Brandon Hooker
Honors Biology
October 18, 2001
INDEPENDENT RESEARCH PROJECT
IMPROVING THE ANTIBACTERIAL EFFECTS OF GARLIC
BACKGROUND REPORT
PURPOSE
For my research project I have chosen to use as my organism, the bacteria Escherichia coli and my variable is garlic. The purpose of my project is to determine if the antibacterial quality of a garlic plant can be increased by spraying additional garlic extract solution on the plant.
HYPOTHESIS
I believe that an enhanced solution of garlic can be an effective antibacterial agent.
THE VARIABLE
First, lets take a look at garlic and its many properties. Garlic has long been known as a healing herb. Many books such as Growing and Using The Healing Herbs by Gaea and Weiss and Garlic Natures Super Healer by Wilen and Wilen have been written about the healing power of garlic. The word garlic comes from the Anglo-Saxon word garleac, meaning spearleek. It is known as the spear plant because of its flat, pointed, spear like leaves. The Latin and botanical name for garlic is Allium sativum, a member of the lily family and related to onions, leeks, chives, scallions, and shallots. The word Allium comes from the Latin word olere, which means to smell.1
Garlic has been around since before recorded history. It is believed to have been grown first in China. For thousands of years is has been used for medicine in that country. Hieroglyphic records show that early Egyptians were aware of garlics antibiotic properties. According to the records, the laborers used large amounts of garlic while building the pyramids. Garlic has been known to guard against plagues and infectious diseases in China and throughout early Europe.2
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Garlic is often referred to as the poor mans penicillin. It is valued for its antibiotic, antiviral properties. High concentration of volatile oil, mucilage, and germanium make this one of the most effective antimicrobial plants available and a very good remedy for the common cold. It is one of the extensively researched and prescribed medicinal plants. Garlic is the only antibacterial that can actually kill infecting bacteria and at the same time protect the body from the infection that is causing the infection. It was interesting to learn that the most sensitive bacterium to garlic is the deadly Bacillus Anthracis that produces the poison Anthrax. Louis Pasteur, the forefather of antibacterial medicine, acknowledged garlic to be as effective as penicillin.3
Some reasons why people use the garlic herb are as follows:
Asthma
Athletes foot
Bacterial Infections
Constipation
Diabetes
Fungal Infections
Heavy-metal Poisoning
High blood pressure
High cholesterol
Wounds
To ward off evil spirits4
Some of the side effects of using garlic for medicinal purposes include dizziness, irritation of the mouth, throat, and stomach, nausea, skin rash or other allergic reactions including asthma, rash, or chest tightness, sweating and vomiting.5
Although garlic is one of the oldest and most revered herbal remedies, research is still incomplete. Scientists do not know if garlic really helps to lower cholesterol or reduce deaths from coronary artery disease. Other potential garlic uses, such as to lower blood pressure, calm an upset stomach or treat AIDS, have not been fully evaluated.
THE ORGANISM
Now lets look at the organism in my research. If we could see bacteria as well with the human eye as we can with the light microscope, much to our surprise, we would see bacteria everywhere. They grow in air, water, foods, and soil, as well as in plant and animal tissue. Any environment that can support life also supports bacteria.
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Bacteria affects man in various ways. Some cause human diseases that can easily be cured and some that we have not found a cure. Some cause plant diseases such as Dutch elm disease, corn smut and some rots of vegetables. On the other hand, most microorganisms do little or no harm and many are vital to life.
From my research, I found that bacteria is a convenient organism to study in genetics, physiology, biochemistry, and cytology because it grows very fast in the laboratory, it is easy to manipulate, and unlike mice or guinea pigs, it requires only a small amount
of laboratory space. As a prokaryotes, bacteria have the advantage of being relatively simple organisms. Therefore, for my project, I decided to use the bacteria Escherichia coli.
Escherichia coli, pronounced as eshrik koli is common bacterium that normally lives in the intestinal tracts of humans and animals, but can cause infection in other parts of the body such as in the urinary tract. It is the most common member of the genus Escherichia, named for Theodor Escherich, a German bacteriologist. Dr. Escherich showed that certain strains of the bacteria were responsible for infant diarrhea and gastroenteritis. At first the bacteria were called Bacterium coli, but the name was later changed to Escherichia coli to honor Dr. Escherich.6
Escherichia coli is also known as E coli. It is a Gram-negative, rod-shaped bacterium propelled by long, rapidly rotating flagella. For those of you like me who may not know what is meant by Gram-negative, let me explain that at this time. Scientists can determine different types of bacteria by their shapes, because some are spherical, some are rodlike, and by the way they stain with a particular chemical preparation called the Gram stain. This method was discovered by a man named Hans Christian Gram of Denmark in the late 1880s. He saw a color difference among bacteria that were contaminating a tissue preparation that he had stained with specific dyes in order to look for damages to the tissue. He noticed that in some samples, bacteria became colored a deep purple by the stain and kept this color during washing. These were called stain positive. Others lost the stain and were able to be counterstained with another, lighter dye and were colored pink; he called these stain negative. In a survey of all forms of bacteria, this simple staining process proved readily useful for identifying different bacteria and placing them into one of two groups. Today this method has become a major way to distinguish bacteria that are classified as either Gram-positive or Gram-negative.7
It is normal to find E coli is a parts of the mouth and gut and it helps protect the intestinal tract from bacterial infection, it aids in digestion and produces small amounts of vitamins B and K. The bacterium, which is also found in soil and water, is frequently
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used in laboratory research and it is said to be the most thoroughly studied life form. There is also a bad kind of E. coli as well. This strain of E. coli is known as
E. coli 0157:H7. This strain can cause hemorrhaging and the loss of blood. This is not the strain of E. coli that I used for my research!
E coli, like similar bacteria, grows when environmental conditions are favorable. If conditions are not suitable, growth occurs slowly or not at all. Some factors that affect growth are water, food, oxygen, pH, and temperature. In my experiment, I chose to use a three per cent glucose agar and an incubator to help grow my culture. I will explain this later in this report.
INTERACTION
Bacteria multiply by simple division, making a copy of their single chromosomes and giving it to their progeny (duplicate or twin). In a laboratory setting and with a nutrient rich culture, and with no predators, some types of bacteria can double their number in twenty minutes. In nature, it often takes days before this occurs because they may not have the proper energy producing materials, and they are in competition with other microorganisms. However, when placed in a three per cent glucose agar in a petri dish, and placed in an incubator for twenty-four hours, the E. coli grew very rapidly.
As I stated in the background information on garlic, garlic does appear to have some antibacterial properties. Therefore, in my research project, I did not just put garlic on the bacteria to see if it would kill it, but a solution of pulverized treated garlic leaves were applied to the bacteria culture in two of the four quadrants in the petri dish. Also, a solution of garlic leaves that were not treated with the garlic extract was also applied to two different quadrants in the bacteria culture. In some quadrants of the petri dish the garlic had a greater antibacterial effect than in the others. I will explain this further in this report.
MATERIALS NEEDED
2 garlic bulbs
Escherichia coli bacteria culture
20 plant containers
petri dish: Nutrient Agar (Peptic Digest of Gelatin, Beef Extract, Agar)
potting soil (enough to fill 20 plant containers)
sterile distilled water
masking tape
sterile swab
marking pen
warm tap water
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knife
isopropyl rubbing alcohol
food processor
dropper
cheesecloth
sterile filter paper disks
3 sterile glass containers
sterilized forceps
2 fine mist atomizers
incubator
thermometer
EXPERIMENT
Two groups of garlic plants were grown: experimental and control. The experimental plants had garlic extract added to their leaves by a foliar spray, while the control group was sprayed only with distilled water. The treated leaves were pulverized into a solution
whose antibacterial effects were analyzed when applied to the culture of Escherichia coli bacteria.
PROCEDURE
Part I
1. From one bulb of garlic get 20 cloves ( so they are the same genetically) and plant one clove into each of the 20 pots containing potting soil. Add the same amount of sterile water to each pot. Water plants as necessary.
2. Label ten of the plants Experimental and ten Control.
3. Grow the plants until the leaves are present and growth is about 6 inches ( 15 cm) in height.
Part II - Prepare the garlic extract solution.
1. Separate the cloves from the other garlic and peel them.
2. Pulverize the cloves in the food processor until they are nearly liquefied.
3. Filter the extract by squeezing as much of the liquid portion as possible through cheesecloth into one glass container.
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4. Combine one part garlic extract with one part distilled water to make up the garlic spray solution.
5. Fill one fine mist atomizer with the garlic solution. Spray each of the experimental plants with two sprays of the solution, and continue to do so every other day.
6. Fill the other fine mist atomizer with distilled water. Spray each of the control plants with two sprays of the water, and continue to do so every other day.
Part III- Prepare the culture dishes.
1. Transfer the Escherichia coli bacteria to the Nutrient Agar treated petri dish with a sterile swab.
2. Mark the bottom of the dish into four eual quadrants. Label two sections Experimental (A and B) and two Control (A and B).
Part IV - Prepare the test materials from each garlic plant.
1. Cut off the green leaves above the cloves.
2. Thoroughly wash the leaves under warm tap water to remove any residue of sprayed materials.
3. Pulverize the leaves of all the experimental plants in an alcohol-sterilized food processor, filter them through cheesecloth into another container, and with the dropper, add three drops of sterile distilled water. Repeat with the control plants. (Keep the mixtures in the sterile containers until they will be used for the four zones in the petri dish.)
Part V - Prepare the petri dish for the zone of inhibition study.
1. Soak two sterile filter paper disks in the garlic test solution made from the leaves of each garlic plant (as described in Part IV)
2. With the forceps, place these two disks onto the two experimental quadrants of the dish. Place two filter disks soaked in the control plant mixture on the two control quadrants of the dish.
3. Incubate the dish for 24 hours at 98.6 degrees Fahrenheit (37 degrees Celsius). Measure the diameter of the zones of inhibition in millimeters and record the data.
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CONCLUSION
My research supports my hypothesis to determine the antibacterial quality of a garlic plant can be increased by foliar applications of a garlic extract solution. It supports my hypothesis by showing limited growth of E.coli bacteria when treated with a foliar garlic solution. In quadrant EA growth extended to .3mm from the center point. While in the quadrant of CA growth was dominate at 3.5mm. In quadrant EB growth was measured to be 1.3 mm. Quadrant CB had extensive growth except for approximately .5 mm. The two experimental and control quadrants differed by greater colonies were formed on the control side of the petri disk. Large colonies were clumped together in the control group. Experimental colonies were dispersed towards the outer edge of the petri disk. There was no growth observed on the filter disks which were treated with the garlic solution. Growth was dominate on the control filter disk treated with distilled water. There was no growth observed closed to the vertex of the petri disk. The diameter of the average growth in the experimental groups was 24.13mm. The greatest antibacterial effect was seen in the quadrants of EA and EB. Yes, The antibacterial quality of the experimental plants were effected by the garlic spray. They were effected by a percentage of 284% bacteria growth retardation. Please sign my guestbook with any comments or reactions you have to my site. You can also contact me at Romeobsmooth@yahoo.com |
