Several selective protein kinase C inhibitors including procyanidins promote hair growth

We have previously reported that procyanidin oligomers selectively promote growth of murine hair epithelial cells in vitro and stimulate anagen induct ion in vivo. We report here the possible relationship between the protein k inase C-inhibiting activity of procyanidins and their hair-growing activity . Of the procyanidins, procyanidin B-2 and procyanidin C-1, which selective ly inhibit protein kinase C, intensively promote hair epithelial cell proli feration in vitro and stimulate anagen induction in vivo. On the other hand , procyanidins, which inhibit both protein kinase C and A, showed relativel y low activity in in vitro and in vivo evaluations. We also found that calp hostin C, which is a selective inhibitor of protein kinase C, possesses hai r epithelial cell growth-promoting activity in vitro and anagen phase-induc ing hair-growing activity in vivo. Other selective protein kinase C inhibit ors, such as hexadecylphosphocholine, palmitoyl-DL-carnitine chloride, and polymyxin B sulfate, also show marked anagen phase-inducing hair-growing ac tivity in vivo. Nonselective protein kinase inhibitors, such as staurospori ne and K252a, inhibit the growth of hair epithelial cells. 1,2-Dioctanoyl-s n-glycerol, a protein kinase C activator, dose-dependently decreases the gr owth of hair epithelial cells. Forskolin, an adenylate cyclase activator, p romotes hair epithelial cell growth and boosts the growth-promoting effect of procyanidin B-2. It is speculated that the hair-growing activity of proc yanidins is related to their protein kinase C-inhibiting activity. Copyrigh t (C) 2000 S. Karger AG. Basel.