RESUMO
Pyrrospirones A and B have been isolated from unpolished rice cultures of the endophytic fungus Neonectria ramulariae Wollenw KS-246. Their absolute stereostructures (1 and 2) were elucidated through spectroscopic methods using 1D and 2D NMR techniques and chemical transformations, including the modified Mosher's method. The compounds exhibited cytotoxicity and induced apoptosis in human promyelocytic leukemia HL-60 cells.
Assuntos
Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Hypocreales/química , Compostos de Espiro/isolamento & purificação , Compostos de Espiro/farmacologia , Alcaloides/química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60 , Humanos , Japão , Estrutura Molecular , Oryza/microbiologia , Compostos de Espiro/químicaRESUMO
Two new cyclic lipopeptides, fusaristatins A (1) and B (2) were isolated from rice cultures of a Fusarium sp. YG-45 in the course of a screening of endophytic fungi. Their structures of 1 and 2 were determined by spectroscopic methods. 2 showed a moderate inhibitory effect on topoisomerases I (IC50: 73 microM) and II (IC50: 98 microM) without cleavable complexes. Furthermore, 1 and 2 showed the growth-inhibitory activity toward lung cancer cells LU 65 with IC50 values of 23 and 7 microM, respectively.
