CEL70:Notebook/BL2104 - 2009 - Group Project

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=Antimicrobial effectiveness of Allium sativum preparation=

Introduction
The increased misuse of antibiotics has given rise to resistance in bacteria (Hawkey 2008), an evolutionary mechanism attributable to natural selection. Improved clinical procedures can decrease the occurrence of multiple drug-resistant microbes, as has been demonstrated with methicillin resistant staphylococcus aureus (MRSA) in American hospitals (Burton 2009), but since it cannot eliminate the problem alternative antimicrobial treatments have to be developed. It is apparently more difficult for bacteria to become resistant to natural biocides, therefore increasing the use of such is considered to be a sensible approach to preventing further resistant strains arising as well as treating those already established.

Background
A natural biocide such as allicin (Cavallito 1944), has been demonstrated to exhibit significant antimicrobial properties (Holzgartner1992), a result mainly attributed to thiol-modifying and antioxidant abilities (Cavallito 1944, Wills 1956, Prasad 1998, Rabinkov 1998). Allicin is chemically unstable and reactive, it is hence not found in intact Allium sativum. Only damaging the compartments associates the non proteinogenic amino acid alliin and its enzyme allinase giving rise to the desired biologically active metabolite (Stoll1951).

Ever since the discovery of allicin’s antimicrobial effects, allicin or allicin derivatives have been marketed in health shops as ‘health promoters’. Due to allicin’s instability, the integrity of such preparations is questionable.

Objective
The objective of this experiment is to demonstrate the effectiveness of commercially available allicin preparations (which is found in garlic) on the skin bacteria Staphylococcus aureus. We expect a minor effect or no effect at all on bacterial growth due to allicin's chemical instability.

MATERIALS

 * HEPES buffer
 * Staph. aureus culture
 * Distilled water
 * Glucose based agar
 * Glass spreader
 * Ethanol 70%
 * commercially available Allium sativum health product
 * Ph meter
 * HCl (aq) 1M
 * NaOH (aq) 1M

PROCEDURE

 * 1) HEPES buffer calibrated to ph 7.50 made up to 500ml
 * 2) Content of garlic capsules extracted.
 * 3) 5x 10x dilution series of Garlic
 * 4) 100ul Staph Aureus spread over series of Sucrose based agar plates using Aseptic technique
 * 5) 100ul of each sample spread over bacteria using Aseptic technique.
 * 6) One undiluted sample, 5x 10x dilution series.
 * 7) One control plate using 100ul HEPES buffer.
 * 8) Incubate at 37˚C for 24 hours
 * 9) Photograph and analyse results

Results
All plates, regardless of the level of treatment, showed the same amount of bacterial growth. The experimental plates also displayed no difference in bacterial growth from the control plate.

Discussion
The results show the antimicrobial ineffectiveness of the commercially available allium sativum preparation tested.

Conclusion
The commercially available allium sativum/allicin preparation tested demonstrated no antimicrobial effectiveness on S. aureus. This has important implications for the health product market, which commonly manufactures items based on new scientific trends. Clinical results may emphasize the benefits of these natural compounds but the evidence must be viewed critically, especially with regard to the conditions under which the results were obtained.