Nitrogenous secondary metabolites

Enns MW, Cox BJ, Parker JD, Guertin JE. (1998). Confirmatory factor analysis of the Beck anxiety and depression inventories in patients with major depression. J Affective Disord. 47(1-3) 195-200. Erdelmeier CA. (1998). Hyperforin, possibly the major non-nitrogenous secondary metabolite of Hypericum perforatum L. Pharmacopsychiatry. 31(suppl 1) 2-6. 

Are non-nitrogenous secondary metabolites better taxonomic markers Whereas flavonoids are found in all three subfamilies, and are thus of limited value at the family/tribal level, isoflavones are obviously restricted to the... 

Alkaloids are nitrogenous secondary metabolites primarily derived from amino acids for both their... 

Erdelmeier CAJ. Hyperforin, possibly the major non-nitrogenous secondary metabolite of Hypericum perforatum L. Pharmacopsychiatry 1998 31 2-6. 

Spenser ID (1969) The biosynthesis of alkaloids and of other nitrogenous secondary metabolites. In Florkin M, Stotz EH (eds) Comprehensive biochemistry, vol 20. Elsevier, Amsterdam New York, p 231 and references cited therein Wilson ML, Coscia CJ (1975) Studies on the early stages of Papaver alkaloid biogenesis. J Am Chem Soc 97 431-433... 

Figure 3.1 Distribution of nitrogenous and non-nitrogenous secondary metabolites among photosynthetic organisms (according to Ireland etal.,...

Figure 3.2 illustrates the same distribution for the invertebrates, where it can be seen that there is no correlation between the percentages of nitrogenous secondary metabolites and the position of each phylum on Luden Cuenot s Tree of Life. It is therefore dearly apparent that to find new nitrogenous metabolites, it is better to seek them among tunicates, bryozoans or sponges than among cni-darians, echinoderms, or mollusks. 

Domoic add is one of the rare nitrogenous secondary metabolites encormtered in the diatoms. Isodomoic acids A-F, all isomers of domoic add, have been isolated from the red alga Chondria armata (Chapter 13). For an overall study on ASP and domoic adds, see Daranas, Norte, and Fernandez, 2001 Clayden, Read, and Hebditch, 2005 Kotaki et al (2005), Ramsdell (2007) and Pulido (2008). 

A culture of the freshwater species Poterioochromonas malhamensis permitted the isolation of an inhibitor of the protein tyrosine kinase (PTK) called malhamensilipin A. This derivative of tetracosane (C24) contains six chlorine atoms and an enol sulfate the exact origin of this compound remains unknown however (Chen et al, 1994). Similar derivatives have been isolated from this same species and from another freshwater species, Ochromonas danica (Haines, 1973). Similar structures have been formd in octocorals (see Chapter 20) and toxic mollusks (see Chapter 23). The absence of nitrogenous secondary metabolites has been reported. 

Assuming that the metabolic pathways are similar in the biosynthesis of related isocyanoterpenes, these studies remain difficult, due in part to the competitive formation of other secondary metabolites. In addition to the common trio (-NC, NCS, -NHCHO) of the nitrogenous functions found attached to these skeletons, analogs such as -CN, -CNO, and -SCN foreshadow the complexity of identifying and selecting specific precursors to be targeted for incorporation into the family of marine isonitriles. 

Alkaloids are compounds that contain nitrogen in a heterocyclic ring and are commonly found in about 15-20% of all vascular plants. Alkaloids are subclassified on the basis of the chemical type of their nitrogen-containing ring. They are formed as secondary metabolites from amino acids and usually present a bitter taste accompanied by toxicity that should help to repel insects and herbivores. Alkaloids are found in seeds, leaves, and roots of plants such as coffee beans, guarana seeds, cocoa beans, mate tea leaves, peppermint leaves, coca leaves, and many other plant sources. The most common alkaloids are caffeine, theophylline, nicotine, codeine, and indole... 

Alkaloids, nitrogen-containing compounds generally found as secondary metabolites in plants, are also classical examples of renewables. In contrast to terpenes, they show a great variety in molecular structure, and the different classes of alkaloids are usually based on their basic ring systems. Many pharmaceutically active... 

Purifications of the methanolic extract of adults and larvae of the New Guinean species Epilachna signatipennis led to the isolation and structure determination of three nitrogen-containing secondary metabolites choline (24), L-hypaphorine (25), and signatipennine (26) (Fig. 5). From a biosynthetic... 

Fig. 5 Nitrogen-containing secondary metabolites found in Epilachna signatipennis...

Molsidomine (8.159, Fig. 8.18), a very special example of a carbamate prodrug that acts by vascular smooth muscle relaxation, is an anti-angina agent effective mainly in the treatment of myocardial ischemia [207], Molsidomine undergoes enzymatic hydrolysis in the liver to form the imine 8.160 (Fig. 8.18) [208]. This metabolite is inactive and unstable, breaking down spontaneously to the A-nitroso secondary metabolite known as Sinl A (8.161, Fig. 8.18). The latter was found to be active, but there are reasons to believe that it acts by releasing nitrogen monoxide in the form of nitroxyl (HNO), which dissociates to the nitroxide ion NO, i. e., the reduced form of NO. 

Perhaps most conspicuous by their absence from the list (cf. Table VIII) are the alkaloids. These substances, generally defined as nitrogen-containing secondary metabolites, are common plant products and usually have distinct physiological activities. Nevertheless, to date no reports seem to have appeared concerning the presence (or absence) of alkaloids as Gossypium metabolites. 

How much a mammal eats of a given plant often depends on the levels of different classes of chemical constituent, notably nutrients and plant secondary metabolites. As in birds, it is not the plant defense compounds alone, but rather complex balances between nitrogen and carbohydrate contents, levels of defense compounds, and fiber that determine palatability. 

The relationship, if any, between the secondary metabolism of L-phenylalanine and carbohydrate degradation during brown-rot wood decay processes has not yet been determined. However, we suspect that the secondary metabolism of this aromatic amino-acid plays an important role in converting monomeric sugars to nitrogen-free metabolites (Shimada, M., and Takahashi, M., In Handbook of Wood and Cellulosic Materials Hon,... 

Table I shows the amounts of secondary metabolites formed on days 11 and 33 (during an incubation of 63 days) for both nitrogen-poor (HC/LN) and nitrogen-rich (HC/HN) cultures (15). The initial C/N ratios of the two cultures were 240 and 24, respectively. Figure 3 shows the variations in the total amounts of the secondary metabolites produced, the weights of the fungal mycelium, and the nitrogen and glucose concentrations remaining in the HC-LN culture media during the incubation period shown.

Figure 3. Relationship between secondary metabolite production, consumption of nitrogen and carbon sources, and growth of the brown-rot fungus Lentinus lepideus (HC-LN medium).

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