Screening of some Algerian medicinal plants for the phenolic compounds and their antioxidant activity

Since recent times, there is a growing interest in the food industry and in preventive health care for the development and evaluation of natural antioxidants from medicinal plant materials. In the present work we have investigated the antioxidant potency of phenolic compounds of 11 indigenous wild plant species from the Algerian Atlas commonly used in Arab folk medicine for a wide range of conditions. The antioxidant activity of each phenolic extracts has been assessed by using the Trolox Equivalent Antioxidant Capacity (TEAC) as a chemical test, and in a dynamic way by a biological assay based on whole blood resistance to free radical aggression. Of the 11 tested plants, 2 showed prominent antioxidant activity: Anthemis arvensis and Artemisia campestris. These plants had a very high level of Trolox equivalents and induced a strong delay of free radical-induced red blood cells hemolysis compared to antioxidant references. Artemisia campestris was the best inhibitor, its effect was far stronger than that of caffeic acid and was more than three times as high as ascorbic acid and two times higher than α-tocopherol efficiency. HPLC analysis showed a good correlation between the antioxidant activity and hydroxycinnamic derivatives. These preliminary results on the in vitro protection of blood against oxidative stress emphasized the benefit of the phenolic compounds of these medicinal plants. Our results enable us to proceed towards more detailed chemical and pharmacological understanding of these plant materials and show the interest of natural antioxidant in medicinal plants for the prevention of much free radical-mediated pathology. © Springer-Verlag 2007.