Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation

Brigitte C. Scott, Okezie I. Aruoma, Patricia J. Evans, Charles O'neill, Albert Van Der Vliet, Carroll E Cross, Hans Tritschler, Barry Halliwell

Research output: Contribution to journalArticle

257 Citations (Scopus)

Abstract

A detailed evaluation of the antioxidant and pro-oxidant properties of lipoic acid (LA) and dihydrolipoic acid (DHLA) was performed. Both compounds are powerful scavengers of hypochlorous acid, able to protect α1-antiproteinase against inactivation by HOCl. LA was a powerful scavenger of hydroxyl radicals (OH-) and could inhibit both iron-dependent OH' generation and peroxidation of ox-brain phospholipid liposomes in the presence of FeCl3 -ascorbate, presumably by binding iron ions and rendering them redox-inactive. By contrast. DHLA accelerated iron-dependent OH- generation and lipid peroxidation, probably by reducing Fe3+ to Fe2+. LA inhibited this pro-oxidant action of DHLA. However, DHLA did not accelerate DNA degradation by a ferric bleomycin complex and slightly inhibited peroxidation of arachidonic acid by the myoglobin-H2O2 system. Under certain circumstances, DHLA accelerated the loss of activity of αantiproteinase exposed to ionizing radiation under a N2O/O2 atmosphere and also the loss of creatine kinase activity in human plasma exposed to gas-phase cigarette smoke. Neither LA nor DHLA reacted with superoxide radical (O2 -) or H2O2 at significant rates, but both were good scavengers of trichloromethylperoxyl radical (CCl3O2). We conclude that LA and DHLA have powerful antioxidant properties. However, DHLA can also exert pro-oxidant properties, both by its iron ion-reducing ability and probably by its ability to generate reactive sulphur-containing radicals that can damage certain proteins, such as α1-antiproteinase and creatine kinase.

Original languageEnglish (US)
Pages (from-to)119-133
Number of pages15
JournalFree Radical Research
Volume20
Issue number2
DOIs
StatePublished - 1994

Fingerprint

Thioctic Acid
Antioxidants
Iron
Reactive Oxygen Species
Creatine Kinase
Ions
Plasma (human)
Hypochlorous Acid
dihydrolipoic acid
Myoglobin
Ionizing radiation
Ionizing Radiation
Atmosphere
Sulfur
Arachidonic Acid
Human Activities
Liposomes
Smoke
Tobacco Products
Superoxides

Keywords

  • Antioxidant
  • Dihydrolipoic acid
  • Hydroxyl radical
  • Hypochlorous acid
  • Lipid peroxidation
  • Lipoic acid
  • Superoxide
  • Trichloromethylperoxyl radical

ASJC Scopus subject areas

  • Biochemistry

Cite this

Scott, B. C., Aruoma, O. I., Evans, P. J., O'neill, C., Van Der Vliet, A., Cross, C. E., ... Halliwell, B. (1994). Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation. Free Radical Research, 20(2), 119-133. https://doi.org/10.3109/10715769409147509

Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation. / Scott, Brigitte C.; Aruoma, Okezie I.; Evans, Patricia J.; O'neill, Charles; Van Der Vliet, Albert; Cross, Carroll E; Tritschler, Hans; Halliwell, Barry.

In: Free Radical Research, Vol. 20, No. 2, 1994, p. 119-133.

Research output: Contribution to journalArticle

Scott, BC, Aruoma, OI, Evans, PJ, O'neill, C, Van Der Vliet, A, Cross, CE, Tritschler, H & Halliwell, B 1994, 'Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation', Free Radical Research, vol. 20, no. 2, pp. 119-133. https://doi.org/10.3109/10715769409147509
Scott, Brigitte C. ; Aruoma, Okezie I. ; Evans, Patricia J. ; O'neill, Charles ; Van Der Vliet, Albert ; Cross, Carroll E ; Tritschler, Hans ; Halliwell, Barry. / Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation. In: Free Radical Research. 1994 ; Vol. 20, No. 2. pp. 119-133.
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