Trees of the genus Aglaia (family Meliaceae) are common components of the lowland equatorial rain forests of S.E. Asia, reaching their greatest abundance in the Malay Peninsula, Sumatra and Borneo. It is not unusual to find twelve different species in any one forest site in these areas. These trees produce timber mainly for local use, their fruits are often edible and medicinal properties are reported for many species. Aglaia is the only source of the group of about 50 known representatives of compounds that bear a unique cyclopenta[b]tetrahydrobenzofuran skeleton. These compounds are more commonly called rocaglate or rocaglamide derivatives, or flavaglines and have been found to have anticancer and pesticide properties. Since the first representative in this group was only discovered in 1982, this one of the few recent examples of a completely new class of plant secondary metabolites of biological promise.
My research began with a study of the reproductive biology of the genus in the lowland rain forests of Peninsular Malaysia, but it soon became apparent that the taxonomy of the genus was in a chaotic state, the most recent (incomplete) revision having been published in 1878. A monograph of the genus was published in 1992, while several regional accounts deal with the genus in more detail at the local level. The monograph provided the first complete account, with descriptions, of all known Aglaia species, their distributions, local uses and medicinal value. The full treatment of the genus attracted further research on related topics such as the bioactivity of phytochemical extracts and the systematic relationships within the genus and between it and other mahogany genera.
Up to 90% of trees in a lowland tropical forest have fleshy fruits, the seeds of which are dispersed by animals. Anything from carnivores, such as tigers, large primates, such as Gorillas, Chimpanzees and Orang Utans, fruit-bats, hornbills, pigeons and large flightless birds, such as cassowaries, to numerous small mammals and birds disperse the seeds of tropical trees and promote regeneration of forest after disturbance, whether natural or man-made. With the exception of very large seeds, which may be dependent on a single disperser, the relationship between fleshy-fruited trees and their dispersers is rarely species-specific. A great deal of variation may be exhibited between forest sites and this is difficult to quantify. A more productive way of approaching the subject is to use morphological and nutritional features of fruits and their dispersers to characterize the qualitative factors operating in these interactions. This has led me to use series of fruit characters and adaptations to fruit-eating by dispersing animals to describe ‘syndromes’ which link fruit-types with their animal dispersers.
The emphasis of my current research is:
- to build on the taxonomic revision of Aglaia, by making information on the genus accessible in the areas of the world where it grows
- to provide a taxonomic base for phytochemical research in Aglaia, identifying to species or subspecies the source of novel compounds and predicting which species might yield further bioactivity
- to find fresh material for DNA-extraction of living plants of Aglaia in their native habitats and to contribute to interpretation of the results of investigations of molecular systematics in the genus
- to continue studies of animal-dispersal of fleshy fruits and its importance for tropical rain forest regeneration