Scientific publications
Flaure Rosette Ehawa Essoung* (Corresponding author)
Other affiliations: Kenyatta University · International Centre of Insect Physiology and Ecology
Brice Mittérant Mba’ning
Bruno Ndjakou Lenta
Etienne Tsamo
S.C. Chhabra
Ahmed Hassanali
Samira A. Mohamed
Wilber Lwande
Journal of Applied Entomology
Abstract Preliminary screening of extracts of the leaves and stems of four Turraea plant species (Meliaceae) on second instar larvae of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) showed that the methanolic extract of Turraea abyssinica leaves possess good toxic potential with LD 50 of 270.7 ppm. Fractionation of this extract led to isolation of a new limonoid derivative, 12α‐diacetoxywalsuranolide (1) and three other known limonoids [1α,7α,12α‐triacetoxy‐4α‐carbomethoxy‐11β‐hydroxy‐14β,15β‐epoxyhavanensin (2), 11‐epi‐21‐hydroxytoonacilide (3), 11β,12α‐diacetoxycedrelone (4)]. The structures of the compounds were established by IR , UV , mass spectrometry and 1D/2D NMR analyses, and in the case of the known compounds, also by comparison with reported data. All the isolates were tested for their larvicidal activities at different dose range against second instar larvae of T. absoluta . They were found to be more active (with LD 50 < 7.0 ppm) compared to the reference compound azadirachtin ( LD 50 value of 7.8 ppm).
