The influence of naphthenic acids and their fractions onto cell membrane permeability

The influence of naphthenic acids (NAs) mixture and their narrow fractions (called NA pH 4, pH 8 and pH 10) onto permeability of beetroot cell membrane is examined. The results showed that the effect depends on treatment duration, concentration and NAs structure. Longer treatment of plant cell membranes with sodium naphthenate (Na-naph) resulted in the increase of membrane permeability (e.g. 4-hour treatment with Na-naph (C=100 μmol L-1) increased membrane permeability about 3 times, while prolongation of treatment to 24 hour resulted in the 18 times increasing of the effect). NAs in the concentration range from 0.1 to 10 μmol L-1 does not change membrane permeability, while membrane permeability is increasing linearly with concentration increasing from 10-100 μmol L-1. The strongest effect expressed fraction pH 8, where bi- and tricyclic carboxylic acids are the most abundant. These structures are predominant in the total NAs mixture as well. Thereby could be explained their closest, but a little bit weaker effect, comparing to NAs present in fraction pH 8. The effect of NAs onto beetroot cell membrane is between the effects of anionic (SDS and LS) and non-ionic surfactants (Triton X-100). [Projekat Ministarstva nauke Republike Srbije, br. 172006. i br. TR31036]