Screening and characterization of active herbal extracts and components stimulating human beta defensing (hBD-3) expression from HaCaT cells

Abstract

Various antimicrobial peptides play important roles as barrier function against bacteria and as innate host immunity. Several major studies have shown reduced expression of human beta defensin (hBD-3) in atopic dermatitis, highlighting the importance of hBD-3. In course of our search for hBD-3 stimulatory herbal souces and biologically active components, we screened 400 oriental herbal extracts using a range of real-time PCRs in the human keratinocyte cell line, HaCaT cells. We found that only six herbal extracts from Rubi Fructus, Lysimachiae Foenumgraeci Herba, Ailanthi Radicis Cortex, Galla Rhois, Peucedani Radix and Albizziae Cortex showed significant hBD-3 stimulatory effects. Although it did not have antimicrobial activity due to the low cytotoxic effect of Ailanthi Radicis Cortex, we further identified hBD-3-stimulating active ingredient in this extract. Efficient activity profiling based on HPLC was performed to identify active components from the extract of Ailanthi Radicis Cortex, and an hBD-3 stimulatory quassinoid component, ailanthone was identified by spectroscopic analysis. The present results show that Ailanthi Radicis Cortex and ailanthone have the potential to stimulate the expression of hBD-3 in HaCaT cells. These findings suggest new possibilities to control bacterial over-colonization found in atopic dermatitis using hBD-3 stimulatory herbal sources and ailanthone.