Interaction of an odorant lactone with model phospholipid bilayers and its strong fluidizing action in yeast membrane

Some odorant lactones are naturally present in fruits or in fermented products; they can also be used as food additives and can be produced by microorganisms at the industrial scale by biotechnological processes. γ-Decalactone was previously shown to have antimicrobial properties. We determined by infrared spectroscopy measurements that this compound rapidly diffused into model phospholipid bilayers (within 2 min), modifying the general physical state of a dimyristoyl-l-α-phosphatidylcholine (DMPC) film. In vivo, the lactone strongly increased membrane fluidity in the model yeast Yarrowia lipolytica, as evaluated by fluorescence anisotropy measurements. This effect was more important than that of benzyl alcohol, which is known as a fluidizing agent in living cells, and may explain the toxic action of γ-decalactone in microorganisms.