RESUMEN
In this study, the chemical components of ethanol extract from the aromatic parts of Syringa oblata were systematically separated and purified by silica gel column chromatography, thin layer plate preparation and liquid phase preparation. Combined with ultraviolet analyzer(UV), infrared analyzer(IR), nuclear magnetic resonance analyzer(NMR), high resolution mass spectrometer(HR-ESI-MS), X-ray diffraction and other spectrum technology as well as literature physicochemical data comparison methods for structural identification, a total of 10 compounds were identified. They were identified as oblatanoid D(1),(-)-T-muurolol(2), oblatanoid E-G(3-5), 14-noreudesma-3-hydroxy-3-en-2,9-dione(6), 1-isopropyl-2,7-dimethylnaphthalene(7), isocoradiol(8), α-calacorene(9), cadin-4-en-1-ß-ol(10). Compound 1 is a new sesquiterpene compound that has not been reported, and the other 9 compounds are isolated from S. oblata for the first time. The compound 1 has a significant protective effect on the LPS-induced inflammatory injury model of RAW264.7 cells.
Asunto(s)
Sesquiterpenos , Syringa , Sesquiterpenos/química , Sesquiterpenos/aislamiento & purificación , Animales , Ratones , Syringa/química , Células RAW 264.7 , Estructura Molecular , Medicamentos Herbarios Chinos/química , Espectroscopía de Resonancia Magnética , Difracción de Rayos XRESUMEN
A continued phytochemical investigation guided by 1H NMR and LC-MS data on the ethanol extract from the peeled stems of Syringa pinnatifolia Hemsl. led to the isolation of 16 undescribed dimeric eremophilane sesquiterpenoids, namely syringenes R-Z (1-9) and A1-G1 (10-16). These structures were elucidated by extensive analysis of spectroscopic data, including HRESIMS, NMR, quantum-mechanics-based computational analysis of NMR chemical shifts, and single-crystal X-ray diffraction analyses, and a concise rule for determination of relative configuration of angular methyl was proposed. The results of the cardioprotective assay demonstrated that 3 exhibits a protective effect against hypoxia-induced injuries in H9c2 cells. This effect was observed at a concentration of 10 µM, with a protective rate of 28.43 ± 11.80%.
Asunto(s)
Sesquiterpenos , Syringa , Syringa/química , Sesquiterpenos Policíclicos , Sesquiterpenos/farmacología , Sesquiterpenos/química , Cristalografía por Rayos X , Espectroscopía de Resonancia Magnética , Estructura MolecularRESUMEN
In the current study, twenty-two stereochemical 9,9'-epoxylignans including 19 undescribed ones were isolated from the ethanol extract of Syringa pinnatifolia in our continuing effort to understand the overall chemical spectrum of this species. These isolates were structurally elucidated by extensive spectroscopic data analysis, X-ray diffraction, modified Mosher's method, and quantum chemical calculations. Meanwhile, the utilization of 13C NMR calculation and the MAEΔΔδ parameter facilitated the stereochemical assignment of groups of lignan stereoisomers. The 13C NMR data were corrected by the averaged errors at each corresponding carbon position in groups of lignan stereoisomers, which improved the theoretic 13C NMR calculation. The finding of the stereochemical structures of 9,9'-epoxylignans is significant. It is helpful to determine the absolute configurations of molecules with the similar core. In addition, these lignans exhibited potential cardioprotective activities on H9c2 cardiomyocytes in vitro and presented significant antioxidant effect.