Hair growth promoting activity of cedrol isolated from the leaves of Platycladus orientalis

Platycladus orientalis (L.) Franco is traditionally known to potentiate hair growth promotion. However, there has been no report on its main active ingredient responsible for the hair growth activity. In the current work, cedrol as a major constituent from P. orientalis was evaluated for its potential on hair growth in vivo. Different concentrations of cedrol (10, 20 and 30 mg/mL) were applied topically over the shaved skin of C57BL/6 mice and monitored for 21 days. Results indicated that cedrol significantly promoted hair growth in a dose-dependent manner, particularly for the female mice. Both male and female mice groups treated with 30 mg/mL cedrol required shorter time than the blank control and 2% minoxidil groups at different growth stages. Compared with the blank control (8.87 mm) and 2% minoxidil (9.94 mm) groups at 21 days, the hair length of female mice treated with 30 mg/mL cedrol showed a remarkable increase with the value of 11.07 mm. Hair in male and female mice groups treated with 30 mg/mL cedrol was heavier than the 2% minoxidil (38.2 and 35.9 mg, respectively) groups with the weight of 42.6 and 45.2 mg, respectively. Further observation of the hair follicle demonstrated that cedrol exerted a remarkable effect on the hair follicle length. These findings suggested that cedrol may be the main active ingredient of P. orientalis and have the potential of becoming a new hair growth promoter.