The antifungal activity of various concentrations of omeprazole (0.1mg/ml,
0.25mg/ml, 0.5mg/ml, 1mg/ml, 2.5mg/ml, 5mg/ml, 10mg/ml, and 20mg/ml) were
studied in different pH media (5 and 7) against Aspergillus niger, and
Trichophyton urbrum.The laboratory results showed the inhibitory effect of
omeprazole against Aspergillus niger at pH 7 and starting from concentration
10mg/ml, and against Trichophyton urbrum starting from 1mg/ml. While its
antifungal activity in a medium with pH 5 was extended to reach the lower
concentrations 0.25mg/ml against selected fungi. Accordingly, omeprazole is pH
dependent.It seems that omeprazole changed cell membrane potential of selected
fungal species which led to depolarization of cell membrane as a result of
inhibition of the proton pump mechanism. This made the fungal cell not willing to
uptake chemicals needed for living.Keywords: omeprazole, proton pump inhibitor,
antifungal agent, Aspergillus niger, and Trichophyton urbrum.