ABSTRACT Gossypium arboreum has been discovered to be a medicinal plant used traditionally in the treatment of several ailments. Research reports have stipulated that the bark, leaves, roots and stem have been used traditionally for the treatment of hypertension, fungal infections and as an abortifacient or emmenagogue or menstruation stimulant.  The objectives of the study was to use the method of hydrodistillation to extract the essential oil of  Gossypium arboreum leaf. To investigate the antimicrobial activity of fresh leaf of  Gossypium arboreum essential oil using different concentrations and testing on different microorganisms. Essential oil of Gossypium arboreum was extracted using the hydrodistillation method. Antimicrobial analysis was carried out on fresh leaf essential oil of Gossypium arboreum using agar-well diffusion method. The essential oil was tested and 122 g of previous clean fresh leaves of Gossypium arboreum was cut into small pieces and packed carefully into a 1 L round bottom flask of a glass Clevenger apparatus. The quantity of the leaves half-filled the flash. Appropriate quantity of pre-heated distillated water was poured into the flask containing the cut leaves and subjected to continuous heating using a heating mantle. The Clevenger condenser was chilled using a chiller to maintain a temperature between 05-12 °C throughout the process for optimum distillation. Early drops of distillate were carefully collected at intervals of four (4) min into samples tubes through the clevenger tap and kept separately as this contains large portion of the essential oil.  The whole hydrodistillation process was carried out in (Triplicate). Each set ran for about an hour and 100 mL of distillate was collected for each set. The collected fractions were put together and the essential oil was extracted using diethyl ether in separating funnel. The result of the antimicrobial activities of Gossypium arboreum reveals that the highest inhibition by the essential oil was recorded that Gossypium arboreum oil was active against Bacillus sp with inhibition zone of 9.0 mm at concentration of 1 L. No activities were observed against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus and Streptococcus sp. The Minimum Inhibitory Concentration for Gossypium arboreum oil extract was 1 L. This was demonstrated against Bacillus sp and the Minimum inhibitory concentration (MIC). for Gossypium arboreum oil extract was 1 L. This was demonstrated against Bacillus sp.   Keywords: Gossypium arboreum, Antimicrobial and essential oil.   TABLE OF CONTENTS Title page    i Certification                                                                                                                          ii Dedication                                                                                                                             iii                                                                                                                                                Acknowledgement     iv Abstract                                                                                                                                  v Tables of contents     vii List of figures      xi List of tables       x  CHAPTER ONE; INTRODUCTION Background to the study 1  Justification for the Study 2 1.3 Botanical Description 8 1.3.1 Plant family 9 1.3.2 Genus 10 1.3.3 Species  10 1.4 Aim and Objectives of the Study  12 CHAPTER TWO: LITERATURE REVIEW 2.1 Ethnobotanical and Folklore Uses of   Gossypium arboreum 13 2.2 Previous Biological Investigation of   Gossypium arboreum 15 2.3 Previous Chemical Investigation of   Gossypium arboreum 17 CHAPTER THREE: MATERIALS AND METHOD Materials and Reagent 21 Methods 21 Plant Preparation  21 3.2.2 Extraction by Hydrodistillation 21 Analysis Of the Essential Oil of the Fresh Leaves of Gossypium arboreum 24 3.3.1 Antimicrobial Assay 24 3.3.1.1 Determination of Antimicrobial Activity (agar well diffusion method) 25 3.3.1.2 Determination of Minimum Inhibitory Concentration (MIC) 26 Determination of Minimum Bactericidal Concentration.(MBC)  27 3.3.2    GC/GC-MS Analysis 27   CHAPTER FOUR: RESULTS 4.1  Yield of Extracted Oil          28 4.2   Result of the Antimicrobial Activity of the Essential Oil of the Fresh Leaves of       30 Gossypium arboreum 4.3   Result of GC/GC – MS Analysis  32 CHAPTER FIVE: DISCUSSION AND CONCLUSION 5.1 Discussion  37 5.2 Conclusion 38 REFERENCES                                                                                                          40            LIST OF TABLES                                                                                                              Table 4.1: Antimicrobial activities of the essential oil from the fresh leaves of G. arboreum  29 Table 4.2: Minimum Inhibitory Concentration (MIC) of the essential oil from the fresh leaves of G. arboreum    30 Table 4.3: Minimum Bactericidal Concentration (MBC) of the essential oil from the fresh leaves of Gossypium arboreum 31 Table 4.4 Chemical composition of  the essential oil of Fresh Gossypium arboreum leaves 33                   LIST OF FIGURES Figure 1.1: Picture of Gossypium arboreum taken by me 8 Figure. 3.1: A Picture of the Hydrodistillation set-up taken during the extraction of essential oil. 23 Figure 4.1: GC –MS chromatogram of the essential oil of the fresh leaves of G. arboreum32                         CHAPTER ONE INTRODUCTION Background to the study Plants are multicellular organisms in the kingdom Plantae that use photosynthesis to make their own food. There are over 300,000 species of plants; common examples of plants include grasses, trees, and shrubs, they produce most of the world’s oxygen, and are important in the food chain, as many organisms eat plants, they have an important role in the world’s ecosystems. Plants are autotrophs; they produce their own food, they do so via photosynthesis, which is the process of making nutrients such as sugars from light energy and carbondioxide (Bryant and Frigaard, 2006). Photosynthesis occurs in cell organelles called chloroplasts, which contain chlorophyll and carotenoids, molecules that absorb light energy and change it into a usable form. Heterotrophs, on the other hand, are organisms that cannot make their own food and must eat other organisms to survive, many heterotrophs eat plants, and other heterotrophs eat animals that have eaten plants (Hogg, 2013). Plants are primary producers in many ecosystems, giving them a vital role in the survival of many other organisms. In addition, oxygen is a byproduct of photosynthesis, and many organisms depend on oxygen to survive (Hogg, 2017). Plants are a good source of food for animals, including humans, because they contain nutrients necessary for survival and initial growth, including many healthy fats, such as omega fats. In fact, the majority of foods consumed by human beings are seed-based foods (Hogg, 2017). Edible seeds include cereals, legumes and nuts. Plant are often pressed to produce rich oils sunflower, flaxseed, rapeseed, sesame. Seeds are typically high in unsaturated fats and, in moderation, are considered a healthy food, although not all seeds are edible (Wikipedia, 2011). 1.2 Justification for the Study  Medicinal plants have received a great deal of scientific attention over the past decades due totheir low toxicity, cost-effectiveness, and promising pharmacological properties (Chouhan et al.,2017). A wide range of efforts have been made on researching the great potentials of plant-extracted phytochemicals as well as their influences on human health (Dar et al.,2017). In this regard, the extractions of essential oils from plants have brought about numerous medicinal values attributed to their useful biological and pharmacological activities (Angelini and Properzi, 2012). Medicinal plants have contributed majorly in the treatment of many diseases and ailments including diabetes mellitus all over the world. In West Africa, particularly Nigeria, broadly identified antidiabetic plants include: Magniferaindica, Vernonia amygdalina, Calotropis procera, Azadirachataindica and  Gossypiumarboreum (Gbolade, 2009).  1.3 Botanical Description  1.3Botanical Description Of  Gossypium arboreum       1.3.1 Plant family of  Gossypium arboretum Gossypium is a genus of flowering plants in the tribe Gossypieae of the mallow family, Malvaceae, from which cotton is harvested. It is native to tropical and subtropical regions of the Old and New Worlds. There are about 50 Gossypium species, making it the largest genus in the tribe Gossypieae, and new species continue to be discovered. The name of the genus is derived from the Arabic word goz, which refers to a soft substance (Jonathan et al., 2009). Gossypium are perennial shrubs most often grown as annuals. Plants are 1–2 m high in modern cropping systems, sometimes higher in traditional, multiannual cropping systems, now largely disappearing (Gledhill, 2008). The leaves are broad and lobed, with three to five (or rarely seven) lobes. The seeds are contained in a capsule called a "boll", each seed surrounded by fibres of two types. These fibres are the more commercially interesting part of the plant and they are separated from the seed by a process called ginning. At the first ginning, the longer fibres, called staples, are removed and these are twisted together to form yarn for making thread and weaving into high quality textiles (Gledhill, 2008). At the second ginning, the shorter fibres, called "linters", are removed, and these are woven into lower quality textiles (which include the eponymous Lint). Commercial species of cotton plant are Gossypium hirsutum (>90% of world production), Gossypium barbadense (3–4%), Gossypium arboreum and Gossypium herbaceum (together, 2%) (Gledhill, 2008).  Many varieties of cotton have been developed by selective breeding and hybridization of these species. Experiments are ongoing to cross-breed various desirable traits of wild cotton species into the principal commercial species, such as resistance to insects and diseases, and drought tolerance. Cotton fibres occur naturally in colours of white, brown, green, and some mixing of these. Most wild cottons are diploid, but a group of five species from America and Pacific islands are tetraploid, apparently due to a single hybridization event around 1.5 to 2 million years ago. The tetraploid species are Gossypium hirsutum, Gossypium tomentosum, Gossypium mustelinum, Gossypium barbadense, and Gossypium darwinii (Jonathan et al., 2009). 1.3.2 Genus of  Gossypium arboreum The genus Gossypium has a long history of taxonomic and evolutionary study. Gossypium comprises about 50 species distributed in warm temperate to tropical zones. The origin of the genus is unknown, but 3 primary centres of diversity exist: in Australia, in north-eastern Africa to Arabia, and in western-central to southern Mexico. The 4 cultivated cottons of the world (the Old World diploids  Gossypium arboreum and  Gossypium herbaceum and the New World tetraploids  Gossypium barbadense and  Gossypium hirsutum) have been domesticated independently in different parts of the world. The taxonomy of  Gossypium is complicated, partly due to the domestication of 4 distinct species and extensive interspecific hybridization Gossypium arboreum and Gossypium herbaceum are included in subgenus  Gossypium.     1.3.3 The Species African-Asian Species Gossypium comprises fourteen species from Africa and Arabia in the most recent taxonomic treatment of the genus (Fryxell, 1992). The Yoruba name is Akese, and gossypium species are divided into two sections, one (section  Gossypium) with four subsections and the other (section Serrata) with a single included species, Gossypium trifurcatum. This latter species, from deserts in eastern Somalia, is poorly understood taxonomically and cytogenetically. The unusual feature of dentate leaves raises the possibility that it may not belong in Gossypium, and may instead be better referred to Cienfuegosia (Fryxell, 1992), a possibility that requires future evaluation. This latter example underscores the provisional nature of much of the taxonomy of the African-Arabian species of  Gossypium. Although there are recent valuable contributions to our knowledge of the group (Vollesen, 1987; Holubec, 1990; Fryxell, 1992), the need remains for basic plant exploration for nursery material and additional taxonomic study. In addition to the uncertain position of Gossypium trifurcatum, the specific status of some taxa within subsection Anomala and especially subsection Pseudopambak is unsure. Within the former, for example, Fryxell differentiates Gossypium triphyllum at the sectional level (as the sole species of section Triphylla) based on some unusual morphological characteristics and similarities to some section Hibiscoidea taxa. Other taxonomic opinion, however (Vollesen, 1987) and molecular data (Wendel and Albert, 1992; Seelananet al., 1997) place this SW African species squarely in section Anomala with the other two B genome species.  Within section Pseudopambak, species recognition and definition are in some cases based on rather limited herbarium material (e.g., Gossypium benadirense, Gossypium bricchettii, Gossypium vollesenii) without the benefit of analyses typically conducted in Gossypium to increase taxonomic confidence, such as “common garden”, cytogenetic, or molecular experiments. Thus, this tentative classification must suffice until additional material becomes available for comparative study. From a cytogenetic standpoint, the African-Arabian species exhibit considerable diversity, collectively accounting for four of the eight genome groups.  Thegenome, comprising the two cultivated cottons Gossypium arboreum and Gossypium herbaceum of subsection Gossypium, has been extensively studied (reviewed in Wendel et al.,., 1989; see also discussion below). The three African species in subsection Anomala make up the B genome, as discussed above. The sole F-genome species, Gossypium longicalyx, is cytogenetically distinct (Phillips and Strickland, 1966), morphologically isolated (Fryxell, 1971; Vali?ek,1978; Vollesen, 1987), and is perhaps adapted to more mesic conditions than any other diploid  Gossypium species. The remaining seven species (subsection Pseudopambak) are considered to possess E genomes, although three of these have not been examined cytogenetically. Efforts to resolve relationships within the entire subgenus Gossypium and to reconstruct its evolutionary history have met with mixed success. On the whole, taxonomic subdivisions within the subgenus appear to correspond to natural lineages that are congruent with cytogenetic designations. Molecular data (Wendel and Albert, 1992; Seelananet al., 1997) uniformly support the recognition of four evolutionary lines, corresponding to the A, B, E, and F genomic groups. Different data sets differ in branch order among these groups. To a certain extent, this phylogenetic ambiguity is expected, given the DNA sequence data (Seelananet al.,1997) implicating an evolutionary history of rapid and early diversification of the primary lineages (and hence, short “interior branches” that are difficult to detect and discern). Notwithstanding this potential roadblock to gathering definitive phylogenetic evidence, additional study of this group is critical, not only for understanding the history of the African-Arabian lineages, but for evaluating earlier speculations that the genus originated in Africa(Hutchinson et al.,1974)        Figure 1.1: Picture of Gossypium arboreum taken by me      1.4 AIM AND OBJECTIVES OF THE STUDY                                                                                                                                                                                                                                                                    Aim of the studyThe aim of this study is to isolate the essential oil, characterize and test for anti-microbial activity of fresh leaves of  Gossypium arboreum. The specific objectives of the study are to; To use the method of hydrodistillation to extract the essential oil of  Gossypium arboreum leaf. To investigate the antimicrobial activity of fresh leaf of  Gossypium arboretum essential oil using different concentrations and testing on different microorganisms.