Plant Growth Activities of Aspyran, Asperentin, and its Analogues Produced by the Fungus Aspergillus sp.

Abstract

Aspyran (1), a novel compound, and the known isocoumarin asperentin (2), also known as cladosporin, together with its analogues 3 - 6 were isolated from Aspergillus sp. and their structures established by spectroscopic methods including 2D NMR spectroscopy. The effects of 1 - 6 on plant growth were examined by bioassays using lettuce and rice seedlings. Compounds 1 and 3 promoted the root growth of the seedlings, while 2 and 5 were inhibitory. Compounds 4 and 6 did not show any effect on the growth of lettuce and rice seedlings, respectively.