Tert-Butylhydroquinone

In foods, TBHQ is used as an antioxidant preservative for unsaturated vegetable oils and many edible animal fats. It does not cause discoloration even in the presence of iron, and does not change flavor or odor of the material to which it is added. It can be combined with other preservatives such as butylated hydroxyanisole (BHA). As a food additive, its E number is E319. It is added to a wide range of foods. Its primary advantage is extending storage life.Fats and oils: formulating and processing for applications, Richard D. O'Brien, page 168

In perfumery, it is used as a fixative to lower the evaporation rate and improve stability.

It is used industrially as a stabilizer to inhibit autopolymerization of organic peroxides.

It is used as an antioxidant in biodiesel.{{Cite journal | doi = 10.1016/j.fuel.2011.06.056| title = Behaviour of the antioxidant tert-butylhydroquinone on the storage stability and corrosive character of biodiesel| journal = Fuel| volume = 90| issue = 11| pages = 3480–3484| year = 2011| last1 = Almeida| first1 = Eduardo S.| last2 = Portela| first2 = Flaysner M.| last3 = Sousa| first3 = Raquel M.F.| last4 = Daniel| first4 = Daniela| last5 = Terrones| first5 = Manuel G.H.| last6 = Richter| first6 = Eduardo M.| last7 = Muñoz| first7 = Rodrigo A.A.| doi-access = free| bibcode = 2011Fuel...90.3480A}}

The European Food Safety Authority (EFSA) and the United States Food and Drug Administration (FDA)[https://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm091048.htm "Food Additive Status List"]. U.S. Food and Drug Administration. Retrieved June 11, 2016. have evaluated TBHQ and determined that it is safe to consume at the concentration allowed in foods.[http://www.efsa.europa.eu/en/efsajournal/pub/84 "Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) on a request from the Commission related to tertiary-Butylhydroquinone (TBHQ)"]. European Food Safety Authority, 12 July 2004 The FDA[http://law.justia.com/cfr/title21/21-3.0.1.1.3.2.1.18.html 21 C.F.R. § 172.185] and European Union both set an upper limit of 0.02% (200mg/kg) of the oil or fat content in foods. It has not been approved in Japan, hence import of food containing TBHQ for selling is not allowed in Japan as of 2007.{{cite web |last1=Kanagawa Prefectural Institute of Public Health |title=TBHQ (t-butylhydroquinone) detected in imported foods |url=https://web.archive.org/web/20210509170418/http://www.eiken.pref.kanagawa.jp/008_topics/files/topics_070207.htm |website=eiken.pref.kanagawa.jp |date=9 January 2007}}

At very high doses, it has some negative health effects on lab animals, such as producing precursors to stomach tumors and damage to DNA.[http://www.inchem.org/documents/jecfa/jecmono/v35je03.htm Tert-Butylhydroquinone] - safety summary from The International Programme on Chemical Safety A number of studies have shown that prolonged exposure to very high doses of TBHQ may be carcinogenic,{{cite journal |vauthors=Gharavi N, El-Kadi A |title=tert-Butylhydroquinone is a novel aryl hydrocarbon receptor ligand |journal=Drug Metab Dispos |volume=33 |issue=3 |pages=365–72 |year=2005 |pmid=15608132 |doi=10.1124/dmd.104.002253|s2cid=5963778 }} especially for stomach tumors.{{Cite journal | last1 = Hirose| first1 = Masao|last2 = Yada| first2 = Hideaki| last3 = Hakoi| first3 = Kazuo| last4 = Takahashi|first4 = Satoru| last5 = Ito| first5 = Nobuyuki| title = Modification of carcinogenesis by -tocopherol, t-butylhydro-quinone, propyl gallate and butylated hydroxytoluene in a rat multi-organ carcinogenesis model|journal = Carcinogenesis| volume = 14| issue = 1| pages = 2359–2364| publisher = Oxford University Press| doi = 10.1093/carcin/14.11.2359|pmid=8242867|display-authors=etal| year = 1993}} Other studies, however, have shown opposite effects including inhibition against HCA-induced carcinogenesis (by depression of metabolic activation) for TBHQ and other phenolic antioxidants (TBHQ was one of several, and not the most potent){{cite journal |vauthors=Hirose M, Takahashi S, Ogawa K, Futakuchi M, Shirai T, Shibutani M, Uneyama C, Toyoda K, Iwata H |title=Chemoprevention of heterocyclic amine-induced carcinogenesis by phenolic compounds in rats |journal=Cancer Lett |volume=143 |issue=2 |pages=173–8 |year=1999 |pmid=10503899 |doi=10.1016/S0304-3835(99)00120-2}} and reduction of nitrosamine-induced carcinogenesis (likely due to phase II enzyme induction via Nrf2).{{cite journal |last1=Gharavi |first1=Negar |last2=Haggarty |first2=Susan |last3=S. El-Kadi |first3=Ayman |title=Chemoprotective and Carcinogenic Effects of tert-Butylhydroquinone and Its Metabolites |journal=Current Drug Metabolism |date=1 January 2007 |volume=8 |issue=1 |pages=1–7 |doi=10.2174/138920007779315035}} The EFSA considers TBHQ to be noncarcinogenic. A 1986 review of scientific literature concerning the toxicity of TBHQ determined that a wide margin of safety exists between the levels of intake by humans and the doses that produce adverse effects in animal studies.{{Cite journal | last1 = Vanesch | first1 = G | title = Toxicology of tert-butylhydroquinone (TBHQ) | journal = Food and Chemical Toxicology | volume = 24 | issue = 10–11 | year = 1986 | pmid = 3542758 | doi = 10.1016/0278-6915(86)90289-9 | pages = 1063–5 }}

In addition, TBHQ has been identified by high-throughput screening as having potential immunotoxic effects in 2021.{{Cite journal|last1=Naidenko|first1=Olga V.|last2=Andrews|first2=David Q.|last3=Temkin|first3=Alexis M.|last4=Stoiber|first4=Tasha|last5=Uche|first5=Uloma Igara|last6=Evans|first6=Sydney|last7=Perrone-Gray|first7=Sean|date=2021-03-24|title=Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food|journal=International Journal of Environmental Research and Public Health|language=en|volume=18|issue=7|pages=3332|doi=10.3390/ijerph18073332|pmid=33804855|pmc=8036665|issn=1660-4601|doi-access=free}} It was previously reported in 2014 that TBHQ enhances allergy response in mice by promoting Th2 cells through Nrf2.{{cite journal |last1=Rockwell |first1=Cheryl |last2=Gangur |first2=Venugopal |last3=Pestka |first3=James |last4=Para |first4=Radhakrishna |last5=Turley |first5=Alexandra |last6=Zagorski |first6=Joseph |last7=Bursley |first7=Jenna |last8=Dover |first8=Heather |title=The Nrf2 activator, tBHQ, exacerbates immediate hypersensitivity response to food allergen (HYP7P.315) |journal=The Journal of Immunology |date=1 May 2014 |volume=192 |issue=1_Supplement |pages=119.30–119.30 |doi=10.4049/jimmunol.192.Supp.119.30}}

Experiments on its genotoxicity at high doses are inconsistent. Its oxidized form TBBQ may be responsible for some toxic effects. There exists a wide margin of safety between food-additive doses and doses used in studies.

There have been reports of vision disturbances in individuals exposed to this chemical.{{multiref|1={{Cite web|url=https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+838|title=T-BUTYLHYDROQUINONE - National Library of Medicine HSDB Database|website=toxnet.nlm.nih.gov|access-date=2019-11-21}}|2=O'Donoghue, J.L. (ed.). Neurotoxicity of Industrial and Commercial Chemicals. Volume I. Boca Raton, FL: CRC Press, Inc., 1985., p. 129 – HSDB cites this source.}}

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Category:Hydroquinones

Category:Food additives

Category:Food antioxidants

Category:Preservatives

Category:Alkylphenols

Category:Tert-butyl compounds

Category:E-number additives