Spirocaracolitone triterpenoids from the bark of Ruptiliocarpon caracolito

Triterpenoids from the bark of Ruptiliocarpon caracolito

Five spirocaracolitone triterpenoids were isolated from the dichloromethane-soluble fraction of the bark of Ruptiliocarpon caracolito, and their structures were determined mainly by application of 1D and 2D NMR spectroscopy. Two known CD-spirotriterpenoids were also isolated from the same source. This brings the total number of known CD-spirotriterpenoids from this source to 17. The discovery of such a large number of closely-related compounds in a single species represents an excellent example of phytochemical redundancy as a defense mechanism.

Impact of constitutive plant natural products on herbivores and pathogensThe present review is one in the special series of reviews on animal–plant interactions

Plants defend themselves from pests with deterrent or toxic phytochemicals. In addition to the development of preformed mechanical barriers such as cutin and suberin, the first line of defense for plants against pathogens and herbivores is constitutive (preformed) biologically active inhibitors. Because of the adaptation of insects and pathogens to these inhibitors, plants have evolved a stunning diversity of new and different bioactive molecules to combat pests. Some representative mechanisms of plant defense include the use of antimicrobial, anitfeedant, and phototoxic molecules. Examples of natural product defenses of specific plant families are also described. Diversity and redundancy in plant defenses is key to slowing pest resistance to host-plant defenses.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, lupanes, oleananes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins; 574 references are cited.