The Effect of Grapefruit Seed Extract, Molkosan, and Olive Leaf Extract on the Growth of Escherichia coli

The purpose of this experiment was to find which combination of the three chosen natural antibiotics (Grapefruit Seed Extract, Molkosan, and Olive Leaf Extract) was most effective against Escherichia coli, and just how effective it was.  In order to determine the efficiency of each of the combinations of natural antibiotics, three small pieces of a coffee filter were soaked in the solutions and placed on top of each of the eleven E. coli covered Petri dishes.  After incubating for forty-eight hours, the zones of inhibition were measured from each of the coffee filter pieces and a three-factor Design of Experiment was conducted to determine the efficiency of the solutions.  The results of this experiment show a broad range of zones of inhibition, ranging anywhere from zero millimeters to fourteen millimeters.  There were a few trials that did not produce any zones of inhibition at all, but overall the results were pretty scattered.

Research Done By:

Katherine Anoyiannakis
South Lake High School

Nicki Diehl
Centerline High School