Methods and Materials
Main Experimental Procedures:
------------------------------- 1) Extraction of herbs -----------------------------
------------------------------- 2) Preparation of Agar ----------------------------
------------------------------- 3) Cultivation of Bacteria --------------------------
------------------------------- 4) Disk Diffusion Assay ---------------------------
Safety Measures:
- Make sure all equipment is washed cleanly with de-ionised-/distilled water
- Wear Gloves throughout the process
- When stirring the mixture until a homogeneous mixture is reached. The solution will be a transparent brown colour.
- Before pouring agar solution into the agar plate, ensure that the solution is cool enough. Water-bath Method may be used.
Preparation of Agar:
Bacteria thrive in agar as the nutrient agar serves as the food for the bacteria. We ensured that the agar solution was clear (not cloudy) before it was poured into the Petri dishes.
Cultivation of Bacteria:
For our project, we worked on saliva from both children and adults. This would ensure an accurate test result. To obtain the saliva, the person spit some saliva on a Petri dish, where we scraped if off using a disposable inoculating loop. The saliva was then streaked on the agar plates made.
Disk Diffusion Assay:
To start, we used the plate, which had cultured bacteria. Then, we made regular sizes of filter paper (about the size of a dime) saturated with different extracts in the centre of the bacteria plates. After which, we sealed the bacteria plate with Para Film and incubated it at 37°C for 24 hours for the effect of the herbs to take place.
Lastly, if a clear ring is found surrounding the filter paper, it indicates that the substance used is able to counter the bacteria. This ring is known as the “Zone Of Inhibition”.
This would show if the bacteria is immune against the solvent.
Materials Used:
Nutrient Agar Powder, Beakers, Test Tubes, Wire Gauze, Syringes, De-ionised water, Petri Dishes, Para film, Spatulas, Filter Papers, Herbs, Honey, Baking Soda, Apple Cider Vinegar, Mortar and Pestle, Bunsen Burners, Forceps, Inoculating Loops, Self-Produced Agar Plates, Bacteria-Cultured Plates for the Disk Diffusion Assay Process.
Gloves, Masks and Alcohol have been used to prevent us from being infected by the bacteria streaked.
Results:
As the agar plates showed minimal zones of inhibition, we have decided to collect the results by using observation.
Results:
As the agar plates showed minimal zones of inhibition, we have decided to collect the results by using observation.
|
Solvent Used | Growth of Bacteria (Disk Diffusion Assay carried out for 24 hours for solvents) |
| De-Ionized Water | Large amount of bacteria |
| Listerine | Less bacteria observed |
| Cardamom | Small zone of inhibition |
| Parsley | Less bacteria observed |
| Cloves | Regular zone of inhibition |
| Rosemary | Less bacteria observed |
| Grapefruit Seeds | Agar plate is relatively clear |
| Sage | Dead bacteria around solvent |
| Eucalyptus | Dead bacteria around agar plate |
| Manuka Honey | Less bacteria observed |
| Baking Soda | Agar Plate is relatively clear |
| Apple Cider Vinegar | Agar plate is quite clear |
Here are some of the pictures of our results: (Click to enlarge)
