, respectively, although they were cytotoxic against microglial cells.
RESUMEN
Formohyperins A-F, previously undescribed meroterpenes, and grandone, a prenylated benzoylphloroglucinol being considered to be one of their biogenetic precursors, were isolated from the flowers of a Hypericaceous plant, Hypericum formosanum Maxim. Detailed spectroscopic analyses showed that formohyperins A-D were meroterpenes with an enolized 3-phenylpropane-1,3-dione moiety. Formohyperins E and F were elucidated as meroterpenes having a 4-benzoyl-5-hydroxycyclopent-4-ene-1,3-dione moiety. Formohyperins A-C and E were optically active, and their absolute configurations were deduced by comparison of the experimental and TDDFT calculated ECD spectra. In contrast, formohyperin D was concluded to be a racemate. Formohyperins A-F and grandone were found to show inhibitory activities against LPS-stimulated IL-1ß production from murine microglial cells with EC50 values of 13.2, 6.6, 8.5, 24.3, 4.1, 10.9, and 3.0 µM, respectively.
Asunto(s)
Hypericum , Floroglucinol , Ratones , Animales , Floroglucinol/farmacología , Floroglucinol/química , Hypericum/química , Flores , Microglía , Prenilación , Estructura MolecularRESUMEN
Six dibenzo-1,4-dioxane derivatives (1-6) were isolated from the roots of a Hypericaceous plant Hypericum ascyron. Spectroscopic analyses revealed 2 and 4-6 to be new compounds. The partial racemic natures of 1-3 were concluded by chiral HPLC analyses, while 5 was confirmed to be a racemate. The absolute configurations 1-4 were deduced on the basis of ECD calculations. Biological activity evaluation of the dibenzo-1,4-dioxane derivatives along with two related compounds: hyperdioxanes A (7) and B (8), previously isolated from the same plant material by our group demonstrated that 7 exhibit an anti-HIV activity (IC50 5.3 µM, TI 7.2) while 8 showed an inhibitory effect on IL-1ß production (inhibition rate: 72.3% at 6.3 µM) from LPS-stimulated microglial cells.
Asunto(s)
Hypericum , Dioxanos , Estructura Molecular , Raíces de PlantasRESUMEN
Five new abietane diterpenes, lophachinins A-E (1-5), and eleven known related diterpenes were isolated from a Mongolian traditional herbal medicine, the aerial parts of Lophanthus chinensis (Lamiaceae). The structures of new diterpenes were assigned by spectroscopic analyses. Lophachinins A (1) and B (2) were abietane diterpene possessing an endoperoxy bridge at C-ring. In contrast, lophachinins C-E (3-5) had an abietane skeleton with an aromatized C-ring. The absolute configuration of 1 was elucidated by application of the modified Mosher's method, while those of 2, 3, and 5 were assigned by chemical conversions. The absolute configuration of lophachinin D (4) was deduced by ECD calculation. Anti-inflammatory activity of isolated diterpenes on microglial cells were evaluated.