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The Effects of Plant Extracts on Bacteria Growth

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Bethany Castro

on 12 December 2013

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Transcript of The Effects of Plant Extracts on Bacteria Growth

The Effects of Plant Extracts on Bacteria Growth
Materials & Methods
Bethany Castro and Alysse Nakasato
Pre-AP Chemistry
Period 4

- Bacteria: Prokaryote cell in Monera kingdom that grows rapidly and live together in groups called colonies
-Eucalyptus leaves
-Aloe leaves
-Alfalfa plant
-Cutting board
-Petri dishes (10)
-Distilled water
-Paper Dots
-Cheese cloth
- Water from Pouhala marsh (bacteria source)
-Chemical antibacterials: Agent that inhibits bacteria growth made from synthetic materials
-Antimicrobial plant: Plant with properties that are destructive/inhibit the growth of microorganisms
-Eucalyptus Globulus (Eucalyptus), Aloe Barbadensis (Aloe Vera), and Medicago Sativa (Alfalfa)
To investigate the effects of plant extracts on the growth of bacteria & trying to discover a more efficient and natural way to inhibit the growth of bacteria
Research Question

Will the different plant extracts affect the amount of bacteria present?
Eucalyptus will inhibit the most bacteria growth
If we add aloe vera, eucalyptus, and alfalfa extracts to different petri dishes of bacteria, then the petri dishes with the eucalyptus extracts will have the least amount of bacteria left because eucalyptus has the most antimicrobial properties. Eucalyptus is also known to produces at least six different natural antiseptics, which are able to kill mold, bacteria, fungus, and viruses.
Origin of the bacteria, the environment that the bacteria is in, the origin of the plant extracts, the time period the bacteria is incubated, the temperature that the bacteria is incubated in, and the time increments the data is collected

Independent Variable
Different plant extracts (Aloe vera, eucalyptus, and alfalfa)
Dependent Variable
Amount of bacteria left on the petri dish after the experiment is conducted
Control Groups
Experimental Groups
Negative control petri dishes full of bacteria with a paper dot soaked in water, and a positive control petri dishes with lysol added.
Different petri dishes full of bacteria with cultured paper dots soaked in aloe vera extract, eucalyptus extract, and alfalfa extract.
Number of Trials
Subject to be tested
-Six trials
-5 test subjects each
-30 data points
Bacteria (diameter of inhibition)
Data Analysis
Problems/Possible Errors
Hypothesis supported
Future Works
"Alfalfa: MedlinePlus Supplements." Alfalfa. 2013. U.S. National Library of Medicine. 13 Sept. 2013 <http://www.nlm.nih.gov/medlineplus/druginfo/natural/19.html>.
"Alfalfa." The Longest Life. N.p., n.d. Web. 12 Sept. 2013.
"Aloe Vera Information From WebMD." Vitamins and supplements lifestyle guide. 2013.
WebMD. 13 Sept. 2013
"Aloe Vera Plant." Panoramio. N.p., n.d. Web. 12 Sept. 2013.

-Original source of bacteria didn't grow, so we had to find an alternative source
-Should have used a different method to put the extracts on the petri dishes, other than using the paper dot method
-Put the extracts on the petri dish using a pipet, instead of soaking a dot in the extract
-More trials
Our hypothesis was supported because the eucalyptus proved to inhibit the growth of bacteria more than the other test groups
In the future, we plan to use a wider variety of plant extracts, or use different things common items with antimicrobial properties like spices (cinnamon, clove, etc...)
Run extracts through cheese cloth
Blend leaves with the appropriate amount of water
Autoclave all items being used
Swab petri dishes with bacteria
Place agar into petri dishes and wait for it to solidify
Soak paper dots in the extracts for a minute
Collect data and repeat each step for every trial
Place soaked dots in petri dishes and incubate
Chop up leaves of plants
Results Cont.
-Eucalyptus had biggest inhibition ring after 1 day
-All experimental groups had ring of killed bacteria
-All three plants contain antimicrobial properties
-Water had no antimicrobial properties
-All three of the plants inhibited the growth of the bacteria more than the lysol did
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