Animals alkaloids

Alkaloids play a very important role in organism metabolism and functional activity. They are metabolic products in plants, animals and micro-organisms. They occur in both vertebrates and invertebrates as endogenous and exogenous compounds. Many of them have a distributing effect on the nervous systems of animals. Alkaloids are the oldest successfully used drugs throughout the historical treatment of many diseases ... 

Braekman, J.C. Daloze, D. Pasteels, J.M. (1998) Alkaloids in animals. Alkaloids Biochemistry Ecology and Medicinal Applications. Roberts, M.F. Wink, M., eds.. Plenum Press, pp. 349-78. 

Basic nitrogen compounds similar to the plant alkaloids also occur in animals, although the description animal alkaloid seldom is used. Certain amines and ammonium compounds play key roles in the function of the central nervous system (Figure 23-3) and the balance of amines in the brain is critical for normal brain functioning. Also, many essential vitamins and hormones are basic nitrogen compounds. Nitrogen bases also are vital constituents of nucleic acid polymers (DNA and RNA) and of proteins (Chapter 25). 

The purine group of alkaloids includes the vegetable alkaloids caffeine, theobromine, theophylline and the animal alkaloids xanthine, hypoxanthine, guanine and adenine. The most common substance which is a purine compound is uric acid, but, though directly related to the alkaloids given above, it is not itself usually considered as an alkaloid. The constitution of uric acid has been fully considered (Part I, p. 442). It is the tri-hydroxy derivative of a substance known as purine which is the mother substance of the purine alkaloids also. 

V. Animal Alkaloids Bearing Alkyl or Functionalized Alkyl Substituents... 

Our knowledge of alkaloids in animals is scant. The so-called protoalkaloids (biogenic amines and their derivatives) are widespread in lower animals (194, 195), and the parallelism between plant and animal metabolism is extensive. Betaines, methylated purines (e.g., paraxan-thine (VI) ), derivatives of histidine (spinacine (VII) of the shark), and kynurenic acid (VIII) are not rare in animals. The animal alkaloids, with the exception of samandarine (Vol. V, p. 321), are characterized as weak bases this is perhaps of importance for their excretion. 

A natural product is a compound synthesized by a plant or an animal. Alkaloids are natural products that contain one or more nitrogen heteroatoms and are found in the leaves, bark, roots, or seeds of plants. Examples include caffeine (found in tea leaves, coffee beans, and cola nuts) and nicotine (found in tobacco leaves). Morphine is an alkaloid obtained from opium, the juice derived from a species of poppy. Morphine is 50 times stronger than aspirin as an analgesic, but it is addictive and suppresses respiration. Heroin is a synthetic compound that is made by acetylating morphine (Section 30.3). 

It has been demonstrated that [carboxy- C]anthranilic acid is also a precursor of the animal alkaloids glomerin (2) and homoglomerin 171). 

Biological Activity of Alkaloids in Plants Biological Activity of Alkaloids in Animals Alkaloids as Allomones and Kairomones Uses of Alkaloids by Man References... 

Glomerine a quinazoline in the defense secretion of the insect Clomeris marginata. The secretion also contains homoglomerine. These two quinazolines may be regarded as animal alkaloids. 

The majority of known S.m. are synthesized by plants. More than 5,000 plant alkaloids have been identified, compared with about SO animal alkaloids. This difference may be related to excretory metabolism. Animals are able to remove from their bodies the endproducts and byproducts of metabolism, whereas plants employ metabolic excretion , i.e. products are accumulated in vacuoles, cell walls and... 

By far the largest number of secondary products, however, is formed in higher plants. In contrast to about 200 animal alkaloids more than 6000 plant alkaloids are known and the same relations exist with other groups of secondary products, e.g., terpenoids, phenolics, and steroids. It appears that this unequal distribution of secondary metabolites is a consequence of a basic difference in the mechanisms of excretion between plants and animals, rather than in the potential of biosynthesis. 

Alkaloids were considered for a long time as specialized products solely of plant metabolism. Yet in recent times alkaloids have been isolated from both vertebrate and invertebrate animals. Some of the animal alkaloids can clearly be traced to a food plant ingested. As an example, the alkaloid castoramine, isolated from the beaver (Castor canadense), resembles the alkaloids of the water lilies, Nuphar spp., which serve as food for the beavers. Some caterpillars accumulate alkaloids from the plants on which they feed. Other alkaloids, however, such as the ones found in toads, salamanders, and some fishes, are true products of animal metabolism. 

Syntheses of the allene functional group have been included in a recent volume. Acetylene- and allene-containing animal alkaloids have been reviewed. ... 

Related C15 quinolizidines and one indolizidine alkaloid have also been found in the exudate from the scent glands of the Canadian beaver Castor fiber) (castoreum, previously used as a fixative in perfumery). For convenience, these animal alkaloids wiU be included in the present discussion. 

---