Isolation of Indole-3-Aldehyde As a Growth Inhibitor of Legionella pneumophila from Diaion HP-20 Resins Used to Culture the Bacteria

Abstract

The addition of Diaion HP-20 resin to a medium can enhance the growth of the Legionella species. We recently reported that elemental sulfur was isolated as a growth-inhibiting substance produced endogenously by Legionella pneumophila from the methanol extracts of the resins used to culture the bacteria. In this study, we attempted to isolate other growth-inhibiting substances involved in the extracts, and identified indole-3-aldehyde as one of the inhibitors. The compound was involved in the medium as a constituent and it weakly inhibited the growth of L. pneumophila, indicating that the compound partly contributes to inhibit the bacterial growth when cultured without HP-20 resins. © 2004, The Society for Antibacterial and Antifungal Agents, Japan. All rights reserved.