African Journal of Biotechnology Vol. 10(17), pp. 3451-3454, 25 April, 2011 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2011 Academic Journals Full Length Research Paper Antioxidant activity and separation of phenolic compounds of Origanum glandulosum from north Algeria by high performance liquid chromatography (HPLC) Oukil Naima, Bedjou Fatiha * , Maiza-Benabdesselam Fadila and Chibane Mohamed Faculty of Life and Nature Sciences -University Abderrahmane MIRA of Béjaia – Terga Ouzemmour – 06000- Béjaia- Algeria Accepted 10 March, 2011 Origanum glandulosum is an endemic plant of North African area (Algeria and Tunisia), used against infections like whooping cough and bronchitis. In this study, its antioxidant activity is evaluated. The results showed that the scavenging effect against DPPH is equal to 6730 mg/ml (IC 50 ). However, the scavenger effect of H 2 O 2 estimated at 60.78% is very strong compared to the effects of BHA, BHT and - tocopherol estimated respectively at 19, 25 and 23%. The scavenger effect of H 2 O 2 is very strong compared to the scavenging of DPPH. A high scavenging effect is generally due to high content of phenolic compounds, phenolic acids and flavonoids. The results may suggest that O. glandulosum extract possesses compounds with antioxidant activity; these substances can play an important role in the prevention of free radical induced diseases. Key words: Phenolic compounds, Origanum glandulosum, HPLC, antioxidant, flavonoids. INTRODUCTION Origanum glandulosum is an endemic widely distributed taxon of the North African region (Algeria and Tunisia). It is considered as brushwood (Quezel and Santa, 1963; Leclerc, 1990; Bendahou et al., 2008). Several studies have shown that O. glandulosum taxon is rich in essential oils, phenolic compounds such as flavonoids and phenolic acids (Benzanger-beauquesne et al., 1980, 1990; Nakiboglu et al., 2007). In Algeria, this plant is used against infections like whooping cough, cough, fever and bronchitis (Bendahou et al., 2008). The purpose of this study was the estimation of the total phenolic content of O. glandulosum using the *Corresponding author. E-mail: fadilamaiza@yahoo.fr. Tel: 00213771449217. Fax: 00213214762. Abbreviations: BHA, Butyl hydroxyanisol; BHT, butyl hydroxyltoluene; DPPH, 1,1 diphenyl-2-picryl hydroxyl. Classical Folin-Ciocalteu reagent, the determination of their antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH assay), the H 2 O 2 scavenging effects and the analysis of the chemical composition of methanolic extract by HPLC chromatography, to estimate the number of major components of this plant. The choice of this investigation is based on two criteria; firstly, there are few studies in this domain in Algeria and the second criterion is the traditional utilization of O. glandulosum. MATERIALS AND METHODS Plant materials Samples of aerial parts (leaves, twigs and flowers) of individual plants were collected in the region of Boukhlifa (Béjaia) (36°41’ 19°, 39’ N; 5°06’ 26°, 56’ S; alt.1.00 Km) during June 2007. Identification of plants was made by the botanical laboratory of Béjaia University. Crude extracts The medicinal plants collected were harvested, dried and ground to