Procyanidin B-2, extracted from apples, promotes hair growth: a laboratory study.
BACKGROUND
We have previously reported that several selective protein kinase C (PKC) inhibitors, including procyanidin B-2, promote hair epithelial cell growth and stimulate anagen induction.


OBJECTIVE
We discuss the hypothesis that the hair-growing activity of procyanidin B-2 is related to its downregulation or inhibition of translocation of PKC isozymes in hair epithelial cells.


METHODS
We examined the effect of procyanidin B-2 on the expression of PKC isozymes in cultured murine hair epithelial cells as well as PKC isozyme localization in murine dorsal skin at different stages in the hair cycle.


RESULTS
We observed that procyanidin B-2 reduces the expression of PKC-alpha, -betaI, -betaII and -eta in cultured murine hair epithelial cells and also inhibits the translocation of these isozymes to the particulate fraction of hair epithelial cells. Our immunohistochemical analyses demonstrated that PKC-alpha, -betaI, -betaII and -eta are specifically expressed in the outer root sheaths of both anagen and telogen hair follicles. The hair matrix at the anagen stage showed no positive staining for these PKC isozymes. Moderate to intense staining for PKC-betaI and -betaII in the epidermis and hair follicles was observed in a telogen-specific manner; however, expression of PKC-alpha and -eta during the telogen stage was not conspicuous. Gö 6976, an inhibitor of calcium-dependent (conventional) PKC, proved to promote hair epithelial cell growth.


CONCLUSIONS
These results suggest that PKC isozymes, especially PKC-betaI and -betaII, play an important role in hair cycle progression and that the hair-growing mechanisms of procyanidin B-2 are at least partially related to its downregulation of PKC isozymes or its inhibition of translocation of PKC isozymes to the particulate fraction of hair epithelial cells.
Kamimura
A
A
Tsukuba Research Laboratories, Kyowa Hakko Kogyo Co., 2, Miyukigaoka, Tsukuba, Ibaraki 305-0841, Japan. ayako.kamimura@kyowa.co.jp
Takahashi
T
T
D000818:Animals; D044946:Biflavonoids; D002392:Catechin / Q000494:pharmacology*; D002478:Cells, Cultured; D015536:Down-Regulation; D004353:Drug Evaluation, Preclinical; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006197:Hair / Q000187:drug effects* / Q000254:growth & development; D007527:Isoenzymes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D044945:Proanthocyanidins; D011493:Protein Kinase C / Q000187:drug effects* / Q000378:metabolism; D012867:Skin / Q000201:enzymology
D044946:Biflavonoids; D007527:Isoenzymes; D044945:Proanthocyanidins; C479578:procyanidin B; C017674:procyanidin; D002392:Catechin; D011493:Protein Kinase C