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J Nat Prod ; 84(3): 790-796, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33371682


Metabolomics analysis detected tambjamine alkaloids in aqueous and EtOAc extracts of the marine invertebrates Virididentula dentata, Tambja stegosauriformis, Tambja brasiliensis, and Roboastra ernsti. Among several tambjamines, the new amino acid derivatives tambjamines M-O (17-19) were identified by Marfey's advanced analysis, UPLC-MS/MS analyses, and total synthesis. The tambjamine diversity increased from the bryozoan V. dentata to its nudibranch predators T. stegosauriformis and T. brasiliensis and attained a higher diversity in R. ernsti, the nudibranch that preys upon T. stegosauriformis and T. brasiliensis. The total tambjamine content also increases among the trophic levels, probably due to biomagnification. Tambjamines A (1), C (3), and D (4) are the major metabolites in the tissues of V. dentata, T. stegosauriformis, T. brasiliensis, and R. ernsti and are likely the main chemical defenses of these marine invertebrates.

Alcaloides/isolamento & purificação , Gastrópodes/química , Pirróis/isolamento & purificação , Animais , Organismos Aquáticos/química , Brasil , Cromatografia Líquida de Alta Pressão , Cadeia Alimentar , Metabolômica , Estrutura Molecular , Espectrometria de Massas em Tandem
Nat Prod Rep ; 34(11): 1264-1301, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28967942


Covering: 2015 and 2016The chemistry and biology of natural guanidines isolated from microbial culture media, from marine invertebrates, as well as from terrestrial plants and animals, are reviewed. Emphasis is directed to the biosynthesis, total synthesis, ecological roles as well as on the evolution of guanidines isolated from natural sources.

Produtos Biológicos , Guanidinas , Animais , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/metabolismo , Guanidinas/química , Guanidinas/isolamento & purificação , Guanidinas/metabolismo , Invertebrados/química , Biologia Marinha , Estrutura Molecular
Microbiol Res ; 168(1): 50-5, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-22819383


Two series of new chitosan derivatives were synthesized by reaction of deacetylated chitosan (CH) with propyl (CH-Propyl) and pentyl (CH-Pentyl) trimethylammonium bromides to obtain derivatives with increasing degrees of substitution (DS). The derivatives were characterized by (1)H NMR and potentiometric titration techniques and their antifungal activities on the mycelial growth of Aspergillus flavus were investigated in vitro. The antifungal activities increase with DS and the more substituted derivatives of both series, CH-Propyl and CH-Pentyl, exhibited antifungal activities respectively three and six times higher than those obtained with commercial and deacetylated chitosan. The minimum inhibitory concentrations (MIC) were evaluated at 24, 48 and 72 h by varying the polymer concentration from 0.5 to 16 g/L and the results showed that the quaternary derivatives inhibited the fungus growth at polymer concentrations four times lower than that obtained with deacetylated chitosan (CH). The chitosans modified with pentyltrimethylammonium bromide exhibited higher activity and results are discussed taking into account the degree of substitution (DS).

Antifúngicos/farmacologia , Aspergillus flavus/efeitos dos fármacos , Quitosana/análogos & derivados , Quitosana/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Quitosana/síntese química , Quitosana/química , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Potenciometria , Relação Estrutura-Atividade , Fatores de Tempo