Journal of Applied Botany and Food Quality 88, 16 - 21 (2015), DOI:10.5073/JABFQ.2015.088.004 1 Department of Plant Breeding and Molecular Genetics, University of Poonch, Rawalakot Azad Kashmir, Pakistan 2 Department of Chemistry, University of Poonch, Rawalakot, Azad Kashmir, Pakistan 3 University of Azad Jammu and Kashmir, Muzaffarabad, Azad Kashmir, Pakistan 4 Phytochemical Research Laboratory, Department of Industrial Pharmacy, Federal University of Santa Maria, Santa Maria, Brazil 5 Department of Biochemistry, University of Baluchistan, Pakistan 6 Pakistan Agricultural Research Centre, Islamabad, Pakistan 7 Department of Eastern Medicine, University of Poonch, Rawalakot, Azad Kashmir, Pakistan Antioxidant activities and phenolic composition of Olive (Olea europaea) leaves Abdul Khaliq 1 , Syed Mubashar Sabir 2* , Syed Dilnawaz Ahmad 3 , Aline Augusti Boligon 4 , Margareth Linde Athayde 4 , Abdul Jabbar 5 , Imtiaz Qamar 6 , Asmatullah Khan 7 (Received October 25, 2014) * Corresponding author Summary The present study compares the antioxidant activities of leaves of eight cultivars of olive. The aqueous extracts of leaves showed inhibition against thiobarbituric acid reactive species (TBARS) induced by pro-oxidant (10 μM FeSO 4 ) in mice liver. The order of the antioxidant activity among cultivars on lipid peroxidation assay is Gemlik > Frantio > Doleca-Agogia > Moriolo > Mission > Uslu > Leccino > Carotina. Different varieties of olive showed good antioxidant properties, IC 50 values ranged between 22.46 to 198 μg/ml on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The major phenolic acids, some flavonoid aglycone and glycosides were identified in leaves by high performance liquid chromatography. Ellagic acid (29.80 ± 0.02 mg/g), caffeic acid (15.73 ± 0.01mg/g), gallic acid (15.69 ± 0.01 mg/g), rutin (34.56 ± 0.03 mg/g), quercetin (16.41 ± 0.01 mg/g), epicatechin (11.04 ± 0.01 mg/g) and quercitrin (15.32 ± 0.03 mg/g) were predominant in infusion of olive. Introduction During metabolism, reactive oxygen species (ROS) are generated spontaneously in cells and are implicated in the aetiology of differ- ent degenerative diseases, like heart diseases, stroke, rheumatoid arthritis, diabetes and cancer (HALLIWELL et al., 1992). A number of studies have shown that the use of polyphenolic compounds found in tea, fruits and vegetables is associated with low risk of these diseases (HERTOG et al., 1993). Consequently, there is a great deal of interest in edible plants that contain antioxidants and health- promoting phytochemicals as potential therapeutic agents. One of such plant is Olive (Olea europaea L.) which belongs to the family Oleaceae and is native to tropical and warm temperate regions of the world. Olive is also considered as multipurpose crop with great yield potential. The tree is famous for its fruit and is also called the olive, is commercially important in the Mediterranean region as an important source of olive oil. The olive is typically distributed in the coastal areas of the eastern Mediterranean Basin, the adjoining coastal areas of southeastern Europe, western Asia and northern Africa as well as northern Iran at the south end of the Caspian Sea. The olive tree possesses medicinal and nutritional values. Over the centuries, extracts obtained from leaves of olive have been used for promoting health and used in preservation. Similarly, olive is a famous folk remedy to treat fever and some tropical diseases such as malaria (SOLER-RIVAS et al., 2000). A study has indicated that extract of olive leaves had a capacity to lower blood pressure in animals and increase blood flow in coronary arteries, relieved arrhythmia and prevented intestinal muscle spasms (BENAVENTE-GARCIA et al., 2000), diarrhea, to treat respiratory and urinary tract infections; olive oil and olive leaf extracts are some of these foodstuffs with recognized medicinal benefits and food preservation properties dating back to the Egyptian empire (MEDINA et al., 2007). Antioxidant activity is used to measure a compound to reduce the pro-oxidants or reactive species of pathologic significance (SOMOGYI et al., 2004). Much attention has been focused on natural antioxidants capable of inhibiting lipid peroxidation which is mediated in several pathological conditions such as atherosclerosis, cancer and aging (FREI, 1994). Ferric reducing antioxidant power (FRAP), total phenolic assay by using the Folin-Ciocalteu reagent, total flavonoid content and DPPH radical scavenging activity are the common methods used to evaluate the antioxidant properties. The demands of natural antioxidants are high for application as nutraceuticals and as food additives because of consumer preferences (KUMAR and CHATOOPADHYAY, 2007). Since antioxidants from plant source are safe and easily available, olive leaves was subjected to determine and quantify various antioxidant activities. There is limited information available on the antioxidant activity and phenolic profile of these olive cultivars. In view of the potential role of olive as dietary source of flavonoids as well as its possible use as functional food, this study was aimed to evaluate the antioxidant and inhibitory effect of eight important cultivars of olive on Fe(II) induced lipid peroxidation and to find out the phenolic profile of olive for their possible use in food and phytotherapy. The DPPH radical activity, total antioxidant activity, phenolic and flavonoid contents of these cultivars were also determined. Materials and methods Chemical and reagents Methanol, formic acid, gallic acid, chlorogenic acid, caffeic acid and ellagic acids purchased from Merck (Darmstadt, Germany). Epi- catechin, quercetin, quercitrin, rutin and kaempferol were acquired from Sigma Chemical Co. (St. Louis, MO, USA). Thiobarbituric acid (TBA), malonaldehyde-bis-dimethyl acetal (MDA), 2,2-diphenyl-1- picrylhydrazyl (DPPH), and ammonium molybdate was purchased from Sigma Aldrich (St. Louis, MO, USA). Ferrous sulphate was obtained from Biochemicals (Lahore). All chemical were of ana- lytical grade. Preparation of the leaves extracts The leaves of different cultivars of olive which include Dolece- Agogia, Mission, Moriolo, Maurino, Carotina, Leccino, Gemlik, Uslu were collected from three locations, Quetta, Zhoab and Lorallia research stations of Pakistan at the same harvesting time. Leaves were washed and dried in hot air at 40 o C and ground to a fine powder in mill. Ground material (5 g) was extracted with hot water (250 ml) for 30 minutes followed by filtration through whatman No.1 filter paper. The obtained residues were re-extracted under the