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1.
Methods Mol Biol ; 2489: 449-457, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35524064

RESUMO

The isolation of pure organic compounds from biological sources, reaction media, or other complex molecular matrixes is the first step to overcome before further biological and chemical investigations. While the isolation of chemicals soluble in organic solvents is commonly accomplished, the isolation of water-soluble organic compounds is less often addressed. We present here a simple method for the isolation of water-soluble organic compounds, using adsorptive macroporous resins and reversed-phase chromatography.


Assuntos
Compostos Orgânicos , Água , Animais , Invertebrados , Solventes , Água/química
2.
Arch Pharm (Weinheim) ; 355(4): e2100441, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35099085

RESUMO

Microbial strains isolated from extreme and understudied environments, such as caves, are still poorly investigated for the production of bioactive secondary metabolites. Investigation of the ethyl acetate extract from the growth medium produced by the soil-derived fungus Aspergillus sp. SDC28, isolated from a Brazilian cave, yielded two anthraquinones: versicolorin C (1) and versiconol (2). The complete assignment of nuclear magnetic resonance and mass spectroscopic data of 1 and 2 was performed for the first time. Moreover, the yet unreported absolute configuration of both compounds was unambiguously established by analysis of experimental and theoretical electronic circular dichroism data. Vibrational circular dichroism was also applied to confirm the absolute stereochemistry of 2. Compounds 1 and 2 showed cytotoxic activity against human ovarian cancer cells (OVCAR3).


Assuntos
Cavernas , Neoplasias Ovarianas , Antraquinonas/farmacologia , Apoptose , Aspergillus/química , Aspergillus/metabolismo , Brasil , Linhagem Celular Tumoral , Dicroísmo Circular , Feminino , Humanos , Estrutura Molecular , Oligodesoxirribonucleotídeos , Solo , Relação Estrutura-Atividade , Tionucleotídeos
3.
Nat Prod Rep ; 39(3): 596-669, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-34647117

RESUMO

Covering period: up to 2019Water-soluble natural products constitute a relevant group of secondary metabolites notably known for presenting potent biological activities. Examples are aminoglycosides, ß-lactam antibiotics, saponins of both terrestrial and marine origin, and marine toxins. Although extensively investigated in the past, particularly during the golden age of antibiotics, hydrophilic fractions have been less scrutinized during the last few decades. This review addresses the possible reasons on why water-soluble metabolites are now under investigated and describes approaches and strategies for the isolation of these natural compounds. It presents examples of several classes of hydrosoluble natural products and how they have been isolated. Novel stationary phases and chromatography techniques are also reviewed, providing a perspective towards a renaissance in the investigation of water-soluble natural products.


Assuntos
Produtos Biológicos , Antibacterianos/farmacologia , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Cromatografia , Toxinas Marinhas , Água
4.
Toxicon ; 203: 139-146, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34653444

RESUMO

The genus Brachycephalus includes small species of aposematic anurans known as microendemic, occurring in the mountains of the Atlantic Forest. Brachycephalus ephippium, B. nodoterga and B. pernix have been reported to contain the neurotoxin tetrodotoxin in skin and viscera. The biological conservation of several Brachycephalus species is currently threatened by climate change, deforestation, and the pandemic caused by the fungus Batrachochytrium dendrobatidis (Bd). Despite the well-known importance of amphibians' associated bacteria in the defensive role against pathogens, there is still a poor understanding of amphibian microbiome composition. The present study investigated the composition of B. pitanga microbial community and the presence of TTX in the host and in cultures of bacterial isolates, using a combination of metagenomics, bacterial culture isolation, mass spectrometry and metabolomic analyses. Results of culture-dependent and -independent analyses characterized the microbial communities associated with the skin and viscera of B. pitanga. Mass spectrometry analysis indicated the presence of TTX in host tissues, while bacterial production of TTX was not observed under the experimental conditions used in this investigation. This is the first report confirming the occurrence of TTX in B. pitanga.


Assuntos
Eugenia , Microbiota , Animais , Anuros , Bactérias , Tetrodotoxina/toxicidade
5.
Chem Commun (Camb) ; 57(47): 5758-5761, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34002741

RESUMO

We report a selective, mild, and efficient C-H functionalization of tryptophan and tryptophan-containing peptides with activated α-bromo-carbonyl compounds under visible-light irradiation. The protocol efficiency is outlined by the wide substrate scope and excellent tolerance of sensitive functional groups present in the amino acid side chains. The method can be successfully extended to access pharmaco-peptide conjugate scaffolds.


Assuntos
Indóis/química , Peptídeos/química , Triptofano/química , Alquilação , Catálise , Estrutura Molecular , Processos Fotoquímicos
6.
Braz J Microbiol ; 52(3): 1201-1214, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33929720

RESUMO

Endophytes are microorganisms that form symbiotic relationships with their host. These microorganisms can produce a variety of secondary metabolites, some of which have inhibitory effects on pests and pathogens or even act to promote plant growth. Due to these characteristics, these microorganisms are used as sources of biologically active substances for a wide range of biotechnological applications. Based on that, the aim of this study was to evaluate the production of metabolites of the endophytic Aspergillus flavus CL7 isolated from Chromolaena laevigata, in four different cultivation conditions, and to determine the antimicrobial, cytotoxic, antiviral, and antioxidant potential of these extracts. The multiphasic approach used to identify this strain was based on morphology and ITS gene sequence analysis. The chemical investigation of A. flavus using potato dextrose and minimal medium, using both stationary and agitated methods, resulted in the isolation of kojic acid, α-cyclopiazonic acid, and 20,25-dihydroxyaflavinine. Another 18 compounds in these extracts were identified by UHPLC-HRMS/MS, of which dideacetyl parasiticolide A has been described for the first time from A. flavus. Aflatoxins, important chemomarkers of A. flavus, were not detected in any of the extracts, thus indicating that the CL7 strain is non-aflatoxigenic. The biological potential of all extracts was evaluated, and the best results were observed for the extract obtained using minimal medium against Trichophyton rubrum and Mycobacterium tuberculosis.


Assuntos
Aspergillus flavus/química , Produtos Biológicos/química , Chromolaena , Aflatoxinas , Aspergillus flavus/genética , Produtos Biológicos/farmacologia , Chromolaena/microbiologia , Endófitos
7.
Nat Prod Rep ; 38(3): 586-667, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33021301

RESUMO

Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.


Assuntos
Anuros/metabolismo , Bactérias/metabolismo , Produtos Biológicos/química , Fungos/metabolismo , Guanidinas/metabolismo , Animais , Organismos Aquáticos/química , Organismos Aquáticos/metabolismo , Bactérias/química , Bactérias/genética , Produtos Biológicos/metabolismo , Fungos/química , Invertebrados/química , Invertebrados/metabolismo , Estrutura Molecular , Plantas/química , Plantas/metabolismo , Saxitoxina/química , Saxitoxina/metabolismo , Metabolismo Secundário , Aranhas/química , Aranhas/metabolismo , Tetrodotoxina/química , Tetrodotoxina/metabolismo
8.
J Nat Prod ; 83(6): 1784-1793, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32525315

RESUMO

Herein reported are results of the chemical and biological investigation of red propolis collected at the Brazilian Northeast coastline. New propolones A-D (1-4), with a 3-{3-[(2-phenylbenzofuran-3-yl)methyl]phenyl}chromane skeleton; propolonones A-C (5-7), with a 3-[3-(3-benzylbenzofuran-2-yl)phenyl]chromane skeleton; and propolol A (8), with a 6-(3-benzylbenzofuran-2-yl)-3-phenylchromane skeleton, were isolated as constituents of Brazilian red propolis by cytotoxicity-guided assays and structurally identified by analysis of their spectroscopic data. Propolone B (2) and propolonone A (5) display significant cytotoxic activities against an ovarian cancer cell line expressing a multiple drug resistance phenotype when compared with doxorubicin.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Própole/química , Antibióticos Antineoplásicos/farmacologia , Brasil , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Neoplasias Ovarianas/tratamento farmacológico
9.
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
10.
Chemosphere ; 242: 125211, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896201

RESUMO

While tetrodotoxin (TTX) is commonly found in pufferfish tissues, it is unclear if bacterial symbionts isolated from pufferfish tissues can produce TTX. In this investigation, UPLC qTOF-MS/MS analysis of tissue extracts obtained from Sphoeroides spengleri and Canthigaster figuereidoi identified TTX in their composition, indicating their consumption is unsafe. UPLC qTOF-MS/MS analysis coupled with Molecular Networking indicated new TTX analogs (methyl-TTX, TTX-acetate, hydroxypropyl-TTX and glycerol-TTX). Bacterial extracts from sixteen strains revealed a compound with a [M+H]+ ion at m/z 320.1088, identical to TTX. However, TTX itself was not detected in these cultures by UPLC-MS/MS. Neurotoxicity of Vibrio A665 purified fraction 2 (with precursor [M+H]+ ion at m/z 320.1088) was significant in human neural stem cells (hNSCs), but the Nav blockage activity was not confirmed by the veratridine/ouabain essays, indicating a possible difference in the mechanism of action between the bacterium A665 purified fraction 2 and TTX. Vibrios symbionts of pufferfish point out involving in the production of TTX precursors.


Assuntos
Microbiota , Tetraodontiformes/fisiologia , Tetrodotoxina/metabolismo , Animais , Brasil , Cromatografia Líquida , Humanos , Espectrometria de Massas em Tandem , Tetraodontiformes/microbiologia , Vibrio
11.
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
12.
Chem Biodivers ; 16(5): e1800644, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30843651

RESUMO

The phytochemical investigation of Grazielia gaudichaudeana aerial parts yielded 15 compounds, including diterpenes, triterpenes, sterols and flavonoids. With exception to ent-kaurenoic acid diterpenes, the compounds isolated are being described for the first time in this species. Some unusual 1 H-NMR chemical shifts of 18-nor-ent-labdane (7-9) led us carry out a conformational analysis by theoretical calculations in order to support the experimental data. Moreover, due to the limitation of studies focused on pharmacological potential of Grazielia gaudichaudeana, the present study was carried out to investigate the antioxidant, antiproliferative, antiviral, antileishmanial and antimicrobial activities from the extract, fractions and isolated compounds obtained from this species. Ethyl acetate fraction showed significant activity in the antiproliferative assay, with GI50 range of 3.9 to 27.2 µg mL-1 . Dichloromethane fraction, rich in diterpenoids, inhibited all human tumor cell lines tested, and the nor-labdane 7 showed potent cytotoxic activity against glioma and ovary cancer cell lines.


Assuntos
Asteraceae/química , Diterpenos/química , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/química , Antiprotozoários/química , Antiprotozoários/isolamento & purificação , Antiprotozoários/farmacologia , Asteraceae/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Leishmania/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Conformação Molecular , Extratos Vegetais/química
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