In vitro antibacterial activity of some aliphatic aldehydes from Olea europaea L.

In the present paper we report the 'in vitro' activity of eight aliphatic l ong-chain aldehydes from olive flavor (hexanal, nonanal, (E)-2-hexenal, (E) -2-eptenal, (E)-2-octenal, (E)-7-nonenal, (E)-2-decenal and (E,E)-2,4-decad ienal) against a number of standard and freshly isolated bacterial strains that may be causal agents of human intestinal and respiratory tract infecti ons. The saturated aldehydes characterized in the present study do not exhi bit significant antibacterial activity, while the cr,P-unsaturated aldehyde s have a broad antimicrobial spectrum and show similar activity against Gra m-positive and Gram-negative microorganisms. The effectiveness of the aldeh ydes under investigation seems to depend not only on the presence of the a, P-double bond, but also on the chain length from the enal group and on the microorganism tested. (C) 2001 Federation of European Microbiological Socie ties. Published by Elsevier Science B.V. All rights reserved.