RESUMO
On our ongoing searching for bioactive natural products derived from entophytes, two polyketides possessing novel skeletons, alternatones A-B (1-2), were identified from the culture of Alternaria alternate L-10. Their structures were established by a combination of spectroscopic and single-crystal X-ray diffraction with Cu Ka radiation. Alternatone A (1) exhibited cytotoxic activity against human hepatoma carcinoma HepG-2 cell line. The putative biosynthetic pathways for compounds 1-2 were also proposed.
Assuntos
Antineoplásicos , Policetídeos , Alternaria/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Estrutura Molecular , Policetídeos/química , Policetídeos/farmacologia , EsqueletoRESUMO
Ansaseomycins are ansamycin-type natural products produced through expression of the asm gene cluster in a heterologous host. A rare berberine bridge enzyme (BBE) like oxidase, AsmF, is encoded in the asm gene cluster. Deletion of asmF led to the accumulation of a series of structurally diverse compounds, all of which lacked the 23-hydroxyl group in naphthalenic motif. Our work demonstrated that AsmF dictated the formation of the naphthalenic hydroxyl group in ansaseomycin biosynthesis.
