Antibacterial modified diketopiperazines from two ascidians of the genus Didemnum

• Autor(a) principal: Kossuga,Miriam H.
• Data de Publicação: 2009
• Outros Autores: Lira,Simone P., McHugh,Shayna, Torres,Yohandra R., Lima,Bruna A., Gonçalves,Reginaldo, Veloso,Katyuscya, Ferreira,Antonio G., Rocha,Rosana M., Berlinck,Roberto G. S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532009000400014
• topic: ascidian; marine; diketopiperazine; absolute configuration; antibiotic

The chemical investigation of the crude extract of an ascidian of the genus Didemnumled to the isolation of the modified diketopiperazine rodriguesines A (1) and (2) as a mixture of homologues, which could be identified by analysis of spectroscopic data including MS/MS experiments. The investigation of a second Didemnumsp. led to the isolation of N-acetyl-rodriguesine A (3) and N-acetyl-rodriguesine B (4). The absolute configuration of compounds 1and 2could be established by hydrolysis and Marfey's analysis and comparison with literature data reported for compound 3, previously obtained as a synthetic product. The mixture of 1and 2displayed moderate antibiotic activity against a clinical isolate of Streptococcus mutansand against S. mutansUA159 and Staphylococcus aureusATCC6538.