STUDIES ON THE ANTIMICROBIAL PROPERTIES OF BARK AND LEAVES OF MONKEY KOLA (COLA MILLENII) ON SOME SELECTED PATHOGENS

ABSTRACT

This study is conducted to analyse the phytochemical component, evaluate the antimicrobial properties of the ethanolic, methanolic and water extracts of Cola millenii  bark and leaves against some clinical Pathogens which are Staphylococcus aureus, Escherichia coli, Salmonella typhi and Candida albicans, to determine the minimum inhibitory concentration, minimum bactericidal concentration(MBC) and minimum fungicidal concentration(MFC). Cola millenii has been used in folk medicine and is a member  of the family Sterculiaceae. The bark and leaves of Cola millenii K Schum were extracted using aqueous(water), ethanolic(organic), methanolic(organic) solvents and were investigated for antimicrobial activity against some pathogenic micro-organisms using agar well diffusion method.  The aqueous extract did not show any significant difference in their activities against the various organisms but the ethanolic extract and methanolic extract had significant activities, ethanolic leaf extract demonstrated the highest activity against  the gram positive  organism(Staphylococcus aureus) tested  with the highest activity(18.00±0.5 mm), and also against the selected test fungi (Candida albicans) with activity (16.00±0.8 mm) zone of inhibition except for Salmonella typhi which did not show any zone of inhibition. Ethanolic bark extract demonstrated the highest activity against  the gram negative organism tested (Escherichia coli) with the highest activity(13.00±0.8 mm), and also against the selected test fungi (Candida albicans) with activity (11.50±0.6 mm) zone of inhibition except for Salmonella typhi which did not show any zone of inhibition. The chloramphenicol and fungisol control showed large zones of inhibition. The minimum inhibitory concentration(MIC) and minimum fungicidal concentration(MFC) of the extract ranges between 125 mg/ml to 250 mg/ml for both the bark and leaves of the plant. The antimicrobial property shown by the plant extract is an evidence of the ethno-medicinal uses of the plant. Cola millenii bark and leaves bioactive component may therefore be extracted and used as antibiotics as the result is comparable with commercially available antibiotics and incorporation of active compounds isolated from the ethanolic extract of Cola millenii into conventional drug preparation`ns can also tackle the challenge posed by drug resistant microorganisms.

CHAPTER ONE

1.0  INTRODUCTION

It has long been recognized that some plant materials exhibit antimicrobial properties. The use of these plant materials as preservatives and as means of preventing microorganism development has become the subject of extensive studies. Tropical Africa sub-region is a home to many potential valuable fruits species whose potentials have not been fully realized. A good number of these fruits species are not yet domesticated. Nevertheless, tangible economic produce are being harvested from their wild (Abitogun et al., 2010). Wild plants which refers to trees, flowers, grasses and vines found in the bushes and even the weeds in the lawn (Giwa et al., 2012). Cola millenii has a rampant growth and it is produce in the wild. Cola millenii, a member of the chocolate family Sterculiaceae (from which nuts are obtained) a tree probably originally from western tropical Africa (Encyclopedia Americana, 1988). The Cola millenii nut is a capsule-shaped fruit composed of fleshy, irregularly shaped seeds. The seeds of Cola may be pink, red or white when fresh, and become brown and hard once they are dried with respect to their different species (Adam et al., 2011). Though, C. millenii seeds are whitish in colour.

 

Many efforts have been made to discover new antimicrobial agents from various kinds of sources such as microorganisms, animals, plants and their products (Adedayo and Ajiboye, 2011). Multiresistant strains of microorganisms are a growing public health concern worldwide (Albuquerque et al., 2007), justifying investments in the search for alternative forms of treatment of infections. As a result, a number of medicinal plants used in indigenous medicine have been tested and found to possess antimicrobial properties (More et al., 2008); which have been used as traditional treatments for numerous human diseases for thousands of years and in many parts of the world. Hence, researchers have recently paid attention to safer phytomedicines and biologically active compounds isolated from plant species like glycosides, saponins, flavonoids, steroids, tannins, alkaloids, terpenes (Kamali and Amir, 2010), used in herbal medicines with acceptable therapeutic index for the development of novel drugs (Pavithra et al., 2010; Sen and Batra, 2012).

 

Plants are the cheapest and safer alternative sources of antimicrobials (Sharif and Banik, 2006), systematic screening of them may result in the discovery of novel effective compounds (Tomoko et al., 2002). As the global scenario is now changing towards the use of non- toxic and eco-friendly products, development of modern drugs from traditional medicinal plants should be emphasized for the control of various human and animal diseases (Dewangan et al., 2010). Hence, the need for testing wild plants for antimicrobial properties.

Various medicinal and pharmacological values have been observed in species of Cola (Daels-Rakotoarison et al., 2003). These make them trusted antimicrobial agents. Traditionally, the leaves, twigs, flower, fruits follicles and bark of Cola nitida and Cola acuminate are used to prepare tonic for dysentery, coughs, diarrhea, vomiting and chest complaint (Burkill, 1995).The leaves of Cola millenii are used in treatment of ringworm, scabies, gonorrhea, dysentery and opthalonia (Odugbemi, 2006). Antimicrobial agents are substances which can be used to control (kill or inhibit) microbial growth and survival on or in a body or an environment (Adedayo and Ajiboye, 2011).

1.1 Objectives of the Study.

 The objectives of this research are

  1. to extract the active antimicrobial agents in the leaves and bark of Cola millenii using ethanol, methanol and water
  2. to screen the phytochemical component of the leaves and bark of Cola millenii (Monkey Kola).
  3. to evaluate the antibacterial and antifungal activity of the ethanolic extract of leaves and bark of Cola millenii (Monkey Kola).
  4. To determine the minimum inhibitory concentration
  5. To determine the minimum bactericidal concentration and minimum fungicidal concentration

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