Post on 04-Apr-2018
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By Alec Bukuhan and Xandro Hizon of S2015
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Significance
We are testing Citronella grass because it is relativelycommon in the Philippines, as well as other parts of
the world, and it is already being commonly used in
things like insect repellant, scented candles and the
like, although it is not well known as an antibacterialagent. This is why we are testing this plant if
proven to have antibacterial qualities; it will be a
great, inexpensive, natural substitute for chemical
antibacterials or more expensive ones. Also, the
already well-established industry of citronella
products will make it easier for manufacturers to
begin making and producing it as an antibacterial.
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Objectives
To extract chemicals in citronella
To properly test the presence of antibacterial
properties
To compare the extract of citronella to alcoholin its effectiveness as an antibacterial agent
To carefully count the number of bacteria in
the agar plates
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Variable
Independent Variable
Presence of the extract of Citronella grass
Cymbopogon nardus
Dependent Variable Number of bacteria Staphylococcusaureus
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Problem
Declarative Form: The researchers
which to find out whether applying
Citronella grass extract to bacteria will
result in the reduction of the bacteriapresent, or in other words, test whether
Citronella grass extract exhibits
antibacterial properties. Question Form: Does Citronella grass
extract exhibit antibacterial properties?
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Hypothesis
If the extract is applied, then there
will be less bacteria present in the
end.
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Scope and Delimitations
The experiment will focus only on testingCitronella Grass or Cymbopogon nardus, andno other plant species. The researchers will usethe colony count test. We used the
Staphylococcus aureus bacteria since it isfound on surfaces and is commonly used to testdisinfectants Lastly, we are testing theCitronella grass extract on its antibacterialproperties, but more on its function as adisinfectant or antiseptic and not as anantibiotic, although these all technically fallunder antibacterial.
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Materials
ME-012 VORTEX MIXER (TYPE 37600)AND THE 0.5-5ML TRANSFERPETTE S
ME-043 CLYDE APAC BIOSAFETY CABINET CLASS II
Alchohol lamp
Incubator
Sterile Microbial Content Test Agar (a litre) Beakers for mixing
100mL capped bottles x8
Petri Dishes x30
Distilled water (1 litre)
Phosphate buffer (540mL)
Already diluted Staphylococcusaureus
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Procedure
1. First, the materials were prepared, including the bacteria cultureStaphylococcusaureusto be used for testing that was already diluted
to the 10^-4 and 10^-5 of the original culture. Note that these two
dilutions are to be used separately.
2. Next, the 10% citronella and the 1% citronella disinfectants were
made by mixing 10mL of the extract to 100mL of water and 1mL of the
extract to 100mL of water respectively. Also, Tween 80 was added to
make the citronella oil dilute.
3. Next, 1mL of the 10^-4 test inoculum was added to the 100mL of
disinfectant, was mixed well and left for 5 minutes. This was done for
both the 10% and 1% citronella disinfectants.
4. Next, 10mL out of the 100mL of the disinfectant with bacteria was putinto 90mL of a Phosphate buffer and mixed well. Again, this was done
for both percentages.
5. Finally, 1mL of that final concoction was plated, (5 plates for each
percentage) and agar was poured into the plates.
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6. Steps 3-5 were done again, except with
the 70% alchohol as a comparison.7. Steps 1-5 were done again, except with
the 10^-5 dilution.
8. The control was made by plating 1mL of
each dilution untreated and also coveredin agar.
9. The plates were incubated at 30-35degrees C for 1-2 days.
10. Once the time elapsed, the colonies werecounted and the results, recorded andcompared.
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Control Groups
Standard TNTC
TNTC
TNTC
TNTC
TNTC
(272,299)
(27,24)
(3,6) (2,0) (0,0)
Positive
Control
- - - (45,
38)
(5,3) - - - - -
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The Effects of the Presence of Citronella Extract to the
Number of Bacteria Staphylococcusaureus
Trial 1 2 3 4 5 Average
70%
Alcohol
0 0 0 0 0 0
1%Citronella
Extract
Solution
1 8 14 7 13 8.6
10%
CitronellaExtract
Solution
3 0 3 1 1 1.6
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The Effects of the Presence of Citronella Extract to the
Number of Bacteria Staphylococcusaureus
Trial 1 2 3 4 5 Average
70%
Alcohol
0 0 0 0 0 0
1%Citronella
Extract
Solution
4 1 2 2 2 2.2
10%
CitronellaExtract
Solution
1 0 0 0 0 0.2
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Analysis
Our data showed that the 1% Citronella Extract solution killsaround 58.64% of the bacteria while the 10% Citronella
Solution kills around 95.57%. This shows that the Citronella
extract does in fact possess some antibacterial properties, more
specifically, disinfecting properties since we used a typical
surface bacteria (Staphylococcus aureus) in our testing. Thismeans that Citronella extract has the potential of being used in
disinfectant products such as what we used is the control set-
up- alcohol. However, In our data, the dilution of 10^-5 yielded
less bacteria than we hoped and planned for, making the results
of that group less definitive, but still usable. The 10^-4 dilutiongroup yielded more bacteria and showed us more dependable
data.
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Conclusion
Citronella grass Cymbopogon nardusdemonstrates antibacterial properties.
It might be as effective as alcohol since
the solution is still only a 10%Citronella solution. In the data, The
10% solution almost killed everything
in both the 10-4
and 10-5
standards
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Recommendation
Include the exposure time of thebacteria to the disinfectant as a variable
Test more standards of dilution (the
10^-4 etc.) to get more definitiveresults
Test the Citronella extract against more
species of bacteria
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Use other methods of testing the extract
other than the colony-counting methodwe used.
Test other concentrations of the extract
in the disinfectant.
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Bibliography
http://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.html
http://citronella-oil.blogspot.com/
http://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspx
http://www.foodsafety.gov/poisoning/cau
ses/bacteriaviruses/staphylococcus/index.html Hizon Laboratory
http://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://citronella-oil.blogspot.com/http://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.foodsafety.gov/poisoning/causes/bacteriaviruses/staphylococcus/index.htmlhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://www.news-medical.net/health/What-is-Staphylococcus-Aureus.aspxhttp://citronella-oil.blogspot.com/http://citronella-oil.blogspot.com/http://citronella-oil.blogspot.com/http://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.htmlhttp://ph.news.yahoo.com/blogs/the-inbox/citronella-grass-boon-farmers-environment-032659995.html