1. The Effect of Oregano Oil on E. coli
Dominic Veltri
Grade 9
Pittsburgh Central Catholic High School

2. Purpose Problem Does Oregano Oil have antimicrobial activity?
Would the consumption of Oregano Oil alter human microflora populations?
To determine the effects of Oregano Oil on E. coli cell survivorship.

3. Oregano Oil Oregano Oil Made of natural components
Used to cook
Oil
Used for therapy or in some doses cooking
Made of natural components
No major side effects
Superior to antibiotics

4. Contents in Oregano Oil
Leaves and flowers of oregano
Naturally grown
Carvacrol
Thymol
Vitamins A, C, E
Iron
Copper
Calcium
Other natural ingredients

5. Microbial Flora
Present in the respiratory, urinary, and digestive tracts as well as on skin.
Consists of mostly bacteria, few protists and fungi.
Most are harmless, but some can cause diseases.
Influences human anatomy, physiology, and overall health

6. Escherichia coli Large and diverse group of gram (-) bacteria
Free living, symbionts, or pathogens
Most strains are not pathogenic
Common mammalian intestinal symbiont
Serve as a common prokaryotic cell model
Environmental prokaryotic model

7. Hypotheses
Null: The Oregano Oil will have no significant effect on the survivorship of E. coli cells.
Alternative: The Oregano Oil concentrations will have a significant negative effect on the survivorship of E. coli cells.

8. Materials Sterile test tubes
Latex Gloves
Laboratory Goggles
Micropipettes
Sidearm Flask
Sterile Filters
Incubator (37o C)
Vortex Machine
E. coli(DH5 Alpha)
LB Agar Plates(LB Media) (1% Tryptone, 0.5% Yeast extract, 1% NaCl)
Spread bars
Ethanol
Matches
Sterile Dilution Fluid (SDF) (100mM KH2PO4, 100mM K2HPO4, 10mM MgSO4, 1mM NaCl)
Oregano Oil
Bunsen Burner

9. Procedure
E. coli was grown until a density of 50 klett spectrophotometer density was reached. This was approximately 10^8 cells/mL.
The culture was diluted in sterile dilution fluid to a concentration of approximately 10^5 cells/mL.
Stocks of the variables were created.
The following ingredients were added to the tubes to create the desired concentrations:

10. Concentration Table 0% (Control) 0.10% 1% 10% E. coli 0.1 ml
0% (Control)
0.10% 1%
10%
E. coli
0.1 ml
Sterile Water
9.9 ml
9.89 ml
9.8 ml
8.9 ml
Oregano Oil
0 ml
0.01 ml
1 ml
Total Volume
10 ml

11. The tubes were allowed to incubate at room temperature for 15 minutes
The tubes were allowed to incubate at room temperature for 15 minutes. The tubes were mixed by inversion during this time period to promote oregano oil and cell contacts.
0.1mL of the aliquots were spread onto the agar plates.
7. The plates were then incubated for 24 hours and the resulting colonies were counted.

12. Oregano Oil’s Effect on E. coli
Alpha: 0.05
p-value: 8.54E-17

13. Dunnett's Test 0.1% 65.44 1% 67.45 10% 68.9 T-Critical= 3.5
Alpha= 0.05
Concentration
T- Value
Significance
0.1%
65.44
Significant 1%
67.45
10%
68.9

14. Conclusions
Oregano Oil has a very significant negative effect on E. coli
Oregano Oil does show signs of having antimicrobial activity
All doses of the variable show significant effect
Oregano Oil seems to reduce survivorship of microflora populations
Oregano Oil might be able to combat E. coli related illnesses

15. Limitations and Extensions
Vary exposures
Vary concentrations
Other cultures of bacteria
More replicates
Test with other spices
Narrow the range of concentrations
Isolate and test ingredients
One exposure time
Exposure to small amount of light
Wide range of variable concentrations
Multiple ingredients

16. Sources
Minton, Barbara L. "Oil of Oregano: A Powerhouse for the Alternative Medicine Cabinet." NaturalNews. N.p., n.d. Web. 07 Jan
"Oregano Oil Benefits Superior To Prescription Antibiotics." Dr. Axe. N.p., n.d. Web. 07 Jan

17. ANOVA Anova: Single Factor SUMMARY Groups Count Sum Average Variance
Column 1 4
1035
258.75
Column 2 56 14 10
Column 3 26
6.5
Column 4 3
0.75
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups
8.54E-17
Within Groups
334.5 12
27.875
Total
190696 15

18. Data Analysis: Single Factor ANOVA
Alpha: 0.05
P-value was 8.54E-17
Interpretation: Null is rejected, significant effect
Type of Effect: The Oregano Oil appeared to have killed E. coli colonies

19. Data Analysis: Dunnett's Test
.1% Concentration: Significant Effect
1% Concentration: Significant Effect
10% Concentration: Significant Effect