Phytic acid

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Phytic acid
Names
IUPAC name
(1R,2R,3S,4S,5R,6S)-cyclohexane-1,2,3,4,5,6-hexayl hexakis[dihydrogen (phosphate)]
Identifiers
83-86-3 YesY
ChEBI CHEBI:17401 YesY
ChemSpider 16735966 YesY
Jmol 3D model Interactive image
PubChem 890
UNII 7IGF0S7R8I YesY
Properties
C6H18O24P6
Molar mass 660.03 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Phytic acid (known as inositol hexakisphosphate (IP6), inositol polyphosphate, or phytate when in salt form), discovered in 1903,[1] a saturated cyclic acid, is the principal storage form of phosphorus in many plant tissues, especially bran and seeds.[2] It can be found in cereals and grains.

Catabolites of phytic acid are called lower inositol polyphosphates. Examples are inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3).

Significance in agriculture

Phosphorus and inositol in phytate form are not, in general, bioavailable to nonruminant animals because these animals lack the digestive enzyme phytase required to remove phosphate from the inositol in the phytate molecule. Ruminants are readily able to digest phytate because of the phytase produced by rumen microorganisms.[3]

In most commercial agriculture, nonruminant livestock, such as swine, fowl, and fish,[4] are fed mainly grains, such as maize, legumes, and soybeans. 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.[3] Excess phosphorus excretion can lead to environmental problems, such as eutrophication.[5]

The bioavailability of phytate phosphorus can be increased by supplementation of the diet with the enzyme phytase.[6]

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.[7] However, reported germination problems have hindered the use of these cultivars thus far. Probability due to its critical role in both phosphorus and metal ion storage.

The use of sprouted grains will reduce the quantity of phytic acids in feed, with no significant reduction of nutritional value.[8]

Phytate variants also have the potential to be used in soil remediation, to immobilize uranium, nickel and other inorganic contaminants.[9]

Biological and physiological roles

Although indigestible for many animals, phytic acid and its metabolites as they occur in seeds and grains have several important roles for the seedling plant.

Most notably, phytic acid functions as a phosphorus store, as an energy store, as a source of cations and as a source of myoinositol (a cell wall precursor). Phytic acid is the principal storage form of phosphorus in plant seeds.[10]

In animal cells, myoinositol polyphosphates are ubiquitous, and phytic acid (myoinositol hexakisphosphate) is the most abundant, with its concentration ranging from 10 to 100 uM in mammalian cells, depending on cell type and developmental stage.[11][12]

This compound is not obtained from the animal diet, but must be synthesized inside the cell from phosphate and inositol (which in turn is produced from glucose, usually in the kidneys). The interaction of intracellular phytic acid with specific intracellular proteins has been investigated in vitro, and these interactions have been found to result in the inhibition or potentiation of the physiological activities of those proteins.[13][14] The best evidence from these studies suggests an intracellular role for phytic acid as a cofactor in DNA repair by nonhomologous end-joining.[13] Other studies using yeast mutants have also suggested intracellular phytic acid may be involved in mRNA export from the nucleus to the cytosol.[15] There are still major gaps in the understanding of this molecule, and the exact pathways of phytic acid and lower inositol phosphate metabolism are still unknown. As such, the exact physiological roles of intracellular phytic acid are still a matter of debate.[16]

Food science

Phytic acid is found within the hulls of nuts, seeds, and grains.[2] In-home food preparation techniques can break down 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.[17]

Phytic acid has a strong binding affinity to important minerals, such as calcium, iron, and zinc, although the binding of calcium with phytic acid is pH-dependent.[18] The binding of phytic acid with iron is more complex, although there certainly is a strong binding affinity, molecules like phenols and tannins also influence the binding.[19] When iron and zinc bind to phytic acid they form insoluble precipitate and are far less absorbable in the intestines. This process can therefore contribute to iron and zinc deficiencies in people whose diets rely on these foods for their mineral intake, such as those in developing countries[20][21] and vegetarians.[22] However, one study correlated decreased osteoporosis risk (indicating normal levels of mineral absorption) with phytic acid consumption.[23] It also acts as an acid, chelating the vitamin niacin, the deficiency of which is known as pellagra.[24] In this regard, it is an antinutrient. For people with a particularly low intake of essential minerals, especially those in developing countries, this effect can be undesirable.

It has been hypothesized, but not tested, that probiotic lactobacilli and other species of endogenous digestive microflora may be a sufficient source of the enzyme phytase to improve mineral absorption. Phytase catalyzes the release of phosphate from phytate and hydrolyses the complexes formed by phytate and metal ions or other cations, rendering them more soluble, which improves and facilitates the absorption of zinc and magnesium.[25]

Food sources of phytic acid [26][27][28][29]
Food [% minimum dry] [% maximum dry]
Linseed 2.15 2.78
Sesame seeds flour 5.36 5.36
Almonds 1.35 3.22
Brazilnuts 1.97 6.34
Coconut 0.36 0.36
Hazelnut 0.65 0.65
Peanut 0.95 1.76
Walnut 0.98 0.98
Maize (Corn) 0.75 2.22
Oat 0.42 1.16
Oat Meal 0.89 2.40
Brown rice 0.84 0.99
Polished rice 0.14 0.60
Wheat 0.39 1.35
Wheat flour 0.25 1.37
Wheat germ 0.08 1.14
Whole wheat bread 0.43 1.05
Beans, pinto 2.38 2.38
Chickpeas 0.56 0.56
Lentils 0.44 0.50
Soybeans 1.00 2.22
Tofu 1.46 2.90
Soy beverage 1.24 1.24
Soy protein concentrate 1.24 2.17
New potato 0.18 0.34
Spinach 0.22 NR
Food sources of phytic acid (fresh weight)[27]
Food [% minimum fresh weight] [% maximum fresh weight]
Taro 0.143 0.195
Cassava 0.114 0.152

Other commercial uses

Phytic acid has been marketed for its alleged anti-cancer properties, based on research by Professor Abulkalam Shamsuddin of the University of Maryland.[30] The US Food and Drug Administration has listed it as a fake cancer "cure",[31] and there is no good evidence that phytic acid has any beneficial role to play in cancer medicine.[32][33][34]

As a food additive, phytic acid is used as the preservative E391.

See also

References

  1. ↑ Mullaney, Edward J.; Ullah, Abul H.J. "Phytases: attributes, catalytic mechanisms, and applications" (PDF). United States Department of Agriculture–Agricultural Research Service. Retrieved May 18, 2012.
  2. 1 2 Phytic acid. phytochemicals.info
  3. 1 2 Klopfenstein, Terry J.; Angel, Rosalina; Cromwell, Gary; Erickson, Galen E.; Fox, Danny G.; Parsons, Carl; Satter, Larry D.; Sutton, Alan L.; Baker, David H. (July 2002). "Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution". Council for Agricultural Science and Technology 21.
  4. ↑ Romarheim, O.H.; Zang, C.; Penn, M.; Liu, Y.-J.; Tian, L.-H.; Skrede, A.; Krogdahl, Å.; Storebakken, T. (2008). "Growth and intestinal morphology in cobia (Rachycentron canadum) fed extruded diets with two types of soybean meal partly replacing fish meal". Aquaculture Nutrition 14 (2): 174–180. doi:10.1111/j.1365-2095.2007.00517.x.
  5. ↑ Mallin, M. A. (2003). "Industrialized Animal Production—A Major Source of Nutrient and Microbial Pollution to Aquatic Ecosystems". Population and Environment 24 (5): 369–385. doi:10.1023/A:1023690824045. JSTOR 27503850.
  6. ↑ Ali, M; Shuja, MN; Zahoor, M; Qadri, I (2010). "Phytic acid:how far have we come". African Journal of Biotechnology 9 (11): 1551–1554..
  7. ↑ Guttieri, M. J.; Peterson, K. M.; Souza, E. J. (2006). "Milling and Baking Quality of Low Phytic Acid Wheat". Crop Science 46 (6): 2403–8. doi:10.2135/cropsci2006.03.0137.
  8. ↑ Malleshi, N. G.; Desikachar, H. S. R. (1986). "Nutritive value of malted millet flours". Plant Foods for Human Nutrition 36 (3): 191–6. doi:10.1007/BF01092036.
  9. ↑ 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.
  10. ↑ Reddy NR, Sathe SK, Salunkhe DK (1982). "Phytates in legumes and cereals". Adv Food Res 28: 1–92. doi:10.1016/s0065-2628(08)60110-x. PMID 6299067.
  11. ↑ 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. doi:10.1016/0006-291X(87)90489-X. PMID 3426614.
  12. ↑ Sasakawa N, Sharif M, Hanley MR (1995). "Metabolism and biological-activities of inositol pentakisphosphate and inositol hexakisphosphate". Biochem Pharmacol 50 (2): 137–146. doi:10.1016/0006-2952(95)00059-9. PMID 7543266.
  13. 1 2 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. doi:10.1016/S0092-8674(00)00061-1. PMID 11030616.
  14. ↑ 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. doi:10.1074/jbc.270.1.214. PMID 7814377.
  15. ↑ York JD, Odom AR, Murphy R, Ives EB, Wente SR (1999). "A phospholipase C-dependent inositol polyphosphate kinase pathway{meaning?} required for efficient messenger RNA export". Science 285 (5424): 96–100. doi:10.1126/science.285.5424.96. PMID 10390371.
  16. ↑ Shears SB (2001). "Assessing the omnipotence of inositol hexakisphosphate". Cell Signalling 13 (3): 151–158. doi:10.1016/S0898-6568(01)00129-2. PMID 11282453.
  17. ↑ "Phytates in cereals and legumes". fao.org.
  18. ↑ 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 (4). doi:10.1007/s00217-004-0912-7.
  19. ↑ 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 (8): 1209–15. doi:10.1002/jsfa.2471.
  20. ↑ 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.
  21. ↑ 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 978-0-309-02117-3.
  22. ↑ American Dietetic, A.; Dietitians Of, C. (2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association 103 (6): 748–765. doi:10.1053/jada.2003.50142. PMID 12778049.
  23. ↑ López-González AA, Grases F, Roca P, Mari B, Vicente-Herrero MT, Costa-Bauzá 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.
  24. ↑ Anderson, Eugene N. (2005). Everyone eats: understanding food and culture. New York: New York University Press. pp. 47–8. ISBN 0-8147-0496-4.
  25. ↑ 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): 1132–5. doi:10.1016/j.mehy.2004.09.030. PMID 16095846.
  26. ↑ Reddy, N. R.; Sathe, Shridhar K. (2001). Food Phytates. Boca Raton: CRC. ISBN 1-56676-867-5.
  27. 1 2 Phillippy, B. Q.; Bland, J. M.; Evens, T. J. (2003). "Ion Chromatography of Phytate in Roots and Tubers". Journal of Agricultural and Food Chemistry 51 (2): 350–3. doi:10.1021/jf025827m. PMID 12517094.
  28. ↑ MacFarlane, B. J.; Bezwoda, W. R.; Bothwell, T. H.; Baynes, R. D.; Bothwell, J. E.; MacPhail, A. P.; Lamparelli, R. D.; Mayet, F (1988). "Inhibitory effect of nuts on iron absorption". The American Journal of Clinical Nutrition 47 (2): 270–4. PMID 3341259.
  29. ↑ Gordon, D. T.; Chao, L. S. (1984). "Relationship of components in wheat bran and spinach to iron bioavailability in the anemic rat". The Journal of Nutrition 114 (3): 526–35. PMID 6321704.
  30. ↑ "SOM Faculty Profile : Abulkalam Shamsuddin". umaryland.edu.
  31. ↑ "187 Fake Cancer "Cures" Consumers Should Avoid". Food and Drug Administration.: Listed as IP-6 Inositol Hexaphosphate
  32. ↑ "Inositol Hexaphosphate". cancer.org.
  33. ↑ "Inositol Hexaphosphate". Memorial Sloan Kettering Cancer Center.
  34. ↑ "ip-6: Uses, Side Effects, Interactions and Warnings – WebMD". webmd.com.
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