ABSTRACT

The antibacterial and phytochemical properties of the leaf, stem and root extracts of Phyllanthus niruri were carried out against Escherichia coli, Pseudomonas aeruginosa, Salmonella sp. and Staphylococcus aureus. The identification of the isolates was done by standard microbiological techniques which include Gram staining and biochemical methods. The various solvents used include: hot water, cold water and ethanol and were used at various concentrations; 250mg/mL, 125mg/mL, 62.5mg/mL, 31.25mg/mL, and 15.625mg/mL. Antibacterial assay showed that hot water extract of   Phyllanthus niruri root had the highest activity against Escherichia coli and Salmonella sp. (32mm), while hot water extracts (leaf) had the highest activity against Staphylococcus aureus (32mm). Ethanol extract (root) has the highest activity against Pseudomonas aeruginosa followed by ethanol extract (stem) and Salmonella sp.(32mm).  Disc diffusion and broth dilution methods were used to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Ethanol extract (leaf) had MIC 125mg/mL against Escherichia coli, and Staphylococcus aureus while Pseudomonas aeruginosa had 62.5mg/mL. Hot water leaf extract had MIC 31.25mg/mL against Staphylococcus aureus. Ethanol extract (stem) had 250mg/mL against Escherichia coli and Salmonella sp.,62.5mg/mL against Pseudomonas aeruginosa and 125mg/mL against Staphylococcus aureus. Minimum Bactericidal Concentration (MBC) was the same as the Minimum Inhibitory Concentration (MIC).

  CHAPTER ONE

1.0 INTRODUCTION

The use of plants in curing illness is as old as man (Grabley, 1999). Large populations of people especially in the developing world rely on folk medicines for the treatment of common infection as well as persistent diseases (Ndukwe et al., 2005). In recent times, there have been increases in antibiotic resistance strains of clinically important pathogens which have led to the emergence of new bacterial strains that are multi-resistant (Albinu et al., 2004). The non availability and high cost of new generation antibiotic with limited effective span has resulted in increase in morbidity and mortality (William, 2000). It is estimated that today,  plant materials are present in or have provided the models for 50% of western drugs (Robber et al., 1996). Many commercially proven drugs used in modern medicine were initially used in crude form in traditional and folk healing practices or for other purpose that suggest potentially useful biological activity. Traditional healers have long used plants to prevent or cure infectious conditions (Clark, 1995). Consequently, this has led to the search for more effective antimicrobial agents among material of plant origin with the aim of discovering potentially useful ingredients that can serve as a source for the synthesis of new antimicrobial drugs (Pretorius et al., 2003). Plants used as antimicrobial, are effective against infectious diseases while simultaneously mitigating many of the side effects that are often associated with synthetic antimicrobials. They are effective, yet gentle (Gill, 2007). Many vegetables are mainly consumed for their nutritional values without much consideration foor their medicinal importance (Aletor and Adeogun, 1995).

The genus Phyllanthus refers to leaves and flowers and is one of such medicinal plants and is still investigated for further findings. The flowers as well as the fruits seem to become one with the leaf. It is a wide spread tropical rainforest plant commonly found in coastal areas.

It comprises of 600-700 species with minor distinguishing features among them.  Phyllanthus amarus, Phyllanthus urinaria  and Phyllanthus niruri are the most employed species. Phyllanthus niruri belongs to the family Phyllanthacae, genus, Phyllanthus and specie niruri. Phyllanthus niruri has its common name stone-breaker (because of its strong root). It is commonly called “ENYIKWONWA” (the same family with ugba) by the Igbo’s in Nigeria. The stem and root have been reported along with the leaves to be of medicinal value (WHO, 2001). The latex form leaves has been used as antimalaria and for the treatment of infections of bacterial origin (Farombi, 2003).

Aims and Objectives

The aims and objectives of this work are to:

Determine the antibacterial activities of Phyllanthus niruri

Determine the chemical constituents that may be present in the extract (ethanol, hot water and cold water).

Determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of Phyllanthus niruri extracts