ABSTRACT
OBJECTIVE@#To investigate the chemical constituents from the leaves of Jatropha curcas and evaluate their inhibition on lipopolysaccharide (LPS)-activated BV-2 microglia cells.@*METHODS@#The n-BuOH extract of the leaves of J. curcas was isolated by macroporous adsorption resin, silica gel, ODS, column chromatography and semi-preparative HPLC. The structures of the compounds were identified by MS, NMR, ECD, and other spectroscopic methods. In addition, anti-neuroinflammatory effects of isolated compounds were evaluated by measuring the production of nitric oxide (NO) in over-activated BV-2 cells.@*RESULTS@#Seventeen compounds, including (7R,8S)-crataegifin A-4-O-β-D-glucopyranoside ( 1), (8R,8'R)-arctigenin ( 2), arctigenin-4'-O-β-D-glucopyranoside ( 3), (-)-syringaresinol ( 4), syringaresinol-4'-O-β-D-glucopyranoside ( 5), (-)-pinoresinol ( 6), pinoresinol-4'-O-β-D-glucopyranoside ( 7), buddlenol D ( 8), (2R,3R)-dihydroquercetin ( 9), (2S,3S)-epicatechin ( 10), (2R,3S)-catechin ( 11), isovitexin ( 12), naringenin-7-O-β-D-glucopyranoside ( 13), chamaejasmin ( 14), neochamaejasmin B ( 15), isoneochamaejasmin A ( 16), and tomentin-5-O-β-D-glucopyranoside ( 17) were isolated and identified. Compounds 2, 4 and 8 significantly inhibited the release of NO in BV-2 microglia activated by LPS, with IC50 values of 18.34, 29.33 and 26.30 μmol/L, respectively.@*CONCLUSION@#Compound 1 is a novel compound, and compounds 2, 3, 8, 14- 17 are isolated from Jatropha genus for the first time. In addition, the lignans significantly inhibited NO release and the inhibitory activity was decreased after glycosylation.
ABSTRACT
Human motion control system has a high degree of nonlinear characteristics. Through quantitative evaluation of the nonlinear coupling strength between surface electromyogram (sEMG) signals, we can get the functional state of the muscles related to the movement, and then explore the mechanism of human motion control. In this paper, wavelet packet decomposition and : coherence analysis are combined to construct an intermuscular cross-frequency coupling analysis model based on wavelet packet- : coherence. In the elbow flexion and extension state with 30% maximum voluntary contraction force (MVC), sEMG signals of 20 healthy adults were collected. Firstly, the subband components were obtained based on wavelet packet decomposition, and then the : coherence of subband signals was calculated to analyze the coupling characteristics between muscles. The results show that the linear coupling strength (frequency ratio 1:1) of the cooperative and antagonistic pairs is higher than that of the nonlinear coupling (frequency ratio 1:2, 2:1 and 1:3, 3:1) under the elbow flexion motion of 30% MVC; the coupling strength decreases with the increase of frequency ratio for the intermuscular nonlinear coupling, and there is no significant difference between the frequency ratio : and : . The intermuscular coupling in beta and gamma bands is mainly reflected in the linear coupling (1:1), nonlinear coupling of low frequency ratio (1:2, 2:1) between synergetic pair and the linear coupling between antagonistic pairs. The results show that the wavelet packet- : coherence method can qualitatively describe the nonlinear coupling strength between muscles, which provides a theoretical reference for further revealing the mechanism of human motion control and the rehabilitation evaluation of patients with motor dysfunction.