Possible Gender Difference in Anti-stress Effect of β-Cryptoxanthin

Beta-cryptoxanthin [β-CRX, (3R)-β, β-caroten-3-ol] is a provitamin A and a potent antioxidant that is abundant in Satsuma mandarin orange (Citrus unshiu MARC.), which is the most popular fruit in Japan. The anti-stress effect of β-CRX on humans was evaluated in fifth-year university students during both routine daily life at the university and at pharmacy practice. The study design was a double-blind group comparison and participants (n=20; female 12, male 8) were randomly assigned to β-CRX-rich orange juice or placebo (β-CRX was removed from orange juice) groups. β-CRX or placebo juice (125 mL, once a day, after breakfast) were consumed from 10 d prior to the pharmacy practice and continued for 10 d into the practice period. To assess participants' anxiety, the state-trait anxiety inventory test was carried out before the pharmacy practice. Salivary α-amylase activity (sAA) was measured as a marker of sympathetic nervous system activity. In the placebo-group, sAA in the evening (post-practice sAA) tended to be higher than sAA in the morning (pre-practice sAA) during both routine daily life at the university and during pharmacy practice. In the β-CRX-group, the increase of post-practice sAA was suppressed in females. These results suggested that β-CRX has an anti-stress effect, at least, in females.