Antimicrobial Properties of Herbs Biology Department, PSU Linda & Reed

Some Background Information  It is generally accepted that many herbs have antimicrobial properties, but how strong are they and in what herbs?  This could be useful as an alternative to antibiotics and to prevent superbugs.  Three common herbs (sage, rosemary, and oregano) were used along with E. coli and S. epidermidis.  We hypothesized that at least one of the herbs would have a zone of inhibition on either bacteria and show that it therefore had antimicrobial properties. Sage Rosemary Oregano

What Was Done  The herbs were measured out into 0.5 tsp. and mixed with 3 mL. of sterile water into test tubes. These were then heated for 15 seconds over the Bunsen burner, wrapped with parafilm, and left to sit for 5 days.  A lawn of bacteria was divided into four quadrants for the sage, rosemary, oregano, and sterile water for a negative control and labelled as such.  S. epidermis -> Gram negative E. coli -> Gram positive  Using tweezers sterilized via Bunsen burner, sterile disks were saturated in the herbs and water then laid on the corresponding quadrant.

Tubes wrapped in parafilm Petri dishes in quadrants and labelled.

Sterile Disks Ta- da!!!

Results  Our hypothesis was that at least one of the herbs would have a zone of inhibition on either bacteria and show that it therefore had antimicrobial properties.  Sadly, we were wrong  None of the herbs had any zone of inhibition.

What we were hoping for….. What we got.

 While our hypothesis was incorrect, that does not mean our theory was incorrect  Ethanol  Not concentrated enough  Because we used two trials, that led to a decrease in false negatives/positive  Sterile water  This could still be further researched  Superbugs  Healthier eating  Cleaning

Thank You For Your Time!