Research Article ISSN 2250-0480 VOL 6/ ISSUE 3/JULY 2016 L - 31 Life science Agricultural science ANTIOXIDANT PROPERTIES OF GALIUM VERUM ISSA LAYALI 1 *, MOHAMMAD ALI EBRAHIMZADEH 2 , MANIJEH JOULAEI 2 1 Department of Biochemistry, Sari Branch, Islamic Azad University, Sari, Iran. 2 Traditional and Complementary Medicine Research Center, Mazandaran University of Medical Sciences, Sari, Iran. ABSTRACT The genus Galium (Rubiaceae), comprised of approximately 1300 species and used for the treatment of a variety of pathological conditions in folk medicine of many cultures. In this study, antioxidant activities of aerial parts of G. verum were investigated employing various in vitro assay systems, i.e. DPPH and nitric oxide radical scavenging, reducing power and H 2 O 2 scavenging. IC 50 for DPPH radical-scavenging activity was 59.6 ± 0.04 µg ml -1 . The extract exhibited potent reducing power at 50 - 800 µg ml -1 that were comparable with Vitamin C. Also, extract showed very strong nitric oxide-scavenging. IC50 was 1.7 ± 0.01 µg ml -1 . Extract was capable of scavenging hydrogen peroxide in a concentration dependent manner. It showed very strong activity. At 50 µg ml -1 , percentage of inhibition was 92.5 %. The extract exhibited very potent antioxidant activities in all tested models. The total amount of phenolic compounds in extract was determined as gallic acid equivalents (753 ± 21 mg g -1 of extract) and total flavonoid contents were calculated as quercetin equivalents (151.25 ± 8.2 mg g -1 of extract) from a calibration curve. This plant was a good source of phenols and contains very high amount of total flavonoids and phenolic compounds. The very potent antioxidant activity may be attributed to the presence of phenols and flavonoids in the extract. KEYWORDS: Antioxidant activity, Galium verum, Radical scavenging, Reducing power. INTRODUCTION Free radicals and reactive oxygen species (ROS) are well known inducers of cellular and tissue pathogenesis leading to more than 100 diseased including inflammatory disorders, malaria, AIDS, heart disease, stroke, arteriosclerosis, diabetes and cancer, Parkinson´s and Alzheimer`s diseases, and aging processes (Di Matteo V. 2003; Nabavi SF et al. 2016). Minimizing oxidative damage may well be one of the most important approaches to the primary prevention of these diseases and health problems. Antioxidants provide protection to living organisms from this damage caused by uncontrolled production of ROS and the concomitant lipid peroxidation, protein damage and DNA strand breaking (Ghosal S. 1996). Antioxidants have been detected in a large number of foods and plant extracts. Among the various medicinal plants, some endemic and edible species are of particular interest because they may be used for producing raw materials or preparations containing phytochemicals with significant antioxidant capacities and high content of mineral with health benefits (Ebrahimzadeh MA et al. 2010a). Although there are some synthetic antioxidant compounds, such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), which are commonly used in processed foods, it has been reported that these compounds may have side effects (Nabavi SF et al. 2016 ). So the use of traditional medicine is widespread, and plants still present a large source of natural antioxidants that might serve as leads for the development of novel drugs.The genus Galium (Rubiaceae), comprised of approximately 1300 species, is used for the treatment of a variety of pathological conditions such as hepatitis and skin infections, as a sedative, diuretic and antidiarrheal and in the treatment of some complaints, gout and epilepsy in folk medicine of many cultures (Bolivar P et al. 2011). Compounds isolated from the genus Galium include iridoid glucosides, triterpene saponins, anthraquinones and flavonoids