Salicylic acid

Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone,[9] and has been listed by the EPA Toxic Substances Control Act (TSCA) Chemical Substance Inventory as an experimental teratogen.[10] The name is from Latin salix for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates.

Salicylic acid
Skeletal formula of salicylic acid
Ball-and-stick model of salicylic acid
Names
Preferred IUPAC name
2-Hydroxybenzoic acid[1]
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.648
EC Number
  • 200-712-3
IUPHAR/BPS
KEGG
RTECS number
  • VO0525000
UNII
CompTox Dashboard (EPA)
  • InChI=1S/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10) Y
    Key: YGSDEFSMJLZEOE-UHFFFAOYSA-N Y
  • InChI=1/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10)
    Key: YGSDEFSMJLZEOE-UHFFFAOYAQ
  • O=C(O)c1ccccc1O
Properties
C7H6O3
Molar mass 138.122 g/mol
Appearance Colorless to white crystals
Odor Odorless
Density 1.443 g/cm3 (20 °C)[2]
Melting point 158.6 °C (317.5 °F; 431.8 K)
Boiling point 200 °C (392 °F; 473 K) decomposes[3]
211 °C (412 °F; 484 K)
at 20 mmHg[2]
Sublimes at 76 °C[4]
  • 1.24 g/L (0 °C)
  • 2.48 g/L (25 °C)
  • 4.14 g/L (40 °C)
  • 17.41 g/L (75 °C)[3]
  • 77.79 g/L (100 °C)[5]
Solubility Soluble in ether, CCl4, benzene, propanol, acetone, ethanol, oil of turpentine, toluene
Solubility in benzene
  • 0.46 g/100 g (11.7 °C)
  • 0.775 g/100 g (25 °C)
  • 0.991 g/100 g (30.5 °C)
  • 2.38 g/100 g (49.4 °C)
  • 4.4 g/100 g (64.2 °C)[3][5]
Solubility in chloroform
  • 2.22 g/100 mL (25 °C)[5]
  • 2.31 g/100 mL (30.5 °C)[3]
Solubility in methanol
  • 40.67 g/100 g (−3 °C)
  • 62.48 g/100 g (21 °C)[3]
Solubility in olive oil 2.43 g/100 g (23 °C)[3]
Solubility in acetone 39.6 g/100 g (23 °C)[3]
log P 2.26
Vapor pressure 10.93 mPa[4]
Acidity (pKa)
  1. 2.97 (25 °C)[6]
  2. 13.82 (20 °C)[3]
UV-vis (λmax) 210 nm, 234 nm, 303 nm (4 mg/dL in ethanol)[4]
−72.23·10−6 cm3/mol
1.565 (20 °C)[2]
Dipole moment
 2.65 D
Thermochemistry
−589.9 kJ/mol
3.025 MJ/mol[7]
Pharmacology
A01AD05 (WHO) B01AC06 (WHO) D01AE12 (WHO) N02BA01 (WHO) S01BC08 (WHO)
Hazards
Occupational safety and health (OHS/OSH):
Eye hazards
 Severe irritation
Skin hazards
 Mild irritation
GHS labelling:[8]
Danger
Hazard statements
 H302, H318
Precautionary statements
 P280, P305+P351+P338
NFPA 704 (fire diamond)
2
1
0
Flash point 157 °C (315 °F; 430 K)
closed cup[4]
Autoignition
temperature
 540 °C (1,004 °F; 813 K)[4]
Lethal dose or concentration (LD, LC):
480 mg/kg (mice, oral)
Safety data sheet (SDS) MSDS
Related compounds
Related compounds
 Methyl salicylate,
Benzoic acid,
Phenol, Aspirin,
4-Hydroxybenzoic acid,
Magnesium salicylate,
Choline salicylate,
Bismuth subsalicylate,
Sulfosalicylic acid,
Salicylate synthase
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Uses

Medicine
Cotton pads soaked in salicylic acid can be used to chemically exfoliate skin.

Salicylic acid as a medication is commonly used to remove the outer layer of the skin. As such, it is used to treat warts, psoriasis, acne vulgaris, ringworm, dandruff, and ichthyosis.[11][12][13][14]

Similar to other hydroxy acids, salicylic acid is an ingredient in many skincare products for the treatment of seborrhoeic dermatitis, acne, psoriasis, calluses, corns, keratosis pilaris, acanthosis nigricans, ichthyosis, and warts.[15]

Uses in manufacturing

Salicylic acid is used as a food preservative, a bactericide, and an antiseptic.[16][17]

Salicylic acid is used in the production of other pharmaceuticals, including 4-aminosalicylic acid, sandulpiride, and landetimide (via salethamide).[18]

Salicylic acid has long been a key starting material for making acetylsalicylic acid (aspirin).[9] Aspirin (acetylsalicylic acid or ASA) is prepared by the esterification of the phenolic hydroxyl group of salicylic acid with the acetyl group from acetic anhydride or acetyl chloride.[19] ASA is the standard to which all the other non-steroidal anti-inflammatory drugs (NSAIDs) are compared. In veterinary medicine, this group of drugs is mainly used for treatment of inflammatory musculoskeletal disorders.[20]

Bismuth subsalicylate, a salt of bismuth and salicylic acid, is the active ingredient in stomach-relief aids such as Pepto-Bismol, is the main ingredient of Kaopectate, and "displays anti-inflammatory action (due to salicylic acid) and also acts as an antacid and mild antibiotic".[21]

Other derivatives include methyl salicylate used as a liniment to soothe joint and muscle pain and choline salicylate used topically to relieve the pain of mouth ulcers. Aminosalicylic acid is used to induce remission in ulcerative colitis, and has been used as an antitubercular agent often administered in association with isoniazid.[22]

Sodium salicylate is a useful phosphor in the vacuum ultraviolet spectral range, with nearly flat quantum efficiency for wavelengths between 10 and 100 nm.[23] It fluoresces in the blue at 420 nm. It is easily prepared on a clean surface by spraying a saturated solution of the salt in methanol followed by evaporation.

Mechanism of action

Salicylic acid modulates COX-1 enzymatic activity to decrease the formation of pro-inflammatory prostaglandins. Salicylate may competitively inhibit prostaglandin formation. Salicylate's antirheumatic (nonsteroidal anti-inflammatory) actions are a result of its analgesic and anti-inflammatory mechanisms.

Salicylic acid works by causing the cells of the epidermis to slough off more readily, preventing pores from clogging up, and allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) competitively with nicotinamide adenine dinucleotide and noncompetitively with UDPG. It also competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor.

The wound-healing retardation action of salicylates is probably due mainly to its inhibitory action on mucopolysaccharide synthesis.[6]

Safety

If high concentrations of salicylic ointment are applied to a large percentage of body surface, high levels of salicylic acid can enter the blood, requiring hemodialysis to avoid further complications.[24]

Production and chemical reactions

Biosynthesis

Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana, it can be synthesized via a phenylalanine-independent pathway.

Industrial synthesis

Sodium salicylate is commercially prepared by treating sodium phenolate (the sodium salt of phenol) with carbon dioxide at high pressure (100 atm) and high temperature (115 °C) – a method known as the Kolbe-Schmitt reaction. Acidification of the product with sulfuric acid gives salicylic acid:

It can also be prepared by the hydrolysis of aspirin (acetylsalicylic acid)[25] or methyl salicylate (oil of wintergreen) with a strong acid or base.

Reactions

Upon heating, salicylic acid converts to phenyl salicylate:[26][9]

2 HOC6H4CO2H → C6H5O2C6H4OH + CO2 + H2O

Further heating gives xanthone.[9]

Salicylic acid as its conjugate base is a chelating agent, with an affinity for iron(III).[27]

Salicylic acid slowly degrades to phenol and carbon dioxide at 200–230 °C:[28]

C6H4OH(CO2H) → C6H5OH + CO2

History
White willow (Salix alba) is a natural source of salicylic acid.

Willow has long been used for medicinal purposes. Dioscorides, whose writings were highly influential for more than 1,500 years,[29] used 'Itea' (which was possibly a species of willow) as a treatment for 'painful intestinal obstructions,' birth control, for 'those who spit blood,' to remove calluses and corns and, externally, as a 'warm pack for gout.' William Turner, in 1597, repeated this, saying that willow bark, 'being burnt to ashes, and steeped in vinegar, takes away corns and other like risings in the feet and toes.'[30] Some of these cures may describe the action of salicylic acid, which can be derived from the salicin present in willow. It is, however, a modern myth that ancient herbalists used willow as a painkiller.[31]

Hippocrates, Galen, Pliny the Elder, and others knew that willow bark could ease pain and reduce fevers.[32][33]

It was used in Europe and China to treat these conditions.[34] This remedy is mentioned in texts from Ancient Egypt, Sumer, and Assyria.[35]

The Cherokee and other Native Americans use an infusion of the bark for fever and other medicinal purposes.[36] In 2014, archaeologists identified traces of salicylic acid on seventh-century pottery fragments found in east-central Colorado.[37]

The Reverend Edward Stone, a vicar from Chipping Norton, Oxfordshire, England, reported in 1763 that the bark of the willow was effective in reducing a fever.[38]

An extract of willow bark, called salicin, after the Latin name for the white willow (Salix alba), was isolated and named by German chemist Johann Andreas Buchner in 1828.[39] A larger amount of the substance was isolated in 1829 by Henri Leroux, a French pharmacist.[40] Raffaele Piria, an Italian chemist, was able to convert the substance into a sugar and a second component, which on oxidation becomes salicylic acid.[41][42] Salicylic acid was also isolated from the herb meadowsweet (Filipendula ulmaria, formerly classified as Spiraea ulmaria) by German researchers in 1839.[43] Their extract caused digestive problems such as gastric irritation, bleeding, diarrhea, and even death when consumed in high doses.

In 1874 the Scottish physician Thomas MacLagan experimented with salicin as a treatment for acute rheumatism, with considerable success, as he reported in The Lancet in 1876.[44] Meanwhile, German scientists tried sodium salicylate with less success and more severe side effects.[45][46]

In 1979, salicylates were found to be involved in induced defenses of tobacco against tobacco mosaic virus.[47] In 1987, salicylic acid was identified as the long-sought signal that causes thermogenic plants, such as the voodoo lily, Sauromatum guttatum, to produce heat.[48]

Dietary sources

Salicylic acid occurs in plants as free salicylic acid and its carboxylated esters and phenolic glycosides. Several studies suggest that humans metabolize salicylic acid in measurable quantities from these plants.[49] High-salicylate beverages and foods include beer, coffee, tea, numerous fruits and vegetables, sweet potato, nuts, and olive oil.[50] Meat, poultry, fish, eggs, dairy products, sugar, breads and cereals have low salicylate content.[50][51]

Some people with sensitivity to dietary salicylates may have symptoms of allergic reaction, such as bronchial asthma, rhinitis, gastrointestinal disorders, or diarrhea, so may need to adopt a low-salicylate diet.[50]

Plant hormone

Salicylic acid is a phenolic phytohormone, and is found in plants with roles in plant growth and development, photosynthesis, transpiration, and ion uptake and transport.[52] Salicylic acid is involved in endogenous signaling, mediating plant defense against pathogens.[53] It plays a role in the resistance to pathogens (i.e. systemic acquired resistance) by inducing the production of pathogenesis-related proteins and other defensive metabolites.[54] SA's defense signaling role is most clearly demonstrated by experiments which do away with it: Delaney et al. 1994, Gaffney et al. 1993, Lawton et al. 1995, and Vernooij et al. 1994 each use Nicotiana tabacum or Arabidopsis expressing nahG, for salicylate hydroxylase. Pathogen inoculation did not produce the customarily high SA levels, SAR was not produced, and no PR genes were expressed in systemic leaves. Indeed, the subjects were more susceptible to virulent – and even normally avirulent – pathogens.[52]

Exogenously, salicylic acid can aid plant development via enhanced seed germination, bud flowering, and fruit ripening, though too high of a concentration of salicylic acid can negatively regulate these developmental processes.[55]

The volatile methyl ester of salicylic acid, methyl salicylate, can also diffuse through the air, facilitating plant-plant communication.[56] Methyl salicylate is taken up by the stomata of the nearby plant, where it can induce an immune response after being converted back to salicylic acid.[57]

Signal transduction

A number of proteins have been identified that interact with SA in plants, especially salicylic acid binding proteins (SABPs) and the NPR genes (Nonexpressor of pathogenesis related genes), which are putative receptors.[58]

See also
  • Salsalate
  • Trolamine salicylate

References
  1. "Front Matter". Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 64. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  2. Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 3.306. ISBN 1-4398-5511-0.
  3. "Salicylic acid". Archived from the original on 2014-05-24. Retrieved 2014-05-23.
  4. CID 338 from PubChem
  5. Atherton Seidell; William F. Linke (1952). Solubilities of Inorganic and Organic Compounds: A Compilation of Solubility Data from the Periodical Literature. Supplement to the third edition containing data published during the years 1939-1949. Van Nostrand.
  6. Wishart DS, Djombou Feunang Y, Guo AC, Lo EJ, Marcu A, Grant JR, Sajed T, Johnson D, Li C, Sayeeda Z, Assempour N, Iynkkaran I, Liu Y, Maciejewski A, Gale N, Wilson A, Chin L, Cummings R, Le D, Pon A, Knox C, Wilson M. "Salycylic acid | DrugBank Online". DrugBank. 5.0.
  7. "Salicylic acid". Archived from the original on 2017-02-15. Retrieved 2014-08-17.
  8. Sigma-Aldrich Co., Salicylic acid.
  9. Boullard O, Leblanc H, Besson B (2000). "Salicylic Acid". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a23_477. ISBN 3527306730.
  10. Lewis Sr RJ (2008). Hazardous Chemicals Desk Reference. John Wiley & Sons. p. 1217. ISBN 9780470334454.
  11. "Salicylic acid". Drugs.com. Archived from the original on 18 January 2017. Retrieved 15 January 2017.
  12. World Health Organization (2009). Stuart MC, Kouimtzi M, Hill SR (eds.). WHO Model Formulary 2008. World Health Organization. p. 310. hdl:10665/44053. ISBN 9789241547659.
  13. "SALICYLIC ACID - National Library of Medicine HSDB Database". toxnet.nlm.nih.gov. Archived from the original on 2018-08-21. Retrieved 2018-08-21.
  14. salicylic acid 17 % Topical Liquid. Kaiser Permanente Drug Encyclopedia. Accessed 28 Sept 2011.
  15. Madan RK, Levitt J (April 2014). "A review of toxicity from topical salicylic acid preparations". Journal of the American Academy of Dermatology. 70 (4): 788–792. doi:10.1016/j.jaad.2013.12.005. PMID 24472429.
  16. "Definition of Salicylic acid". MedicineNet.com. Archived from the original on 2011-12-09. Retrieved 2010-10-12.
  17. Greene SA (2013). Sittig's Handbook of Pesticides and Agricultural Chemicals. William Andrew. ISBN 9780815519034.
  18. "Medicines containing the active ingredient salicylic acid - (emc)". www.medicines.org.uk. Retrieved 2022-10-23.
  19. Watson, David G (2011). Pharmaceutical chemistry. Edinburgh: Churchill Livingstone. p. 273. ISBN 9780702048500. Retrieved 21 May 2022.
  20. "ACETYLSALICYLIC ACID, SODIUM ACETYLSALICYLATE, ACETYLSALICYLIC ACID DL-LYSINE AND CARBASALATE CALCIUM SUMMARY REPORT" (PDF). No. EMEA/MRL/695/99–FINAL. COMMITTEE FOR VETERINARY MEDICINAL PRODUCTS. The European Agency for the Evaluation of Medicinal Products Veterinary Medicines and Inspections. November 1999.
  21. "Bismuth subsalicylate". PubChem. United States National Institutes of Health. Archived from the original on 1 February 2014. Retrieved 24 January 2014.
  22. "Aminosalicylic acid". Drugbank Online.
  23. Samson, James (1976). Techniques of Vacuum Ultraviolet Spectroscopy. Wiley, .
  24. Péc J, Strmenová M, Palencárová E, Pullmann R, Funiaková S, Visnovský P, et al. (October 1992). "Salicylate intoxication after use of topical salicylic acid ointment by a patient with psoriasis". Cutis. 50 (4): 307–309. PMID 1424799.
  25. "Hydrolysis of ASA to SA". Archived from the original on August 8, 2007. Retrieved July 31, 2007.
  26. Kuriakose G, Nagaraju N (2004). "Selective Synthesis of Phenyl Salicylate (Salol) by Esterification Reaction over Solid Acid Catalysts". Journal of Molecular Catalysis A: Chemical. 223 (1–2): 155–159. doi:10.1016/j.molcata.2004.03.057.
  27. Jordan RB (1983). "Metal(III)-Salicylate Complexes: Protonated Species and Rate-Controlling Formation Steps". Inorganic Chemistry. 22 (26): 4160–4161. doi:10.1021/ic00168a070.
  28. Kaeding WW (1 September 1964). "Oxidation of Aromatic Acids. IV. Decarboxylation of Salicylic Acids". The Journal of Organic Chemistry. 29 (9): 2556–2559. doi:10.1021/jo01032a016.
  29. Dioscorides P. "De Materia Medica" (PDF).
  30. Turner W. "The Herball, or Generall Historie of Plantes". Retrieved 8 January 2022.
  31. Martyr P. "Hippocrates and willow bark? What you know about the history of aspirin is probably wrong". Retrieved 9 January 2022.
  32. Norn S, Permin H, Kruse PR, Kruse E (2009). "From willow bark to acetylsalicylic acid". Dansk Medicinhistorisk Årbog (in Danish). 37: 79–98. PMID 20509453. S2CID 10053542.
  33. Vane JR (2000). "The fight against rheumatism: from willow bark to COX-1 sparing drugs". J Physiol Pharmacol. 51(4 Pt 1) (4 Pt 1): 573–86. PMID 11192932.
  34. "Willow bark". University of Maryland Medical Center. University of Maryland. Archived from the original on 24 December 2011. Retrieved 19 December 2011.
  35. Goldberg DR (Summer 2009). "Aspirin: Turn of the Century Miracle Drug". Chemical Heritage Magazine. 27 (2): 26–30. Archived from the original on 20 March 2018. Retrieved 24 March 2018.
  36. Hemel PB, Chiltoskey MU (1975). Cherokee Plants and Their Uses – A 400 Year History. Sylva, NC: Herald Publishing Co.; cited in Moerman D. "A Database of Foods, Drugs, Dyes and Fibers of Native American Peoples, Derived from Plants". Archived from the original on 2007-12-06. A search of this database for "salix AND medicine" finds 63 entries.
  37. "1,300-Year-Old Pottery Found in Colorado Contains Ancient 'Natural Aspirin'". 12 August 2014. Archived from the original on 2014-08-13. Retrieved 2014-08-13.
  38. Stone, Edmund (1763). "An Account of the Success of the Bark of the Willow in the Cure of Agues". Philosophical Transactions of the Royal Society of London. 53: 195–200. doi:10.1098/rstl.1763.0033.
  39. Buchner, A. (1828). "Ueber das Rigatellische Fiebermittel und über eine in der Weidenrinde entdeckte alcaloidische Substanz" [On Rigatelli's antipyretic [i.e., anti-fever drug] and on an alkaloid substance discovered in willow bark]. Repertorium für die Pharmacie. Bei J. L. Schrag. pp. 405–. Noch ist es mir aber nicht geglückt, den bittern Bestandtheil der Weide, den ich Salicin nennen will, ganz frei von allem Färbestoff darzustellen. [I have still not succeeded in preparing the bitter component of willow, which I will name salicin, completely free from colored matter]
  40. See:
  41. Piria (1838). "Sur de neuveaux produits extraits de la salicine" [On new products extracted from salicine]. Comptes rendus. 6: 620–624. Archived from the original on 2017-07-27. p. 622: Piria mentions "Hydrure de salicyle" (hydrogen salicylate, i.e., salicylic acid).
  42. Jeffreys, Diarmuid (2005). Aspirin: the remarkable story of a wonder drug. New York: Bloomsbury. pp. 38–40. ISBN 978-1-58234-600-7.
  43. Löwig, C.; Weidmann, S. (1839). "III. Untersuchungen mit dem destillierten Wasser der Blüthen von Spiraea Ulmaria" [III. Investigations of the water distilled from the blossoms of Spiraea ulmaria]. Annalen der Physik und Chemie; Beiträge zur Organischen Chemie (Contributions to Organic Chemistry) (46): 57–83. Löwig and Weidman called salicylic acid Spiräasaure (spiraea acid)
  44. MacLagan TJ (28 October 1876). "The treatment of acute rheumatism by salicin". The Lancet. 108 (2774): 383. doi:10.1016/S0140-6736(02)49509-8.
  45. MacLagan T (1900). "The treatment of acute rheumatism". The Lancet. 155 (3998): 1904. doi:10.1016/S0140-6736(01)70583-1.
  46. Buchanan WW, Kean WF (June 2002). "The Treatment of Acute Rheumatism by Salicin, by T.J. Maclagan — The Lancet, 1876". The Journal of Rheumatology. 29 (6): 1321–1323. PMID 12064852.
  47. Raskin I (July 1992). "Salicylate, A New Plant Hormone". Plant Physiology. 99 (3): 799–803. doi:10.1104/pp.99.3.799. PMC 1080546. PMID 16669002.
  48. Raskin I, Ehmann A, Melander WR, Meeuse BJ (September 1987). "Salicylic Acid: A Natural Inducer of Heat Production in Arum Lilies". Science. 237 (4822): 1601–2. Bibcode:1987Sci...237.1601R. doi:10.1126/science.237.4822.1601. PMID 17834449. S2CID 3108513.
  49. Malakar S, Gibson PR, Barrett JS, Muir JG (1 April 2017). "Naturally occurring dietary salicylates: A closer look at common Australian foods". Journal of Food Composition and Analysis. 57: 31–39. doi:10.1016/j.jfca.2016.12.008.
  50. "Low salicylate diet". Drugs.com. 19 February 2019. Archived from the original on 16 December 2019. Retrieved 16 December 2019.
  51. Swain AR, Dutton SP, Truswell AS (August 1985). "Salicylates in foods" (PDF). Journal of the American Dietetic Association. 85 (8): 950–960. doi:10.1016/S0002-8223(21)03743-3. PMID 4019987. S2CID 42796737. Archived (PDF) from the original on 2019-04-05. Retrieved 2019-12-16.
  52. Vlot AC, Dempsey DA, Klessig DF (2009). "Salicylic Acid, a multifaceted hormone to combat disease". Annual Review of Phytopathology. 47: 177–206. doi:10.1146/annurev.phyto.050908.135202. PMID 19400653.
  53. Hayat, S. & Ahmad, A. (2007). Salicylic Acid – A Plant Hormone. Springer. ISBN 978-1-4020-5183-8.
  54. Hooft Van Huijsduijnen RA, Alblas SW, De Rijk RH, Bol JF (1986). "Induction by Salicylic Acid of Pathogenesis-related Proteins or Resistance to Alfalfa Mosaic Virus Infection in Various Plant Species". Journal of General Virology. 67 (10): 2135–2143. doi:10.1099/0022-1317-67-10-2135.
  55. Koo YM, Heo AY, Choi HW (February 2020). "Salicylic Acid as a Safe Plant Protector and Growth Regulator". The Plant Pathology Journal. 36 (1): 1–10. doi:10.5423/PPJ.RW.12.2019.0295. PMC 7012573. PMID 32089657.
  56. Taiz L, Zeiger E (2002). Plant physiology. Sunderland, Mass: Sinauer Associates. p. 306. ISBN 0-87893-823-0. OCLC 50002466. Archived from the original on 2014-03-05.
  57. Chamovitz D (2012). What A Plant Knows - A Field Guide to the Senses of your Garden - and Beyond. Oxford, England: Oneworld. ISBN 978-1-85168-910-1. OCLC 775030365.
  58. Kumar, D. 2014. Salicylic acid signaling in disease resistance. Plant Science 228:127–134.

Further reading
Wikimedia Commons has media related to Salicylic acid.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.