Improvement in Quality of Sleep by the Intake of Saffron—derived Crocin and Safranal―A Randomized, Double—blind, Placebo—controlled, Parallel—group Trial―

Saffron, a spice, is the dried stigma of a perennial of the family Iridaceae, originating from South-western Asia. In addition to being used as a spice, is known for its sedative and analgesic effects and is used in herbal medicine in China and other countries. Due to these effects, it is known to induce relaxation and improve sleep. The pharmacologically active components are thought to be crocin and safranal. To investigate the effects of saffron extract on sleep, we conducted a placebo-controlled parallel-group trial with 52 individuals who consumed a dietary supplement containing saffron extract. The main evaluation items were the Oguri-Shirakawa-Azumi sleep inventory MA version（OSA-MA）and sleep analysis by electroencephalography （EEG）. Finally, a total of 45 individuals were analyzed. As for the OSA-MA, the group which consumed the saffron supplement showed significant improvement compared to the control group regarding sleepiness upon rising, initiation and maintenance of sleep, and frequent dreaming. Analysis of EEG recordings during sleep showed that the group that consumed the saffron supplement experienced significantly shorter sleep onset latency and significantlyreduced nocturnal awakening. Furthermore, the time spent in non-REM sleep increased. Thus, saffron extract, containing crocin and safranal, encourages sleep onset, increases deep sleep, reduces nocturnal awakening, and improves sleep rhythm. The study was registered with the University Hospital Medical Information Network（UMIN）Clinical Trial Registry before implementation（UMIN000035882）.