摘要:
Two new 4-phenyl-phenalenone-type phytoalexins (2, 3) have been isolated from rhizomes of Musa acuminata infected with the fungus Fusarium oxysporum. The structures of the new phytoalexins were elucidated on the basis of spectroscopic evidence, chemical correlation and synthesis from commercial phenalen-1-one. The chemical shift for all of the hydrogen and carbon atoms in the substances were unambiguously established by mono- and bidimensional, homo- and heteronuclear NMR experiments (H-1 NMR, C-13 NMR COSY, HMQC and HMBC). In preliminary ''in vitro'' assays, the new phytoalexins have shown inhibitory activity on the growth of the germinative tube of Fusarium oxysporum f. sp. cubense race 4.