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Four pyrazines were isolated from the n-butanol fraction of Hypecoum erectum L. by using various chromatographic methods, including MCI gel, ODS, silica gel and semi-preparative HPLC. The structures of the isolated compounds were identified as hyperectpyrazin A (1), 1′S-(6-methylpyrazin-2-yl)-ethane-1′,2′-diol (2), 2-hydroxymethyl-6-methylpyrazin (3) and pyrazine-2-carboxylic acid (4) by spectroscopy methods (1D NMR, 2D NMR, UV, IR, MS, etc.). The absolute configuration of compound 2 was determined by using the Mo2(OAc)4 induced CD analysis for the first time. Compound 1 was a new compound, compounds 2-4 were isolated from H. erectum for the first time. Compounds 1-4 were evaluated for their inhibition against acetylcholinesterase and nitric oxide generation induced by lipopolysaccharide-RAW264.7 macrophage cells. At a concentration of 50 μmol·L-1, compounds 2 and 4 displayed inhibitory effects on acetylcholinesterase with the inhibition rates of 44.40% and 43.99%, respectively.
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Objective To explore the sensitivity and the molecular mechanism of cisplatinresistance ovarian cancer cell line C13 to proteasome inhibitors and the combination with cisplatin. Methods After different treatments, methyl thiazolyl tetrazolium (MTT) assay was applied to examine the cell viability, annexin-V/propidium iodide(PI) apoptosis detection kit was used to determine the apoptosis rate of different groups, western blot assay was introduced to evaluate the expression levels of Fas-associated death domain-like interleukin-1 beta converting enzyme inhibitory protein (cFLIPs), and the activity of caspase-8 was examined. Results MTT assay shown that the cell viability ratios of combination group at serial time points from 12, 24, 36, 48, 60, 72 hours were ( 56.0 ± 8.4 ) %, (44.7 ± 7.3 ) %, ( 33.7 ±11.2) %, (27.6 ± 8.0) %, (27. 6 ± 7.6) % and (28.1 ± 2.4) %, which were much lower than those of cisplatin group (P <0.05). After treated for 24 hours, apoptosis rates of cisplatin group, bortezomib group and combination group were ( 16.7 ± 1.7) %, (23.4 ± 2.1 ) % and (26.9 ± 1.6) %, respectively. The rate of combination group was much higher than that of non-treated group and that of cisplatin group or bortezomib group ( P < 0.05 ). Western blot assay showed the changes of expression levels of cFLIPs, which were downregulated seriously after cisplatin, bortezomib or combination treatment [ (43.2 ± 2.3 )% vs( 75.7 ± 3.0)%vs (67.9 ± 2.1 ) %, P < 0.05 ]. The caspase-8 activity of combination group was (5.6 ± 1.6) folds than that of non-treated group, which was higher than those of other two groups [ ( 2.3 ± 1.0) and (4.2 ± 0.9 ) folds,P < 0.05 ]. Conclusions The tumor cell lethal effect of cisplatin could be increase significantly by the combination application of proteasome inhibitors, bortezomib. And the cFLIPs/caspase-8 signaling pathway may be play an important role in the molecular mechanism of the combination treatment.
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Objective To explore the semitivity of ovarian cancer cell line SKOV3 to paclitaxel,oroteasome inhibitors,bortezomib,and their combination.Methods The methyl thiazolyl tetrazolitim (MTT)assay was applied to examine the cell viability after treatment.The annexin V-propidium iodide apoptosis detection kit was used to determine the apoptosis rate of different groups.Western blot assay was used to evaluate the expression levels of phosphorylated protein kinase B(AKT)and glycogen synthase kinase-3 beta(GSK-3β).Results In MTT assay,the cell viability ratios of the combination group at serial time points from 12,24,36,48 and 72 hours Were(65.2±5.8)%,(58.3±14.4)%,(35.3±5.0)%,(19.2±1.5)%,and(11.4 ±2.5)%,which were significantly lower than those of the paclitaxel group (P<0.05).After arug treatments,apoptosis rates of paclitaxel group,bortezomib group and the combination group were (14.7±0.5)%,(15.1±0.8)%and(20.5±0.7)%respectively.The rate of the combination group was significantly higher than that of non-treated group and paclitaxel group(P<0.05).Western blot assay showed the changes in expression levels of phosphorylated AKT and GSK-3β,which were decreased significantly after paclitaxd and bortezomib combination treatment [(3.2±0.8)%,(19.3±0.4)%;P<0.05].Conclusions The lethal effect of paclitaxel on tumor cells could be increased significantly by its combination with proteasome inhibitors,bertezomib.The AKT/GSK-3β signaling pathway plays an important role in the molecular mechanism of the combination treatment.
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AimTo investigate the influence of tetramethylpyrazine(ligustrazine, Lig) on oxygen consumption and superoxide during the respiratory burst of human neutrophils. MethodsIt was observed by using ESR spin trapping, spin probe oxymetry and luminol-dependent chemiluminesence(CL) . Results Lig had no influence on oxygen consumption during the respiratory burst of neutrophils(P＞0.05), but had remarkable inhibition on CL response generated by neutrophils(P＜0.01), and had scavenging effect on O2 and OH ·generated by neutrophils, which were demonstrated in xanthine/ xanthine oxidase system and Fentons reaction(P＜0.01) . ConclusionLig has no inhibiting effect on oxygen metabolic function of neutrophils,but protects tissue from injury caused by activated neutrophils through scavenging oxygen radicals.
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0.05), but had remarkable inhibition on CL response generated by neutrophils(P