β-cryptoxanthin induces UCP-1 expression via RAR pathway in adipose tissue.

While beta-cryptoxanthin is hypothesized to have a preventive effect on lifestyle-related diseases, its underlying mechanisms are unknown. We investigated the effect of beta-cryptoxanthin on energy metabolism in adipose tissues and its underlying mechanism. CS7BL/6J mice were fed a high-fat diet (60% kcal fat) containing 0 or 0.05% beta-cryptoxanthin for 12 weeks. beta-cryptoxanthin treatment was found to reduce body fat gain and plasma glucose level, while increasing energy expenditure. The expression of uncoupling protein (UCP) 1 was elevated in adipose tissues in the treatment group. Furthermore, the in vivo assays showed that the Ucp 1 mRNA expression was higher in the beta-cryptoxanthin treatment group, an effect that disappeared upon cotreatment with a retinoic acid receptor (RAR) antagonist. In conclusion, we report that beta-cryptoxanthin reduces body fat and body weight gain and that beta-cryptoxanthin increases the expression of UCP1 via the RAR pathway.