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ANTIBACTERIAL ACTIVITY AND PHYTOCHEMICAL SCREENING OF BITTER COLA (GARCINIA KOLA) EXTRACTS AGAINST SOME SELECTED PATHOGENIC BACTERIA

ABSTRACT

This study was carried out to evaluate the antibacterial activity and Phytochemical screening of Bitter Cola (Garcinia kola) extracts against some Selected Pathogenic Bacteria. Garcinia kola seeds and leaves were screened for their anti bacterial activities using 1% hydrochloric acid, diethylether, acetic acid (ethanoic acid) and acetone. The seeds and leaves were dried and ground into powdered form. 10g of the ground seeds and leaves were in four sets. 90ml of the extraction solvents was added to each set. The seed and leaf extracts were tested on clinical isolates of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes using Agar Diffusion Method. Phytochemical screening of the Garcinia kola extracts revealed the presence of some bioactive components like tannins, alkaloids and steroids. These components determine the antibacterial activity of the seed and leaf extracts. The findings of the screening revealed the presence of only carbohydrates and steroids in the aqueous extract while other constituents tested for were absent. The finding of the antibacterial activity of the extracts shows that none of the test organisms was sensitive to any of the aqueous extract concentrations prepared. That is, all organisms developed complete resistance to the extract. Only Proteus mirabilis was sensitive to the methanolic extract at concentration of 700 mg/ml, 350 mg/ml and 175 mg/ml with zones of inhibitions of 18 mm, 15 mm and 11 mm respectively, while other organisms tested were completely resistant. The minimum bactericidal concentration (MBC) for the methanolic extract on Proteus mirabilis revealed that the extract was bactericidal at the minimum concentration of 350 mg/ml.  The results from this study, provides scientific evidence that Garcinia kola has the capability of inhibiting the growth of pathogenic micro organisms; thus it will be useful in tropical medicine for the treatment of microbial infections.

 CHAPTER ONE

INTRODUCTION

1.1       Background of the Study

            Garcinia kola, also known as bitter kola, is a nut-bearing tropical tree native to Nigeria’s coastal rainforests. It was named after a man called Garcin, who lived and wrote about the plant in the 18th century (Macmillan, 2014). It has a bitter taste followed by slight sweetness. Despite its bitter taste, Garcinia kola nuts are commonly eaten as a snack and used for their stimulant effects, due to high caffeine content. G.kola is mostly found in the southern part of Nigeria (Ayensu, 2018). Garcinia kola contains antibacterial properties, according to clinical data. They are effective in the treatment of infectious disease while simultaneously mitigating many of the side effects that are often associated with synthetic antimicrobials (Iwu, 2013). They are effective, yet gentle. They exhibit response to specific organs or systems in the body.

Garcinia kola commonly called bitter kola belongs to the family Gulttiferae, it is a nut bearing tropical tree native to Nigeria’s coastal rainforest and it’s cultivated for its economic importance (Cheek, 2007). The plant tree is about 12m high with fruits produced from July to October. The fruits have subglobose, reddish-yellow and about 2.5 inches in diameter, containing two (2) to four (4) ellipsoid brown seeds embedded in an orange coloured pulp (Keay, Mukhtar, Shuaibu, 1999).

            Garcinia kola was name after a man called “Garcin” who lived and wrote about the plant in the 18^th century (Macmillan, 1949). Garcinia kola has a bitter taste followed y slight sweetness. Despite its bitter taste Garcinia kola nuts are commonly eaten as a snack and used for their stimulant effects due to high caffeine content (Hutchinson & Dalziel, 1954). The bitter Kola plants is found in other Western African Countries across the places where it grows in Nigeria, it is known by various names such as Orogbo in Yoruba, Aku-ilu in Igbo and Namijingoro in Hausa (Dalziel, 2016, Mishu, 2011). The plant seed exhibits very potent pharmacological activities such as antioxidant, antibacterial, antiviral, antifungal and anti-inflammatory properties (Adegboye, Akinpelu and Okoh, 2008). They termed these seeds as “Miracle drug”.

            Salmonella typhi has killed over 600,000 people annually all over the world. It is transmitted through food and water, causing high fever, headache, nausea, loss of appetite, diarrhea, enlargement of the spleen and strong resistance to the innate immune response system (Falkow, Monack and Munler, 2004). Increase in multi-drug resistance, adaptation and survival in the S. typhi population are consequences of continuous exposures to chemically based medicines (Philippi, Shanahen, Many and Christopher, 1998).

1.2       Statement of the Problem

            The antibacterial resistance to commonly used antibiotics couple with the emergence of new and re-emerging diseases has led to a search for newer and alternative compounds for the treatment of drug-resistant infections. The use of medicinal plants globally has become very important in primary health care especially in developing countries. Many pharmacognostical and pharmacological investigations are carried out to find new drugs (Newman, Cragg and Snader, 2003).

            The challenge of emergence of multi-drug resistant strains of S. typhi which are able to adapt and survive antibiotics as they are introduction to orthodox medicine (Philippi, 1998), will be reduced through the ethno-botanical approaches. The medicinal values of these plants are in some chemical substances. The use of ethnobotanicals as antimicrobials stems from limitations due to toxicity, side effects and multiple resistances of micro organisms associated with contemporary antimicrobials therapy (Salih, Ahmed, Ammad, 2019).

The use of plants for medicinal purposes continues to this day, usually in the form of traditional medicine, which is now recognized by the World Health Organization as a building block for primary health care. The plat Garcinia kola is one of such plants.

Previous studies reported the antibacterial activity of G. kola. Despite the few works done on the antisalmonella activity of G. kola, investigatios related to the possible mechanisms of action of G. kola extracts are still not very much explored.

1.3       Aim and Objectives of the Study

1.3.1    Aim of the Study

            The aim of this research is to evaluate the antibacterial Activity and Phytochemical Screening of Bitter Cola (Garcinia kola) extracts against some Selected Pathogenic Bacteria.

1.3.2    Specific Objectives of the Study

1. To determine the antibacterial activity of Gracinia kola extracts on some selected pathogenic bacteria
2. To determine the minimum inhibitory concentration (MIC) of Gracinia kola extracts on some selected pathogenic bacteria
3. To determine the minimum bacteriadial concentration (MBC) of Gacinia kola seed extracts on some selected pathogenic bacteiria
4. To access the chemical composition of Gracinia kola seed extracts

 1.4       Justification of the Study

            Many studies have been on Garcinia kola seeds. They have not indicated the importance of the seed extract biological activities particularly on salmonella typhi without another plant introduced. Thus the need for the research which could be further exploited for the development of new and potent antimicrobials.

1.5       Scope of the Study

            The focus of this study is on the antibacterial Activity and Phytochemical Screening of Bitter Cola (Garcinia kola) extracts against some Selected Pathogenic Bacteria

1.6       Significance of the Study

            The importance of the study is to analyze the importance of Garcinia kola seed extract on some selected pathogenic bacteria since Garcinia has been known to produce certain anti-microbial properties.

1.7       Operational Definition of Terms

Antibacterial: Is anything that destroys bacteria or suppresses their growth or their ability to reproduce. Furthermore, heat, chemicals such as chlorine and antibiotic drugs all have antibacterial properties.

Extracts: Extracts is the process to withdraw (as the medicinally active components of a plant or animal tissue) by physical or chemical process, also to treat with a solvent so as to remove a soluble substance.

Phytochemicals: Are chemical compounds produced by plants generally to help them resist fungi, bacteria and plant virus infections and also consumption by insects and other animals

Screening: Is the evaluation or investigation of something as part of a methodical survey, to assess suitability for a particular role or purpose.

Activity: In chemical thermodynamics, activity (symbol a) is a measure of the effective concentration of a species in a mixture, in the sense that the species chemical potential depends on the activity of a real solution in the same way that it would depend on concentration for an ideal solution.