ANALYSIS, ISOLATION AND INSECTICIDAL ACTIVITY OF LINEAR FURANOCOUMARINS AND OTHER COUMARIN DERIVATIVES FROM PEUCEDANUM (APIACEAE, APIOIDEAE)

Peucedanum arenarium Waldst. & Kit., P. austriacum (Jacq.) Koch, P. co riaceum Reichenb., P. longifolium Waldst. & Kit, P. officinale L., P. oreoselinum (L.) Moench, P. ostruthium L., and P. palustre (L.) Moench accumulate different structural types of coumarins including simple c oumarins, linear furanocoumarins, linear dihydropyranocoumarins, angul ar dihydrofuranocoumarins and angular dihydropyranocoumarins. Linear f uranocoumarins, known for various biological activities, include some well-known antifeedants, such as bergapten, isopimpinellin, and xantho toxin. The aim of this investigation was to screen the diverse coumari ns from Peucedanum for insecticidal activity. LC was used to analyze a nd isolate coumarins for the bioassays. A growth inhibition bioassay w ith 17 derivatives, comprising all structural types from Peucedanum, c arried out with Spodoptera littoralis (Boisduval) (Lepidoptera: Noctui dae) as test organism, indicated the majority of the linear furanocoum arins and the angular dihydrofuranocoumarin athamantin as active compo unds. Oxygenation of the prenyl residue of linear furanocoumarins decr eased activity. Further formation of an ester with angelic acid even r esulted in complete inactivity. Five active linear furanocoumarins, be rgapten, isopimpinellin, xanthotoxin, isoimperatorin, and imperatorin, and two linear furanocoumarins with a substituted furan ring, peuceda nin and 8-methoxypeucedanin, were compared in a dietary utilization bi oassay. Relative growth rate (RGR) and relative consumption rate (RCR) divided the tested coumarins in three groups of similar activity. Iso pimpinellin and peucedanin slightly decreased RGR and RCR of the treat ed larvae, and xanthotoxin, isoimperatorin, and 8-methoxypeucedanin he avily decreased RGR and RCR. Bergapten and imperatorin differed by the lowest RGR values and rather high RCR values. The effects caused by t hese two coumarins indicate specific postingestive toxicity. The resul ts obtained in this study add to the reputation of coumarins to be an effective chemical defense, postulating that chemical diversity is a n ecessary trait for well-defended plants.