RESUMO
Two new pyrroloiminoquinone alkaloids of the discorhabdin class, along with 12 compounds including one previously described synthetic derivative of the same and related skeletal classes, were isolated from the sponge Sceptrella sp., collected from Gageodo, Korea. The structures of these new compounds, designated as (-)-3-dihydrodiscorhabdin D (11) and (-)-discorhabdin Z (12), were determined by combined spectroscopic analyses. Compound 12 possesses an unusual hemiaminal group among the discorhabdin alkaloids. These compounds exhibited moderate to significant cytotoxicity, antibacterial activity, and inhibitory activity against sortase A.
Assuntos
Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/isolamento & purificação , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Poríferos/química , Quinonas/isolamento & purificação , Quinonas/farmacologia , Alcaloides/química , Aminoaciltransferases/antagonistas & inibidores , Animais , Antibacterianos/química , Antineoplásicos/química , Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Cisteína Endopeptidases , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Células K562 , Biologia Marinha , Micrococcus luteus/efeitos dos fármacos , Ressonância Magnética Nuclear Biomolecular , Proteus vulgaris/efeitos dos fármacos , Quinonas/química , Salmonella typhimurium/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , EstereoisomerismoRESUMO
Eleven new meroditerpenoids (7-11, 14-17, 19, 20) and nine known compounds (1-6, 12, 13, 18) were isolated from the brown alga Sargassum siliquastrum. Combined chemical and spectroscopic analyses revealed a common tetraprenyl hydroquinone structure; these compounds belonged to the nahocol, isonahocol, and sargahydroquinoic acid classes. The dihydroquinone moiety of 20 was unique and unprecedented in a brown alga. Stereochemical assignments were made for several of the known compounds based on their chemical reactivity. These compounds exhibited moderate to significant radical-scavenging activity as well as weak inhibitory activities against sortase A and isocitrate lyase.
