Hair growth promotion, cytotoxicity and skin permeability evaluations of Carthamus tinctorius floret extract

Abstract

Introduction: Carthamus tinctorius L., a member of the family Compositae, is a Thai plant traditionally used for hair treatment. Our previous studies showed that C. tinctorius floret ethanolic extract (CTE) could stimulate the hair growth-related gene and suppress the hair loss-associated gene expression in dermal papilla cells. Furthermore, this plant extract promoted the growth of hair in mice. Method: In this study, the effect of CTE on the length of cultured hair follicle was examined. Moreover, the toxicity of CTE on keratinocytes (HaCaT), melanocytes (B16F10) and dermal papilla cells (DPCs) was investigated. Besides, the skin permeability of CTE also was measured. Results: The results revealed that CTE showed a significant increase in length of cultured hair follicles. For cytotoxic assay, after 24 h incubation the cultured cells were evaluated by using MTT assay, the high IC₅₀ of CTE on HaCaT, B16F10 and DPCs were 2.19±0.11, 3.62±0.69, and >5.00 mg/ml, respectively. The permeability of CTE from side by side diffusion cell method through porcine skin over 24 h was measured with UV-HPLC, the permeation rate in water vehicle of hydroxysafflor yellow A, a chemical component of CTE, was 82.01 µg/cm²/ h. When the enhancers including propylene glycol and ethanol were added in the vehicle, the permeation rate raised up to 141.44 µg/cm²/ h. Conclusion: The results suggest that CTE has potential as a safe hair growth promoter with high skin permeation and it is suitable for further development as a topical agent.