Abstract
Five Vincetoxicum taxa (V. canescens subsp. canescens, V.
canescens subsp. pedunculata, V. fuscatum subsp. fuscatum, V.
fuscatum subsp. boissieri and V. parviflorum) were investigated
for insect antifeedant activity against Spodoptera littoralis and
Leptinotarsa decemlineata. At a dose of 500 μg/cm2, 12 extracts
were 100 % feeding deterrent, while 6 extracts showed 86.3-
99.3 % antifeedant activity. The effective doses (ED50) of the
total ethanol extract from V. canescens subsp. pedunculata
and of the methanol: dichloromethane (1:1) extract from V.
parviflorum were 12, and 18 μg/cm2, respectively, against S.
littoralis, and that of the total ethanol extract from V. fuscatum
subsp. fuscatum was 25 μg/cm2 against L. decemlineata. The
dichloromethane extracts of V. parviflorum and V. canescens
subsp. pedunculata inhibited the growth of S. littoralis with
ED50 values of 0.08 and 0.09 mg/g, respectively, and their LD50
values for larval mortality were 1.07 and 1.03 mg/g, respectively.
Phytochemical analysis revealed the presence of cardiotonic
glycosides, sugars, flavonoids and alkaloids in all investigated
taxa. In the dichloromethane and methanol:dichloromethane
(1:1) extracts, phenanthroindolizidine alkaloids were detected
by LC/MS/MS.