INSECT GROWTH-INHIBITORS FROM MACHILUS-JAPONICA

The neolignans, licarin henyl)-3,4-dimethyl-5-piperonyltetrahydro-fura n],( -)-machilusin and (2S,3S)-2,3-dihydro-7-methoxy-3- -dimethoxyphen yl)-5-trans(1-propenyl)-benzofuran], 5-trans-(l-propenyl)benzofuran], were identified as bioactive constituents in leaves of Japanese Machil us japonica. All compounds exhibited growth inhibition activity agains t larvae of the insect Spodoptera litura. The most abundant constituen t was xyphenyl)-3,4-dimethyl-5-piperonyltetrahydrofuran] (0.05% dry wt ), a new natural product, while ihydro-7-methoxy-3-methyl-2-(3,4-dimet hoxyphenyl)- 5-trans-(1-propenyl)-benzofuran] had the highest activity against the test insect (0.01% dry wt, EC(50)=0.13%w/w). A possible s ynergistic action of these compounds with other M. japonica components is discussed.