Secondary metabolites, also known as natural products, are those products (chemical compounds) of metabolism that are not essential for normal growth, development or reproduction of an organism. In this sense they are "secondary". The function or importance of these compounds to the organism's development is usually of ecological nature as they are used as defence against predators (herbivores, pathogens etc.), for interspecies competition, and to facilitate the reproductive processes. Contrary to primary metabolites these compounds are not ubiquitous in the living organisms who produce them nor are they necessarily expressed continuously. Although plants are better known as a source of secondary metabolites, bacterium, fungi and many ocean organisms (sponges, tunicates, corals, snails) are very interesting sources, too. Secondary metabolites can be classified by their chemical structure or physical properties into one or more of the following groups: alkaloids, terpenoids, polyketides, aliphatic, aromatic, and heteroaromatic organic acids, phenols, iridoids, steroids, saponins, peptides, ethereal oils, resins and balsams. List of most important secondary metabolites of plants: * Class ''Alkaloids'': ** Hyoscyamine, present in ''Datura stramonium'' ** Atropine, present in ''Atropa belladonna'', Deadly nightshade ** Cocaine, present in ''Erythroxylon coca'' the Coca plant ** * Class ''Terpenoids'': ** Azadirachtin A, present in Azadirachta indica, Neem tree ** Artemisinin, present in Artemisia annua Chinese wormwood * Class ''Aliphatic'', ''Aromatic'' and ''Heteroaromatic'' organic acids: ** * Class ''Polyketides'': ** * Class ''Phenols'': ** Resveratrol, present in Vine, Peanut ** * Class ''Iridoids'': ** * Class ''Steroids'': ** * Class ''Volatile oils'', ''Resins'' and ''Balsams'': ** * Class ''Saponins'': Plant physiology Metabolism
The article says: ''Secondary metabolites, also known as natural products, are those products (chemical compounds) of metabolism that are not essential for normal growth, development or reproduction of an organism.'' Isn't that a rather outdated view of secondary metabolites? I thought the term ''secondary metabolite'' referred to the fact that they were products of ''secondary'' (rather than ''primary'' metabolic pathways). Am I mistaken? User:Guettarda 20:16, 23 Feb 2005 (UTC) So what is the difference between primary and secondary pathways? They lead to primary and secondary metabolites! Sure, primary and secondary pathways have different specific characteristics as a result of the different function of their products and the different evolutionary forces acting on them. But it makes no sense to me to define the differences between primary and secondary metabolites by characteristics of their pathways. You might be interested to read Nat. Prod. Rep. 20:382 (2003 [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12964834]) for a brilliant analysis of the evolution and properties of secondary pathways. User:Cacycle 10:10, 24 Feb 2005 (UTC) :Sorry if my comment was unclear; what I took issue with was the statement: ''not essential for normal growth, development or reproduction of an organism.'' While it may not be the intent of the sentance, it reads like something out of the old school view of secondary metabolites - that they are (to quote Firn and Jone, the paper you referenced): ''waste products or accidents of metabolism''...which they most obviously are not. If they are not essential, then odds are they would be eliminated through natural selection - a point that Firn and Jones made quite strongly. I don't quite see how one would separate "essential" from "non-essential" compounds, and if one did you would end up re-defining the idea of "secondary metabolite"...a compound used in pollinator attraction would not be secondary if the plant has specific pollinator requirements (''e.g.'', ''Coryanthes''), but would be if it were involved in defense against a pathogen which was only present in some populations. But if the plants had no resistance to a given pathogen it might have a much greater impact on the population. For example, if American chestnut had a compound that defended it against chestnut blight, that would be ''essential for its reproduction'', because almost no chestnuts are able to reproduce because stems that are large enough to flower are all killed by the blight (with the exception of some populations, see [http://www.ingentaconnect.com/content/bsc/jecol/2004/00000092/00000004/art00011;jsessionid=9kj413km3jhsj.henrietta]). So without defensive compounds (often "secondary metabolites) many species might be wiped out by pathogens. "Essential" ''vs.'' "non-essential" is really scale-dependent. :As to the second part, as far as I know the term "secondary metabolite" ''came from'' the idea of secondary metabolism...so the naming reflects historical ideas about "primary" and "secondary" metabolism. Now, as Firn and Jones pointed out, the idea of primary and secondary metabolism is probably mistaken, but that doesn't change the reason that "secondary metabolites" are so-called. User:Guettarda 16:05, 24 Feb 2005 (UTC)
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Words begining with Secondary_metabolite:
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Secondary metabolite
Secondary metabolites, also known as natural products, are those products (chemical compounds) of metabolism that are not essential for normal growth, development or reproduction of an organism. In this sense they are "secondary". The function or importance of these compounds to the organism's development is usually of ecological nature as they are used as defence against predators (herbivores, pathogens etc.), for interspecies competition, and to facilitate the reproductive processes. Contrary to primary metabolites these compounds are not ubiquitous in the living organisms who produce them nor are they necessarily expressed continuously. Although plants are better known as a source of secondary metabolites, bacterium, fungi and many ocean organisms (sponges, tunicates, corals, snails) are very interesting sources, too. Secondary metabolites can be classified by their chemical structure or physical properties into one or more of the following groups: alkaloids, terpenoids, polyketides, aliphatic, aromatic, and heteroaromatic organic acids, phenols, iridoids, steroids, saponins, peptides, ethereal oils, resins and balsams. List of most important secondary metabolites of plants: * Class ''Alkaloids'': ** Hyoscyamine, present in ''Datura stramonium'' ** Atropine, present in ''Atropa belladonna'', Deadly nightshade ** Cocaine, present in ''Erythroxylon coca'' the Coca plant ** * Class ''Terpenoids'': ** Azadirachtin A, present in Azadirachta indica, Neem tree ** Artemisinin, present in Artemisia annua Chinese wormwood * Class ''Aliphatic'', ''Aromatic'' and ''Heteroaromatic'' organic acids: ** * Class ''Polyketides'': ** * Class ''Phenols'': ** Resveratrol, present in Vine, Peanut ** * Class ''Iridoids'': ** * Class ''Steroids'': ** * Class ''Volatile oils'', ''Resins'' and ''Balsams'': ** * Class ''Saponins'': Plant physiology Metabolism
Secondary metabolite
The article says: ''Secondary metabolites, also known as natural products, are those products (chemical compounds) of metabolism that are not essential for normal growth, development or reproduction of an organism.'' Isn't that a rather outdated view of secondary metabolites? I thought the term ''secondary metabolite'' referred to the fact that they were products of ''secondary'' (rather than ''primary'' metabolic pathways). Am I mistaken? User:Guettarda 20:16, 23 Feb 2005 (UTC) So what is the difference between primary and secondary pathways? They lead to primary and secondary metabolites! Sure, primary and secondary pathways have different specific characteristics as a result of the different function of their products and the different evolutionary forces acting on them. But it makes no sense to me to define the differences between primary and secondary metabolites by characteristics of their pathways. You might be interested to read Nat. Prod. Rep. 20:382 (2003 [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12964834]) for a brilliant analysis of the evolution and properties of secondary pathways. User:Cacycle 10:10, 24 Feb 2005 (UTC) :Sorry if my comment was unclear; what I took issue with was the statement: ''not essential for normal growth, development or reproduction of an organism.'' While it may not be the intent of the sentance, it reads like something out of the old school view of secondary metabolites - that they are (to quote Firn and Jone, the paper you referenced): ''waste products or accidents of metabolism''...which they most obviously are not. If they are not essential, then odds are they would be eliminated through natural selection - a point that Firn and Jones made quite strongly. I don't quite see how one would separate "essential" from "non-essential" compounds, and if one did you would end up re-defining the idea of "secondary metabolite"...a compound used in pollinator attraction would not be secondary if the plant has specific pollinator requirements (''e.g.'', ''Coryanthes''), but would be if it were involved in defense against a pathogen which was only present in some populations. But if the plants had no resistance to a given pathogen it might have a much greater impact on the population. For example, if American chestnut had a compound that defended it against chestnut blight, that would be ''essential for its reproduction'', because almost no chestnuts are able to reproduce because stems that are large enough to flower are all killed by the blight (with the exception of some populations, see [http://www.ingentaconnect.com/content/bsc/jecol/2004/00000092/00000004/art00011;jsessionid=9kj413km3jhsj.henrietta]). So without defensive compounds (often "secondary metabolites) many species might be wiped out by pathogens. "Essential" ''vs.'' "non-essential" is really scale-dependent. :As to the second part, as far as I know the term "secondary metabolite" ''came from'' the idea of secondary metabolism...so the naming reflects historical ideas about "primary" and "secondary" metabolism. Now, as Firn and Jones pointed out, the idea of primary and secondary metabolism is probably mistaken, but that doesn't change the reason that "secondary metabolites" are so-called. User:Guettarda 16:05, 24 Feb 2005 (UTC)
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SB | SC | SD | SE | SF | SG | SH | SI | SJ | SK | SL | SM | SN | SO | SP | SR | SS | ST | SU | SW | SX | SY | SZ |Words begining with Secondary_metabolite:
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