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

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