Fatty Acids and Derivatives as Antimicrobial Agents

Abstract

The structural relationships of 30 straight-chain fatty acids and derivatives and their bactericidal properties were studied with 8 gram-negative and 12 grampositive organisms. Chain length, unsaturation (cis, trans), and functional group were all variables considered in this study. Our data indicate that C12 (lauric acid) is the most inhibitory saturated fatty acid against gram-positive organisms. Monoenoic acid (C18:l) was more inhibitory than saturated fatty acid, but was less active than dienoic derivatives (C182). Other unsaturated compounds were less acti-e than C182. Alcohols and glyceryl esters were active only against gram-positive organisms. In general, esterification of the carboxyl group led to a compound which was less active; monoglycerides were the sole exception. Amine derivatives, contrary to results with fatty acids, esters, and amides, showed activity against both gram-positive and gram-negative organisms.The antifungal and bactericidal properties of fatty acids are well known (5,12,22 Standard solutions (suspensions) at 1,000 ,ug/ml were twofold serially diluted with additional broth to a concentration of 125 ,ug/ml. A 4-ml amount of each dilution was then quickly, and with constant agitation, dispensed into appropriately labeled screw-capped glass tubes (16 by 125 mm). The tubes were sterilized with steam at 15 psi for 15 min. After sterilization, all tubes were cooled and incubated overnight at 35 C to insure sterility.If a compound was found to have inhibitory activity at concentrations lower than 125 ,g/ml, the testing was continued to a final concentration of 1.5 ,ug/ml for each active compound. All compounds were compared on a molar (micromoles/milliliter) rather than on a mass basis.

Glycerol Monolaurate Inhibits the Effects of Gram-Positive Select Agents on Eukaryotic Cells

“…GML is generally recognized as safe by the Food and Drug Administration for oral use because of past safety experience and is used as an additive to foods and cosmetics (19)(20)(21). GML is a surfactant comprised of glycerol and a 12 carbon fatty acid which is found naturally in human breast milk.…”

Sensitivity of staphylococci to fatty acids: novel inactivation of linolenic acid by serum

“…The inhibitory capacity might increase with the degree of unsaturation so that linolenic acid (which contains three double bonds) is the most inhibitory, linoleic (two double bonds) less so, with oleic (one double bond) and stearic (saturated) with insignificant antibacterial properties (Butcher, King and Dyke, 1976; KO, Heczko and Pulverer, 1978;Heczko, et al, 1979). However, linoleic acid can be more inhibitory to bacteria than linolenic (Bayliss, 1936;Fuller and Moore, 1967;Kabara et al (1972). The amount of free linoleic acid in normal skin exceeds that of linolenic acid (Wilkinson, 1972) so the precise significance of the presence of these and other acids is not clear.…”

Stable Concentrated Emulsions of the 1-Monoglyceride of Capric Acid (Monocaprin) with Microbicidal Activities against the Food-Borne Bacteria Campylobacter jejuni , Salmonella spp., and Escherichia coli

“…The microbicidal activities of lipids, particularly fatty acids and their 1-monoglycerides, have been tested against a number of bacterial species (8,14,15). More recently, bacteria such as Chlamydia trachomatis, Neisseria gonorrhoeae, Helicobacter pylori, Staphylococcus aureus, and streptococci of groups A and B were found to be rapidly killed by fatty acids and monoglycerides, although with a considerable difference in activity profiles (3,4,5,6).…”