Many secondary compounds are still unknown. Recent estimates (Mendelsohn and Balick 1995) suggest that there are more than 300 undiscovered potential pharmaceuticals in tropical forests. In the race to discover novel compounds in the rapidly disappearing rain forests, Raffauf has cataloged Dragendorff s reagent test results from 30,000 samples (from 19,000 different plant species and about 4,000 genera). Samples were taken from 315 families of higher plants, including ferns, Gymnosperms and Angiosperms.
After a brief introduction about methods, Raffauf lists his extensive database alphabetically, by family. Each family has a short paragraph noting economic uses and plant distribution. This is followed by a list of species that tested positive with Dragendorff's reagent, and then a list of species that tested negative for alkaloids. For some well known families, the author also includes pertinent alkaloid references.
This book obviously includes years of data collection, and is an essential resource for those interested in pharmacognosy or alkaloid chemistry. It is, in essence, a road map showing all the detours and potholes that normally accompany natural products research. 'The book has, however, some shortcomings. While material sampled was from South America, New Guinea and Africa, there are no source locations given for tested species. Also, as the author points out, Dragendorff s reagent can give false test results. Still, a high percentage of the 3,200 species that tested positive should actually contain alkaloids. As these alkaloids are identified, they will play a critical role in our understanding of plant taxonomy. When the alkaloids are tested for biological activity, they may represent a huge benefit to society as new medicines. - Michelle A. Briggs, Department of Biology, Lycoming College, Williamsport, PA
Mendelsohn, R. and M.J. Balick. 1995. The value of undiscovered pharmaceuticals in tropical forests. Economic Botany 49 (2):223-228