Secondary metabolite

Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism.[1] Unlike primary metabolites, absence of secondary metabolites does not result in immediate death, but rather in long-term impairment of the organism's survivability, fecundity, or aesthetics, or perhaps in no significant change at all. Secondary metabolites are often restricted to a narrow set of species within a phylogenetic group.[2] Secondary metabolites often play an important role in plant defense against herbivory[3] and other interspecies defenses.[4] Humans use secondary metabolites as medicines, flavorings, and recreational drugs.

Human Health Implications

Most polyphenol nutraceuticals from plant origin must undergo intestinal transformations, by microbiota and enterocyte enzymes, in order to be absorbed at enterocyte and colonocyte levels. This gives rise to diverse beneficial effects in the consumer, including a vast array of protective effects against viruses, bacteria, and protozoan parasites. [5]


Most of the secondary metabolites of interest to humankind fit into categories which classify secondary metabolites based on their biosynthetic origin. Since secondary metabolites are often created by modified primary metabolite synthases, or "borrow" substrates of primary metabolite origin, these categories should not be interpreted as saying that all molecules in the category are secondary metabolites (for example the steroid category), but rather that there are secondary metabolites in these categories.

Small "small molecules"

Big "small molecules", produced by large, modular, "molecular factories"

Non-"small molecules" - DNA, RNA, ribosome, or polysaccharide "classical" biopolymers

See also

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  1. ^ Fraenkel, Gottfried S. (May 1959). "The raison d'Etre of secondary plant substances". Science 129 (3361): 1466–1470. PMID 13658975. doi:10.1126/science.129.3361.1466. 
  2. ^ "Chemical plants". Retrieved 2008-12-19. 
  3. ^ Stamp, Nancy (March 2003). "Out of the quagmire of plant defense hypotheses". The Quarterly Review of Biology 78 (1): 23–55. PMID 12661508. doi:10.1086/367580. 
  4. ^ Samuni-Blank, M; Izhaki, I; Dearing, MD; Gerchman, Y; Trabelcy, B; Lotan, A; Karasov, WH; Arad, Z (2012). "Intraspecific Directed Deterrence by the Mustard Oil Bomb in a Desert Plant". Current Biology 22 (13): 1218–1220. doi:10.1016/j.cub.2012.04.051. 
  5. ^
  6. ^ Chizzali, Cornelia and Beerhues, Ludger (2012). "Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans". Beilstein J. Org. Chem. 8: 613–620. doi:10.3762/bjoc.8.68.