RESUMEN
Eupulcherol A (1), a novel triterpenoid with an unprecedented carbon skeleton, was isolated from Euphorbia pulcherrima. Its structure was determined by comprehensive analysis of spectroscopic data, including HRESIMS and 1D and 2D NMR, and the absolute configuration was defined by single crystal X-ray diffraction analysis. Biological studies showed that compound 1 possessed anti-Alzheimer's disease (AD) bioactivity, which could delay paralysis of transgenic AD Caenorhabditis elegans. A plausible biogenetic pathway for eupulcherol A (1) was also proposed.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Antiprotozoarios/farmacología , Caenorhabditis elegans/efectos de los fármacos , Euphorbia/química , Triterpenos/farmacología , Enfermedad de Alzheimer/parasitología , Animales , Antiprotozoarios/química , Antiprotozoarios/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Relación Estructura-Actividad , Triterpenos/química , Triterpenos/aislamiento & purificaciónRESUMEN
Nardochinins A-D (1-4), four novel sesquiterpenoids, along with four known ones were isolated from the underground parts of Nardostachys chinensis Batal in ethanol. Their structures were determined by extensive spectroscopic methods and single-crystal X-ray diffraction. Nardochinin A (1) possessed a norsesquiterpene skeleton with an unusual 3/6/5/5 tetracyclic ring system, which had not appeared in natural products. Nardochinins B (2) and C (3) were the first time found naturally occurring sesquiterpenoids with a 4,5-seco-nardosinane skeleton. Besides, compound 3 represented an unprecedented 4,5-seco-nardosinane type norsesquiterpenoid with losing an isopropenyl at C-6 compared with 2 in the structural framework. Nardochinin D (4) was a novel, highly oxygenated valerenane-type sesquiterpenoid possessing a rare 3,12-epoxy group and an unusual 9,11-epoxy group. The anti-Alzheimer's disease (AD) activities of 1-4 were also evaluated using the Caenorhabditis elegans AD pathological model, and nardochinin B (2) had the highest anti-AD activity.
RESUMEN
Narjatamanins A (1) and B (2), a pair of epimers possessing a novel 2,3-seco-iridoid skeleton with an unusual 1,10-oxygen bridge, were isolated from the whole plants of Nardostachys jatamansi. Their structures were elucidated by a combination of various spectroscopic methods, including HRESIMS, IR and 1D and 2D NMR techniques. The absolute configurations of 1 and 2 were established by electronic circular dichroism (ECD) calculations. The pharmacological activities of 1 and 2 to alleviate AD-like symptoms were also evaluated using the Caenorhabditis elegans Alzheimer's disease (AD) pathological model, and narjatamanins A (1) and B (2) showed statistically significant delay in the worm paralysis phenotype of AD-like symptoms.