3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cycl...3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cyclodextrin molecule. The thermodynamic pararneters of thecomplexing process can be estimated utilizing the spectrophotometric data.展开更多
Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environ...Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.展开更多
BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against...BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.展开更多
The sweet potato weevil(Cylas formicarius(Fab.)(Coleoptera: Brentidae)) is a pest that feeds on sweet potato(Ipomoea batatas(L.) Lam.(Solanales: Convolvulaceae)), causing substantial economic losses annually. However,...The sweet potato weevil(Cylas formicarius(Fab.)(Coleoptera: Brentidae)) is a pest that feeds on sweet potato(Ipomoea batatas(L.) Lam.(Solanales: Convolvulaceae)), causing substantial economic losses annually. However, no safe and effective methods have been found to protect sweet potato from this pest. Herbivore-induced plant volatiles(HIPVs)promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated. To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels. Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated. The production of(Z)-3-hexenyl acetate(z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm. Ipomoea batatas ocimene synthase(IbOS) is first reported here as a key gene in allo-ocimene synthesis. Insect-induced wounding promoted the production of the substrate,(Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene,respectively. Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils. These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.展开更多
This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the solvent.The pretreatment was followed by...This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the solvent.The pretreatment was followed by enzymatic hydrolysis through which the process efficiency for biomass conversion to monomeric sugars was determined.The results show that 43 wt%of switchgrass was dissolved in IL after 2 h of pretreatment at 160℃ with 15 wt%solid loading.A 120 h enzymatic hydrolysis of the pretreated switchgrass results in 96%glucan and 98%xylan conversion.[C2C1Im][OAc]pretreatment has been successfully scaled up to 40 kg with improved sugar titers and yields relative to bench scale(6 kg).The mass flow of the overall process was established and the major scale-up challenges of the process were identified.展开更多
AIM: To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action. METHODS: The cytotoxic effect of alisol B acetate on SGC7901 cells was measu...AIM: To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action. METHODS: The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential (△Ψm) were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases (PI3K). RESULTS: Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time-and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 μmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt. CONCLUSION: Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.展开更多
Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation bet...Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.展开更多
A comprehensive exploration of the aminolysis mechanism for methyl indole-3-acetate with ammonia is carried out by employing the B3 LYP/6-311++G(d,p), M06-2 X/6-311++G(d,p) and MP2/6-311++G(d,p)//M06-2 X/6-311++G(d,p)...A comprehensive exploration of the aminolysis mechanism for methyl indole-3-acetate with ammonia is carried out by employing the B3 LYP/6-311++G(d,p), M06-2 X/6-311++G(d,p) and MP2/6-311++G(d,p)//M06-2 X/6-311++G(d,p) levels. Two alterative reaction channels of the concerted and addition/elimination stepwise processes including the uncatalyzed, base-catalyzed reactions are taken into consideration. Subsequently, the substituent effects and solvent effects in methanol are also evaluated at the M06-2 X/6-311++G(d,p) level. The calculated results indicate that the calculated values of M06-2 X level are quite close to those of MP2, the stepwise pathway has more advantages to the concerted one for all of the reaction processes and the catalyst facilitates the proton migration and decreases the energy barriers as well. It is shown that the most preferred mechanism is the based-catalyzed stepwise process, the substituent of NH2 group slightly accelerates all the aminolysis reaction processes, and the solvent effect does not remarkably change the mechanism of the reaction.展开更多
Semicarbazones, 1,1-diacetates and acetals are efficiently converted to their corresponding carbonyl compounds using synergistic effect between KBrO3 and MoO3 in refluxing CH3CN-H2O in good to high yields.
Objective: To investigate the antioxidant and anti-caspase 3 effect of chitosan-Pinus merkusii extract nanoparticle on lead acetate-induced toxicity in rat testis. Methods: Chitosan-Pinus merkusii nanoparticles were i...Objective: To investigate the antioxidant and anti-caspase 3 effect of chitosan-Pinus merkusii extract nanoparticle on lead acetate-induced toxicity in rat testis. Methods: Chitosan-Pinus merkusii nanoparticles were identified by dynamic light scattering and scanning electron microscope. The male rats were divided into control group (rats were given with distilled water);lead acetate group [rats were injected with lead acetate 20 mg/kg body weight (BW) i.p.], and the treatment group (rats were given the chitosan-Pinus merkusii nanoparticle 150 mg;300 mg;600 mg/kg BW orally and were injected with lead acetate 20 mg/kg BW). The testis tissues were collected to evaluate the malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), histological evaluations of testis damage, and the caspase 3 mRNA expression was measured by reverse transcription-polymerase chain reaction. Results: The dynamic light scattering showed that the size of chitosan-Pinus merkusii nanoparticle was (530.2±38.2) nm. The scanning electron microscope images of the chitosan-Pinus merkusii nanoparticles showed an irregular shape, and the morphology surface showed the rough surface. The treatment with lead acetate resulted in significantly increasing MDA level and caspase 3 mRNA expression, and significantly decreasing level of SOD and GPx when compared with control group. The treatment with the chitosan-Pinus merkusii nanoparticle 600 mg/kg BW but not 150 and 300 mg/kg BW significantly decreased the MDA levels, caspase 3 mRNA expression, and also increased level of SOD and GPx when compared with lead acetate group. The lead acetate induced loss of the normal structure of testicular cells and necrosis, whereas treatment with chitosan-Pinus merkusii nanoparticle inhibited testicular cell necrosis. Conclusions: It can be concluded that chitosan-Pinus merkusii nanoparticle protects rat testis from oxidative damage and apoptosis caused by lead acetate, through increasing antioxidant and inhibiting caspase 3 expression.展开更多
The new title compound, chiral 2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been conf...The new title compound, chiral 2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been confirmed by IR, 1H NMR, 13C NMR, LC-MS (ESI) and single-crystal X-ray diffraction. (R)-2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl acetate crystallizes in monoclinic, space group P21/c with a = 11.867(2), b = 8.4087(2), c = 14.325(6) A^°, β = 117.59(2)°, Z = 4, V = 1266.9(6) A^°3, Dc = 1.307 g/cm^3, F(000) = 528, μ(MoKα) = 0.097 mm-1, R = 0.0453 and wR = 0.1237; (S)-2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl acetate belongs to the triclinic system, space group P with a = 8.2647(17), b = 8.7034(17), c = 9.5479(19) A^°, α = 105.33(3), β = 100.95(3), γ = 105.14(3)°, Z = 2, V = 614.1(2) A^°3, Dc = 1.348 g/cm^3, F(000) = 264, μ(MoKα) = 0.10 mm-1, R = 0.0613 and wR = 0.1037. Both of the molecules prefer to form crystal packing through C–H…O hydrogen bonds.展开更多
This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with t...This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.展开更多
Objective: To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods: In vitro anti-tumor activity was assayed in adenoma cells A549 and hum...Objective: To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods: In vitro anti-tumor activity was assayed in adenoma cells A549 and human liver cancer cells Bel-7402 using MTT method, and half-inhibitory concentration (IC50) were observed. In vivo the pulmonary adenoma LA795 cells was selected and the conventional assay method of anti-tumor activity was employed. 5, 7.5, 10 mg/kg of 17a α-D-homo-ethynylestradiol-3-acetate was administered by i.p., and tumor-inhibitory rate, thymus and spleen indexes, bone marrow cells (BMC) were observed. Results: IC50 of 17a α-D-homo-ethynylestradiol-3-acetate in vitro for A549 and Bel-7402 cells were 12.28 μg/ml and 17.79 μg/ml, respectively. In vivo the highest tumor-inhibitory rates for LA795 was 60.0% (P〈0.01). The drug had hardly any side-effect in spleen indexes, thymus indexes, and BMC compared with control mice. Nevertheless, compared with the positive control drug cyclophosphamide (CY), thymus and spleen indexes, BMC showed obvious differences (P〈0.01). Conclusion: 17a α-D-homo-ethynylestradiol-3-acetate has obvious anti-tumor activities in vitro and in vivo with low side-effect, thus worth further investigation.展开更多
文摘3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cyclodextrin molecule. The thermodynamic pararneters of thecomplexing process can be estimated utilizing the spectrophotometric data.
基金the China Scholarship Council(CSC)for funding(no.201806310116)。
文摘Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.
文摘BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.
基金supported by the National Natural Science Foundation of China–Guangdong Natural Science Foundation Joint Project (U1701234)。
文摘The sweet potato weevil(Cylas formicarius(Fab.)(Coleoptera: Brentidae)) is a pest that feeds on sweet potato(Ipomoea batatas(L.) Lam.(Solanales: Convolvulaceae)), causing substantial economic losses annually. However, no safe and effective methods have been found to protect sweet potato from this pest. Herbivore-induced plant volatiles(HIPVs)promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated. To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels. Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated. The production of(Z)-3-hexenyl acetate(z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm. Ipomoea batatas ocimene synthase(IbOS) is first reported here as a key gene in allo-ocimene synthesis. Insect-induced wounding promoted the production of the substrate,(Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene,respectively. Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils. These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.
基金the funding support from The Bioenergy Technologies Office (BETO) within the US DOE’s Office of Energy Efficiency and Renewable Energythe funding support from the American Recovery and Reinvestment Actsupported by the US DOE’s Office of Science, Biological and Environmental Research program through contract DE-AC02-05CH11231 between Lawrence Berkeley National Laboratory and the U.S. Department of Energy
文摘This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the solvent.The pretreatment was followed by enzymatic hydrolysis through which the process efficiency for biomass conversion to monomeric sugars was determined.The results show that 43 wt%of switchgrass was dissolved in IL after 2 h of pretreatment at 160℃ with 15 wt%solid loading.A 120 h enzymatic hydrolysis of the pretreated switchgrass results in 96%glucan and 98%xylan conversion.[C2C1Im][OAc]pretreatment has been successfully scaled up to 40 kg with improved sugar titers and yields relative to bench scale(6 kg).The mass flow of the overall process was established and the major scale-up challenges of the process were identified.
文摘AIM: To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action. METHODS: The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential (△Ψm) were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases (PI3K). RESULTS: Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time-and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 μmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt. CONCLUSION: Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.
基金Project supported by the National Natural Science Foundation of China (No. 20336010) and the National Basic Research Program (973)of China (No. 2003CB716008)
文摘Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.
基金supported by the Special Funds of the National Natural Science Foundation of China(No.11347161)
文摘A comprehensive exploration of the aminolysis mechanism for methyl indole-3-acetate with ammonia is carried out by employing the B3 LYP/6-311++G(d,p), M06-2 X/6-311++G(d,p) and MP2/6-311++G(d,p)//M06-2 X/6-311++G(d,p) levels. Two alterative reaction channels of the concerted and addition/elimination stepwise processes including the uncatalyzed, base-catalyzed reactions are taken into consideration. Subsequently, the substituent effects and solvent effects in methanol are also evaluated at the M06-2 X/6-311++G(d,p) level. The calculated results indicate that the calculated values of M06-2 X level are quite close to those of MP2, the stepwise pathway has more advantages to the concerted one for all of the reaction processes and the catalyst facilitates the proton migration and decreases the energy barriers as well. It is shown that the most preferred mechanism is the based-catalyzed stepwise process, the substituent of NH2 group slightly accelerates all the aminolysis reaction processes, and the solvent effect does not remarkably change the mechanism of the reaction.
基金The partial support of this work by the University of Guilan Research Council is gratefully acknowledged.
文摘Semicarbazones, 1,1-diacetates and acetals are efficiently converted to their corresponding carbonyl compounds using synergistic effect between KBrO3 and MoO3 in refluxing CH3CN-H2O in good to high yields.
文摘Objective: To investigate the antioxidant and anti-caspase 3 effect of chitosan-Pinus merkusii extract nanoparticle on lead acetate-induced toxicity in rat testis. Methods: Chitosan-Pinus merkusii nanoparticles were identified by dynamic light scattering and scanning electron microscope. The male rats were divided into control group (rats were given with distilled water);lead acetate group [rats were injected with lead acetate 20 mg/kg body weight (BW) i.p.], and the treatment group (rats were given the chitosan-Pinus merkusii nanoparticle 150 mg;300 mg;600 mg/kg BW orally and were injected with lead acetate 20 mg/kg BW). The testis tissues were collected to evaluate the malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), histological evaluations of testis damage, and the caspase 3 mRNA expression was measured by reverse transcription-polymerase chain reaction. Results: The dynamic light scattering showed that the size of chitosan-Pinus merkusii nanoparticle was (530.2±38.2) nm. The scanning electron microscope images of the chitosan-Pinus merkusii nanoparticles showed an irregular shape, and the morphology surface showed the rough surface. The treatment with lead acetate resulted in significantly increasing MDA level and caspase 3 mRNA expression, and significantly decreasing level of SOD and GPx when compared with control group. The treatment with the chitosan-Pinus merkusii nanoparticle 600 mg/kg BW but not 150 and 300 mg/kg BW significantly decreased the MDA levels, caspase 3 mRNA expression, and also increased level of SOD and GPx when compared with lead acetate group. The lead acetate induced loss of the normal structure of testicular cells and necrosis, whereas treatment with chitosan-Pinus merkusii nanoparticle inhibited testicular cell necrosis. Conclusions: It can be concluded that chitosan-Pinus merkusii nanoparticle protects rat testis from oxidative damage and apoptosis caused by lead acetate, through increasing antioxidant and inhibiting caspase 3 expression.
基金supported by the National Natural Science Foundation of China(No.31572042)Natural Science Foundation of Heilongjiang Province(B201303)the Research Science Foundation in Technology Innovation of Harbin(No.2015RAYXJ010)
文摘The new title compound, chiral 2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been confirmed by IR, 1H NMR, 13C NMR, LC-MS (ESI) and single-crystal X-ray diffraction. (R)-2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl acetate crystallizes in monoclinic, space group P21/c with a = 11.867(2), b = 8.4087(2), c = 14.325(6) A^°, β = 117.59(2)°, Z = 4, V = 1266.9(6) A^°3, Dc = 1.307 g/cm^3, F(000) = 528, μ(MoKα) = 0.097 mm-1, R = 0.0453 and wR = 0.1237; (S)-2-(3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl acetate belongs to the triclinic system, space group P with a = 8.2647(17), b = 8.7034(17), c = 9.5479(19) A^°, α = 105.33(3), β = 100.95(3), γ = 105.14(3)°, Z = 2, V = 614.1(2) A^°3, Dc = 1.348 g/cm^3, F(000) = 264, μ(MoKα) = 0.10 mm-1, R = 0.0613 and wR = 0.1037. Both of the molecules prefer to form crystal packing through C–H…O hydrogen bonds.
文摘This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.
基金the grant from Tianjin Nature Science Fund Key Item(No.043802411)
文摘Objective: To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods: In vitro anti-tumor activity was assayed in adenoma cells A549 and human liver cancer cells Bel-7402 using MTT method, and half-inhibitory concentration (IC50) were observed. In vivo the pulmonary adenoma LA795 cells was selected and the conventional assay method of anti-tumor activity was employed. 5, 7.5, 10 mg/kg of 17a α-D-homo-ethynylestradiol-3-acetate was administered by i.p., and tumor-inhibitory rate, thymus and spleen indexes, bone marrow cells (BMC) were observed. Results: IC50 of 17a α-D-homo-ethynylestradiol-3-acetate in vitro for A549 and Bel-7402 cells were 12.28 μg/ml and 17.79 μg/ml, respectively. In vivo the highest tumor-inhibitory rates for LA795 was 60.0% (P〈0.01). The drug had hardly any side-effect in spleen indexes, thymus indexes, and BMC compared with control mice. Nevertheless, compared with the positive control drug cyclophosphamide (CY), thymus and spleen indexes, BMC showed obvious differences (P〈0.01). Conclusion: 17a α-D-homo-ethynylestradiol-3-acetate has obvious anti-tumor activities in vitro and in vivo with low side-effect, thus worth further investigation.