Epidemiological investigations have reported that the habit of drinking tea reduces the risk of developing a mental disorder, including anxiety disorder and depression. Theaflavins, black tea polyphenols, show antibacterial and anti-oxidative effects, but their effects on brain function, especially mental condition, have not been elucidated. The present study demonstrated that theaflavins increased dopamine (DA) turnover in the frontal cortex and showed an anxiolytic effect in mice. Theaflavin consumption increased the time spent by mice in the open arms of an elevated plus maze test. Theaflavin administration increased the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) and the ratios of DOPAC/DA and (DOPAC+homovanillic acids)/DA indicating DA turnover, in the frontal cortex. These results suggest that the consumption of theaflavins induced anxiolytic effects via activation of the dopaminergic system in the frontal cortex, which support the findings of previous epidemiological studies. Theaflavins in black tea may be helpful to reduce anxiety in daily life. (150/150 words).
Keywords: Anxiety; black tea polyphenol; dopamine; theaflavin.