O.S. DESOUKY**, G.M. HASSAN*, NABILA S. SELIM**

* Department of Ionizing Radiation Metrology, Institute for Standards (NIS), Tersa Street, El-Haram El-Giza, P.O. Box: 136 Giza, Egypt
**Radiation Physics Department, National Centre for Radiation Research and Technology (NCRRT), POB.29, Cairo, Egypt

Abstract. Lipoic acid is considered as an ideal therapeutic antioxidant because it is a naturally existing, low molecular weigh compounds with very powerful antioxidant effects in both aqueous and lipid domains. The aim of this work was to study in vitro the ability of α-lipoic acid to protect hemoglobin against the oxidative damage resulted from two different sources: exposure to gamma radiation and β-thalassemic disease. In β-thalassemia, the oxidative stress was found prior to the incubation with α-lipoic acid, while, the irradiated samples were incubated before the exposure to gamma radiation. EPR is used in this study, since it allows the determination of the concentration of unpaired electrons present in a sample even if the exact nature of the free radical is not known. In this study the EPR spectra had been recorded by means of a standard X-band spectrometer operating at 9.5 GHz. There was a significant increase in the EPR signal of the free radical (S4) at g = 2.0000 ± 0.00060 in irradiated hemoglobin and β-thalassemia major. The percentage of increasing was 106% and 69% in the free radical signal intensity in irradiated and -thalassemia major samples respectively comparing to the control value. In case of addition of α-lipoic acid to the irradiated blood and thalassemia major, the signal intensity of the free radical was diminished by factor 41% and 43% respectively. The obtained results confirmed that the exogenously supplied with α-lipoic acid had an antioxidant properties and is effective in decreasing the damage caused by reactive oxygen species (ROS).
Key words: Lipoic acid, hemoglobin, thalassemia, gamma radiation.

Corresponding author’s e-mail: omardesouky@yahoo.com

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