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1.
Theriogenology ; 223: 1-10, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38642435

RESUMO

Heat stress reduces the number of Sertoli cells, which is closely related to an imbalanced redox status. Glutamate functions to maintain the equilibrium of redox homeostasis. However, the role of glutamate in heat treated Sertoli cells remains unclear. Herein, Sertoli cells from 3-week-old piglets were treated at 44 °C for 30 min (heat stress). Glutamate levels increased significantly following heat stress treatment, followed by a gradual decrease during recovery, while glutathione (GSH) showed a gradual increase. The addition of exogenous glutamate (700 µM) to Sertoli cells before heat stress significantly reduced the heat stress-induced apoptosis rate, mediated by enhanced levels of antioxidant substances (superoxide dismutase (SOD), total antioxidant capacity (TAC), and GSH) and reduced levels of oxidative substances (reactive oxygen species (ROS) and malondialdehyde (MDA)). Glutamate addition to Sertoli cells before heat stress upregulated the levels of glutamate-cysteine ligase, modifier subunit (Gclm), glutathione synthetase (Gss), thioredoxin (Trx1) and B-cell leukemia/lymphoma 2 (Bcl-2), and the ratio of phosphorylated Akt (protein kinase B)/total Akt. However, it decreased the levels of Bcl2-associated X protein (Bax) and cleaved-caspase 3. Addition of the inhibitor of glutaminase (Gls1), Bptes (Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide, 30 µM)to Sertoli cells before heat stress reversed these effects. These results inferred that glutamate rescued heat stress-induced apoptosis in Sertoli cells by enhancing activity of antioxidant enzymes and activating the Trx1-Akt pathway. Thus, glutamate supplementation might represent a novel strategy to alleviate the negative effect of heat stress.


Assuntos
Antioxidantes , Apoptose , Ácido Glutâmico , Resposta ao Choque Térmico , Proteínas Proto-Oncogênicas c-akt , Células de Sertoli , Transdução de Sinais , Animais , Células de Sertoli/efeitos dos fármacos , Células de Sertoli/metabolismo , Masculino , Apoptose/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Antioxidantes/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Suínos , Tiorredoxinas/metabolismo , Células Cultivadas
2.
Theriogenology ; 215: 281-289, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38103405

RESUMO

Heat stress leads to the accumulation of lipid peroxides in Sertoli cells. Unrestricted lipid peroxidation of catalyzed polyunsaturated fatty acids by Cytochrome P450 (CYP) drive the ferroptosis. However, little is known about the role of CYP cyclooxygenase in heat stress-induced ferroptosis in Sertoli cells. In this study, we investigated the relationship between CYP cyclooxygenase and heat stress-induced ferroptosis in porcine Sertoli cells, as well as whether Ras-JNK signaling is involved in the process. The results showed that heat stress significantly increased the expression of cytochrome P450 cyclooxygenase 2C9 (CYP2C9) and the content of epoxyeicosatrienoic acids (EETs), although there are no significant effect on the expression of cytochrome P450 cyclooxygenase 2J2 (CYP2J2) and cytochrome P450 cyclooxygenase 2C8 (CYP2C8). In addition, heat stress reduced the cell viability, the protein expression level of glutathione peroxidase 4 (GPX4) and Ferritin (all P < 0.01) while increased the level of intracellular reactive oxygen species (ROS) and the protein level of Transferrin receptor 1(TFR1) (both P < 0.01), as well as activating the Ras-JNK signaling pathway. Ferrostatin-1, a ferroptosis-specific inhibitor, reduced ROS levels and the protein level of TFR1 (both P < 0.01), but elevated the cell viability, the protein level of GPX4, and Ferritin (all P < 0.01). Sulfaphenazole, a specific inhibitor of CYP2C9 or two small interfering RNAs targaring CYP2C9 enhanced the cell viability (all P < 0.01), while reduced the content of EETs (all P < 0.01) and inhibited the Ras-JNK signaling and ferroptosis under heat stress. Salirasib, a specific inhibitor of Ras, significantly elevated the cell viability, whereas reduced the level of intracellular ROS and inhibited the phosphorylation of JNK, and alleviated heat stress-induced ferroptosis in porcine Sertoli cells. Notably, there is no effect on the expression of CYP2C9 and the content of EETs. These results indicate that heat stress can induce ferroptosis in Sertoli cells by increasing the expression of CYP2C9 and the content of EETs, which in true activates the Ras-JNK signaling pathway, but there is no feedback from Ras-JNK signaling to the expression of CYP2C9. Our study finds a novel heat stress-induced cell death model of Sertoli cells as well as providing the therapeutic potential for anti-ferroptosis.


Assuntos
Ferroptose , Células de Sertoli , Masculino , Animais , Suínos , Espécies Reativas de Oxigênio/metabolismo , Células de Sertoli/metabolismo , Citocromo P-450 CYP2C9/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Ciclo-Oxigenase 2/metabolismo , Resposta ao Choque Térmico , Ferritinas
3.
J Autism Dev Disord ; 2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36526869

RESUMO

In today's era, the number of people suffering from mental disorders has increased significantly, which has become a public health event, and its treatment plans and means are difficult, especially in the special environment of the post-epidemic era, traditional simple treatment cannot meet the ever-changing diseases. This article from the current situation of mental health and its treatment environment in our country, in the face of mental disorder crowd healing the practical significance of the innovation design, digital media curative cloud travel APP the research path of service design, technical implementation, operation methods, innovative thinking dimensions to explore how to age for people in the face of disorder in the outbreak of curative services digital media design. In order to provide some reference and reference value for the development of spiritual healing industry, the design ideas and methods of smart cloud tourism APP service are designed and studied in terms of user travel experience, service process optimization, service interface innovation and service contact point design.

4.
J Pineal Res ; 73(3): e12819, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35906194

RESUMO

Sertoli cells (SCs) provide structural and nutritional support for developing germ cells. Normal glucose metabolism of SCs is necessary for spermatogenesis. Melatonin could alleviate the effects of heat stress on spermatogenesis. However, the influences of heat stress on glucose metabolism in SCs remain unclear, and the potential protective mechanisms of melatonin on SCs need more exploration. In this study, boar SCs were treated at 43°C for 30 min, and different concentrations of melatonin were added to protect SCs from heat stress-induced impairment. These results showed that heat stress-induced oxidative stress caused cell apoptosis, inhibited the pentose phosphate pathway, and decreased the ATP content. Furthermore, heat stress increased the expressions of glucose intake- and glycolytic-related enzymes, which enhanced the glycolysis activity to compensate for the energy deficit. Melatonin relieved heat stress-induced oxidative stress and apoptosis by activating the Kelch-like ECH-associated protein 1 (KEAP1)/NF-E2-related factor 2 signaling pathway to increase the capacity of antioxidants. In addition, melatonin enhanced heat-shock protein 90 (HSP90) expression through melatonin receptor 1B (MTNR1B), thereby stabilizing hypoxia-inducible factor-1α (HIF-1α). Activation of the HIF-1α signaling pathway enhanced glycolysis, promoted the pentose phosphate pathway, and increased cell viability. Our results suggest that melatonin reprograms glucose metabolism in SCs through the MTNR1B-HSP90-HIF-1α axis and provides a theoretical basis for preventing heat stress injury.


Assuntos
Melatonina , Animais , Glucose/farmacologia , Proteínas de Choque Térmico HSP90/metabolismo , Resposta ao Choque Térmico , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Masculino , Melatonina/metabolismo , Melatonina/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Células de Sertoli/metabolismo , Suínos
5.
Polymers (Basel) ; 14(9)2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35566885

RESUMO

Natural hydrogels are growing in interest as a priority for wound healing. Plant polysaccharides have a variety of biological pharmacological activities, and chitosan hydrogels have proven strong antimicrobial effects, but hydrogels prepared with polysaccharides alone have certain deficiencies. Polysaccharides from flowers of Lonicera japonica Thunb. (LP) and the aerial parts of Mentha canadensis L. (MP) were extracted and oxidized by sodium periodate (NaIO4) and then cross-linked with oxidized-carboxymethylated chitosan (O-CCS) to develop oxidized plant- polysaccharides-chitosan hydrogels (OPHs). SEM observation showed that OPHs had porous interior structures with interconnecting pores. The OPHs showed good swelling, water-retention ability, blood coagulation, cytocompatibility properties, and low cytotoxicity (classed as grade 1 according to United States Pharmacopoeia), which met the requirements for wound dressings. Then the cutaneous wound-healing effect was evaluated in BALB/C mice model, after 7 days treatment, the wound-closure rate of OPHs groups were all greater than 50%, and after 14 days, all were greater than 90%, while the value of the control group was only 72.6%. Of them, OPH-2 and OPH-3 were more favorable to the wound-healing process, as the promotion was more significant. The plant polysaccharides and CS-based hydrogel should be a candidate for cutaneous wound dressings.

6.
Biomass Convers Biorefin ; : 1-17, 2022 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-35342681

RESUMO

In this study, the second-order model, Fick's second law of diffusion, and the Peleg model were used to evaluate the extraction kinetic model of polysaccharide (CPP) from Codonopsis pilosula. The characteristic functional groups, surface structure, and physical and chemical properties of CPP were analyzed by multi-spectroscopic and microscopic techniques. The results showed that the extraction process agreed well with the second-order model, Fick's second diffusion law, and Peleg model. Rheological tests showed that CPP exhibited different viscosity changes under different conditions (Solution viscosity was inversely proportional to temperature, time, etc.; proportional to polysaccharide concentration, Na+ content, etc.). CPP was composed of molecular aggregates composed of small particles, with more pore structure and basically completely decomposed at 130 °C. The hypoglycemic study showed that CPP had a strong inhibitory effect on α-glycosidase than α-amylase. The morphology and subsequent structural features, anti-diabetic potential, and rheological properties of CPP were revealed to provide a theoretical basis for the development of pharmaceutical preparations or health food and functional food for the treatment of diabetes. Supplementary Information: The online version contains supplementary material available at 10.1007/s13399-022-02518-w.

7.
Theriogenology ; 185: 6-15, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35344833

RESUMO

Heat stress reduces the number of Sertoli cells and impairs spermatogenesis. Mounting evidence indicates that lipid homeostasis is fundamental to cell survival. However, little is known about the role of lipid peroxides in the heat stress-induced apoptosis of Sertoli cells. In the present study, we used metabolomics to explore the changes of lipid peroxides in porcine Sertoli cells under heat stress using liquid chromatograph-mass spectrometry. These results showed a notable increase in the content of 8-hydroxyeicosatetraenoic acid (8-HETE), and 15-hydroxyeicosatetraenoic acid (15-HETE). Furthermore, we found that among arachidonate lipoxygenases, heat stress significantly increased the expression of arachidonate 15-lipoxygenase type B (ALOX15B). Moreover, baicalein, a specific inhibitor of ALOX15B, reduced the content of 8-HETE and 15-HETE, and decreased the apoptosis rate in heat stress-treated porcine Sertoli cells. In addition, baicalein and small interfering RNAs targeting ALOX15B increased the content of 8-HETE and 15-HETE, and activated the p38-p53 pathway, causing apoptosis in heat stress treated porcine Sertoli cells. Interestingly, a p38 inhibitor decreased the expression of ALOX15B, reduced the content of 8-HETE and 15-HETE, and decreased the expression of p53 and the apoptosis rate in heat stress treated porcine Sertoli cells. A p53 inhibitor had similar effect on Sertoli cells. These results indicated that heat stress enhanced the expression of ALOX15B, increased the content of 8-HETE and 15-HETE, and activated the p38-p53 pathway to cause apoptosis. ALOX15B and lipid peroxides obtained feedback from the p38-p53 pathway. Our findings will help to reveal the mechanism of lipid metabolism in Sertoli cells, and could provide a new targeted substrate for anti-heat stress strategies.


Assuntos
Peróxidos Lipídicos , Células de Sertoli , Animais , Apoptose , Resposta ao Choque Térmico , Peróxidos Lipídicos/farmacologia , Masculino , Suínos , Proteína Supressora de Tumor p53
8.
Biomed Mater ; 17(2)2022 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-35090145

RESUMO

The crude polysaccharide (CPNP) ofCodonopsis pilosulawas obtained by hot-water extraction technology. The extraction kinetic model established according to Fick's first law of diffusion and related parameters of polysaccharide was studied. CPNP microcapsules were prepared by blending with sodium alginate, Ca2+ions and crude CPNP. The quality control (drug loading rate, embedding rate and release rate, etc) of CPNP microcapsules were analyzed by pharmacopeas standards. The structure feature of CPNP microcapsules also were determined with various methods. The wound healing ability of CPNP microcapsules loading with different concentration of CPNP was evaluated using the rat wound model. The activity of various enzymes and the expression levels of pro-inflammatory factors in the model skin tissue also were determined by enzyme linked immunosorbent assay (ELISA). Hematoxylin-eosin staining (HE), Masson, immunohistochemistry were used to investigate the external application effect of CPNP microcapsules on skin wound repair. The extraction kinetics of CPNP was established with the linear correlation coefficient (R2) of 0.83-0.93, implied that the extraction process was fitted well with the Fick's first law of diffusion. The CPNP has good compatibility with sodium alginate and Ca2+ions by SEM and TEM observation, and the particle size of CPNP microcapsules was 21.25 ± 2.84 µm with the good degradation rate, loading rate (61.59%) and encapsulation rate (55.99%), maximum swelling rate (397.380 ± 25.321%). Compared with control group, the redness, and swelling, bleeding, infection, and exudate of the damaged skin decreased significantly after CPNP microcapsules treatment, and the CPNP microcapsules groups exhibited good wound healing function with less inflammatory cell infiltration. The pathological structure showed that in the CPNP microcapsules group, more newborn capillaries, complete skin structure, and relatively tight and orderly arrangement of collagen fibers were observed in the skin of rats. CPNP microcapsules could effectively inhibit the high expression of pro-inflammatory factors in damaged skin, and significantly increase the contents of related enzymes (GSH-Px, T-AOC, LPO) and collagen fibers. The relative expression levels of genes (VEGF and miRNA21) in the CPNP microcapsules group were higher than those in the model group and the negative group. The above results suggested that the CPNP microcapsules could controlled-release the CPNP to the wound surface, and then played a better role in antibacterial, anti-inflammatory and skin wound repair.


Assuntos
MicroRNAs , Cicatrização , Animais , Cápsulas , Cinética , Polissacarídeos , Ratos , Pele
9.
Biomed Mater ; 16(4)2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33626520

RESUMO

In this study, the extraction conditions ofNostoc communeVauch polysaccharide (NCVP) were optimized by single factor and orthogonal experiments. Then, the NCVP microcapsules (NCVPM) were prepared. After analyzing the microcapsule structural and thermal characteristics, the skin wound healing ability was studied by establishing back trauma rat models. Results showed that the NCVP yield was 10.37% under the following optimum conditions: 210 min extraction time, solid-liquid ratio of 1:50 and extraction temperature of 90 °C. The overall performance of the microcapsule was the best when the concentration of sodium alginate, calcium chloride and chitosan was 2%, 3% and 0.3%, respectively. NCVPM had spherical morphology, typical microcapsule structural characteristics and good thermal stability, and NCVP was dispersed in the microcapsules. NCVPM showed good biocompatibility and biodegradability, which met the requirements for slow-release polymer materials. After 14 days of treatment, the wound healing rate was 92.4%, the cells were arranged neatly and regularly, the cell nucleus became large and elliptical, the cell had a tendency to divide, and the fibers and microvessel were significantly more. By evaluating the mechanism, NCVPM could increase the content of hydroxyproline and glutathione to protect cells from oxidative damage, leading in turn to accelerated wound healing and shorter wound healing times. It could also accelerate cell division, collagen and microvascular production by increasing transcription levels of vascular endothelial growth factor mRNA and miRNA-21.


Assuntos
Quitosana , Cicatrização , Animais , Cápsulas , Quitosana/química , Polissacarídeos/química , Ratos , Fator A de Crescimento do Endotélio Vascular/metabolismo
10.
RSC Adv ; 9(66): 38477-38485, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-35540228

RESUMO

Ca/ZrCu/ZSM-5 catalysts containing different Zr contents were prepared by incipient wetness impregnation. The catalysts were tested for the selective catalytic reduction (SCR) of NO x with ammonia and characterized by N2-BET, N2O titration, XRD, NH3-TPD, H2-TPR, and XPS techniques. In the temperature range of 100-170 °C, after calcium impregnation, NO x conversion over the Cu/ZSM-5 catalyst decreased by 11.3-24.3%, while that over Zr0.10/Cu/ZSM-5 only decreased by 3.8-12.2%. The improvement of the calcium poisoning resistance of the ZrCu/ZSM-5 catalyst is mainly attributed to an increase in the dispersion and the surface concentration of Cu. Moreover, the addition of zirconium promotes the reduction of CuO by decreasing the interaction between CuO and CaO, which also contributes to the improvement of resistance to CaO poisoning. The apparent activation energy and turnover frequency for the SCR reaction over the Ca/Zr x Cu/ZSM-5 catalysts were calculated and discussed.

11.
Arch Biochem Biophys ; 637: 48-55, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29191386

RESUMO

Accumulating documents have revealed that microRNAs (miRNAs) play critical roles in the development and progression of tumors. MiR-429 has been reported to be involved in regulating various cellular processes. However, its biological role and underlying mechanism in hepatocellular carcinoma (HCC) still need to be further studied. The present study aimed to investigate the function of miR-429 in the progression of HCC. In terms of this paper, it was found that miR-429 was down-regulated in HCC tissues and cells. After being transfected with miR-429 mimics, miR-429 decreased the migratory capacity and reversed the EMT to MET in HCC cells. RAB23 was confirmed as a target of miR-429. Rescue assays further verified that the function of miR-429 in HCC cells was exerted through targeting RAB23. In general, it was concluded that the signal pathway miR-429/RAB23 might be a potential target for HCC treatment.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Proteínas rab de Ligação ao GTP/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/secundário , Linhagem Celular Tumoral , Movimento Celular , Regulação para Baixo , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , MicroRNAs/metabolismo , Mimetismo Molecular , Transdução de Sinais , Transfecção , Regulação para Cima , Proteínas rab de Ligação ao GTP/metabolismo
12.
Opt Lett ; 42(17): 3315-3318, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28957092

RESUMO

An initial roughness is assumed in the most accepted Sipe-Drude model to analyze laser-induced periodic surface structures (LIPSS). However, the direct experimental observation for the crucial parameters is still lacking. The generation of nanoparticles and low-spatial frequency LIPSS (LSFL) (LIPSS with a periodicity close to laser wavelength) on a silicon surface upon a single pulse and subsequent pulses irradiation, respectively, is observed experimentally. Finite-difference time-domain (FDTD) simulation indicates that the nanoparticles generated with the first pulse enhance the local electric field greatly. Based on the experimental extrapolated parameters, FDTD-η maps have been calculated. The results show that the inhomogeneous energy deposition, which leads to the formation of LSFL, is mainly from the modulation of the nanoparticles with a radius of around 100 nm.

13.
Nat Prod Res ; 31(21): 2527-2530, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28423923

RESUMO

A new wortmannine derivative named wortmannine E (1) was isolated from Talaromyces wortmannii LGT-4, an endophytic fungus of Tripterygium wilfordii. Its structure was established by 1D and 2D NMR spectra.


Assuntos
Androstadienos/química , Talaromyces/química , Tripterygium/microbiologia , Androstadienos/isolamento & purificação , Endófitos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Wortmanina
14.
Fitoterapia ; 113: 158-63, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27520493

RESUMO

Four novel lactams, colletotrilactam A-D (1-4), along with six known compounds (5-10) were isolated from the culture broth of Colletotrichum gloeosporioides GT-7, a fungal endophyte of Uncaria rhynchophylla. The structures of these compounds were elucidated by comprehensive NMR spectroscopy. Isolates were tested for monoamine oxidase (MAO) inhibitory activity and compound 9 showed potent MAO inhibitory activity with IC50 value of 8.93±0.34µg/mL, when the IC50 value of iproniazid as a standard was 1.80±0.5µg/mL.


Assuntos
Colletotrichum/química , Lactamas/química , Inibidores da Monoaminoxidase/química , Uncaria/microbiologia , Endófitos/química , Lactamas/isolamento & purificação , Estrutura Molecular , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/isolamento & purificação
15.
J Nat Prod ; 69(10): 1425-8, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17067155

RESUMO

Two new guaianolides, named chinensiolides D (5) and E (6), were isolated from Ixeris chinensis Nakai, and their structures were determined to be 10alpha-hydroxy-3-oxoguaia-11(13)-eno-12,6alpha-lactone (5) and 10alpha-hydroxy-3beta-O-[2,6-di(p-hydroxyphenylacetyl)-beta-glucopylanosyl]guaia-4(15),11(13)-dieno-12,6alpha-lactone (6). The first isolation of (11S)-10alpha-hydroxy-3-oxoguaia-4-eno-12,6alpha-lactone (4) from natural sources and its characterization are also reported. Chinenciolide E (6) showed significant growth inhibitory activity toward VA-13 malignant lung tumor cells (IC50 = 0.72 microM).


Assuntos
Antineoplásicos Fitogênicos , Asteraceae/química , Medicamentos de Ervas Chinesas , Plantas Medicinais/química , Sesquiterpenos de Guaiano , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Medicamentos de Ervas Chinesas/farmacologia , Humanos , Concentração Inibidora 50 , Molécula 1 de Adesão Intercelular/biossíntese , Molécula 1 de Adesão Intercelular/efeitos dos fármacos , Estrutura Molecular , Sesquiterpenos de Guaiano/química , Sesquiterpenos de Guaiano/isolamento & purificação , Sesquiterpenos de Guaiano/farmacologia , Células Tumorais Cultivadas
16.
J Nat Prod ; 65(12): 1927-9, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12502342

RESUMO

Three new guaianolides, 10alpha-hydroxy-3-oxoguaia-4(15),11(13)-dieno-12,6alpha-lactone (1), 10alpha-hydroxy-3-oxo-4betaH-guaia-11(13)-eno-12,6alpha-lactone (2), and 10alpha-hydroxy-3-oxoguaia-4,11(13)-dieno-12,6alpha-lactone (3), named chinensiolides A, B, and C were isolated from the whole plant of Siyekucai (Ixeris chinensis). The structures were determined by HREIMS, UV, IR, and one- and two-dimensional NMR techniques ((1)H and (13)C NMR, COSY, HMQC, HMBC, and NOE difference and NOESY experiments). Compounds 1 and 2 were indicated to be a mixture of flexible conformers by analyses of their 1D NOE and NOESY spectra as well as the temperature dependence of their (1)H and (13)C NMR spectra. Chinensiolide B (2) was transformed to chinensiolide C (3) in a three-step conversion.


Assuntos
Asteraceae/química , Lactonas/química , Lactonas/isolamento & purificação , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Catálise , China , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Temperatura
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