Free radical
A free radical is a molecule with an unpaired electron. The molecule is reactive and seeks another electron to pair.[1] Free radicals are involved in the mechanisms of damage associated with disease development. Examples are hydrogen peroxide, hypochlorite, nitric oxide and nitrogen dioxide.[2]
A radical is an atom or group of an (?) which possesses electric charge.[3] There are two types of radicals: Cation and anion. Cation are positively charged while anion are negatively charged.[4] Examples of cation are Calcium (Ca2+), Potassium (K+), Hydrogen (H+).[5] Examples of anion are Iodide (I-), Chlorine (Cl-) and Hydroxide (OH-).[6]
The need for antioxidants in peoples’ daily life is becoming more critical with increased exposure to free radicals.[7] Pollution, cigarette smoke, drugs, illness and stress can increase our exposure.
Free Radical Media
The hydroxyl radical, Lewis structure shown, contains one unpaired electron.
Lewis dot structure of a Hydroxide ion compared to a hydroxyl radical
Homolysis of a bromine molecule producing two bromine radicals
Homolysis of dibenzoyl peroxide producing two benzoyloxy radicals
Lithium Naphthalenide in tetrahydrofuran viewed through light
Radical abstraction between a benzoyloxy radical and hydrogen bromide
Radical addition of a bromine radical to a substituted alkene
A radical elimination reaction where benzoyloxy radical breaks down into a phenyl radical and a carbon dioxide molecule
The radical derived from α-tocopherol
Molecular orbital diagram of a radical with an electron-donating group
References
- ↑ Rice-Evans, C. (1999). “Screening of phenolics and flavonoids for antioxidant activity”. In: Antioxidant Food Supplements in Human Health. Academic Press, p. 239–253.
- ↑ Afzal, M., Armstrong, D. (2002). “Fractionation of herbal medicine for identifying antioxidant activity”. In: Armstrong, D. (Ed.) Methods in Molecular Biology, vol. 186: Oxidative Stress Biomarkers and Antioxidant Protocols, Humana Press Inc.
- ↑ "Radical | Chemistry | Britannica". britannica.com. Retrieved 2021-11-22.
- ↑ "Cation vs. Anion: The Difference Between Them Is Electrifying". dictionary.com. 2021-07-27. Retrieved 2021-11-22.
- ↑ "What is Cation? Review Your Chemistry Concepts".
- ↑ Gorm, Mary; Writer, y White Staff. "Ion Examples With Positive & Negative Charges". yourdictionary.com. Retrieved 2021-11-22.
- ↑ Percival, M. (1998). “Antioxidants”. Clinical Nutrition Insights 1/96 Rev. 10/98. http://acudoc.com/Antioxidants.PDF
