CHAPTER ONE INTRODUCTION 1.1 BACKGROUND OF THE STUDY
Since ancient times Allium cepa (onion) Liliaceae of the family have an important dietary resource and have bben of interst for edicinal purpose (Rose et al., 2005) Allium is the largest and important representative genus of the liliceae family comprising 450 species.
Onion (Allium cepa) is the bulbous plant widely cultivated in almost every country of the world (Hannan et al., 2010). Onion (Allium cepa) is also known as the bulb onion, common onion and garden onion. It has a globose bulb that is underground part of the stem; it is biennial and perennial, it is widely distributed in the temperature regions.
Its ancestral wild original form is not known although escapes from cultivation have become established in some region. Allium cepa in floral of North America.
The onion plant has a fan of hollow bluish green leaves and the bulb at base of the plant begins to swell when a certain day-length is readied.
The crop is harvested and dried and the onion are ready for use or storage. Some varieties of Allium cepa such as shallors and potato onion produce mulitiple bulbs. Onions are cultivated and used around the world. As a food item, they are usually served cooked, as a vegetable or part of a prepared savoury dish, but can also be eaten raw or used to make pickles or chutneys. Onion (Allium cepa) us used commonly in foods stuff and traditional remedy in the treatment of a variety of disorders. Onion bulbs have numerous organic Sulphur compounds, flavonoids and phenolic acids with proven anti-bacterials, antioxidant and hypolidemia efficacy (Melvin-Joe et al., 2009; Srinivasan et al, 2004).
The potency of Onion (Allium cepa) as medicinal plants is due to its high context of vitamins, trace elements, amino acids and several organosulphur compounds has been acknowledged over 5000 years (Balick and Paul, 1996). The pharmacological evidence for the use Onion (Allium cepa) as an anti-asthmatic, anti-hypertensive, anti-hyperglycemia, anti-hyperlipidemia and anti-tumour agent has been reported (Stajner and Varga, 2003) antimicrobial compounds of plants can be found in extracts taken from different parts of the plant including leaves, flowers of buds, roots, seeds, rhizomes, fruits, and other parts. Much attention has been paid on antimicrobial compound with natural origin to the general recognized as safe (GRAS) criteria, and their nutritional effects and impact on health (Appendinic et al., 2002, Embuscado et al., 2009). In this regard, several studies have shown that terpenoid, the flavonoids kaenfferol and quercetin, and alkylcysterine sulfoxides in the edible Onion (Allium cepa L.) extract are the most important chemical compositions of antioxidants, disinfectants and anti-inflammatory compounds, and as active and natural anti-pathogens (Younes Anzabi, 2014). Moreover, they show antibacterial activity against many microorganisms both in vitro and clinical cases of some infectious disease (Griffiths et al., 2002; Moneni and Zamanzad, 2010). Furthermore, for this purpose, the antibacterial actively activity of essential oils and plant extracts against pathogenic bacteria with food source, in media and in food or food models has been studied in some researches (Erfani et al., 2006, Fazcara et al., 2012). Nigeria, in terms of climate and geographical location, is one of the best places in the world for medicinal plant growth, and in the past it has been the source of production and consumption of medicinal plants.
1.2 STATEMENT OF THE PROBLEM
Bacterial disease have risen in recent times and there are incidences of antimicrobial resistance against various chemotherapeutic and antimicrobial agents, the treatment and handling of bacterial infections requires special consideration that may otherwise lead to grave prognosis (Kuldeep et al., 2014). Herbs have been a valuable source of medication in virtually all cultures and societies worldwide due to their important antimicrobial principles and phytoconstituent and wider therapeutic potentials. As various extracts of herbs and medicinal plants are being reported with antibacterial activities, much effort should be made in their identification, studying biologically active ingredients, efficiency and potency testing and scientific validation for their significant and practical multi-beneficial orders. In this study, the potential of Onion (Allium cepa) extract as antibiotic would be determined in this research.
1.3 AIM AND OBJECTIVES 1.3.1 AIM OF THE STUDY
The aim of this project is the determination and evaluation of the potential of Onion (Allium cepa) extract in inhibiting growth of bacteria in vitro. This involves cultivating the extract of Onion (Allium cepa) with another nutrient medium.
1.3.2 OBJECTIVES OF THE STUDY
The specific objectives of this project research are as follows:
1. To obtain onion from Bori market.
2. To extract the active ingredients form the procured onions.
3. To apply the onion extract on bacteriological media inoculated with bacteria.
4. To determine the zone of inhibition compared with antibiotics.
1.4 SIGNIFICANCE OF THE STUDY
The study has considered available information on the usefulness of Allium cepa. This study will establish the validity of claims on the antimicrobial efficacy of Allium cepa extract. The potency will be compared with other established antibiotics.
1.5 SCOPE OF THE STUDY
The scope of the study is to effectively determine the potential of Onion (Allium cepa) extract as antibiotics. It will be restricted to conventional laboratory methods of determination of antimicrobial activity using zone of inhibition as parameter.