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1.
J Nat Prod ; 84(3): 790-796, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33371682

RESUMO

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.

2.
Bioorg Chem ; 100: 103921, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32464403

RESUMO

Enterococci are gram-positive, widespread nosocomial pathogens that in recent years have developed resistance to various commonly employed antibiotics. Since finding new infection-control agents based on secondary metabolites from organisms has proved successful for decades, natural products are potentially useful sources of compounds with activity against enterococci. Herein are reported the results of a natural product library screening based on a whole-cell assay against a gram-positive model organism, which led to the isolation of a series of anacardic acids identified by analysis of their spectroscopic data and by chemical derivatizations. Merulinic acid C was identified as the most active anacardic acid derivative obtained against antibiotic-resistant enterococci. Fluorescence microscopy analyses showed that merulinic acid C targets the bacterial membrane without affecting the peptidoglycan and causes rapid cellular ATP leakage from cells. Merulinic acid C was shown to be synergistic with gentamicin against Enterococcus faecium, indicating that this compound could inspire the development of new antibiotic combinations effective against drug-resistant pathogens.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterococcus faecium/efeitos dos fármacos , Gentamicinas/farmacologia , Sinergismo Farmacológico , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/metabolismo , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Hidroxibenzoatos/farmacologia
3.
J Nat Prod ; 83(1): 55-65, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31895573

RESUMO

A new method of screening was developed to generate 770 organic and water-soluble fractions from extracts of nine species of marine sponges, from the growth media of 18 species of marine-derived fungi, and from the growth media of 13 species of endophytic fungi. The screening results indicated that water-soluble fractions displayed significant bioactivity in cytotoxic, antibiotic, anti-Leishmania, anti-Trypanosoma cruzi, and inhibition of proteasome assays. Purification of water-soluble fractions from the growth medium of Penicillium solitum IS1-A provided the new glutamic acid derivatives solitumine A (1), solitumine B (2), and solitumidines A-D (3-6). The structures of compounds 1-6 have been established by analysis of spectroscopic data, chemical derivatizations, and vibrational circular dichroism calculations. Although no biological activity could be observed for compounds 1-6, the new structures reported for 1-6 indicate that the investigation of water-soluble natural products represents a relevant strategy in finding new secondary metabolites.


Assuntos
Glutamatos/química , Regiões Antárticas , Fungos/química , Estrutura Molecular , Penicillium/química , Água
4.
Nat Prod Rep ; 36(7): 981-1004, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31049509

RESUMO

Covering: up to 2019The discovery of new bioactive natural products gained momentum during the last few decades, resulting from instrumentation advances, from the expansion of genome mining and regulation, as well as by exploration of untapped biological sources. However, water-soluble, volatile, minor and photosensitive natural products are yet poorly known. This review discusses the literature reporting the isolation strategies for some of these metabolites. Analysis of minor metabolites at sub-milligram level are also presented, since analytical instrumentation enabling structure assignment in minute quantities is now routine. Major trends related to natural products discovery are discussed, under the light of further developments in biodiscovery.


Assuntos
Produtos Biológicos/isolamento & purificação , Produtos Biológicos/química , Produtos Biológicos/efeitos da radiação , Interações Hidrofóbicas e Hidrofílicas , Luz , Estrutura Molecular , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/efeitos da radiação
5.
J Nat Prod ; 81(1): 188-202, 2018 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-29297684

RESUMO

The isolation and identification of a series of new pseudoceratidine (1) derivatives from the sponge Tedania brasiliensis enabled the evaluation of their antiparasitic activity against Plasmodium falciparum, Leishmania (Leishmania) amazonensis, Leishmania (Leishmania) infantum, and Trypanosoma cruzi, the causative agents of malaria, cutaneous leishmaniasis, visceral leishmaniasis, and Chagas disease, respectively. The new 3-debromopseudoceratidine (4), 20-debromopseudoceratidine (5), 4-bromopseudoceratidine (6), 19-bromopseudoceratidine (7), and 4,19-dibromopseudoceratidine (8) are reported. New tedamides A-D (9-12), with an unprecedented 4-bromo-4-methoxy-5-oxo-4,5-dihydro-1H-pyrrole-2-carboxamide moiety, are also described. Compounds 4 and 5, 6 and 7, 9 and 10, and 11 and 12 have been isolated as pairs of inseparable structural isomers differing in their sites of bromination or oxidation. Tedamides 9+10 and 11+12 were obtained as optically active pairs, indicating an enzymatic formation rather than an artifactual origin. N12-Acetylpseudoceratidine (2) and N12-formylpseudoceratidine (3) were obtained by derivatization of pseudoceratidine (1). The antiparasitic activity of pseudoceratidine (1) led us to synthesize 23 derivatives (16, 17, 20, 21, 23, 25, 27-29, 31, 33, 35, 38, 39, 42, 43, 46, 47, 50, and 51) with variations in the polyamine chain and aromatic moiety in sufficient amounts for biological evaluation in antiparasitic assays. The measured antimalarial activity of pseudoceratidine (1) and derivatives 4, 5, 16, 23, 25, 31, and 50 provided an initial SAR evaluation of these compounds as potential leads for antiparasitics against Leishmania amastigotes and against P. falciparum. The results obtained indicate that pseudoceratidine represents a promising scaffold for the development of new antimalarial drugs.


Assuntos
Alcaloides/química , Alcaloides/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Poríferos/química , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Antiprotozoários/química , Antiprotozoários/farmacologia , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos
6.
Nat Prod Rep ; 34(11): 1264-1301, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28967942

RESUMO

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.


Assuntos
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
7.
Curr Top Med Chem ; 14(2): 191-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24359202

RESUMO

Phenanthroindolizidine alkaloids are a well-known class of compounds due to their interesting biological activities, especially anticancer ones. Represented by more than 60 substances, they are mainly isolated from plants of the Moraceae and Asclepiadaceae families. In the last 30 years, a great effort has been made aiming the synthesis of these compounds and analogues to be applied in medicinal chemistry.


Assuntos
Alcaloides/síntese química , Indolizinas/química , Fenantrolinas/química , Alcaloides/isolamento & purificação , Apocynaceae/química , Técnicas de Química Sintética , Moraceae/química
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