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PHYTATE-- IP6 MOLECULE


Phytic acid --(IP6)

 

Phytic acid (known as inositol hexakisphosphate (IP6), or phytate when in salt form) is the principal storage form of phosphorus in many plant tissues, especially bran and seeds.[1] Phytate is not digestable to humans or non-ruminant animals, however, so it is not a source of either inositol or phosphate if eaten directly. Morever, it chelates and thus makes unabsorbable certain important minor minerals such as zinc and iron, and to a lesser extent, also macro minerals such as calcium and magnesium.Catabolites of phytic acid are called lower inositol polyphosphates. Examples are Inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3).

 

Significance in agriculture

Phosphorus in phytate form is, in general, not bioavailable to non-ruminant animals because they lack the digestive enzyme phytase, which is required to separate phosphorus from the phytate molecule. On the other hand, ruminants readily use phytate because of the phytase produced by rumen microorganisms.[2]

In most commercial agriculture, non-ruminant livestock such as swine, fowl, and fish[3] are fed mainly grains such as maize, and legumes such as soybeans.[citation needed] Because phytate from these grains and beans is unavailable for absorption, the unabsorbed phytate passes through the gastrointestinal tract, elevating the amount of phosphorus in the manure.[2] Excess phosphorus excretion can lead to environmental problems such as eutrophication.[4]

The bioavailability of phytate phosphorus can be increased by supplementation of the diet with the enzyme phytase.[5] Also, viable low-phytic acid mutant lines have been developed in several crop species in which the seeds have drastically reduced levels of phytic acid and concomitant increases in inorganic phosphorus.[6] However, reported germination problems have hindered the use of these cultivars thus far.

The use of sprouted grains will reduce the quantity of phytic acids in feed, with no significant reduction of nutritional value.[7]

Phytates also have the potential to be used in soil remediation, to immobilize uranium, nickel and other inorganic contaminants.[8]

Food science

Phytic acid is found within the hulls of nuts, seeds, and grains.[1] In-home food preparation techniques can reduce the phytic acid in all of these foods. Simply cooking the food will reduce the phytic acid to some degree. More effective methods are soaking in an acid medium, lactic acid fermentation, and sprouting.[9]

Phytic acid has a strong binding affinity to important minerals such as calcium, magnesium, iron, and zinc. When a mineral binds to phytic acid, it becomes insoluble, precipitates and will be nonabsorbable in the intestines. This process can therefore contribute to mineral deficiencies in people whose diets rely on these foods for their mineral intake, such as those in developing countries.[10][11] Contrary to that, one study correlated decreased osteoporosis risk with phytic acid consumption.[12] It also acts as an acid, chelating the vitamin niacin, the deficiency of which is known as pellagra.[13] In this regard, it is an anti-nutrient, despite its possible therapeutic effects (see below). For people with a particularly low intake of essential minerals, especially those in developing countries, this effect can be undesirable.

Binding of calcium with phytic acid depends on pH.[14]

"Probiotic lactobacilli, and other species of the endogenous digestive microflora as well, are an important source of the enzyme phytase which catalyses the release of phosphate from phytate and hydrolyses the complexes formed by phytate and metal ions or other cations, rendering them more soluble, ultimately improving and facilitating their intestinal absorption"[15]

Ascorbic Acid (vitamin C) can reduce phytic acid effects on iron.[16]

Food sources of Phytic Acid[17]
Food [% minimum dry] [% maximum dry]
Sesame seeds flour 5.36 5.36
Brazilnuts 1.97 6.34
Almonds 1.35 3.22
Tofu 1.46 2.90
Linseed 2.15 2.78
Oat Meal 0.89 2.40
Beans, pinto 2.38 2.38
Soy protein concentrate 1.24 2.17
Soybeans 1.00 2.22
Corn 0.75 2.22
Peanuts 1.05 1.76
Wheat flour 0.25 1.37
Wheat 0.39 1.35
Soy beverage 1.24 1.24
Oat 0.42 1.16
Wheat germ 0.08 1.14
Whole wheat bread 0.43 1.05
Brown rice 0.84 0.99
Polished rice 0.14 0.60
Chickpeas 0.56 0.56
Lentils 0.44 0.50

Therapeutic uses

Phytic acid may be considered a phytonutrient, providing an antioxidant effect.[1][18] Phytic acid's mineral binding properties may also prevent colon cancer by reducing oxidative stress in the lumen of the intestinal tract.[19] Researchers now believe that phytic acid, found in the fiber of legumes and grains, is the major ingredient responsible for preventing colon cancer and other cancers.[1][20]

In vitro studies using a cell culture model have suggested that phytic acid may have a neuroprotective effect by chelating iron.[21] Similar types of cell-culture studies have found that phytic acid significantly decreased apoptotic cell death induced by 1-methyl-4-phenylpyridinium. It is also known that, at least in rodents, phytic acid crosses the blood-brain barrier,[22] and so, there is a strong possibility that neuroprotection occurs in vivo as well.

Phytic acid's chelating effect may serve to prevent, inhibit, or even cure some cancers by depriving those cells of the minerals (especially iron) they need to reproduce.[1] The deprivation of essential minerals like iron would, much like other broad treatments for cancers, also have negative effects on non-cancerous cells. It is unknown whether this would affect other cells in the body that require iron (such as red blood cells) or whether the deprivation of minerals is more localized to the internal colon region.[citation needed]

Phytic acid is one of few chelating therapies used for uranium removal.[23]

Ironically it has also been shown that phytic acid is a required cofactor for YopJ, a toxin from Yersinia pestis.[24] It is also a required cofactor for the related toxin AvrA from Salmonella typhimurium.[24]

As a food additive, phytic acid is used as a preservative with E number E391.

Biological and physiological roles

In seeds and grains, Phytic acid and its metabolites have several important roles. Most notably, phytic acid functions as a phosphorus store, as an energy store, as a source of cations and as a source of myo-inositol (a cell wall precursor). Phytic acid is the principal storage forms of phosphorus in plant seeds.[25]

In animal cells, myo-inositol polyphosphates are ubiquitous and phytic acid (myo-inositol hexakisphosphate) is the most abundant, with its concentration ranging from 10 to 100 uM in mammalian cells depending on cell type and developmental stage.[26][27] The interaction of phytic acid with specific intracellular proteins has been investigated in vŠitro, and these interactions have been found to result in the inhibition or potentiation of the physiological activities of those proteins.[28][29] The best evidence from these studies suggests an intracellular role for phytic acid as a cofactor in DNA repair by non-homologous end-joining.[28] Other studies using yeast mutants have also suggested that intracellular phytic acid may be involved in mRNA export from the nucleus to the cytosol.[30] There are still major gaps in the understanding of this molecule and the exact pathways of phytic acid and lower inositol posphate metabolism are still unknown. As such, the exact physiological roles of intracellular phytic acid are still a matter of debate.[31]

References

  1. Phytic acid
  2. Klopfenstein, Terry J.; Angel, Rosalina; Cromwell, Gary; Erickson, Galen E.; Fox, Danny G.; Parsons, Carl; Satter, Larry D.; Sutton, Alan L. et al. (July 2002). "Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution". Council for Agricultural Science and Technology 21. http://digitalcommons.unl.edu/animalscifacpub/518/. 
  3. title=Growth and intestinal morphology in cobia (Rachycenton canadum) fed extruded diets with two types of soybean meal partially replacing fish mealfish.Romarheim, O.H.; Zang, C.; Penn, M.; Liu, Y.-J.; Tian, L.-H.; Skrede, A.; Krogdahl, Å.; Storebakken, T. (2008). Aquaculture Nutrition 14: 174-180. doi:10.1111/j.1365-2095.2007.00517.x. 
  4. Mallin, Michael A. (2003). Population and Environment 24: 369-85. doi:10.1023/A:1023690824045. 
  5. Ali, M; Shuja, MN; Zahoor, M; Qadri, I (2010). "Phytic acid:how far have we come". African Journal of Biotechnology 9 (11): 1551-1554. http://www.academicjournals.org/AJB. .
  6. Guttieri, M. J.; Peterson, K. M.; Souza, E. J. (2006). "Milling and Baking Quality of Low Phytic Acid Wheat". Crop Science 46: 2403-8. doi:10.2135/cropsci2006.03.0137. 
  7. Malleshi, N. G.; Desikachar, H. S. R. (1986). "Nutritive value of malted millet flours". Plant Foods for Human Nutrition 36: 191-6. doi:10.1007/BF01092036. 
  8. Seaman JC, Hutchison JM, Jackson BP, Vulava VM (2003). "In situ treatment of metals in contaminated soils with phytate". Journal of Environmental Quality 32 (1): 153-61. doi:10.2134/jeq2003.0153. PMID 12549554. http://jeq.scijournals.org/cgi/pmidlookup?view=long&pmid=12549554. 
  9. Phytates in cereals and legumes
  10. Hurrell RF (September 2003). "Influence of vegetable protein sources on trace element and mineral bioavailability". The Journal of Nutrition 133 (9): 2973S-7S. PMID 12949395. http://jn.nutrition.org/cgi/pmidlookup?view=long&pmid=12949395. 
  11. Committee on Food Protection, Food and Nutrition Board, National Research Council (1973). "Phytates". Toxicants Occurring Naturally in Foods. National Academy of Sciences. pp. 363-371. ISBN 9780309021173. http://books.google.com/?id=lIsrAAAAYAAJ&pg=PA363. 
  12. Lopez-González AA, Grases F, Roca P, Mari B, Vicente-Herrero MT, Costa-Bauzer A (December 2008). "Phytate (myo-inositol hexaphosphate) and risk factors for osteoporosis". Journal of Medicinal Food 11 (4): 747-52. doi:10.1089/jmf.2008.0087. PMID 19053869. 
  13. Anderson, Eugene N. (2005). Everyone eats: understanding food and culture. New York: New York University Press. pp. 47-8. http://books.google.com/?id=3xWt_kWk6L8C&pg=PT55. 
  14. Dendougui, Ferial; Schwedt, Georg (2004). "In vitro analysis of binding capacities of calcium to phytic acid in different food samples". European Food Research and Technology 219. doi:10.1007/s00217-004-0912-7. 
  15. Famularo G, De Simone C, Pandey V, Sahu AR, Minisola G (2005). "Probiotic lactobacilli: an innovative tool to correct the malabsorption syndrome of vegetarians?". Med. Hypotheses 65 (6): 113-5. doi:10.1016/j.mehy.2004.09.030. PMID 16095846. 
  16. Prom-U-Thai, Chanakan; Huang, Longbin; Glahn, Raymond P; Welch, Ross M; Fukai, Shu; Rerkasem, Benjavan (2006). "Iron (Fe) bioavailability and the distribution of anti-Fe nutrition biochemicals in the unpolished, polished grain and bran fraction of five rice genotypes". Journal of the Science of Food and Agriculture 86: 120-15. doi:10.1002/jsfa.2471. 
  17. Reddy, N. R.; Sathe, Shridhar K. (2001). Food Phytates. Boca Raton: CRC.
  18. "From Antinutrient to Phytonutrient: Phytic Acid Gains Respect". Environmental Nutrition (Belvoir Media Group). April 2004. http://www.environmentalnutrition.com/pub/27_4/asken/150961-1.html. [unreliable source?]
  19. Vucenik I, Shamsuddin AM (November 2003). "Cancer inhibition by inositol hexaphosphate (IP6) and inositol: from laboratory to clinic". The Journal of Nutrition 133 (11 Suppl 1): 3778S-3784S. PMID 14608114. http://jn.nutrition.org/cgi/pmidlookup?view=long&pmid=14608114. 
  20. Jenab M, Thompson LU (August 2000). "Phytic acid in wheat bran affects colon morphology, cell differentiation and apoptosis". Carcinogenesis 21 (8): 1547-52. doi:10.1093/carcin/21.8.1547. PMID 10910957. 
  21. Xu Q, Kanthasamy AG, Reddy MB (March 2008). "Neuroprotective effect of the natural iron chelator, phytic acid in a cell culture model of Parkinson's disease". Toxicology 245 (1-2): 101-8. doi:10.1016/j.tox.2007.12.017. PMID 18255213. 
  22. Grases F, Simonet BM, Prieto RM, March JG (August 2001). "Phytate levels in diverse rat tissues: influence of dietary phytate". The British Journal of Nutrition 86 (2): 225-31. doi:10.1079/BJN2001389. PMID 11502236. 
  23. Cebrian D, Tapia A, Real A, Morcillo MA (2007). "Inositol hexaphosphate: a potential chelating agent for uranium". Radiation Protection Dosimetry 127 (1-4): 477-9. doi:10.1093/rpd/ncm356. PMID 17627956. 
  24. Mittal R, Peak-Chew SY, Sade RS, Vallis Y, McMahon HT (2010). "The acetyltransferase activity of the bacterial toxin YopJ of Yersinia is activated by eukaryotic host cell inositol hexakisphosphate". J Biol Chem 285 (26): 19927-34. doi:10.1074/jbc.M110.126581. PMID 20430892. PMC 2888404. http://www.jbc.org/content/early/2010/04/29/jbc.M110.126581.long. 
  25. Reddy NR, Sathe SK, Salunkhe DK (1982). "Phytates in legumes and cereals". Adv Food Res 28: 1-92. PMID 6299067. 
  26. Szwergold BS, Graham RA, Brown TR (1987). "Observation of inositol pentakis- and hexakis-phosphates in mammalian tissues by 31P NMR". Biochem Biophys Res Commun 149 (3): 874-881. PMID 3426614. 
  27. Sasakawa N, Sharif M, Hanley MR (1995). "Metabolism and biological-activities of inositol pentakisphosphate and inositol hexakisphosphate". Biochem Pharmacol 50 (2): 137-146. PMID 7543266. 
  28. Hanakahi LA, Bartlet-Jones M, Chappell C, Pappin D, West SC (2000). "Binding of inositol phosphate to DNA-PK and stimulation of double-strand break repair". Cell 102 (6): 721-729. PMID 11030616. 
  29. Norris FA, Ungewickell E, Majerus PW (1995). "Inositol hexakisphosphate binds to clathrin assembly protein 3 (AP-3/AP180) and inhibits clathrin cage assembly in vitro". J Biol Chem 270 (1): 214-217. PMID 7814377. 
  30. York JD, Odom AR, Murphy R, Ives EB, Wente SR (1999). "A phospholipase C-dependent inositol polyphosphate kinase pathway required for efficient messenger RNA export". Science (Washington, D.C.) 285 (5424): 96-100. doi:10.1126/science.285.5424.96. PMID 10390371. 
  31. Shears SB (2001). "Assessing the omnipotence of inositol hexakisphosphate". Cell Signalling 13 (3): 151-158. PMID 11282453. 
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