Diversity of natural products

The structural diversity of natural products with antimalarial activity from marine and freshwater sources are stunning, ranging from isonitrile-containing derivatives to depsipeptides through peroxides and alkaloids. 

This book is designed to provide an all encompassing vision of the diversity of natural products in the perspective of biodiversity. Both living organisms and fossil remains are taken into account, without any bias for either the sea, land, or extreme environments. Understandably, however, this is not intended to be a comprehensive portrait of natural product diversity, which would be beyond my resources and would demand a multi-volume treatment. 

At any event, microorganisms remain far less known than conspicuous species. Microorganisms are subject to high dispersal, as in the recently discovered gene flow for planktonic foraminifers of Arctic and Antarctic waters (Darling 2000). The composition ofthe soil may be also relevant (Yaalon 2000). This is why making an estimate of the diversity of natural products is difflcult. 

Vankar 2000), behave similarly. These functional groups do not affect the planar skeleton, which is our basis of judgn nt of the diversity of natural products. 

Examination of the charts in Chapters 6.1.1 to 6.1.3 shows that the American and eastern tropical areas contribute more that the African tropics to the diversity of natural products. In particular the African tropics are poor in terpenoids, except secologanin, which is involved on a world basis in the formation of mixed-biogenesis alkaloids. 

Lakes, rivers, swamps, and marshes - common in temperate areas - contribute little to the diversity of natural products. Abundant dull-green grass and dull-colored fish and moUusks characterize lakes and rivers, in contrasts with the vivid colors of tropical fish and seaweeds. Haplosclerid sponges are occasionally abundant in freshwater, but their secondary metabolism is limited to demospongic acids (Dembisky 1994), in contrast with the variety of metabolites from marine sponges in the same order. Where not for cyanobacteria (which are as rich of unusual metabolites as the marine strains), tropical amphibians, and aquatic fimgi, freshwater ecosystems would have passed unnoticed in this book. 

The South Pacific has contributed modestly to the diversity of natural products, although the Chilean coasts remain to be adequately explored. Worth noticing are diterpenes of cyclolabdane class and C,5 oxocane acetogenins (Chart 7.7.I/FA/PO). 

Like the South Pacific, the South Atlantic also scarcely contributed to the diversity of natural products. Pregnane steroids from ascidians of the Argentine coast are the most unusual metabolites. 

The diversity of natural products of the Black Sea is also modest, including unexceptional metabolites from red seaweeds (Gtiven 1970 Hamberg 1992) and brown seaweeds (Milkova 1997), fetty acids (Christie 1994) and sterols from sponges and other invertebrates (Milkova 1997), and common terpenoids from bryozoans (Hadjieva 1987). 

Graphs in Chapter 11 have shown that, at skeletal level, the diversity of natural products is highest for the Indo-Pacific area. Although a similar semiquantitative analysis for the actual metabolites is difficult to make, the trend is expected to be the same because of the highly interacting forms of life, semiochemicals in coral reefe should prove an even more common system of communication than in... 

Threats from the introduction of alien species Alien species hinder isolation, and thus speciation, especially ecological speciation, and replace the indigenous species that regress and often disappear (Gibbons 1996 Tregenza 1999). If the introduction of alien species is massive, major problems may be posed to the diversity of natural products. 

These ideas may be translated to natural product diversity. Ecosystems of greater natural product diversity are expected to be more robust (which, by analogy, may be termed natural product redundancy). Under conditions of high diversity, a semiochemical that disappears may be replaced by another one, in a fine tuning of the ecosystem. In contrast, compensation in an ecosystem of scarce natural product diversity needs drastic changes. Thus, the diversity of natural products may be taken as a measure of the contribution to biological evolution. 

Grabowski, ., Baringhaus, . -H., Schneider, G. (2008) Scaffold diversity of natural products inspiration for combinatorial library design. Nat Prod Rep 25, 892-904. 

Natural Product Discovery, Molecular Biological Approaches to Natural Products in Microbes, Chemical Diversity of Natural Products An Overview Terpenoids in Plants... 

Marine Namral Products, Chemical Diversity of Chemical Diversity of Natural Products in Plants Pharmaceuticals Natural Products and Natural Product Models Natural Products as Anticancer Agents Chemical Ecology An Overview... 

In summary, the marine environment contains a wealth of plants, animals and microorganisms. Due to their unique adaptations to their ocean habitat, they contain a wide diversity of natural products. These compounds have shown activity in a variety of assays which have relevance to human diseases. As our understanding of the molecular basis of disease expands, these compounds and ones yet to be discovered will provide lead compounds for human therapeutic treatment. Innovations in synthesis, fermentation of symbionts as well as in manipulation of biosynthetic genes will allow us to produce sufficient material for clinical use of the compounds. Marine organisms provide a unique opportunity for access to chemical diversity. 

Plants produce a large diversity of natural products, the so-called secondary metabolites. These are of great importance for the plant for its interaction with the environment due to their roles as pollinator attractants, for symbiosis and for defence against attacks by microorganisms, other plants or animals. Moreover, they are economically important to man as a source of pharmaceuticals, flavours, fragrances, insecticides, dyes, food additives, toxins, etc. Structures of an estimated 200,000 natural products have been elucidated [1] and each year approximately 4,000-5,000 novel compounds are characterised. 

In the food industry, these natural products have now been classified under a new class of food called nutraceuticals or functional foods, because these products provide a health benefit beyond basic nutrition 22, 23). According to Wilkinson 24), most of the nutraceuticals used in the food industry are plant derived. Further, Addae-Mensah (25), showed that the world trade in medicinal plants accounts for about 30% of the total dmg market and was estimated excluding plants used as raw material sources for the essential oils required to manufacture cosmetics, food additives and other non-medicinal purposes. The increased recogiution of the value of natural products in the pharmaceutical, neutraceutical, cosmetic and other industries have created a huge demand for raw natural products. By taking Rooibos tea as an example from South Africa, Wilson 26) in detail describes the demand for Rooibos from different countries. However, for many natural products estimation of the actual demand is very difficult and the data sparse given the diversity of natural products used across industries and production variation within and across countries and the lack of... 

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