Extract of Plumbago zeylanica enhances the growth of hair follicle dermal papilla cells with down-regulation of 5α-reductase type II.

Abstract

Cellular senescence, a phenomenon of irreversible growth arrest of mammalian cells, is involved in various age-related phenomena in organisms. Hair follicle dermal papilla (DP) cells play important roles in the regulation of hair growth and loss. We examined the implication of cellular senescence of DP cells in androgenetic alopecia (AGA), the most common form of male hair loss, and searched for the compounds that have a beneficial effect on the prevention of AGA. Expression of the 5α-reductase type II (SRD5A2) gene, which plays a key role in the development of AGA, was examined by quantitative RT-PCR and Western blotting analysis in DP cells. Besides, DP cells were cultured with the extracts of herbs used in traditional Ayurvedic medicine to search for the compounds that have a beneficial effect on the growth of DP cells. We found that expression of the SRD5A2 was up-regulated in senescent DP cells. We also found that the herbal extract of Plumbago zeylanica (root) enhanced the growth of DP cells and down-regulated the expression of SRD5A2 in DP cells. Further, plumbagin, an ingredient of Pzeylanica, would be responsible for the above effects of Pzeylanica. These results suggested the possibility that senescent DP cells may have a role in the development of AGA through up-regulating SRD5A2 expression, and the Pzeylanica extract and plumbagin may suppress its development through enhancing the growth of DP cells and down-regulating SRD5A2 expression in DP cells.