A new horizon into the central effect of quercetin on human vigilance in normal healthy volunteers

Abstract

Background: Quercetin is one of the dietary flavonoids found in citrus fruits and leafy vegetables as well as seeds and green tea. Its name comes from Quercetum and belongs to flavonol class which is not synthesized in the human body. Many studies revealed a significant effect of quercetin in advancing psychomotor/cognitive performances and reversing the neurotoxin-induced neuronal damage. Therefore, the present study aimed to illustrate the central effect of quercetin on human vigilance and in normal healthy volunteers. Subjects and Methods: A total of fifty healthy volunteers with a mean age of 23 years were enrolled in this experimental study; they were divided into two groups: Group I: twenty healthy volunteers treated with placebo (500 mg/day starch capsule) for 2 weeks and Group II: thirty healthy volunteers treated with quercetin 500 mg/day for 2 weeks. Each volunteer in each group was subjected to vigilance-psychomotor testing by Leeds psychomotor performance tester which measures Psychomotor-vigilance test (PVT) and Cortical arousal activity (CAA). Results: Quercetin produced a more significant effect on total reaction time, recognition reaction time, movement reaction time, fusion index, % fusion (P < 0.01), and flicker percentage (P < 0.05) compared to control, but quercetin produced an insignificant effect on CFFd, critical flicker-fusion frequency, and flicker index. Conclusion: Quercetin improves psychomotor performance and CAA in normal healthy volunteers.