RESUMO
The chemical investigation of the mangrove endophytic fungus Aspergillus sp. 085242 afforded eight isocoumarin derivatives 1-8 and one isoquinoline 9. Asperisocoumarins A and B (1 and 2) were new furoisocoumarins, and asperisocoumarins E and F (5 and 6) were new isocoumarins. Their structures were established by analysis of their spectroscopic data and the absolute configuration of compound 2 was unambiguously determined by X-ray structure analysis and ECD calculation. Moreover, the absolute configurations of compounds 3-5 were assigned by comparison of their ECD spectra with isocoumarins described in the literature. Asperisocoumarins C and D (3 and 4) were fully characterized spectroscopically and isolated from a natural source for the first time. Asperisocoumarins A-D (1-4) related to the class of furo[3,2-h]isocoumarins are rarely occurring in natural sources. Compounds 2, 5, and 6 showed moderate α-glucosidase inhibitory activity with IC50 of 87.8, 52.3, and 95.6 µM, respectively. In addition, compounds 1 and 3 exhibited weak radical scavenging activity with EC50 values of 125 and 138 µM, respectively.
RESUMO
Racemic dinaphthalenone derivatives, (±)-asperlone A (1) and (±)-asperlone B (2), and two new azaphilones, 6'-hydroxy-(R)-mitorubrinic acid (3) and purpurquinone D (4), along with four known compounds, (-)-mitorubrinic acid (5), (-)-mitorubrin (6), purpurquinone A (7) and orsellinic acid (8), were isolated from the cultures of Aspergillus sp. 16-5C. The structures were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR spectra and the structures of 1 further confirmed by single-crystal X-ray diffraction analysis, while the absolute configuration of 3 and 4 were determined by comparing their optical rotation and CD with those of the literature, respectively. Compounds 1, 2 and 6 exhibited potent inhibitory effects against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with IC50 values of 4.24 ± 0.41, 4.32 ± 0.60 and 3.99 ± 0.34 µM, respectively.
Assuntos
Aspergillus/química , Compostos Heterocíclicos de 4 ou mais Anéis/isolamento & purificação , Naftóis/isolamento & purificação , Proteínas de Bactérias/antagonistas & inibidores , Compostos Heterocíclicos de 4 ou mais Anéis/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Naftóis/química , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Difração de Raios XRESUMO
A new alterporriol-type anthranoid dimer, alterporriol S (1), along with seven known anthraquinone derivatives, (+)-aS-alterporriol C (2), hydroxybostrycin (3), halorosellinia A (4), tetrahydrobostrycin (5), 9α-hydroxydihydrodesoxybostrycin (6), austrocortinin (7) and 6-methylquinizarin (8), were isolated from the culture broth of the mangrove fungus, Alternaria sp. (SK11), from the South China Sea. Their structures and the relative configurations were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR spectra. The absolute configurations of 1 and the axial configuration of 2 were defined by experimental and theoretical ECD spectroscopy. 1 was identified as the first member of alterporriols consisting of a unique C-10-C-2' linkage. Atropisomer 2 exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with an IC50 value 8.70 µM.
Assuntos
Alternaria/química , Antraquinonas/química , Antraquinonas/farmacologia , Antituberculosos/química , Antituberculosos/farmacologia , Avicennia/microbiologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Fermentação , Testes de Sensibilidade Microbiana , Modelos Moleculares , Conformação Molecular , Mycobacterium tuberculosis/efeitos dos fármacosRESUMO
A new anthraquinone, asperquinone A (1), and four known anthraquinone derivatives 2-5 were isolated from the mangrove endophytic fungus Aspergillus sp. 16-5C. These structures were elucidated by spectroscopic analysis and the absolute configuration of 1 was unambiguously determined by ECD calculation. Compounds 1-5 showed no significant inhibitory effect against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB).
Assuntos
Aspergillus , Mycobacterium tuberculosis , Aspergillus/química , Fungos , Análise Espectral , Antraquinonas/farmacologia , Estrutura MolecularRESUMO
A pair of enantiomeric indole diketopiperazine alkaloid dimers [(-)- and (+)-asperginulin A (1a and 1b)] with an unprecedented 6/5/4/5/6 pentacyclic skeleton were isolated from the mangrove endophytic fungus Aspergillus sp. SK-28. The enantiomeric dimers were separated by chiral-phase HPLC. Their structures including absolute configurations were elucidated by spectroscopic analysis, X-ray diffraction, and quantum chemical calculation. (+)-Asperginulin A (1b) exhibited antifouling activity against the barnacle Balanus reticulatus.
Assuntos
Alcaloides , Aspergillus/química , Dicetopiperazinas , Endófitos/química , Indóis , Rhizophoraceae/microbiologia , Alcaloides/química , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Animais , Incrustação Biológica , Dicetopiperazinas/química , Dicetopiperazinas/isolamento & purificação , Dicetopiperazinas/farmacologia , Dimerização , Indóis/química , Indóis/isolamento & purificação , Indóis/farmacologia , Estrutura Molecular , Estereoisomerismo , Thoracica/efeitos dos fármacosRESUMO
Xylanthraquinone (1), a new anthraquinone, along with three known compounds, altersolanol A (2), deoxybostrycin (3) and bostrycin (4) was isolated from the fungus Xylaria sp. 2508 from the South China Sea. The structures of these compounds were identified by NMR experiments, and the absolute configuration of compound 1 was further confirmed by single-crystal X-ray diffraction with Cu Kα radiation. Compounds 1-4 did not show inhibitory activities against Mycobacterium tuberculosis protein tyrosine phosphatase B (IC50 values more than 100 µM).