FUNGICIDAL ACTION OF CAPRYLIC ACID FOR CANDIDA ALBICANS

I. QUANTITATIVE OBSERVATION OF THE ACTION

Abstract

The anti-fungal property of caprylic acid on C. albicans, particularly its fungicidal activity, has been studied by colony count using an ordinary plating method and a modification of an electrophoretic method.
Caprylic acid exhibits the most remarkable fungistatic and fungicidal properties of all the normal saturated fatty acids with even numbered carbon atoms studied. The fungicidal activity of caprylic acid depends upon the concentration of the acid, the period of contact and the pH of the media.
The fungicidal action of caprylic acid is considerably reduced by the simultaneous addition of several agents such as serum, carbohydrate, and polyhydric alcohol. This protective effect, however, disappears after the contact with the acid for 3 hr. Furthermore, when the cells of the organism are once exposed to caprylic acid, its fungicidal activity is not affected by washing them with distilled water. These quantitative and biochemical facts suggest that the adsorption of caprylic acid to the yeast cells must be extremely strong and specific.