CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND TO THE STUDY
Medicinal plants are plants which contains substances that can be used for therapeutic purposes or which are precursors for the synthesis of useful drugs. The medicinal value of these plants lies in some chemical substances that produce a definite physiological action on the human body. Medicinal plant have continued to attract attention in the global search for effective methods of using plants’ parts(e.g. seeds, stems, leaves, roots, peel, bark etc) for the treatment of many diseases affecting humans. Many important drugs used in medicine today are directly or indirectly derived from plants due to its bioactive constituents such as; alkaloids, steroids, tannins e.t.c. (Hill, 1952).
In recent years, secondary plant metabolites previously with unknown pharmacological activities have been extensively investigated as sources of medicinal agents. Thus is anticipated that photochemical with adequate antimicrobial efficacy will be use for treatment of bacterial infections.
The avocado (PerseaAmericana) belongs to the Lauraceaefamily of tropical and Mediterranean trees and shrubs; other members of this family include: laurel, cinnamon, safaris and green-heart (a timber of the Guiana’s). The avocado is thought to have originated from Mexico and Central South America; for thousands of years and till today, it has been a popular food in those places. In the mid 17th Century, they were introduced to West Africa, Mauritius and India.
The world is facing explosive increase in resistant strains of microorganisms. It poses a serious challenge to primary health care in un developing countries, with negative consequences on the economy. Antibiotics such as penicillin and erythromycin which used to have a high efficacy against bacteria species and strains, have become less effective, due to the increased resistance of many bacteria.
Previous
and recent studies have shown that the leaf, back and seed extract of avocado
pear (P. americana) are rich sources
of photochemical such as saponins, steroids, alkaloids, as such a source
of (Idriset al 2010. and Ilozueet al,
2014). However information on antimicrobial effect of avocado pear peel extract
in Enugu is scanty. Therefore this works aims to determine and evaluate the
antimicrobial activity of avocado pear peel extract in Enugu.
CHAPTER TWO
LITERATURE REVIEW
2.1 AVOCADO
The avocado is a tropical tree which grows well and abundantly in Samoa. It is one of the many agricultural produce which is highly under-utilized in the country. The unpopularity of the fruit amongst consumers results in a lot of fruits going to waste every time it is in season. This makes the need for value added products using such local agricultural produce very important not only to reduce food waste but also for the economic benefit of the country.
The avocado fruit is rich in nutrients, high in proteins, antioxidants and dietary fiber is perhaps the most poorly conceived and misunderstood fruit of all times. This is mainly attributed to its high fat and calorie content and so most nutritionists and dieticians either advise against it or to use it “sparingly” (Bergh, 2012).
2.2 HISTORICAL ORIGIN OF THE PLANT
The avocado (alligator pear or aguacate as commonly known) is scientifically known as Persea Americanaof the family Lauraceae and is a native plant of Southern Mexico and Central America . The word avocado comes from the Aztec word ahuacatlwhich is translated by the Spaniards as aquacade meaning “testicle” due to its shape. Historical records of the usage of the plant exist from 7000 B.C. of its cultivation from 6000 B.C. and continuous use in all the well known archeological sites of Mexico. (Doughari, 2010)
2.3 VARIETIES OF AVOCADO
There are three races of avocado:
Guatemalan
Mexican
West India
While each has distinctive features, cross-pollination permits the development of unlimited varieties.
Mexican is the hardest of the group and the most tolerant of cold conditions. Mature trees can tolerate temperatures to 5oC without damages, however flowers are frost prone. Zutano, Bacon, Shephard and the rootstock Duke are all Mexican types.
The Guatemalan race is from the tropical highlands. It requires a cool tropical climate without extremes of humidity and temperature. Trees can withstand light frost to 2oC. Gwen and Reed are varieties from this race.
The West Indian race originated in the humid low lands of tropical Central America. This race is the most tolerant to saline soil and water. They are the most susceptible to cold weather. (Murakoshi, 2010).