Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 11(1): 2442, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415220

RESUMO

Berry phase associated with energy bands in crystals can lead to quantised observables like quantised dipole polarizations in one-dimensional topological insulators. Recent theories have generalised the concept of quantised dipoles to multipoles, resulting in the discovery of multipole topological insulators which exhibit a hierarchy of multipole topology: a quantised octupole moment in a three-dimensional bulk induces quantised quadrupole moments on its two-dimensional surfaces, which in turn induce quantised dipole moments on one-dimensional hinges. Here, we report on the realisation of an octupole topological insulator in a three-dimensional acoustic metamaterial. We observe zero-dimensional topological corner states, one-dimensional gapped hinge states, two-dimensional gapped surface states, and three-dimensional gapped bulk states, representing the hierarchy of octupole, quadrupole and dipole moments. Conditions for forming a nontrivial octupole moment are demonstrated by comparisons with two different lattice configurations having trivial octupole moments. Our work establishes the multipole topology and its full hierarchy in three-dimensional geometries.

2.
Nat Commun ; 10(1): 5185, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31729392

RESUMO

Three-dimensional (3D) gapless topological phases can be classified by the dimensionality of the band degeneracies, including zero-dimensional (0D) nodal points, one-dimensional (1D) nodal lines, and two-dimensional (2D) nodal surfaces. Both nodal points and nodal lines have been realized recently in photonics and acoustics. However, a nodal surface has never been observed in any classical-wave system. Here, we report on the experimental observation of a twofold symmetry-enforced nodal surface in a 3D chiral acoustic crystal. In particular, the demonstrated nodal surface carries a topological charge of 2, constituting the first realization of a higher-dimensional topologically-charged band degeneracy. Using direct acoustic field measurements, we observe the projected nodal surface and its Fermi-arc-like surface states and demonstrate topologically-induced robustness of the surface states against disorders. This discovery of a higher-dimensional topologically-charged band degeneracy paves the way toward further explorations of the physics and applications of new topological semimetal phases.

3.
Adv Sci (Weinh) ; 6(20): 1901307, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31637167

RESUMO

It is reported both experimentally and numerically that dual-band acoustic Fano resonances (AFRs) of low-frequency sound are realized by a compound unit array composed of two types of multiple-cavity unit cells with different inner radii. Eigenmode analyses show that two types of monopolar Mie resonance (MMR) modes can be observed below 650 Hz, which arise from the coupling resonance of the overall structure and the Helmholtz resonance of each resonance cavity, respectively. Based on the MMRs with the out-of-phase characteristic induced by the mutual coupling of the two types of unit cells, the dual-band AFRs, in which the quality factor of the AFR II can exceed 600 when the ratio of the inner radii is closed to 1.0, can be observed. More interestingly, the application of the dual-band AFRs in sound encryption communication is further discussed. The proposed multiple-cavity unit cell and its associated dual-band AFRs provide diverse routes to design multiband sound devices with versatile applications, such as filtering, sensing, and communication.

4.
Sci Rep ; 9(1): 8355, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175315

RESUMO

The recent rapid development of acoustic logic devices has opened up the possibilities of sound computing and information processing. However, simultaneous realization of acoustic logic devices with subwavelength size, broad bandwidth and passive structure still poses a great challenge. To overcome it, we propose a subwavelength acoustic logic gate which consists of binary-phase passive unit cells placed into a multi-port waveguide. Based on the phase manipulations of the unit cells, we experimentally and numerically realize three basic logic gates OR, NOT and AND, and a composite logic gate XOR with a uniform threshold of 0.4 Pa based on linear acoustic interferences. More importantly, We also design a composite logic gate XNOR by a four-port waveguide, and composite logic gates NOR and NAND and a logic operation A⊙(B+C) based on two logic gates. We demonstrate a 0.6λ-length, 0.3λ-width, and 0.2-fractional bandwidth acoustic logic gate constructed by passive structures, which may lead to important advances in various applications, such as acoustic computing, acoustic information processing and integrated acoustics.

5.
Adv Mater ; 30(46): e1805002, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30294812

RESUMO

Topological acoustics has recently revolutionized fundamental concepts of acoustic propagation, giving rise to strikingly unique acoustic edge modes immune to backscattering. Despite the rapid progress in this field, simultaneous realization of reconfigurability, intelligentization, and automatic control over acoustic propagation paths is posing a great challenge. This challenge is overcome by proposing the concept of a programmable acoustic topological insulator based on two digital elements "0" or "1," which consist of honeycomb-lattice sonic crystals made of cylindrical rods with different diameters. The acoustic propagation paths in the topological insulators can be controlled automatically by programming different coding sequences, which arises from efficient transformation of pseudospin-dependent edge modes on both interfaces of the digital elements. More importantly, a unique unit is experimentally fabricated that has either a "0" or "1" response automatically manipulated by an air cylinder, and design topological insulators with programmable functionality, to realize three digital acoustic devices, such as a single-pole double-throw switch, a single-pole single-throw switch, and a tunable logic gate. The proposed programmable topological insulators may enable future intelligent acoustic devices with exciting reconfigurable and programmable functionalities, which may lead to important advances in various applications, such as integrated acoustics, acoustic security, and information processing.

6.
Sci Rep ; 7(1): 8151, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28811586

RESUMO

Acoustic metamaterials and metasurfaces provide great flexibility for manipulating sound waves and promise unprecedented functionality, ranging from transformation acoustics, acoustic cloaking, acoustic imaging to acoustic rerouting. However, the design of artificial structures with both broad bandwidth and multifunctionality remains challenging with traditional design approaches. Here we present a design and realization of a broadband acoustic metafiber bundle. Very different from previously reported acoustic metamaterials and metasurfaces, not only the metafiber structure is simple, flexible and tunable, but also the metafiber bundle has the advantages of broad bandwidth, high transmission, no resonance-induced energy loss and unchangeable output wavefront owing to eigenmodes in the passbands of the metafiber. Besides, it could also achieve arbitrary complex modulations of cylindrical and plane acoustic wavefronts. The metafiber bundles realize the exciting multifunctionality of both acoustic metamaterials and metasurfaces in a broad frequency range, which provides diverse routes to design novel acoustic devices with versatile applications.

7.
Rev Sci Instrum ; 87(8): 084901, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27587144

RESUMO

We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

8.
Eur J Pharmacol ; 789: 370-384, 2016 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-27448502

RESUMO

Stephanthraniline A (STA), a C21 steroid isolated from Stephanotis mucronata (Blanco) Merr., was previously shown to inhibit T cells activation and proliferation in vitro and in vivo. The purpose of this study was to further evaluate the in vivo immunosuppressive activity of STA and to elucidate its potential mechanisms. The results showed that pretreatment with STA significantly attenuated concanavalin A (Con A)-induced hepatitis and reduced CD4(+) T cells activation and aggregation in hepatic tissue in mice. STA directly suppressed the activation and proliferation of Con A-induced CD4(+) T cells, and inhibited NFAT, NFκB and MAPK signaling cascades in activated CD4(+) T cells in vitro. Moreover, it was proved that STA inhibited T cells activation and proliferation through proximal T cell-receptor (TCR) signaling- and Ca(2+) signaling-independent way. The molecular docking studies predicted that STA could tight bind to PKCθ via five hydrogen. The further findings indicated STA directly inhibited PKCθ kinase activity, and its phosphorylation in activated CD4(+) T cells in vitro. Collectively, the present study indicated that STA could protect against CD4(+) T cell-mediated immunological hepatitis in mice through PKCθ and its downstream NFAT, NFκB and MAPK signaling cascades. These results highlight the potential of STA as an effective leading compound for use in the treatment of CD4(+) T cell-mediated inflammatory and autoimmune diseases.


Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Diterpenos/farmacologia , Hepatite/tratamento farmacológico , Hepatite/imunologia , Isoenzimas/antagonistas & inibidores , Ativação Linfocitária/efeitos dos fármacos , Proteína Quinase C/antagonistas & inibidores , Animais , Sinalização do Cálcio/efeitos dos fármacos , Domínio Catalítico , Agregação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Diterpenos/metabolismo , Diterpenos/uso terapêutico , Feminino , Hepatite/metabolismo , Hepatite/patologia , Isoenzimas/química , Isoenzimas/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Simulação de Acoplamento Molecular , NF-kappa B/metabolismo , Fatores de Transcrição NFATC/metabolismo , Fosforilação/efeitos dos fármacos , Proteína Quinase C/química , Proteína Quinase C/metabolismo , Proteína Quinase C-theta , Proteínas Quinases/metabolismo
9.
Phytomedicine ; 23(5): 460-7, 2016 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-27064004

RESUMO

BACKGROUND: Compounds that possess a pyrrolidone skeleton are a rich resource for the discovery of nootropic drugs. Oleracein E (OE), which possesses both tetrahydroisoquinoline and pyrrolidone skeletons, was first isolated from the medicinal plant Portulaca oleracea L. and was thought to be an active component in the cognition-improvement effect induced by this herb. The aim of this study was to investigate the effect of OE on cognitive impairment in senescent mice and its underlying mechanism of action. METHOD: Senescent Kunming mice were established by the intraperitoneal injection of D-galactose (D-gal, 1250 mg/kg/d) and NaNO2 (90 mg/kg/d) for 8 weeks. OE (3 mg/kg/d, 15 mg/kg/d) was orally administered for 8 weeks, and the nootropic drug piracetam (PA, 400 mg/kg/d) was used as a positive control. A Morris water maze was used to assess cognitive ability. GSH and MDA levels and T-AOC, SOD, and CAT activities in the brain or plasma were determined. Hippocampal morphology was observed by HE staining, and expression of the anti-apoptotic protein Bcl-2 and the pro-apoptotic proteins Bax and Caspase-3 was observed by immunohistochemical staining. RESULTS: Large-dosage treatments with D-gal/NaNO2 for 8 weeks significantly reduced survival, impaired spatial memory capacity, compensatorily up-regulated GSH level and T-AOC and SOD activities, decreased CAT activity, and induced hippocampal neuronal damage and apoptosis as reflected by the apparent low expression of Bcl-2 and high expression of Bax and Caspase-3. OE significantly prolonged lifespan and was more potent than PA. Similar to PA, OE at 15 mg/kg/d improved memory capacity. The underlying mechanism of action was related to the reversal of abnormal brain antioxidant biomarkers (GSH, T-AOC, and SOD) to normal levels and the inhibition of hippocampal neuronal apoptosis. CONCLUSION: OE from P. oleracea is an active compound for improving cognitive function and is also a candidate nootropic drug for the treatment of age-related dementia.


Assuntos
Alcaloides/farmacologia , Transtornos da Memória/tratamento farmacológico , Nootrópicos/farmacologia , Fenóis/farmacologia , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Cognição/efeitos dos fármacos , Transtornos Cognitivos/tratamento farmacológico , Galactose/efeitos adversos , Hipocampo/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Camundongos , Piracetam/farmacologia , Portulaca/química , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Nitrito de Sódio/efeitos adversos , Superóxido Dismutase/metabolismo , Taxa de Sobrevida , Proteína X Associada a bcl-2/metabolismo
10.
J Nat Prod ; 78(11): 2588-97, 2015 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-26562741

RESUMO

A polyamide column chromatography method using an aqueous ammonia mobile phase was developed for large-scale accumulation of water-soluble indoline amide glucosides from a medicinal plant, Portulaca oleracea. Ten new [oleraceins H, I, K, L, N, O, P, Q, R, S (1-10)] and four known [oleraceins A-D (11-14)] indoline amide glucosides were further purified and structurally characterized by various chromatographic and spectroscopic methods. The DPPH radical scavenging activities of oleraceins K (5) and L (6), with EC50 values of 15.30 and 16.13 µM, respectively, were twice that of a natural antioxidant, vitamin C; the EC50 values of the 12 other indoline amides, which ranged from 29.05 to 43.52 µM, were similar to that of vitamin C. Structure-activity relationships indicated that the DPPH radical scavenging activities of these indoline amides correlate with the numbers and positions of the phenolic hydroxy groups.


Assuntos
Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Compostos de Bifenilo/farmacologia , Medicamentos de Ervas Chinesas/isolamento & purificação , Medicamentos de Ervas Chinesas/farmacologia , Depuradores de Radicais Livres/isolamento & purificação , Depuradores de Radicais Livres/farmacologia , Indóis/isolamento & purificação , Indóis/farmacologia , Fenóis/isolamento & purificação , Fenóis/farmacologia , Picratos/farmacologia , Plantas Medicinais/química , Portulaca/química , Alcaloides/química , Antioxidantes/química , Medicamentos de Ervas Chinesas/química , Depuradores de Radicais Livres/química , Glucosídeos/química , Indóis/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Fenóis/química , Componentes Aéreos da Planta/química , Relação Estrutura-Atividade
11.
J Ethnopharmacol ; 153(3): 831-9, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24690776

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: The larvae of Musca domestica (Diptera: Muscidae) have been used traditionally for malnutritional stagnation, decubital necrosis, osteomyelitis, ecthyma and lip scald and also to treat coma and gastric cancer in the traditional Chinese medicine. Its in vitro antitumor activity and immunomodulatory effect in naïve mice in relation to the traditional uses were also reported. However, the in vivo antitumor effect of this insect and its mechanism of action have not yet been well studied. The objectives of this study were to evaluate the in vivo antitumor potential of the peptide fraction from Musca domestica larvae (MDPF) and to elucidate its immunological mechanisms. MATERIALS AND METHODS: The mice inoculated with sarcoma S180 cells were orally administered with MDPF at three doses for 10 days. The effects of MDPF on the growth of mouse S180 sarcoma, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), production and mRNA expression of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured. RESULTS: MDPF could significantly not only inhibit the growth of mouse transplanted S180 sarcoma, but also promote splenocytes proliferation, NK cell and CTL activity from splenocytes, and enhance serum antigen-specific IgG, IgG2a and IgG2b antibody levels in S180-bearing mice. MDPF also significantly promoted the production of IFN-γ and up-regulated the mRNA expression levels of IFN-γ and Th1 transcription factors T-bet and STAT-4 in splenocytes from the S180-bearing mice. However, Th2 cytokine IL-10 and transcription factors GATA-3 and STAT-6 were not significantly changed both at transcriptional and protein levels following MDPF treatment. CONCLUSIONS: MDPF significantly inhibit the growth of transplantable tumor in mice and its in vivo antitumor activity might be achieved by switching-on of Th1-based protective cell-mediated immunity. MDPF could act as antitumor agent with immunomodulatory activity.


Assuntos
Antineoplásicos , Produtos Biológicos , Moscas Domésticas , Fatores Imunológicos , Peptídeos , Sarcoma 180/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Linhagem Celular Tumoral , Feminino , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Interferon gama/genética , Interferon gama/imunologia , Interleucina-10/genética , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Larva/química , Masculino , Camundongos Endogâmicos ICR , Peptídeos/farmacologia , Peptídeos/uso terapêutico , RNA Mensageiro/metabolismo , Sarcoma 180/imunologia , Baço/citologia , Baço/imunologia , Linfócitos T Citotóxicos/efeitos dos fármacos , Linfócitos T Citotóxicos/imunologia , Fatores de Transcrição/genética
12.
J Acoust Soc Am ; 131(2): EL150-5, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22352615

RESUMO

A two-dimensional cylindrical acoustic concentrator is designed with multilayered alternative homogeneous materials, which can focus acoustic field and enhance acoustic energy in a given area. The frequency response analysis of the acoustic concentrator demonstrates that the acoustic energy can be concentrated within the device over a wide frequency band. Meanwhile, there are contradictory relations between the acoustic concentrating performances in the inner region and the scattering properties in the outer region of these concentrators. When the contradictory relations satisfy compromise balance, the concentration ratio can reach at least 70%.

13.
Chem Biodivers ; 7(3): 677-89, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20232336

RESUMO

The development of an effective influenza vaccine is urgently important for controlling outbreaks of the highly pathogenic avian influenza virus (HPAIV) and reducing the impact of pandemics. The use of an adjuvant in such a vaccine can significantly contribute to improve the immunogenicity. To explore a novel and safe adjuvant for improving the potency of influenza vaccines, platycodin D (1), a saponin from the root of Platycodon grandiflorum, was evaluated for the adjuvant potentials on the specific cellular and humoral immune responses to Newcastle disease virus-based recombinant avian influenza vaccine (rL-H5) in mice. Compound 1 significantly promoted the concanavalin A (Con A)-, the lipopolysaccharide (LPS)-, and the antigen-induced splenocyte proliferation and enhanced the serum antigen-specific IgG, IgG1, IgG2a, and IgG2b antibody titers (P<0.05, P<0.01, or P<0.001) in mice immunized with rL-H5. The mRNA expressions of Th1/Th2 cytokines (IFN-gamma and IL-10) and transcription factors (T-bet and GATA-3) in splenocytes were also markedly up-regulated by 1, compared with the control group immunized with rL-H5 alone (P<0.01 or P<0.001). In addition, 1 remarkably increased the killing activities of natural killer (NK) cells from splenocytes in the immunized mice (P<0.05), which may have important implications for the vaccination against the avian influenza virus. We concluded that 1 could improve the immunogenicity of the rL-H5 vaccine by enhancing both humoral and cellular immune responses in mice, and that 1 is a promising adjuvant for influenza vaccines.


Assuntos
Adjuvantes Imunológicos/farmacologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Saponinas/farmacologia , Triterpenos/farmacologia , Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/isolamento & purificação , Animais , Anticorpos Antivirais/sangue , Aves , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Camundongos , Vírus da Doença de Newcastle/genética , Raízes de Plantas/química , Platycodon/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Saponinas/química , Saponinas/isolamento & purificação , Triterpenos/química , Triterpenos/isolamento & purificação
14.
Chem Biodivers ; 7(1): 178-85, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20087984

RESUMO

Platycodin D2 (1), a less hemolytic saponin from the root of Platycodon grandiflorum than platycodin D (2), was evaluated for the potential to enhance specific cellular and humoral immune responses to hepatitis B surface antigen (HBsAg) in mice. It significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and HBsAg-induced splenocyte proliferation in HBsAg-immunized mice (P<0.05, P<0.01, and P<0.001, resp.). HBsAg-specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the serum were also markedly enhanced by 1 compared to the HBsAg control group (P<0.01 or P<0.001). Moreover, 1 significantly promoted the production of Th1 (IL-2 and IFN-gamma) and Th2 (IL-4 and IL-10) cytokines from splenocytes in the HBsAg-immunized mice (P<0.001). The adjuvant potential of 1 on splenocyte proliferation, serum HBsAg-specific IgG2a and IgG2b antibody response, as well as Th1-cytokine secretion from splenocytes in the HBsAg-immunized mice was higher than that of Alum. The results suggest that 1 could improve both cellular and humoral immune responses to HBsAg in mice. Hence, 1 might be a promising adjuvant for hepatitis B vaccine with dual Th1- and Th2-potentiating activity.


Assuntos
Adjuvantes Imunológicos/química , Antígenos de Superfície da Hepatite B/imunologia , Platycodon/química , Saponinas/química , Adjuvantes Imunológicos/farmacologia , Animais , Citocinas/metabolismo , Imunoglobulina G/metabolismo , Camundongos , Raízes de Plantas/química , Saponinas/farmacologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologia , Células Th2/metabolismo , Triterpenos/química
15.
Immunopharmacol Immunotoxicol ; 31(4): 625-30, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19874232

RESUMO

Artemisia annua has been widely used to treat autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis in traditional Chinese medicine. In this study, the ethanol extract of A. annua (EEAA) was evaluated for the immunosuppressive potentials on mice splenocyte proliferation in vitro, and the specific antibody and cellular immune responses in the ovalbumin (OVA)-immunized mice. EEAA significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. EEAA also significantly suppressed Con A-, LPS- and OVA-induced splenocyte proliferation in the OVA-immunized mice in a dose-dependent manner. Meanwhile, the OVA-specific serum IgG, IgG1 and IgG2b antibody levels in the OVA-immunized mice were markedly reduced by EEAA. The results suggest that EEAA could suppress the cellular and humoral response in mice. This study provided evidence to understand the therapeutic effects of A. annua for treatment of some autoimmune diseases and an immunosuppressive natural products to further researches to be developed as immunosuppressant.


Assuntos
Artemisia annua/imunologia , Medicamentos de Ervas Chinesas/farmacologia , Imunoglobulina G/farmacologia , Imunossupressores/farmacologia , Ovalbumina/imunologia , Animais , Proliferação de Células , Células Cultivadas , Medicamentos de Ervas Chinesas/isolamento & purificação , Etanol/farmacologia , Feminino , Imunoglobulina G/sangue , Imunossupressores/isolamento & purificação , Camundongos , Camundongos Endogâmicos ICR , Ovalbumina/farmacologia , Componentes Aéreos da Planta , Baço/citologia , Baço/efeitos dos fármacos , Baço/imunologia
16.
Chem Biodivers ; 6(8): 1243-53, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19697343

RESUMO

3beta,6beta-dihydroxyolean-12-en-27-oic acid (1) is a pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis. To evaluate the in vivo antitumor potential and to elucidate its immunological mechanisms, effect of 1 on the growth of mouse-transplantable tumors, and the immune response in naive and tumor-bearing mice were investigated. The mice inoculated with mouse tumor cell lines were orally treated with 1 at the doses of 40, 60, and 80 mg/kg for 10 days. The effects of 1 on the growth of mouse-transplantable S180 sarcoma and H22 hepatoma, splenocyte proliferation, cytotoxic T lymphocyte (CTL) activity, natural killer (NK) cell activity, and production of interleukin-2 (IL-2) from splenocytes in S180-bearing mice were measured. Furthermore, the effect of 1 on 2,4-dinitrofluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) reactions and the sheep red blood cell (SRBC)-induced antibody response in naive mice were also studied. Compound 1 could not only significantly inhibit the growth of mouse transplantable S180 sarcoma and H22 hepatoma, increase splenocytes proliferation, CTL and NK cell activity, and the level of IL-2 secreted by splenocytes in tumor-bearing mice, but also remarkably promote the DTH reaction and enhance anti-SRBC antibody titers in naive mice. These results suggested that 1 could improve both cellular and humoral immune response, and could act as antitumor agent with immunomodulatory activity.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Fatores Imunológicos/uso terapêutico , Ácido Oleanólico/análogos & derivados , Animais , Feminino , Hipersensibilidade Tardia/tratamento farmacológico , Interleucina-2/metabolismo , Masculino , Camundongos , Ácido Oleanólico/uso terapêutico , Sarcoma 180/tratamento farmacológico
17.
Chem Biodivers ; 6(6): 916-23, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19551733

RESUMO

Stemucronatoside L (SML), isolated from Stephanotis mucronata, could suppress the activation of T cells in vitro. However, the mechanisms responsible for its immunosuppressive activity remain poorly understood. The purpose of this study was to investigate whether SML could suppress Th1/Th2 immune responses and to characterize the cellular mechanisms involved. Effects of SML on T-lymphocyte subsets and the production of Th1 cytokines IL-2 and IFN-gamma, and Th2 cytokines IL-4 and IL-10 from ConA-stimulated mice splenocytes were detected by flow-cytometric analysis and ELISA method, respectively. Furthermore, effects of SML on mRNA expression level of Th1/Th2 cytokines and transcription factors T-bet and GATA-3 were evaluated by RT-PCR analysis. SML not only significantly decreased the percentage of CD4(+) T cells and the CD4(+)/CD8(+) ratio, but reduced the production of Th1/Th2 cytokines in a concentration-dependent manner. The mRNA expression levels of Th1/Th2 cytokines and transcription factors (T-bet and GATA-3) were also suppressed by SML. These results suggested that SML could simultaneously inhibit Th1/Th2 immune responses by suppressing gene expression of Th1/Th2 cytokines and transcription factors.


Assuntos
Apocynaceae/química , Glicosídeos/química , Raízes de Plantas/química , Pregnanos/química , Saponinas/química , Células Th1/efeitos dos fármacos , Células Th2/efeitos dos fármacos , Animais , Concanavalina A/farmacologia , Feminino , Fator de Transcrição GATA3/genética , Fator de Transcrição GATA3/metabolismo , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Interferon gama/genética , Interferon gama/metabolismo , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-2/genética , Interleucina-2/metabolismo , Interleucina-4/genética , Interleucina-4/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Pregnanos/isolamento & purificação , Pregnanos/farmacologia , Saponinas/isolamento & purificação , Saponinas/farmacologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Células Th1/imunologia , Células Th2/imunologia
18.
J Ethnopharmacol ; 125(2): 310-7, 2009 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-19559777

RESUMO

AIM OF THE STUDY: The roots of Actinidia eriantha Benth (Actinidiaceae) have been used for cancers in the Chinese folk medicine. The present study aimed at evaluating the antitumor potentials of the polysaccharides from the roots of Actinidia eriantha and elucidating their immunological mechanisms by determining the effects on the growth of tumor transplanted in mice and the immune response in tumor-bearing mice. MATERIALS AND METHODS: The total polysaccharide AEP and fours purified polysaccharides AEPA, AEPB, AEPC and AEPD were isolated and purified from the roots of Actinidia eriantha by hot water extraction, ethanol precipitation, dialysis and gel filtration. Their effects on the growth of mouse transplantable tumor, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL), production of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured. RESULTS: AEP and four purified polysaccharides could not only significantly inhibit the growth of mouse transplantable tumor, but also remarkably promote splenocytes proliferation, NK cell and CTL activity, IL-2 and IFN-gamma production from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice. CONCLUSIONS: The antitumor activity of AEP and four purified polysaccharides might be achieved by improving immune response, and the composition of the monosaccharides, uronic acid contents and molecular weight could affect their antitumor and immunomodulatory activity.


Assuntos
Actinidia/química , Antineoplásicos Fitogênicos/uso terapêutico , Citocinas/metabolismo , Fatores Imunológicos/uso terapêutico , Linfócitos/metabolismo , Neoplasias Experimentais/tratamento farmacológico , Polissacarídeos/uso terapêutico , Animais , Anticorpos/sangue , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fatores Imunológicos/isolamento & purificação , Fatores Imunológicos/farmacologia , Interferon gama/metabolismo , Interleucina-2/metabolismo , Células Matadoras Naturais/metabolismo , Masculino , Camundongos , Transplante de Neoplasias , Fitoterapia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Raízes de Plantas , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Sarcoma 180 , Baço/citologia , Linfócitos T Citotóxicos/metabolismo
19.
Vaccine ; 27(33): 4388-401, 2009 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-19450632

RESUMO

Immunostimulatory complexes (ISCOMs) are particulate antigen delivery systems composed of antigen, cholesterol, phospholipid and saponin, while ISCOMATRIX is a particulate adjuvant comprising cholesterol, phospholipid and saponin but without antigen. The combination of an antigen with ISCOMATRIX is called an ISCOMATRIX vaccine. ISCOMs and ISCOMATRIX combine the advantages of a particulate carrier system with the presence of an in-built adjuvant (Quil A) and consequently have been found to be more immunogenic, while removing its haemolytic activity of the saponin, producing less toxicity. ISCOMs and ISCOMATRIX vaccines have now been shown to induce strong antigen-specific cellular or humoral immune responses to a broad range of antigens of viral, bacterial, parasite origin or tumor in a number of animal species including non-human primates and humans. These vaccines produced by well controlled and reproducible processes have also been evaluated in human clinical trials. In this review, we summarize the recent progress of ISCOMs and ISCOMATRIX, including preparation technology as well as their application in humans and veterinary vaccine designs with particular emphasis on the current understanding of the properties and features of ISCOMs and ISCOMATRIX vaccines to induce immune responses. The mechanisms of adjuvanticity are also discussed in the light of recent findings.


Assuntos
Adjuvantes Imunológicos/farmacologia , Colesterol/imunologia , ISCOMs/imunologia , Fosfolipídeos/imunologia , Saponinas/imunologia , Apresentação do Antígeno , Apoptose , Linfócitos T CD8-Positivos/imunologia , Vacinas Anticâncer/imunologia , Química Farmacêutica/métodos , Colesterol/farmacologia , Citocinas/imunologia , Combinação de Medicamentos , Humanos , ISCOMs/farmacologia , Fosfolipídeos/farmacologia , Quillaja/química , Saponinas/farmacologia , Vacinas Virais/imunologia
20.
Vaccine ; 27(30): 3984-91, 2009 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-19389450

RESUMO

The plant polysaccharides are recognized as an effective biological response modifier with low toxicity. In this study, the water-soluble polysaccharide from the roots of Actinidia eriantha (AEPS) was evaluated for its toxicity and adjuvant potential on the specific cellular and humoral immune responses to ovalbumin (OVA) in mice. AEP did not cause any mortality and side effects when mice were administered subcutaneously twice at the dose up to 5.0mg at intervals of 7 days. The mice were immunized subcutaneously with OVA 100 microg alone or with OVA 100 microg dissolved in saline containing Quil A (10 microg) or AEPS (25, 50, or 100 microg) on days 1 and 15. Two weeks later, splenocyte proliferation, natural killer (NK) cell activity, production and mRNA expression of cytokines from splenocytes, and serum OVA-specific antibody titers were measured. The Con A-, LPS-, and OVA-induced splenocyte proliferation and the serum OVA-specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the immunized mice were significantly enhanced by AEPS (P<0.05, P<0.01 or P<0.001). AEPS also significantly promoted the production of Th1 (IL-2 and IFN-gamma) and Th2 (IL-10) cytokines and up-regulated the mRNA expression of IL-2, IFN-gamma, IL-4 and IL-10 cytokines and T-bet and GATA-3 transcription factors in splenocytes from the immunized mice (P<0.05, P<0.01 or P<0.001). Besides, AEPS remarkably increased the killing activities of NK cells from splenocytes in the immunized mice (P<0.01 or P<0.001). The results indicated that AEPS had strong potential to increase both cellular and humoral immune responses and elicit a balanced Th1/Th2 response, and that AEPS may be a safe and efficacious adjuvant candidate suitable for a wide spectrum of prophylactic and therapeutic vaccines.


Assuntos
Actinidia/química , Adjuvantes Imunológicos/farmacologia , Raízes de Plantas/química , Polissacarídeos/farmacologia , Células Th1/imunologia , Células Th2/imunologia , Adjuvantes Imunológicos/isolamento & purificação , Adjuvantes Imunológicos/toxicidade , Animais , Anticorpos/sangue , Proliferação de Células , Citocinas/metabolismo , Feminino , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos ICR , Ovalbumina/imunologia , Polissacarídeos/isolamento & purificação , Polissacarídeos/toxicidade , Baço/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA