This study examined the inhibitory effect of
forsythiaside-A, a natural substance derived from Forsythia suspensa (F. suspensa), on entry into catagen induced by
dihydrotestosterone (DHT) in an
androgenic alopecia mouse model. In vitro experiment comparing
finasteride with
forsythiaside-A showed that
forsythiaside-A treatment resulted in a 30% greater inhibition of DHT-induced apoptosis in human hair dermal papilla cell (HHDPCs) and human keratinocytes (HaCaTs). In vivo experiment showed that mouse hair density and thickness were increased by 50% and 30%, respectively, in the
forsythiaside-A-treated group when compared to a DHT group. Tissue histological results revealed that the
forsythiaside-A-treated group had an increase in size and shape of the hair follicles and a 1.5 times increase in the follicle anagen/telogen ratio when compared to the
finasteride group. Western blot examination of TGF-β2 expression related to apoptosis signaling in mouse skin verified that
forsythiaside-A reduced the expression of TGF-β2 by 75% and suppressed apoptosis by reducing the expression of
caspase-9 by 40%, and
caspase-3 by 53%, which play an roles up-regulator in the apoptosis signal. The
forsythiaside-A group also showed a 60% increase in the Bcl-2/Bax ratio, which is
a factor related to mitochondrial apoptosis. Our results indicated that
forsythiaside-A prevents apoptosis by similar mechanism with
finasteride, but
forsythiaside-A is more effective than
finasteride. In summary,
forsythiaside-A controlled the apoptosis of hair cells and retarded the entry into the catagen phase and therefore represents a
natural product with much potential for use as a treatment for
androgenic alopecia.