Inhibitory activities of some traditional Chinese herbs against testosterone 5α-reductase and effects of Cacumen platycladi on hair re-growth in testosterone-treated mice

Abstract

Ethnopharmacological relevance: Many traditional Chinese medicines (TCM) have been used for hundreds of years for hair blackening and hair nourishing, and now many of them are commonly used in Chinese herbal shampoo to nourish the hair and promote hair growth.

Aims of the study: The present study was performed to screen 5α-reductase (5αR) inhibitors from traditional Chinese medicines, evaluate its hair growth promoting activity in vivo, and further investigate its effects on androgen metabolism and the expression of 5αR II in hair follicles.

Materials and methods: Nine TCM which were dried, ground and extracted by maceration with 75% ethanol or distilled water were used for screening 5αR inhibitors, and enzymes were extracted from the rat epididymis. The leaves of Platycladus orientalis (L.) Franco was used to evaluate the in vivo anti-androgenic activity. Skin color was observed daily and the hair re-growth was assessed by assigning the hair growth score. The longitudinal sections of hair follicles were used for observing follicle morphology, classifying of distinct stages of hair follicle morphogenesis and calculate the average score. The transverse sections were used for determination of hair follicle counts. Testosterone (T), Dihydrotestosterone (DHT) and Estradiol (E2) levels in serum and skin tissue were detected by ELISA kits. The immunofluorescence assay was used to detect the influence of CP-ext on 5αR expression in dorsal skin.

Results: We found the extract of Ganoderma lucidum (GL-ext), Polygonum multiflori (PM-ext), Cacumen platycladi (CP-ext) and Cynomorium songaricum (CS-ext) showed stronger 5αR inhibitory activity. CP-ext (5mg and 2mg/mouse/day) could significantly shorten the time of the dorsal skin darkening and got longhaired (P<0.01), and showed high hair re-growth promoting activity. Furthermore the histological data of hair follicles in each group showed that CP-ext could promote the growth of hair follicle and slowed down hair follicles enter the telogen. What's more CP-ext significantly reduced DHT levels and down-regulated the expression of 5αRⅡin skin (P<0.01).

Conclusions: GL-ext, PM-ext, CP-ext and CS-ext showed strong 5αR inhibitory activity. CP-ext possesses high hair growth promoting activity in the in vivo androgen-sensitive mouse model via inhibiting the 5αR activity, decreasing the DHT levels and in turn suppressing the expression of 5αR. Our study may contribute to the development of a new generation of herbal supplements with clearer material basis of pharmacodynamic for treating androgenic alopecia (AGA).

Keywords: 5α-reductase; Androgenic alopecia; Dihydrotestosterone; Hair re-growth; Immunofluorescence; Traditional Chinese medicines.