The relationship between the chemical structure of fatty acids and their mycobactericidal activity.
The bactericidal activity of long-chain fatty acids on mycobacteria was examined by exposing the organisms to these acids at 0.04 mM in 0.05 M acetate buffer (pH 5.6). The lethal effect of saturated fatty acids was related to the chain-length of hydrocarbon, C14:0 being the strongest in the activity and longer and shorter fatty acids being less active. Unsaturation, isomerism and the presence of alpha-hydroxy group were found to be other factors governing the activity. The lethal effect was greater in the order of C18:3 greater than C18:2 greater than C18:1(cis) greater than C18:1(trans) greater than alpha-OH C18:0 greater than C18:0. C20:4 was placed between C18:3 and C18:2 in this respect. Esterification of C14:0,  C18:1 and C20:4 to methyl esters and cholesteryl esters abolished completely the bactericidal activity of these acids, suggesting the requirement of carboxyl group for the activity. The relationship between the fatty acid structure and the lethal effect was discussed in reference to these observations.
D055598:Chemical Phenomena; D002621:Chemistry; D002788:Cholesterol Esters / Q000494:pharmacology; D003470:Culture Media; D005227:Fatty Acids / Q000032:analysis / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D006838:Hydrocarbons / Q000494:pharmacology; D008738:Methyl Ethers / Q000494:pharmacology; D009163:Mycobacterium bovis / Q000187:drug effects*; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D014774:Virulence / Q000187:drug effects
D002788:Cholesterol Esters; D003470:Culture Media; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D006838:Hydrocarbons; D008738:Methyl Ethers