USTILOXINS, ANTIMITOTIC CYCLIC-PEPTIDES FROM FALSE SMUT BALLS ON RICEPANICLES CAUSED BY USTILAGINOIDEA VIRENS

Ustiloxins A (1a), B (1b), C (1c), D (1d) and E (1e), antimitotic pept ides, have been isolated from the water extract of false smut balls ca used on the panicles of rice plant by a fungus Ustilaginoidea virens. The structure of 1b was assigned from its spectral property and its am ino acid analysis in relation to 1a whose structure was determined pre viously by a conbination of X-ray crystallographic and amino acid anal yses. Structures of 1c and 1d were elucidated by their spectroscopic d ata, specially based on their H-1 and C-13 NMR spectra. Bioactivities of these compounds against microtubule assembly as well as manmal, pla nt and fungal cells have been studied.