Limonoids from Toona ciliata and speculations on their chemosystematic and ecological significance

Abstract

Evolution of limonoids in the Meliaceae appears to be consistent with the resistance of Melioideae against the shoot borer Hypsipyla. The limonoid chemistry of Toona, which has shown absence of attacks of H. grandella, is reminiscent of Melioidease. An investigation of T. ciliata, has led to the identification of two novel meliacin butenolides, 21-hydroxycedrelonelide and 23-hydroxycedrelonelide, two known limonoids, cedrelone and 23-hydroxytoonacilide, and sitosterol, α-amyrin and β-amyrin acylated with fatty acids. Three known coumarins, siderin, scopoletin and isofraxidin were also isolated. All structures were established from spectral data. Some 13C NMR signals for cedrelone are reassigned.