In Vivo Hair Growth Promotion Effects of Ultra-High Molecular Weight Poly-γ-Glutamic Acid from Bacillus subtilis (Chungkookjang)

We investigated the effect of ultra-high molecular weight poly-gamma-glutamic acid (UHMW gamma-PGA) on hair loss in vitro and in vivo. 5-Alpha reductase is an enzyme that metabolizes the male hormone testosterone into dihydrotestosterone. By performing an in vitro experiment to analyze the inhibitory effects of UHMW gamma-PGA on 5-alpha reductase activity, we determined that UHMW gamma-PGA did in fact inhibit 5-alpha reductase activity, indicating the use of UHMW gamma-PGA as a potential 5-alpha reductase inhibitor in the treatment of men with androgenetic alopecia. To evaluate the promotion of hair growth in vivo, we topically applied UHMW gamma-PGA and minoxidil on the shaved dorsal skin of telogenic C57BL/6 mice for 4 weeks. At 4 weeks, the groups treated with UHMW gamma-PGA showed hair growth on more than 50% of the shaved skin, whereas the control group showed less hair growth. To investigate the progression of hair follicles in the hair cycle, hematoxylin and eosin staining was performed. Histological observations revealed that the appearance of hair follicles was earlier in the UHMW gamma-PGA-treated group than in the control group. The number of hair follicles on the relative area of shaved skin in the UHMW gamma-PGA-treated group was higher than that observed on the shaved skin in the control group. These results indicate that UHMW gamma-PGA can promote hair growth by effectively inducing the anagen phase in telogenic C57BL/6 mice.