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, 2,2´-
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 (Fe2+) 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 (Fe2+) activities. Also, those various antioxidant activities were compared to BHA, BHT
α-tocopherol and trolox as references antioxidant compounds.
Serotonin, antioxidant activity, metal chelating, reducing power, radical scavenging.
Ataturk University, Faculty of Sciences, Department of Chemistry, 25240-Erzurum, Turkey.