RESUMO
BACKGROUND Endophytic fungi, present mainly in the Ascomycota and Basidiomycota phyla, are associated with different plants and represent important producers of bioactive natural products. Brazil has a rich biodiversity of plant species, including those reported as being endemic. Among the endemic Brazilian plant species, Vellozia gigantea (Velloziaceae) is threatened by extinction and is a promising target to recover endophytic fungi. OBJECTIVE The present study focused on bioprospecting of bioactive compounds of the endophytic fungi associated with V. gigantea, an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. METHODS The capability of 285 fungal isolates to produce antimicrobial and antimalarial activities was examined. Fungi were grown at solid-state fermentation to recover their crude extracts in dichloromethane. Bioactive extracts were analysed by chromatographic fractionation and NMR and displayed compounds with antimicrobial, antimycobacterial, and antimalarial activities. FINDINGS Five fungi produced antimicrobial and antimalarial compounds. Extracts of Diaporthe miriciae showed antifungal, antibacterial, and antimalarial activities; Trichoderma effusum displayed selective antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare; and three Penicillium species showed antibacterial activity. D. miriciae extract contained highly functionalised secondary metabolites, yielding the compound epoxycytochalasin H with high antimalarial activity against the chloroquine-resistant strain of Plasmodium falciparum, with an IC50 approximately 3.5-fold lower than that with chloroquine. MAIN CONCLUSION Our results indicate that V. gigantea may represent a microhabitat repository hotspot of potential fungi producers of bioactive compounds and suggest that endophytic fungal communities might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland.
Assuntos
Plasmodium/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Magnoliopsida/classificação , Magnoliopsida/microbiologia , Fungos Mitospóricos/efeitos dos fármacos , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Clima Tropical , Bioensaio , Candida/efeitos dos fármacos , Endófitos/químicaRESUMO
BACKGROUND: Endophytic fungi, present mainly in the Ascomycota and Basidiomycota phyla, are associated with different plants and represent important producers of bioactive natural products. Brazil has a rich biodiversity of plant species, including those reported as being endemic. Among the endemic Brazilian plant species, Vellozia gigantea (Velloziaceae) is threatened by extinction and is a promising target to recover endophytic fungi. OBJECTIVE: The present study focused on bioprospecting of bioactive compounds of the endophytic fungi associated with V. gigantea, an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. METHODS: The capability of 285 fungal isolates to produce antimicrobial and antimalarial activities was examined. Fungi were grown at solid-state fermentation to recover their crude extracts in dichloromethane. Bioactive extracts were analysed by chromatographic fractionation and NMR and displayed compounds with antimicrobial, antimycobacterial, and antimalarial activities. FINDINGS: Five fungi produced antimicrobial and antimalarial compounds. Extracts of Diaporthe miriciae showed antifungal, antibacterial, and antimalarial activities; Trichoderma effusum displayed selective antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare; and three Penicillium species showed antibacterial activity. D. miriciae extract contained highly functionalised secondary metabolites, yielding the compound epoxycytochalasin H with high antimalarial activity against the chloroquine-resistant strain of Plasmodium falciparum, with an IC50 approximately 3.5-fold lower than that with chloroquine. MAIN CONCLUSION: Our results indicate that V. gigantea may represent a microhabitat repository hotspot of potential fungi producers of bioactive compounds and suggest that endophytic fungal communities might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antimaláricos/farmacologia , Endófitos/química , Magnoliopsida/microbiologia , Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Antimaláricos/isolamento & purificação , Bioensaio , Candida/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Magnoliopsida/classificação , Testes de Sensibilidade Microbiana , Fungos Mitospóricos/efeitos dos fármacos , Plasmodium/efeitos dos fármacos , Clima TropicalRESUMO
Two new flavonoids, rac-6-formyl-5,7-dihydroxyflavanone (1) and 2',6'-dihydroxy-4'-methoxy-3'-methylchalcone (2), together with five known derivatives, rac-8-formyl-5,7-dihydroxyflavanone (3), 4',6'-dihydroxy-2'-methoxy-3'-methyldihydrochalcone (4), rac-7-hydroxy-5-methoxy-6-methylflavanone (5), 3'-formyl-2',4',6'-trihydroxy-5'-methyldihydrochalcone (6), and 3'-formyl-2',4',6'-trihydroxydihydrochalcone (7), were isolated from the leaves of Eugenia rigida. The individual (S)- and (R)-enantiomers of 1 and 3, together with the corresponding formylated flavones 8 (6-formyl-5,7-dihydroxyflavone) and 9 (8-formyl-5,7-dihydroxyflavone), as well as 2',4',6'-trihydroxychalcone (10), 3'-formyl-2',4',6'-trihydroxychalcone (11), and the corresponding 3'-formyl-2',4',6'-trihydroxydihydrochalcone (7) and 2',4',6'-trihydroxydihydrochalcone (12), were synthesized. The structures of the isolated and synthetic compounds were established via NMR, HRESIMS, and electronic circular dichroism data. In addition, the structures of 3, 5, and 8 were confirmed by single-crystal X-ray diffraction crystallography. The isolated and synthetic flavonoids were evaluated for their antimicrobial and cytotoxic activities against a panel of microorganisms and solid tumor cell lines.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Chalconas/isolamento & purificação , Chalconas/farmacologia , Eugenia/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Antineoplásicos Fitogênicos/química , Candida albicans/efeitos dos fármacos , Chalconas/química , Cryptococcus neoformans/efeitos dos fármacos , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/efeitos dos fármacos , Flavanonas , Flavonoides/química , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Complexo Mycobacterium avium/efeitos dos fármacos , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Pseudomonas aeruginosa/efeitos dos fármacos , Porto Rico , Staphylococcus aureus/efeitos dos fármacosRESUMO
Four diterpenes with biological activity were isolated from Salvia deserta roots. Taxodione was considered leishmanicidal with an IC50 value of 1.46 µM (0.46 mg/L) against Leishmania donovani and also exhibited antifungal and antimicrobial activities. Ferruginol displayed the greatest activity [24-h IC50 of 4.5 µM (1.29 mg/L)] against the fish pathogenic bacteria Streptococcus iniae. The crude extract fraction that contained the isolated compounds 7-O-acetylhorminone and horminone showed stronger in vitro antibacterial activity (1.3 mg/L for Staphylococcus aureus and 1.1 mg/L for methicillin-resistant S. aureus) than the compounds tested alone. 7-O-Acetylhorminone and horminone exhibited a synergistic effect against methicillin-resistant S. aureus (FIC of 0.2), and horminone had better activity against S. aureus with respect to other compounds isolated from S. deserta roots. In larvicidal bioassays, these extracts and isolated pure compounds did not show any activity at the highest dose of 125 mg/L against 1-d-old Aedes aegypti larvae.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antiprotozoários/farmacologia , Diterpenos/farmacologia , Extratos Vegetais/farmacologia , Antimaláricos/farmacologia , Leishmania donovani/efeitos dos fármacos , Raízes de Plantas/química , SalviaRESUMO
This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. A total of 81 fungal isolates obtained were identified as 29 Ascomycota taxa by sequencing different regions of DNA. Cladosporium halotolerans, Penicillium chrysogenum and Penicillium cf. citrinum were the most frequent species, which occur at least in four different altitudes. The diversity and similarity indices ranged in the fungal communities across the latitudinal gradient. The Fisher-α index displayed the higher values for the fungal communities obtained from the siltstone and fine matrix of pyroclastic rocks with finer grain size, which are more degraded. A total of 23 fungal extracts displayed activity against the different targets screened. The extract of P. chrysogenum afforded the compounds α-linolenic acid and ergosterol endoperoxide, which were active against Cryptococcus neoformans and methicillin-resistance Staphylococcus aureus respectively. Our study represents the first report of a new habitat of fungi associated with rocks of the Atacama Desert and indicated the presence of interesting fungal community, including species related with saprobes, parasite/pathogen and mycotoxigenic taxa. The geological characteristics of the rocks, associated with the presence of rich resident/resilient fungal communities suggests that the rocks may provide a favourable microenvironment fungal colonization, survival and dispersal in extreme conditions.
Assuntos
Ascomicetos/metabolismo , Cladosporium/metabolismo , Cryptococcus neoformans/efeitos dos fármacos , Sedimentos Geológicos/microbiologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Penicillium/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Chile , Cladosporium/classificação , Cladosporium/genética , Cladosporium/isolamento & purificação , Clima Desértico , Ecologia , Ecossistema , Dados de Sequência Molecular , Penicillium/classificação , Penicillium/genética , Penicillium/isolamento & purificaçãoRESUMO
Analogs of curcuphenol/elvirol, naturally occurring bisabolane sesquiterpenes, were prepared in six steps from alkyl-α-tetralones employing an aromatization reaction of cyclic dienone precursors and olefination of the key aldehyde intermediates. The in vitro antifungal activities of 6a, 6b, 6d, and 6g are also reported.
Assuntos
Aldeídos/química , Antifúngicos/química , Sesquiterpenos/química , Antifúngicos/síntese química , Antifúngicos/farmacologia , Ciclização , Testes de Sensibilidade Microbiana , Sesquiterpenos/síntese química , Sesquiterpenos/farmacologiaRESUMO
Bioassay-guided fractionation of a root extract of Sorocea muriculata led to the isolation and identification of two new oxygen heterocyclic Diels-Alder-type adducts, sorocenols G (1) and H (2), along with lupeol-3-(3' R-hydroxytetradecanoate) and oxyresveratrol. The structures of 1 and 2 were elucidated using 1D and 2D NMR spectroscopic and HRMS data and by comparison with reported values. The absolute configurations of 1 and 2 were established by analysis of their experimental and theoretically calculated CD spectra. Compounds 1 and 2 showed significant and selective activity against methicillin-resistant Staphylococcus aureus with IC50 values of 1.5 and 0.5 microM, respectively. Compound 2 also displayed antifungal activity against Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, with IC 50 values of 5.4, 5.4, and 10.0 microM, respectively.
Assuntos
Antibacterianos , Benzofuranos/química , Benzofuranos/isolamento & purificação , Resistência a Meticilina/efeitos dos fármacos , Moraceae/química , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Aspergillus fumigatus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oxigênio/química , Peru , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Raízes de Plantas/química , Estilbenos/química , Estilbenos/isolamento & purificaçãoRESUMO
A whole-cell-based assay using Saccharomyces cerevisiae strains that overexpress Candida albicans CDR1 and MDR1 efflux pumps has been employed to screen natural product extracts for reversal of fluconazole resistance. The tropical green alga Penicillus capitatus was selected for bioassay-guided isolation, leading to the identification of capisterones A and B (1 and 2), which were recently isolated from this alga and shown to possess antifungal activity against the marine pathogen Lindra thallasiae. Current work has assigned their absolute configurations using electronic circular dichroism and determined their preferred conformations in solution based on detailed NOE analysis. Compounds 1 and 2 significantly enhanced fluconazole activity in S. cerevisiae, but did not show inherent antifungal activity when tested against several opportunistic pathogens or cytotoxicity to several human cancer and noncancerous cell lines (up to 35 microM). These compounds may have a potential for combination therapy of fungal infections caused by clinically relevant azole-resistant strains.
Assuntos
Antifúngicos , Clorófitas/química , Fluconazol/farmacologia , Saccharomyces cerevisiae/metabolismo , Esteróis , Triterpenos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Bahamas , Candida albicans/química , Candida albicans/metabolismo , Farmacorresistência Fúngica , Ensaios de Seleção de Medicamentos Antitumorais , Proteínas Fúngicas/metabolismo , Humanos , Biologia Marinha , Proteínas de Membrana Transportadoras/metabolismo , Estrutura Molecular , Esteróis/química , Esteróis/isolamento & purificação , Esteróis/farmacologia , Triterpenos/química , Triterpenos/isolamento & purificação , Triterpenos/farmacologiaRESUMO
Antifungal bioassay-guided isolation of the ethanol extract of the roots of Pentagonia gigantifolia yielded 6-octadecynoic acid (1) and the new 6-nonadecynoic acid (2). Compounds 1 and 2 inhibited the growth of fluconazole-susceptible and -resistant Candida albicans strains. Their antifungal potencies were comparable to those of amphotericin B and fluconazole. Of particular significance is the low cytotoxicity and specific activity of 1 and 2 against C. albicans.
Assuntos
Antifúngicos/isolamento & purificação , Candida albicans/efeitos dos fármacos , Ácidos Graxos Monoinsaturados/isolamento & purificação , Anfotericina B/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Resistência Microbiana a Medicamentos , Ácidos Graxos Monoinsaturados/química , Ácidos Graxos Monoinsaturados/farmacologia , Fluconazol/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Metilação , Testes de Sensibilidade Microbiana , Estrutura Molecular , Peru , Raízes de Plantas/química , EsfingolipídeosRESUMO
Machaerium multiflorum yielded two additional new (+)-trans-hexahydrodibenzopyrans (HHDBP's), machaeriol C (1) and machaeriol D (2), and three new 5,6-seco-HHDBP's, machaeridiol A (3), machaeridiol B (4), and machaeridiol C (5). Their structures and stereochemistries were determined by 1D and 2D NMR data, including HMBC, NOESY, and circular dichroism experiments. Machaeriol C (1) demonstrated in vitro antibacterial activity against Staphylococcus aureus (IC(50) 0.65 microg/mL) and methicillin-resistant S. aureus (MRSA) (IC(50) 0.70 microg/mL), while its corresponding 5,6-seco-analogues machaeridiol A (3) and machaeridiol B (4) showed antibacterial activity against S. aureus and MRSA (IC(50) 1.0-2.6 microg/mL) and antifungal activity against Candida albicans (IC(50), 2.0-3.5 microg/mL). In addition, machaeridiol B (4) demonstrated antiparasitic activities against Plasmodium falciparum D6 and W2 clones and Leishmania donavani with IC(50) values of 0.64, 0.22, and 0.9 microg/mL, respectively.
Assuntos
Anti-Infecciosos/isolamento & purificação , Antimaláricos/isolamento & purificação , Antiparasitários/isolamento & purificação , Benzopiranos/isolamento & purificação , Fabaceae/química , Plantas Medicinais/química , Animais , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antimaláricos/química , Antimaláricos/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Benzopiranos/química , Benzopiranos/farmacologia , Candida albicans/efeitos dos fármacos , Concentração Inibidora 50 , Leishmania donovani/efeitos dos fármacos , Resistência a Meticilina , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Casca de Planta/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , EstereoisomerismoRESUMO
Genipatriol (1), a new 2alpha,3beta-dihydroxylated cycloartane triterpene, was isolated from the aerial parts of Genipa spruceana. The structure of genipatriol was determined by a combination of spectroscopic methods.
Assuntos
Rubiaceae/química , Triterpenos/isolamento & purificação , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Estereoisomerismo , Triterpenos/química , Triterpenos/farmacologiaRESUMO
Activity-guided fractionation of an ethanol extract of Lycopodium cernuum for Candida albicans secreted aspartic proteases (SAP) inhibition resulted in the identification of six new (1-6) and four known (7-10) serratene triterpenes, along with the known apigenin-4'-O-(2' ',6' '-di-O-p-coumaroyl)-beta-D-glucopyranoside (11). On the basis of spectroscopic analysis, the structures of 1-10 were established as 3beta,14alpha,15alpha,21beta,29-pentahydroxyserratane-24-oic acid (lycernuic acid C, 1), 3beta,14alpha,15alpha,21beta-tetrahydroxyserratane-24-oic acid (lycernuic acid D, 2), 3beta,14beta,21beta-trihydroxyserratane-24-oic acid (lycernuic acid E, 3), 3beta,21beta,29-trihydroxy-16-oxoserrat-14-en-24-methyl ester (lycernuic ketone A, 4), 3alpha,21beta,29-trihydroxy-16-oxoserrat-14-en-24-methyl ester (lycernuic ketone B, 5), 3alpha,21beta,24-trihydroxyserrat-14-en-16-one (lycernuic ketone C, 6), 3beta,21beta-dihydroxyserrat-14-en-24-oic acid (lycernuic acid A, 7), 3beta,21beta,29-trihydroxyserrat-14-en-24-oic acid (lycernuic acid B, 8), serrat-14-en-3beta,21beta-diol (9), and serrat-14-en-3beta,21alpha-diol (10). The 13C NMR data for the known compounds 7 and 8 are reported for the first time. Compounds 1 and 11 showed inhibitory effects against C. albicans secreted aspartic proteases (SAP) with IC50 of 20 and 8.5 microg/mL, respectively, while the other compounds were inactive.
Assuntos
Antifúngicos/isolamento & purificação , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Candida albicans/efeitos dos fármacos , Inibidores Enzimáticos/isolamento & purificação , Lycopodiaceae/química , Plantas Medicinais/química , Inibidores de Proteases/isolamento & purificação , Triterpenos/isolamento & purificação , Acetilação , Antifúngicos/química , Antifúngicos/farmacologia , Cromatografia Líquida de Alta Pressão , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Hidrólise , Concentração Inibidora 50 , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-Atividade , Triterpenos/química , Triterpenos/farmacologiaRESUMO
A phytochemical investigation of the CHCl(3) fraction of an ethanol extract of the root of Guatteria multivenia furnished nine compounds, of which four are sesquiterpenes (1-4) and five are alkaloids (5-9). Of the four sesquiterpenes, two are new (1, 3), named guatterin A (1) and dihydromadolin-K (3), and two are known (2, 4), identified as madolin-K (2) and madolin-W (4). The five known alkaloids were identified as liriodenine (5), lysicamine (6), lanuginosine (7), guadiscine (8), and O-methylpallidine (9). All the known compounds were isolated from this species for the first time. Structures of the new compounds were determined by extensive NMR studies, including DEPT, COSY, HMQC, HMBC, and NOESY. Compound 7 showed weak inhibitory effect against Candida albicans secreted aspartic proteases (SAP) with IC(50) of 45 microg/mL. Compound 5 was found to have antimicrobial activity against C. albicans, Cryptococcusneoformans, Staphylococcus aureus, and methicillin-resistant S. aureus (MRS) with IC(50)/MIC values of 3.5/6.25, 2.0/12.5, 2.0/3.13, and 2.0/3.13 microg/mL, respectively.