Water-based extracts of Zizania latifolia inhibit Staphylococcus aureus infection through the induction of human beta-defensin 2 expression in HaCaT cells.

Zizania latifolia is a perennial herb belonging to the family Gramineae that has been used as a health food in Asian countries. In this study, we investigated the antimicrobial effect of Z. latifolia, which increased human beta-defensin 2 (hBD2) expression in HaCaT cells. hBD2 expression was further increased in cells treated with Z. latifolia extracts and subsequently infected with Staphylococcus aureus. Inversely, S. aureus infection decreased after treatment. The induction of hBD2 in HaCaT cells was mediated by the Toll-like receptor 2 (TLR2) signaling pathway, including the activation of extracellular signal-regulated kinase (ERK) and activator protein 1 (AP-1). Further study using siRNA revealed that hBD2 played an important role in the inhibition of S. aureus infection in HaCaT cells. Our data suggest that Z. latifolia extracts can be used as an antimicrobial ingredient for skin treatment formulas.