a-Lipoic acid and its reduced form, DHLA, have
been referred to as "a universal antioxidant" that func
tions in both membrane and aqueous phases. 9 Both
a-lipoic acid and DHLA have substantial antioxidant
properties. These include their ability to directly
quench a variety of reactive oxygen species, inhibit
reactive oxygen-generators, and spare other antioxidants.
A number of experimental as well as clinical studies
point to the usefulness of ot-lipoic acid as a therapeutic
agent for such diverse disease conditions as myocardial
and cerebral ischemia-reperfusion injury, heavy-metal
poisoning, radiation damage, diabetes, neurodegenerative
diseases, and AIDS. High doses of ot-lipoic acid
are approved in Germany for treatment of diabetic
polyneuropathy. Furthermore, the interesting antioxidant
properties of a-lipoic acid and its interaction with
other important antioxidants like vitamin E, ascorbate,
and glutathione will provide a fertile field for continued
research.