Bis- and Tris- Indole Alkaloids from Edwardsiella tarda

Abstract:

In order to investigate the potential of pathogens for drug discovery, the secondary metabolites of Edwardsiella tarda were studied. As a result, five indole alkaloids were isolated by column chromatography over silica gel, Sephadex LH-20, and HPLC preparation. By spectroscopic analysis, their structures were identified as bis(1H-indol-3-yl)phenylmethane (1), 1,1-bis(1H-indol- 3-yl)-2-phenylethane (2), (2S)-3,3-bis(1H-indol-3-yl)propane-1,2-diol (3), 1H,1￠H,1￠￠H-3,2￠:3￠,3￠￠- terindole (4), and (3,2￠:2￠,3￠￠-terindolin)-3￠-one (5), respectively. To the best our knowledge, compounds 1, 2 and 4 were isolated as the natural products for the first time. Both compounds 1 and 3 showed weak anti-bacterial activity against Clostridium perfringens with MIC values of 0.125 g/L.

Key words:Edwardsiella tarda, Bis- and tris- indole alkaloids, Anti-bacterial activity