John T. Romeo - Böcker

Throughout the tropics, vast areas of rainforest and other biologically diverse lands are being cleared for agricultural or related uses. Rainforests, the most dramatic example of tropical habitat destrucLion, are estimated to be disappearing at the rate of up to 20.4 million hectares per year world-wide (based on FAO estimates; see World Resources 1990-1991, Oxford University Press)­ more than 2% of the total area covered by tropical rainforests per year. Destruction of these complex habitats results in the irreversible loss of both plant and animal diversity, and dramatically illustraLes the need to investigate these threatened species for potentially useful constituents-especially the identification and characterization of novel biologically-active phytochemicals with pharmacologiical and/or pesticidal properties. This volume is based on papers presented by invited speakers at an international symposium entitled "Phytochemical POlential of Tropical Plants: held in conjunction with the second joint meeting of the Phytochemical nd Societies of Europe and North America, as well as the 32 annual meeting of the latter society. The meeting was held at the Deauville Hotel, Miami Beach, Florida, USA from August 8-12,1992. One hundred and twenty-five participants from more than 20 countries attended this meeting.

Phytochemicals from medicinal plants are receiving ever greater attention in the scientific literature, in medicine, and in the world economy in general. For example, the global value of plant-derived pharmaceuticals will reach $500 billion in the year 2000 in the OECD countries. In the developing countries, over-the-counter remedies and "ethical phytomedicines," which are standardized toxicologically and clinically defined crude drugs, are seen as a promising low­ cost alternatives in primary health care. The field also has benefited greatly in recent years from the interaction of the study of traditional ethnobotanical knowledge and the application of modem phytochemical analysis and biological activity studies to medicinal plants. The papers on this topic assembled in the present volume were presented at the annual meeting of the Phytochemical Society of North America, held in Mexico City, August 15-19, 1994. This meeting location was chosen at the time of entry of Mexico into the North American Free Trade Agreement as another way to celebrate the closer ties between Mexico, the United States, and Canada. The meeting site was the historic Calinda Geneve Hotel in Mexico City, a most appropriate site to host a group of phytochemists, since it was the address of Russel Marker. Marker lived at the hotel, and his famous papers on steroidal saponins from Dioscorea composita, which launched the birth control pill, bear the address of the hotel.

Diversity within and among living organisms is both a biological impera­ tive and a biological conundrum. Phenotypic and genotypic diversity is the critical currency ofecological interactions and the evolution of life. Thus, it is not unexpected to find vast phytochemical diversity among plants. However, among the most compelling questions which arise among those interested in ecological phytochemistry is the extent, nature, and reasons for the diversity of chemieals in plants. The idea that natural products (secondary metabolites) are accidents of metabolism and have no biological function is an old one which has resurfaced recently under a new term "redundancy. " Redundancy in the broader sense can be viewed as duplication of effort. The co-occurrence of several classes of phytochemieals in a given plant may be redundancy. Is there unnecessary duplication of chemical defense systems and ifso, why? What selective forces have produced this result? On the other hand, why does the same compound often have multiple functions? At a symposium of the Phytochemical Society of North America held in August 1995, in Sault Ste. Marie, Ontario, Canada, the topic "Phytochernical Redundancy in Ecological Interactions" was discussed. The chapters in this volume are based on that symposium. They both stimulate thought and provide some working hypotheses for future research. It is being increasingly recognized that functional diversity and multiplicity of function of natural products is the norm rather than the exception.

Since 1994, the Phytochemical Society of North America has devoted its annual symposia to topics with biological perspectives. Our last four volumes have dealt with medicinal plants (1994), plant/insect interactions (1995), food phytochemicals (1996), and plant/microbe interactions (1997), respectively. The Symposium held in Pullman, Washington, July 26-31, 1998 brought many aspects of these previous symposia once again to the forefront. This time, however, there was greater emphasis on the potential applications of phytochemistry to the diverse topics of human health and nutrition and plant defense. As we learned about innovative uses of molecular biology as it is being applied to these topics, we were reminded once again of the biochemical th foundation on which these advances rest. On the occasion of the 75 birthday of G.H. Neal Towers, which we were privileged to celebrate, a perspective of where we began and how far we have advanced was made patently real for those in attendance. The papers assembled in this volume were presented during the Sympo- sium. Roughly grouped under three broad topics, they include: I.Drug Discov- ery and Pathway Engineering toward New MedicinallNutriceutical Targets (papers by Cragg, Croteau, Thompson, Costa, McLaughlin, Dixon, and Matern), 2. Roles for Polyphenols-Biosynthesis and Applications (Gross, Hillis, Haslam, and Ferreira), 3. New Chemical Prospects and Plant Defense (Asakawa, Selmar, Houghton, and Mizutani).

This volume is based on papers presented by invited speakers at a symposium entitled "Plant Nitrogen Metabolism" held in conjunction with the 28th Annual Meeting of the Phytochemical Society of North America. The meeting took place on the campus of the University of Iowa at Iowa City during June 26-30, 1988, and attracted 110 participants from 11 countries. The goal of the symposium was to trace the pathway by which nitrogen passes from soil and atmosphere into both primary and secondary nitrogenous metabolites, focusing upon areas which were felt to be most rapidly expanding. From nodulines (nodule specific proteins) and GS/GOGAT mutants to sugar mimics (polyhydroxyalkaloids) and herbicide inhibitors of amino acid metabolism, research in nitrogen metabolism has expanded into areas barely envisioned only a few years ago. Both the nitrogen specialist and the general plant biochemist will be pleased by the range of topics covered here. Following an overview in Chapter 1 of plant nitrogen metabolism, the remaining chapters are loosely organized into three groups. Chapters 2-6 deal primarily with the biochemistry and molecular biology of nitrogen assimilation and transport, Chapters 7-9 with amino acid metabolism, and Chapters 10-12 with secondary metabolites.

Since 1994, the Phytochemical Society of North America has devoted its annual symposia to topics with biological perspectives. Our last four volumes have dealt with medicinal plants (1994), plant/insect interactions (1995), food phytochemicals (1996), and plant/microbe interactions (1997), respectively. The Symposium held in Pullman, Washington, July 26-31, 1998 brought many aspects of these previous symposia once again to the forefront. This time, however, there was greater emphasis on the potential applications of phytochemistry to the diverse topics of human health and nutrition and plant defense. As we learned about innovative uses of molecular biology as it is being applied to these topics, we were reminded once again of the biochemical th foundation on which these advances rest. On the occasion of the 75 birthday of G.H. Neal Towers, which we were privileged to celebrate, a perspective of where we began and how far we have advanced was made patently real for those in attendance. The papers assembled in this volume were presented during the Sympo- sium. Roughly grouped under three broad topics, they include: I.Drug Discov- ery and Pathway Engineering toward New MedicinallNutriceutical Targets (papers by Cragg, Croteau, Thompson, Costa, McLaughlin, Dixon, and Matern), 2. Roles for Polyphenols-Biosynthesis and Applications (Gross, Hillis, Haslam, and Ferreira), 3. New Chemical Prospects and Plant Defense (Asakawa, Selmar, Houghton, and Mizutani).

The papers assembled in this volume were originally presented at the joint meeting of the Phytochemical Society of North America and Phytochemical Society of Europe held in Noordwijkerhout, The Netherlands, April 20-23, 1997. The meeting was organized by an international panel of scientists from both societies. The symposium from which the related contributions on phytochemi- cal signaling and plant-microbe interactions were taken was entitled "Commu- nication of Plants with the Environment." The chapters included in this volume cover traditional areas in plant chemical ecology, as well as address fundamental issues on the involvemerrt ofphytochemicals in intra- and interspecific signaling, applications of the knowledge gained from such studies, and evolutionary origins. T.he term microbes is used here in the broadest sense to encompass bacteria, fungi, and nematodes. An array of plant and fungal metabolites ranging from simple phenolics, salicylic acid, hydroxamic acids, flavonoids, polysaccharides, fatty acid derived octadecanoids, to trichothecenes and perylenequinones are discussed.A number of important themes emerge: i) the multifunctional roles of many phytochemi- cals, ii) the power of molecular techniques for studying biosynthetic pathways and gene function, iii) the central role of natural products in pathogenesis and disease resistance, and iv) the identification of promising areas for future research and development of applications. The opening chapter by Osbourn et al. discusses the emerging role and significance of saponins as antifungal agents, compounds already well-docu- mented as important mediators of plant-insect interactions. McCormick et al.

Phytochemists are aware that their focus of interest is receiving attention from a wider segment of society and from a greater diversity of disciplines within the scientific community than ever before. Nonetheless, they were bemused to learn three years ago that "until recently scientists didn't even know phytochemi­ cals existed" (Newsweek, April 24, 1994). Changing public perception of the positive contributions of phytochemicals to human well-being has foundations in scientific advances. With popular reports emphasizing the important implica­ tions of phytochemicals in the daily lives of people, there is a pressing need for those working in this area to explain their diverse scientific activities to the public. Chemicals from plant foods are linked through epidemiological and ex­ perimental studies with reduced incidence of chronic degenerative diseases. Phytomedicines, standardized according to particular constituents, are making increasing contributions to health care. Naturally occurring constituents of plants are recognized as fundamental to the appeal, quality, and marketability of food products. In light of such developments, perceptions by phytochemists of their own discipline and its applications are expanding. Until recently, food phyto­ chemistry largely implied food toxicants. Food plants were familiar, but seldom the source of novel economically important compounds. Increasingly sophisti­ cated methods of analysis, however, have opened new opportunities for under­ standing the nature and functions offood constituents, and for manipulating them to improve the quality, acceptability, and value of food products.

Diversity within and among living organisms is both a biological impera­ tive and a biological conundrum. Phenotypic and genotypic diversity is the critical currency ofecological interactions and the evolution of life. Thus, it is not unexpected to find vast phytochemical diversity among plants. However, among the most compelling questions which arise among those interested in ecological phytochemistry is the extent, nature, and reasons for the diversity of chemieals in plants. The idea that natural products (secondary metabolites) are accidents of metabolism and have no biological function is an old one which has resurfaced recently under a new term "redundancy. " Redundancy in the broader sense can be viewed as duplication of effort. The co-occurrence of several classes of phytochemieals in a given plant may be redundancy. Is there unnecessary duplication of chemical defense systems and ifso, why? What selective forces have produced this result? On the other hand, why does the same compound often have multiple functions? At a symposium of the Phytochemical Society of North America held in August 1995, in Sault Ste. Marie, Ontario, Canada, the topic "Phytochernical Redundancy in Ecological Interactions" was discussed. The chapters in this volume are based on that symposium. They both stimulate thought and provide some working hypotheses for future research. It is being increasingly recognized that functional diversity and multiplicity of function of natural products is the norm rather than the exception.

Phytochemicals from medicinal plants are receiving ever greater attention in the scientific literature, in medicine, and in the world economy in general. For example, the global value of plant-derived pharmaceuticals will reach $500 billion in the year 2000 in the OECD countries. In the developing countries, over-the-counter remedies and "ethical phytomedicines," which are standardized toxicologically and clinically defined crude drugs, are seen as a promising low­ cost alternatives in primary health care. The field also has benefited greatly in recent years from the interaction of the study of traditional ethnobotanical knowledge and the application of modem phytochemical analysis and biological activity studies to medicinal plants. The papers on this topic assembled in the present volume were presented at the annual meeting of the Phytochemical Society of North America, held in Mexico City, August 15-19, 1994. This meeting location was chosen at the time of entry of Mexico into the North American Free Trade Agreement as another way to celebrate the closer ties between Mexico, the United States, and Canada. The meeting site was the historic Calinda Geneve Hotel in Mexico City, a most appropriate site to host a group of phytochemists, since it was the address of Russel Marker. Marker lived at the hotel, and his famous papers on steroidal saponins from Dioscorea composita, which launched the birth control pill, bear the address of the hotel.