The effects of phytochemicals on circadian rhythm and related diseases.

A circadian rhythm is any biological activity rhythm driven by internal circadian clocks (∼24 h) and entrained by external signals. Its disruption leads to the development of many diseases, including obesity, metabolic syndrome, and cancer. However, not many medical treatments for circadian rhythm disorder has been applied. Several phytochemicals demonstrate the ability to prevent or even treat circadian-related diseases and function as circadian modulators. In this review, we briefly summarize the molecular architecture of circadian rhythm in mammals and circadian-related diseases. The effects of various phytochemicals such as caffeine, quercetin, cinnamic acid, and resveratrol on circadian clocks are highlighted. Potential application of diet therapy for circadian disorder and future research directions are also discussed.