Plant chemicals in the evolution of mammals and humans

The relation between primates and fleshy fruits was established in the early-mid Eocene (55 to 48 million years bp) when the tropical forests reached their maximum latitudinal extent (Collinson and Hooker, 1991). Plants have formed a significant part of the diet throughout human evolution and there can be no doubt that a wide range of plant chemicals was thereby ingested. Although there is evidence to suggest that the evolution of plant secondary compounds was closely influenced by their...

Why preserve the chemical diversity of plants

The chemical industry seeks novel, single active molecules which can preferably be synthesised in a laboratory. The evolutionary pressure on plants has apparently caused them to maintain an arsenal of strategically useful compounds which can be varied in response to changing ecological pressures. These needs have been met by mixtures of metabolically-related variants on particular skeletal themes, frequently complex and only isolated or synthesised with difficulty. The observed activity of...

The structural range of plant secondary metabolites

A full description of the range of plant compounds is outside the scope of this chapter but may be found in a number of recent texts such as Mann (1987) and Luckner (1990). An overview of those classes most commonly found is presented here. The dividing line between primary and secondary metabolism is unclear. The two are connected in that primary metabolites provide the starting material for secondary metabolites which are largely formed from three principal starting materials (Mann, 1987) 1....

NCI Plant Screening Program Phase II 1986present3

In 1986, NCI initiated three 5-year contracts for a renewed plant collection program with the Missouri Botanical Garden, the New York Botanical Garden (NYBG) and the University of Illinois. The initial contracts totaled 2.7 million and the contracts were reawarded for a further 5 years to the incumbents in September 1991. Each collecting institution is currently responsible for collecting 1500 samples of 0.3-1.0 kg (dry weight) per year plus voucher samples. One of the voucher samples must be...

Medicinal Plants Of Introduction

The value of biodiversity as a source of pharmaceutically active substances has been the subject of a number of studies, for example Pearce and Puroshothaman (this volume), McNeely (1988), Farnsworth and Soejarto (1985) and Principe (1991). This value is now being cited as one of the many arguments for conserving natural habitats and, in particular, tropical forests which contain the largest number of plant species. These analyses, however, ignore the additional role of these as sources of...

Conclusions

First, it discussed the rapid rise in interest in medicinal biodiversity found predominantly in developing countries. Both fear and economic fortune enter the calculus of policymakers and industrialists in developed countries with regard to biodiversity conservation. I also explored the salient differences between Western and traditional systems of property. It is evident, though, that the property system of industrialised countries is being forced on the...

The US National Cancer Institutes plant screening program

In 1937, the US NCI was founded in order to initiate and coordinate research related to cancer. In 1955, the NCI created the Cancer Chemotherapy National Service Center (CCNSC) with the aim of developing a program of screening chemical substances for anti-cancer activity. Initially envisioned as a voluntary cooperative cancer chemotherapy program, the CCNSC has gradually grown into a major drug research and development unit. CCNSC (now incorporated into NCI's Developmental Therapeutics Program)...

NCI Plant Screening Program Phase I 195582

The screening of plants did not begin in a major way until 1960 when NCI reached an agreement with the US Department of Agriculture (USDA) for the annual collection of large numbers of plant samples. Starting with the US and Mexico, the USDA and other subcontractors scoured 60 countries for plant samples during the first phase of the NCI natural products program. By the end of the first phase, Suffness and Douros (1979) estimated that NCI was receiving about 35CKMOOO plant samples a year, of...

Conclusion

Ethnobotany is not the only avenue for new drug discovery, nor the only source of models for conservation, but the body of knowledge it represents is founded on long-term experience with both subjects. The divisions created by expanding economies and advancing technologies have served to separate the demand for natural products or traditional knowledge from the protection of their sources. There is still so little known about biological diversity and the chemical activity it contains, hence...

Secondary plant metabolites and the chemical industry

The first secondary compound to be isolated in a pure form was morphine from the opium poppy, in the early nineteenth century. Although it took almost 50 years for its structure to be elucidated, this nevertheless signalled the beginning of pharmacy as an exact science of fully characterised molecules given in regulated doses. The techniques of isolation, characterisation and synthesis gradually improved during the nineteenth century, and gave rise to a modern chemical industry based not on...

Methods of drug development

Austel and Kutter (1980) suggest that there are three methods for obtaining lead compounds or chemical structures for drug development by reference to compounds and structures that are known to demonstrate activity relative to the disease target, by random screening of compounds and structures - the 'empirical' approach, and by utilizing knowledge of the biomolecular processes that play an important role in disease - 'rational' drug design. Two major sources of leads that are based on known...

Conclusions conservation of medicinal plants habitats and indigenous technical knowledge

In conclusion we can surmise that in general the two major threats to medicinal plants are first, the loss of habitat (through land use conversion, agricultural expansion and so on) which results in the loss of both known and unknown species and second, the overexploitation of known species as a result in increased demand. Related to these two is the associated loss of indigenous knowledge and expertise. To what extent are these processes underway in Ghana The review of Ghanaian case studies...

The role of ethnobotany in pharmaceutical prospecting

Plants have been the cornerstone of medicinal therapies for thousands of years and continue to be an essential part of health care for much of the world. The traditional origins of many current pharmaceuticals have been obscured by the process of drug development, such as aspirin from willow bark (Salix spp.), reserpine for hypertension from the Indian Snake Root (Rauwolfia serpentina) and D-tubocurarine, widely used as a muscle relaxant in surgery, from arrow poisons (Chondodendron tomentosum,...

Biodiversity conservation in perspective

In view of the increasing importance attached to tropical medicinal plants by multinational corporations and some research organisations in industrialised countries, many species face the danger of extinction or disappearance from unscrupulous overharvesting. This threat is very real as evidenced by reported losses of some species in recent times. Most of the depletions are not natural but are a consequence of the heightened interest in screening medicinal plants, largely identified by...

Medicinal plants in Ghana

This section examines information on the use of medicinal plants collated from a number of case studies of different regions and ecosystems in Ghana. The management of plant habitats, the evidence of overexploitation and scarcity, and the effects of environmental and land use change is reviewed. A brief profile of the country, and an overview of the health system and concepts of illness and treatment, and the role of traditional healers, of which herbalists form the majority, is included. Ghana...