Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2013Radical scavenging and antioxidant capacity of serotonin
Sarikaya, S. Beyza Öztürk; Gülçin, Ilhami
Serotonin is a monoamine neurotransmitter and biochemically derived from tryptophan. The present paper examines the in vitro antioxidant and radical scavenging capacity of serotonin using different in vitro methodologies. For the determination of antioxidant activity of serotonin, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2́-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe3+-Fe2+ transformation method, superoxide anion radical scavenging by riboflavin-methionine-illuminate system, H2O2 scavenging and ferrous ions (Fe +) chelating activities of serotonin were performed. Also, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox, a water-soluble analog of α-tocopherol, were used as the reference antioxidant radical scavenger compounds. Serotonin completely inhibited lipid peroxidation of a linoleic acid emulsion at 15 μg/mL concentration. On the other hand, the above mentioned standard antioxidants displayed inhibition of 92.2, 99.6, 84.6 and 95.6% on peroxidation of linoleic acid emulsion, respectively at the 45 μg/mL concentration. In addition, serotonin was effective in DPPH· scavenging, ABTS•+ radical scavenging, superoxide anion radical scavenging, H2O2 scavenging, ferric ions (Fe3+) reducing power and metal chelating on ferrous ions (Fe+) activities. Also, those various antioxidant activities were compared to BHA, BHT α-tocopherol and trolox as references antioxidant compounds.
- MakaleYalnız künye2011Polyphenol contents and antioxidant properties of medlar (Mespilus germanica L.)
Gülçin, Ilhami; Topal, Fevzi; Sarikaya, S. Beyza Öztürk; Bursal, Ercan; Bilsel, Gökhan; Gören, Ahmet C.
Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), N,N-dimethyl-p-phenylenediamine (DMPD•+), and superoxide anion radicals (O2•-) scavenging activity, hydrogen peroxide (H2O2), ferric ions (Fe 3+) and cupric ions (Cu 2+) reducing ability, Fe 3+ -TPTZ reducing ability, ferrous ions (Fe2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits.