Accumulation and Antifungal Spectrum of 4'-Methoxyaucuparin as a New Phytoalexin in Rhaphiolepis umbellata Makino.

Accumulation and antifungal activity of a newly isolated phytoalexin, 4'-methoxyaucuparin, were described. The phytoalexin was accumulated in the leaves of Rhaphiolepis umbellata Makino inoculated with Pestalotiopsis sp. or Entomosporium mespili. Accumulation of 4'-methoxyaucuparin also occurred with treatment of 10-3M NaN3 or HgCl2 as abiotic elicitors. Of the elicitors tested, HgCl2 was found to be the most effective, being able to induce 4'-methoxyaucuparin at the concentration of 4, 385μg g-1 fresh weight. The inhibitory action of 4'-methoxyaucuparin against Pestalotiopsis sp., pathogenic fungus of R. umbellata, was weaker than that against non pathogenic fungi.