(Return to Clinical Studies page)
ALPHA-LIPOIC ACID, A POWERFUL ANTIOXIDANT IN ATHLETES
Zembron-Lacny A, Szyszka K, Szygula Z. (2007). Effect of cysteine derivatives administration in healthy
men exposed to intense resistance exercise by evaluation of pro-antioxidant ratio. J Physiol Sci.
57(6):343-8.
The aim of this study was to ascertain the influence of cysteine derivatives on pro-antioxidant equilibrium and
to compare the antioxidant effectiveness of N-acetylcysteine, alpha-lipoic acid, and taurine by using Loverro's
coefficient (pro-antioxidant ratio) in healthy men exposed to intensity-resistance exercise. Fifty-five men were
randomly assigned to one of four groups: control (CON, placebo), N-acetylcysteine (NAC 1.8 g.day(-1), 3 days),
alpha-lipoic acid (LIP 1.2 g.day(-1), 3 days), or taurine (TAU 3 g.day(-1), 3 days). The erythrocyte superoxide
dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities, lipid peroxidation products (TBARS),
and plasma protein thiol concentrations were evaluated. The P/A ratio was determined from the mean values of TBARS,
SOD, GPx, and CAT. The applied exercise at maximal intensity induced the significant changes in pro-antioxidant
equilibrium toward peroxidation, which was proved by a 25% increase in TBARS concentration in the CON group. The
peroxidation was significantly diminished by NAC (-14%) and LIP (-16%), whereas TAU had no effect on the TBARS
concentration. Cysteine derivatives administration prevented exercise-induced decline in SOD activity and increased
in GPx activity during exercise. CAT activity changed only in the LIP group. The estimation of P/A ratio showed the
lowest level of pro-antioxidant equilibrium after LIP administration. In the CON group, P/A ratio was directly
correlated with the protein thiols level (r = 0.495, p < 0.001). These data confirm the antioxidant action of
tested cysteine derivatives, particularly lipoic acid, and demonstrate the practical application of P/A ratio to
evaluate the effectiveness of antioxidants in athletes.
--------------------------------------------------------------
Marangon K, Devaraj S, Tirosh O, Packer L, Jialal I. (1999). Comparison of the effect of alpha-lipoic
acid and alpha-tocopherol supplementation on measures of oxidative stress. Free Radic Biol Med.
27(9-10):1114-21.
In vitro studies have shown that alpha-lipoic acid (LA) is an antioxidant. There is a paucity of studies on LA
supplementation in humans. Therefore, the aim of this study was to assess the effect of oral supplementation with
LA alone and in combination with alpha-tocopherol (AT) on measures of oxidative stress. A total of 31 healthy
adults were supplemented for 2 months either with LA (600 mg/d, n = 16), or with AT (400 IU/d, n = 15) alone, and
then with the combination of both for 2 additional months. At baseline, after 2 and 4 months of supplementation,
urine for F2-isoprostanes, plasma for protein carbonyl measurement and low-density lipoprotein (LDL) oxidative
susceptibility was collected. Plasma oxidizability was assessed after incubation with 100 mM 2,2'-azobis
(2-amidinopropane) hydrochloride (AAPH) for 4 h at 37 degrees C. LDL was subjected to copper- and AAPH-catalyzed
oxidation at 37 degrees C over 5 h and the lag time was computed. LA significantly increased the lag time of LDL
lipid peroxide formation for both copper-catalyzed and AAPH-induced LDL oxidalion (p < .05), decreased urinary
F2-isoprostanes levels (p < .05), and plasma carbonyl levels after AAPH oxidation (p < .001). AT prolonged
LDL lag time of lipid peroxide formation (p < .01 ) and conjugated dienes (p < .01) after copper-catalyzed
LDL oxidation, decreased urinary F2-isoprostanes (p < .001), but had no effect on plasma carbonyls. The addition
of LA to AT did not produce an additional significant improvement in the measures of oxidative stress. In
conclusion, LA supplementation functions as an antioxidant, because it decreases plasma- and LDL-oxidation and
urinary isoprostanes.
Legal notice: The patent-pending EPO-BOOST™ formula is proprietary to Biomedical Research
Laboratories, LLC. Biomedical Research Laboratories, LLC has been successful in defending its intellectual property
and prosecuting all unauthorized uses or violations to the fullest extent of both domestic and international
law.
| 
