THE ANTIBIOTIC EFFECT OF GARLIC ON STAPHYLOCCUS AUREUS AND ESCHERICHIA COLI

1.3 BACKGROUND OF THE STUDY
Since ancient time, naturally occurring plants have played an important role in the discovery of new therapeutic agents. Almost all antibiotics are subjected to the problem of bacterial resistance. Therefore, newer herbal antibacterial compounds from plants and their semisynthetic derivatives to overcome the resistance are under investigation.

Garlic has had an important dietary and medicinal role for centuries. Most of its prophylactic and therapeutic effects are ascribed to specific oil- and water-soluble organosulfur compounds, which are responsible for the typical odor and flavor of garlic (Block, 2010). During crushing or cutting of the clove, the odorless amino acid alliin, present in the garlic clove, is metabolized by the enzyme allinase (a cysteine sulfoxide lyase) to yield allicin and other thiosulfinates that are the source of the characteristic odor of garlic. Thiosulfinates and other secondary metabolites of garlic, including 7-glutamyl peptides, scordinins, steroids, terpenoids, flavonoids and other phenols, may be responsible for the range of therapeutic effects reported for garlic. Reuter et al. (1996) recently reviewed the therapeutic effects of garlic, namely, effects on the cardiovascular system, antibiotic, anticancer, antioxidant, immunomodulatory, anti-inflammatory, hypoglycemic and hormone-like effects. This study will focus on recent research on protective effects of garlic against Helicobacter pylori and other bacterial infections.

There is extensive literature on the antibacterial effects of fresh garlic juice, aqueous and alcoholic extracts, lyophilized powders, steam distilled oil and other commercial preparations of garlic. Fenwick and Hanley (1985) undertook a thorough review of the antibacterial effects of garlic and other allium vegetables up to mid-1984; more recently, the antibacterial effects of garlic have been studied by Reuter et al. (1996). Garlic has been reported to inhibit Aerobacter, Aeromonas, Bacillus, Citrella, Citrobacter, Clostridium, Enterobacter, Escherichia, Klebsiella, Lactobacillus, Leuconostoc, Micrococcus, Mycobacterium, Proteus, Providencia, Pseudomonas, Salmonella, Serratia, Shigella, Staphylococcus, Streptococcus and Vibrio. Noteworthy among the reported findings are the following: 1) Garlic exhibits a broad antibiotic spectrum against gram-positive and gram-negative bacteria (Kabelik and Hejtmankova-Uhrova, 1998). 2) Enterotoxic coli strains and other pathogenic intestinal bacteria, which are responsible for diarrhea in humans and animals, are more easily inhibited by garlic than the normal intestinal flora (Caldwell and Danzer 1988; Kumar and Sharma, 1992; Rees et al., 1993). 3) Garlic is active even against organisms that have become resistant to antibiotics (Jezowa et al., 1996). 4) The combination of garlic extracts with antibiotics leads to partial or total synergism (Didry et al., 1992). 5) A garlic oil preparation showed good antituberculosis activity in guinea pigs with a intraperitoneal dose of 0.5 mg kg-1 (Jain, 1993). 6) Complete lack of resistance of bacteria to garlic has been found (Dankert et al., 2014; Singh and Shukla, 1994). 7) As a result of the bactericidal activity of garlic, toxin production by the bacteria is also prevented (Dewitt et al., 1979).

1.2 OBJECTIVES OF STUDY
The specific objectives of this study is to determine the antibiotic effect of garlic on Staphyloccus aureus and Escherichia coli. The study shows that the medicinal values of leaves lie in their component phytochemicals such as alkaloids, tannins, flovonoids and other phenolic compound.

1.3 SCOPE OF STUDY
The study will cover the qualitative and quantitative analysis that is involved in the determination of antibiotic effect of garlic on Staphyloccus aureus and Escherichia coli .

1.4 SIGNIFICANCE OF STUDY
This study will be of significance importance to students of Science Laboratory Technology as it touches on their area of specialization and also to student from other to other related field. The study also reveals the medicinal importance of garlic.