A TLC bioautographic assay for the detection of nitrofurantoin resistance reversal compound.

A simple TLC bioautographic method was developed for detection of antibiotic resistance reversal agents. In this study, the retention factor values of the components of some essential oils not previously shown to have any antibacterial activity were evaluated on nitrofurantoin supplemented agar media. The active component of Artemisia annua, Artemisia dracunculus and Eucalyptus globulus essential oils was piperitone which increased the antibacterial activity of nitrofurantoin against Enterobacter cloacae. Piperitone was not detected in the essential oil of Humulus lupulus and we could not observe any clear areas in this bioautographic method.