Antibacterial Activity of Long Chain Fatty Acids and the Reversal with Calcium, Magnesium, Ergocalciferol and Cholesterol

Abstract

SUMMARY: Screening tests indicated that Gram positive bacteria are inhibited by long chain fatty acids. No inhibition was demonstrated with Gram negative bacteria. The minimum inhibitory concentrations (MIC) for a series of the fatty acids are presented. Growth curves in the presence of linolenic acid showed increases in lag phase duration and calcium addition reversed this effect, thus indicating the arbitrary nature of the MIC values. Bactericidal studies showed lauric acid to be the most active saturated fatty acid but the activity was less than that of the C 18 unsaturated fatty acids. Oleic acid was more effective than elaidic acid. Calcium ions, cholesterol and ergocalciferol reversed the activities of lauric and linoleic acids but magnesium ions effectively counteracted lauric acid only. A physicochemical explanation for the relative activities has been attempted.