Plant growth inhibition by a sesquiterpene ketoalcohol, cyperolone, isolated from purple nutsedge tubers.

Abstract

A sesquiterpene ketoalcohol, cyperolone, was isolated from nutsedge essential oil, and its inhibition of the growth of rice and lettuce seedlings was investigated. Cyperolone was a stronger inhibitor than sesquiterpene ketones such as cyperotundone and α-cyperone. Cyperolone completely inhibited the growth of lettuce seedlings at the concentration of 4.2×10-3M, at which it did not inhibit the germination of lettuce seeds. Accordingly, cyperolone-related compounds were synthesized to study the mode of the inhibitory action, and were tested plant bioassays. The diol, dione and trione derivatives inhibited growth less than the cyperolone and sesquiterpene ketones. Dihydrocyperolone was strongly inhibitory. These results suggested that the inhibitory effect of cyperolone may be due to the C-3 hydroxyl and C-4 carbonyl in its structure.