Antioksidan: Béda antarrépisi
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Baris ka-9:
Dumasar kaleyuranana, antioksidan dibagi dua rupa: leyur dina [[cai]] ([[hidrofil]]ik) atawa dina [[lipid]] ([[hidrofob]]ik). Sacara umum, antioksidan nu leyur-cai meta jeung oksidan dina [[sitoplasma]] sél jeung [[plasma getih]], sedengkeun antioksidan nu leyur-lipid nyegah [[mémbran sél]] tina panarajang [[peroksidasi]] lipid<ref name=Sies/>. Sanyawaan ieu bisa disintésis di jero awak atawa diserep tina katuangan<ref name=Vertuani/>. Rupa-rupa antioksidan aya dina kadar nu béda-béda dina cairan awak jeung jaringan. Misalna waé [[glutation]] atawa [[ubiquinon]] lolobana aya di jero sél, sedengkeun [[asam urat]] ampir rata di sakuliah awak (tempo tabél di handap).
Kapentingan jeung interaksi antara rupa-rupa antioksidan téh pajeulit, boga [[sinérgi]] jeung silih pangaruhan katergantungan antara hiji métabolit jeung nu séjénna sarta sistem-sistem énzimna<ref>{{cite journal |author=Chaudière J, Ferrari-Iliou R |title=Intracellular antioxidants: from chemical to biochemical mechanisms |journal=Food Chem Toxicol |volume=37 |issue=9–10 |pages=949 – 62 |year= |pmid=10541450}}</ref><ref>{{cite journal |author=Sies H |title=Strategies of antioxidant defense |journal=Eur J Biochem |volume=215 |issue=2 |pages=213 – 9 |year=1993 |pmid=7688300}}</ref>. Peta hiji antioksidan bisa jadi gumantung kana fungsi anggota séjén dina sistem antioksidan<ref name=Vertuani/>. Ku kituna, panyalindungan anu disadiakeun ku hiji antioksidan téh gumantung kana kadarna, réaktivitasna ka sajenis spésiés oksigén réaktif, sarta status antioksidan séjén anu aub dina réaksina<ref name=Vertuani/>.
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Baris ka-70:
Vitamin E is the collective name for a set of eight related [[tocopherol]]s and [[tocotrienol]]s, which are fat-soluble antioxidant vitamins.<ref name=Herrera>{{cite journal |author=Herrera E, Barbas C |title=Vitamin E: action, metabolism and perspectives |journal=J Physiol Biochem |volume=57 |issue=2 |pages=43 – 56 |year=2001 |pmid=11579997}}</ref> Of these, α-tocopherol has been most studied as it has the highest [[bioavailability]], with the body preferentially absorbing and metabolising this form.<ref name=Brigelius>{{cite journal |author=Brigelius-Flohé R, Traber M |title=Vitamin E: function and metabolism |url=http://www.fasebj.org/cgi/content/full/13/10/1145 |journal=FASEB J |volume=13 |issue=10 |pages=1145 – 55 |year=1999 |pmid=10385606}}</ref> The α-tocopherol form is the most important lipid-soluble antioxidant and protects cell membranes against oxidation by reacting with the lipid radicals produced in the [[lipid peroxidation]] [[chain reaction]].<ref name=Herrera/> This removes the free radical intermediates and prevents the propagation reaction from continuing. The oxidised α-tocopheroxyl radicals produced in this process may be recycled back to the active reduced form through reduction by ascorbate, retinol or ubiquinol.<ref>{{cite journal |author=Wang X, Quinn P |title=Vitamin E and its function in membranes |journal=Prog Lipid Res |volume=38 |issue=4 |pages=309 – 36 |year=1999 |pmid=10793887}}</ref> The functions of the other forms of vitamin E are less well-studied, although γ-tocopherol is a [[nucleophile]] that may react with [[electrophile|electrophilic]] mutagens,<ref name=Brigelius/> and tocotrienols may have a specialised role in neuroprotection.<ref>{{cite journal |author=Sen C, Khanna S, Roy S |title=Tocotrienols: Vitamin E beyond tocopherols |url=http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1790869&blobtype=pdf |journal=Life Sci |volume=78 |issue=18 |pages=2088 – 98 |year=2006 |pmid=16458936}}</ref>
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== Baca ogé ==
* [[Téori radikal bébas]]
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