*Corresponding author, e-mail: sevindik27@gmail.com Research Article GU J Sci 31(3): 707-711 (2018) Gazi University Journal of Science http://dergipark.gov.tr/gujs Phenolic Content and Antioxidant Potential of Terfezia boudieri Mustafa SEVINDIK 1,* , Mustafa PEHLIVAN 2 , Muhittin DOGAN 3 , Zeliha SELAMOGLU 4 1 Department of Biology, Faculty of Science, Akdeniz University, 07058, Antalya, Turkey 2 Nurdagı Vocational School, Gaziantep University, 27310, Gaziantep, Turkey 3 Department of Biology, Faculty of Science and Literature, Gaziantep University, 27310, Gaziantep, Turkey 4 Department of Medical Biology, Faculty of Medicine, Nigde Omer Halisdemir University, 07058, Nigde, Turkey Article Info Abstract The present study aimed to determine the phenolic content, total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) of Terfezia boudieri Chatin, known as truffle mushroom. In this context, phenolic content was determined with an HPLC device. TAS, TOS and OSI were determined with Rel Assay kits. As a result of the conducted analyses, 30.89 mg/kg gallic acid, 554.64 mg/kg syringic acid and 5.52 mg/kg 4-hydroxybenzoic acid were determined in the mushroom. It was determined that TAS value was 2.332 ± 0.034, TOS value was 26.945±0.144 and OSI value was 1.156±0.011. It was suggested to avoid excessive consumption of mushrooms collected in this region due to the high TOS value. It was also considered that samples collected in appropriate regions could be consumed as a good antioxidant source based on the determined OSI. Received: 13/10/2017 Accepted: 20/04/2018 Keywords Terfezia boudieri Phenolic content Antioxidant Oxidant 1. INTRODUCTION In addition to their nutritional properties, mushrooms, which are common on Earth including several species, are also significant natural sources in medicine. Mushrooms are organisms that exhibit cosmopolitan deployment and have become a popular gastronomical item in several countries and societies [1]. Mushrooms could be designated as functional nutrients due to their health benefits, as well as their nutritional properties. In recent years, consumer interest in functional nutrients has been augmented due to the increased interest in health, nutrition and prevention of diseases [2,3]. Plants contain several phytochemicals with medicinal properties in their stems. It was determined that mushrooms, like plants, contain certain bioactive compounds and thus, exert significant biological activities [4]. Certain mushroom species harbor rich antioxidant compounds such as phenolic compounds and tocopherols [5]. In addition to the antioxidant properties of these bioactive compounds, they were shown to possess several medical antibacterial effects such as antimicrobial, antitumor, anti- inflammatory, DNA protective action and immunosuppressive agents [6-10]. Today, these bioactive compounds that were identified by molecular research are increasingly used in the production of pharmacological products [11,12]. Thus, identification of new natural resources and determination of the compounds these natural sources produce are very important for the production of pharmacological products. The present study aimed to determine the total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) and phenolic content of Terfezia boudieri Chatin mushroom.