Abstract
Plant growth inhibitory polyacetylenes have been isolated from the insect galls on flower buds of Hedera rhombea Bean (Araliaceae) formed by the ivy flower bud gall midge, Asphondylia sp. (Cecidomyiidae), and their structures elucidated by spectroscopic and chemical means. The EC50 values for roots/hypocotyls growth of cress (Lepidium sativum L.) seedlings were 7.0×10−5/8.0×10−5 M for (Z)-8-acetoxy-1,2-epoxy-3-oxoheptadeca-9-ene-4,6-diyne, 9.5×10−5/9.0×10−5 M for (Z)-8-acetoxy-3-oxoheptadeca-1,9-diene-4,6-diyne, 2.5×10−5/5.5×10−6 M for (Z)-8-acetoxy-1-methoxy-3-oxoheptadeca-9-ene-4,6-diyne, and 7.5×10−5/2.0×10−6 M for falcarindiol, respectively. On the other hand, 8-acetoxyfalcarinol exhibited lower inhibition on roots and hypocotyls growth. Among these compounds, (Z)-8-acetoxy-1-methoxy-3-oxoheptadeca-9-ene-4,6-diyne exhibited the strongest inhibitiory effect on root growth of cress seedlings, whereas against hypocotyl growth of cress seedlings, falcarindiol showed the strongest inhibition.