ABSTRACT
The order Rutales, including the families Rutaceae, Meliaceae, Simaroubaceae and Cneo-
raceae, is among the richest and most diverse sources of secondary metabolites in the
Angiospermae. Almost every part of the trees, leaves, bark and seeds, have long been
used for medicinal and plant protection purposes. The most characteristic metabolites of
the Rutales are limonoids, which are tetranortriterpenoids derived from tirucallane
(H-20) or euphane (H-20) triterpenoids with a 4,4,8-trimethyl-17-furanylsteroidal
skeleton. They have also attracted considerable interest because of their fascinating
structural diversity and their wide range of biological activity. In particular, they charac-
terize members of the family Meliaceae, where they are abundant and varied.
