Fungitoxicity of fatty acids against dermatophytes

Abstract

Summary. Ten saturated and three unsaturated fatty acids over a wide spectrum of their carbon chain length were tested for their fungitoxicity against five dermatophytes. The experiments showed that short chain saturated fatty acids (C 7:0‐C 11:0) are more toxic to dermatophytes than long chain ones (> C 12:0). The antifungal activity decreases with increasing carbon chain length in the even‐numbered carbon chain series. Odd‐numbered carbon fatty acids show irregularities in these respects. Undecanoic acid (C11:0) is outstandingly most toxic in the C7:0‐C18:0 series. Polyunsaturated fatty acids are more toxic than their corresponding saturated acids. The per cent growth inhibition decreased from day 4 to day 12 at all concentrations suggesting the degradation and/or utilization of fatty acids by the fungi during the observation period. The results are discussed on the background of the biochemistry of fatty acids. Zusammenfassung. Zehn gesättigte und drei ungesättigte Fettsäuren unterschiedlicher Koh‐lenstoflkettenlänge wurden auf ihre Fungitoxizität gegen fünf Dermatophyten geprüft. Die Studie führte zu folgenden Ergebnissen: Kurzkettige gesättigte Fettsäuren (C7: 0‐C11:0) sind toxi‐scher als langkettige (>C12:0). Die antimyze‐tische Aktivität sinkt mit steigender Kettenlänge in der geradzahligen C‐Kettenserie, während ungeradzahlige Fettsäuren Irregularitäten zeigen. Undekanonsäure (C11:0) ist die am starksten toxische in der C7:0‐C18: O‐Reihe. Mehrfach ungesättigte Fettsäuren sind toxischer als ihre korrespondierenden gesättigten Fettsäuren. Der Prozentsatz der Wachstumshemmung nahm vom Bebrütungstag 4 bis Tag 12 bei allen Konzentrationen ab. Dies spricht für einen Abbau bzw. eine Nutzung der Fettsäuren durch die Pilze während der Beobachtungsdauer. Die Befunde werden auf dem Hintergrund der Biochemie der Fettsäuren diskutiert.

In vitro susceptibility to antimycotic drug undecanoic acid, a medium-chain fatty acid, is nutrient-dependent in the dermatophyte Trichophyton rubrum

“…Undecanoic acid (UDA), a medium-chain fatty acid, is the most fungitoxic in the C 7:0 -C 18:0 series, which has been used in the treatment of dermatophytoses in humans (Ammendola et al 2009;Garg and Muller 1993). Trichophyton rubrum is a cosmopolitan and anthropophilic fungus able to invade keratinized tissue, causing infection in human skin and nails.…”

10-Undecanhydroxamic acid, a hydroxamate derivative of the undecanoic acid, has strong antimicrobial activity through a mechanism that limits iron availability

“…In this work we have explored the possibility to increase the efficacy and spectrum of activity of an antimicrobial fatty acid by the introduction of an iron‐chelating chemical group potentially able to interfere with iron homeostasis. The effectiveness of fatty acids and their derivatives as antimicrobial agents against bacteria and fungi has been known for a long time (Kabara et al ., 1972; Garg & Müller, 1993), and a large number of studies have established that long‐chain unsaturated fatty acids play a role in natural host defence against pathogens in human milk, skin and mucosal secretions (Thormar & Hilmarsson, 2007). Even though the mechanisms by which fatty acids inhibit microbial growth are poorly understood, these compounds are already employed in antifungal formulations for the treatment of mycotic infections (i.e.…”

Inhibition of growth of dermatophytes by Indian hair oils

“…Higher toxicity of amla and cantharidine oils over the other two is due to their higher contents of unsaturated C 18 fatty acids: unsaturated fatty acids were more toxic than saturated ones [13]. O n the other hand the specificity of coconut oil to T. mentagrophytes may possibly be due to its high contents of lauric and myristic acids as these two fatty acids showed higher toxicity to the fungus in our growth inhibition experiments [13]. Long chain fatty acids were found to be least toxic [13], which might be responsible for the lowest toxicity found with mustard oil which constituted > 55% > C 20 fatty acids.…”

“…The oil was emulsified aseptically in the liquefied medium and the mixture distributed into the Petri dishes as described previously [13]. A disc of 5 mm diameter for each test species, obtained from the periphery of 12-d-old culture, was inoculated in the centre of each Petri dish.…”