Bleaching of Serratia marcescens by some coumarins: a spectrophotometric study.

Recently, we reported that umbelliprenin inhibits the red pigment production in Serratia marcescens . In this current investigation the bleaching effect of the umbelliprenin was further studied using the spectrophotometric method, and its IC 50 was calculated. Also in this study the effect of the other coumarins extracted from Ferula persica roots were evaluated for depigmentation of Serratia marcescens . None of these compounds appeared to have a bleaching effect against a test strain at certain concentrations. Comparing the structures of the different coumarins showed that the linear sesquiterpene part of the umbelliprenin structure may be essential for the bleaching effect of S. marcescens . ((c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).