Polyphenols analysed by UHPLC-ESI-MS/MS and antioxidant activities of molasses, acorn and leaves of oak (Quercus robur subsp. pedunculiflora) Ercan Bursal 1 , Remzi Boğa 2 1 Muş Alparslan University, School of Health, Department of Nursing, Muş, Turkey - E-mail: ercanbursal@gmail.com; 2 Muş Alparslan University, Faculty of Science and Arts, Department of Biology, Muş, Turkey Summary. Objectives: Te leaves of oak trees have been boiled in water and the extracts have been evaporated to produce oak molasses. Colloidal precipitants have been widely used as dietary molasses since have very ef- fective antiseptic functions as alternative medicine for ages in some parts of the world. Present study aimed to investigate the biological activities of oak products for elucidating the scientifc basis of alternative medicine. Tus, antioxidant activities of ethanol and water extracts of acorn, leaves and molasses of oak trees (Quercus robur subsp. pedunculiflora) were evaluated. Results: We determined antioxidant activities of extracts by difer- ent in vitro methods including DPPH free radical scavenging, ABTS •+ radical scavenging, total antioxidant activity determination by ferric thiocyanate method, reducing power by FRAP methods, separately. Te re- sults were compared with BHA, BHT and ascorbic acid as standard antioxidant compounds. Te acorn seed extract, which presented the highest antioxidant potential, was the most efective scavenger against DPPH free radical. Also, phenolic compounds of the molasses were identifed by UHPLC-ESI-MS/MS. Te high- est phenolic compound was quinic acid (4556 ± 219 ppb). Conclusion: Acorns and leaves of oak trees (Quercus robur subsp. pedunculiflora), as well as traditional oak molasses” have high antioxidant potential for the food industry as a food ingredient to produce functional food products. Key words: Antioxidant, phenolic acid, nutrition, acorn, Quercus, LC-MS/MS Progress in Nutrition 2018; Vol. 20, Supplement 1: 167-175 DOI: 10.23751/pn.v20i1-S.5311 © Mattioli 1885 Original article Abbreviations BHA: Butylated Hydroxy Anisole, BHT: Butylated Hydroxy Toluene, Vit C: Vitamin C, MYE: ethanol extract of oak leaves, MYS: water extract of oak leaves, PKE: ethanol extract of acorn shell, PKS: water extract of acorn shell, PÇE: ethanol extract of acorn seed, PÇS: water extract of acorn seed, GPE: ethanol extract of oak molasses, GPS: water extract of oak molasses Introduction Oak is classifed in the genus of Quercus, which includes more than 300 species. Oak trees are char- acterized by spirally arranged leaves and acorn fruits. Te acorn is the nut of oak that contains a single seed. Some animals such as birds, horses, squirrels, pigs, bears, and small mammals consume large amounts of acorns because of their taste and abundanct. Acorns have been used as a source of food for many cultures around the world especially in famine. Acorns have frequently been used as food substitutes. Te nutri- tional compositions of acorns were determined and large amounts of water, protein, carbohydrates, fats, and some minerals were detected (1). Acorns contain tannins, which are plant polyphenols and also found in several beverages including red wine, beer, cof- fee, black tea, green tea, and many foodstufs such as