RESUMO
Sea hares of Aplysia genus are recognized as a source of a diverse range of metabolites. 5α,8α-Endoperoxides belong to a group of oxidized sterols commonly found in marine organisms and display several bioactivities, including antimicrobial, anti-tumor, and immunomodulatory properties. Herein we report the isolation of 5α,8α-epidioxycholest-6-en-3ß-ol (EnP(5,8)) from Aplysia depilans Gmelin, based on bioguided fractionation and nuclear magnetic resonance (NMR) analysis, as well as the first disclosure of its anti-inflammatory properties. EnP(5,8) revealed capacity to decrease cellular nitric oxide (NO) levels in RAW 264.7 macrophages treated with lipopolysaccharide (LPS) by downregulation of the Nos2 (inducible nitric oxide synthase, iNOS) gene. Moreover, EnP(5,8) also inhibited the LPS-induced expression of cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) at the mRNA and protein levels. Mild selective inhibition of COX-2 enzyme activity was also evidenced. Our findings provide evidence of EnP(5,8) as a potential lead drug molecule for the development of new anti-inflammatory agents.
Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Aplysia/química , Ésteres do Colesterol/química , Ésteres do Colesterol/farmacologia , Ergosterol/análogos & derivados , Macrófagos/efeitos dos fármacos , Adjuvantes Imunológicos/farmacologia , Animais , Anti-Inflamatórios/isolamento & purificação , Fracionamento Químico , Ésteres do Colesterol/isolamento & purificação , Regulação para Baixo/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Ergosterol/química , Ergosterol/isolamento & purificação , Ergosterol/farmacologia , Lipopolissacarídeos/farmacologia , Espectroscopia de Ressonância Magnética , Camundongos , Óxido Nítrico Sintase Tipo II/genética , Células RAW 264.7RESUMO
This study reports the comparative molecular modeling, docking and dynamic simulations of human alpha9alpha10 nicotinic acetylcholine receptors complexed with acetylcholine, nicotine and alpha-conotoxin RgIA, using as templates the crystal structures of Aplysia californica and Lymnaea stagnalis acetylcholine binding proteins. The molecular dynamics simulations showed that Arg112 in the complementary alpha10(-) subunit, is a determinant for recognition in the site that binds small ligands. However, Glu195 in the principal alpha9(+), and Asp114 in the complementary alpha10(-) subunit, might confer the potency and selectivity to alpha-conotoxin RgIA when interacting with Arg7 and Arg9 of this ligand.
Assuntos
Modelos Moleculares , Receptores Nicotínicos/química , Acetilcolina/química , Aminoácidos , Animais , Aplysia/química , Sítios de Ligação , Simulação por Computador , Conotoxinas/química , Humanos , Lymnaea/química , Nicotina/química , Ligação ProteicaRESUMO
The purple ink of the sea hare Aplysia punctata contains a 60 kDa protein with tumoricidal activity. This A. punctata ink toxin (APIT) kills tumor cells within 6--8h in an apoptosis independent manner by the production of high amounts of hydrogen peroxide which induce a necrotic form of oxidative stress. Here, we describe the biochemical features of APIT associated with its anti-tumor activity. APIT is a weakly glycosylated FAD-binding L-amino acid oxidase that catalyzes the oxidative deamination of L-lysine and L-arginine and thereby produces hydrogen peroxide (H(2)O(2)), ammonia (NH(4)(+)) and the corresponding alpha-keto acids. The tumoricidal effect is completely abrogated in the absence of the amino acids L-lysine and L-arginine. The enzyme is stable at temperatures from 0 to 50 degrees C. Similar to other FAD-binding enzymes, it is resistant against tryptic digest. Even digest with proteinase K fails to degrade the enzyme. Cloning of the APIT gene and subsequent sequencing revealed a FAD-binding domain followed by a so-called GG-motif, which is typical for L-amino acid oxidases. Strongest homology exists to escapin, aplysianin A precursor, the cyplasins L and S and achacin.
Assuntos
Aplysia/enzimologia , L-Aminoácido Oxidase/química , Venenos de Moluscos/enzimologia , Sequência de Aminoácidos , Animais , Antineoplásicos/química , Antineoplásicos/toxicidade , Aplysia/química , Morte Celular , Clonagem Molecular , DNA Complementar/biossíntese , DNA Complementar/genética , Endopeptidase K/química , Glicoproteínas/química , Humanos , Hidrólise , Indicadores e Reagentes , Células Jurkat , L-Aminoácido Oxidase/síntese química , Dados de Sequência Molecular , Necrose , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Tripsina/químicaRESUMO
OBJECTIVE: To apply conidia of Pyricularia Oryzae to the screening of antimitotic constituents from marine animal sea hare. METHOD: To extract and fractionate active portions from sea hare through detecting deformation of mycelia germinated from conidia of P. Oryzae P-2b, in comparison with the cytotoxic test results in vitro. RESULT: Two active portions, of which IC50 against P388 and HL-60 was 23.4, 18.6 and 19.4, 12.5 micrograms.ml-1, respectively, were screened from this animal. CONCLUSION: This bioassay method was efficiently applied to the primary screening of antimitotic portions from marine animals for the first time. Being convenient, speedy and cheap, the screening model is suitable for the bioassay of active constituents from marine life.