Hair regenerative activities of flavonoid-rich extract of Equisetum hyemale L. (Equisetaceae) in chemically-induced alopecia in Sprague Dawley rats

Context: The prevalence of alopecia around the world is high and awareness continuously increased due to social stigma. There are limited commercially-available medications for the management of different forms of baldness, most of which are prohibitively expensive and presents with various adverse effects. Aims: To evaluate the flavonoid-rich ethyl acetate extract of Equisetum hyemale stem for its hair-regenerative properties in chemically-induced alopecia in Sprague Dawley rats. Methods: Various concentrations of the flavonoid-rich extract of E. hyemale were applied in depilated areas in dorsal rat skin after chemical induction of alopecia. Evidence of hair growth was observed for 28 days in a weekly basis. Histopathological analysis of rat skin was performed to demonstrate evidence of follicular hair growth. Results: The abundance of flavonoids in the ethyl acetate extract was established by total flavonoid contents and LC-MS analyses. The 2.5% E. hyemale extract exhibited hair-regenerative properties with high tensile strengths, combined masses and follicular growth, which was comparable to the positive control, 5% minoxidil (p>0.05). The highest rate of hair follicular development was observed in the telogen phase in rat skin after 28 days of treatment. Conclusions: The flavonoid-rich ethyl acetate extract of E. hyemale exhibits in situ hair-regenerative properties in chemically-induced alopecia in rats at 2.5% w/v concentration.