The effects of some hair oils and unsaturated fatty acids on experimentally induced dermatophytosis

Antifungal activities of pelargonic and capric acid on Microsporum gypseum

The inhibitory effects of pelargonic and capric acid on Microsporum gypseum were examined. Solid and liquid Sabouraud glucose media containing different concentrations of pelargonic and capric acid were separately prepared and inoculated with the suspension of mycelium and spores of M. gypseum and incubated at 25 degrees C for 1 month. The culture media were examined periodically for fungal growth and the minimum inhibitory concentration (MIC) of each fatty acid was determined. The MIC for capric acid was 0.02 mg ml-1 and for pelargonic acid 0.04 mg ml-1 on solid media and 0.075 mg ml-1 for capric acid and 0.05 mg ml-1 for pelargonic acid in the liquid media.

Fungitoxicity of essential oils against dermatophytes

Sixteen essential oils were screened in vitro for their fungitoxicity against the two dermatophytes Trichophyton rubrum and Microsporum gypseum. Five oils (from Artemisia nelagrica, Caesulia axillaris, Chenopodium ambrosioides, Cymbopogon citratus and Mentha arvensis) showed strong activity and were assessed for their fungitoxicity against eight other dermatophytes as well as against Aspergillus fumigatus and Cladosporium trichoides. These five essential oils by formulation of ointments were able to cure experimental ringworm in guinea pigs within 7 to 12 days. Artemisia oil was found to be the most effective essential oil.

Fungitoxicity of fatty acids against dermatophytes

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 (C 11:0) is outstandingly most toxic in the C 7:0-C 18:0 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.

Inhibition of growth of dermatophytes by Indian hair oils

A survey on the use of hair oils for hair dressings by the Indian population revealed that mustard oil is preferred by males and coconut oil by females. Amla oil is used equally by both. These oils contain different percentages of various saturated and unsaturated fatty acids which largely determine their toxicity against dermatophytes. For Microsporum canis, M. gypseum and Trichophyton rubrum, amla oil was most toxic, followed by cantharidine and coconut oil, while Trichophyton mentagrophytes was most susceptible to coconut oil followed by amla and cantharidine oil. Mustard oil showed least toxicity to all four test species. The rarity of tinea capitis in India has been concluded to be due to the common use of hair oils by the Indian population.