THE ANTIMICROBIAL ACTIVITIES OF CAMADOL-METHANOL EXTRACT OF CASHEW NUT

THE ANTIMICROBIAL ACTIVITIES OF CAMADOL-METHANOL EXTRACT OF CASHEW NUT

ABSTRACT

The antimicrobial activity of alcoholic extract of cashew nut (Anacardium occidentale) was tested on some pathogenic microorganisms collected from the laboratory. Fresh cashew nuts were macerated and extracted using absolute methanol at a dilution ratio of 1:2 for 24 hours at room temperature. This extract was filtered using a Whatman filter paper No. 40 into a conical flask and the filtrate heated at 60°C for 45 minutes to remove the methanol. The filtrate was used to fill 5mm diameter wells on nutrient agar plates (a total of 120 organisms comprising 20 Salmonella typhi, 20 Pseudomonas aeruginosa, and 10 Enterococcus faecalis were used for this assay). The following organisms were sensitive to crude extract of cashew nut with mean zone of inhibition of 15mm for Escherichia coli, 20mm for Pseudomonas aeruginosa, 17mm for both Staphylococcus aureus and Klebsiella species, 12mm for Enterococcus faecalis, and 10mm Salmonella typhi. This study shows that cashew nut extract has antimicrobial activity against a reasonable range of pathogenic microorganisms and it is advised that further research should be carried out to make it formulate available for use.

CHAPTER ONE

1.0       INTRODUCTION

Cashew is perennial tree crop which belongs to the family Anacardiaceae.

It is believed to have originated from the northernpart of South America from where it spread to many tropical countries including Nigeria (Rosen and Fordice, 2003).

Cashew is an evergreen shrub or tree and grows best on well drained sandy soils with an annual rainfall of at least 900mm. Cashew trees thrive on soils which are too poor and too dry for most other crops. Cashew was originally grown for reforestation scheme and preventing further erosion in some parts of Nigeria (Cruickshank et al., 2011). The use of the tree was further extended when Nigerians embraced the fact that cashew nuts can be processed for commercial purposes. This led to the large scale production of cashew crops. Cashew farming now attracts much commercial interest and a lot of money is spent in processing them into useful product such as cashew nut, shell oil and cashew kernels. Cashew is also grown for its fleshy apple which is very rich in its food values (Aderiye and Mbadiwe,2003). The low commercial value hitherto attached to the cashew crop was associated with underutilization of the apple, marked by considerable

fruit wastage annually. Various products can now be made from cashew apples; these include fruit juice, jam, pickles, date-like caramel syrups

and wines (Rune et al., 2006). The leaves, bark and roots of the tree have been used for medicinal purposes by native healers. The growing resistance of microorganisms to conventional antimicrobial agents is becoming a source of concern to clinical microbiologists all over the world. As a result, efforts are being made to develop antimicrobial agents from local sources for use in chemotherapeutic regimes.

In contribution to this search, this study evaluates the effect of cashew nut extract on the growth of pathogenic microorganisms frequently associated with human infections (Ohler, 2010)

1.1       Background of the Study

Plants are important in our everyday existence. They provide our foods, produce the oxygen we breathe, and serve as raw materials for many industrial products such as clothes, foot wears and so many others. Plants also provide raw materials for our buildings and in the manufacture of bio-fuels, dyes, perfumes, pesticides, adsorbents and drugs. The plant kingdom has proven to be the most useful in the treatment of diseases and they provide an important source of all the world’s pharmaceuticals. The most important of these bioactive constituents of plants are steroids, terpenoids, carotenoids, flavanoids, alkaloids, tannins and glycosides. Plants have served a valuable starting material for drug development (Cruickshank et al., 2011). Antibiotics or antimicrobial substances like saponins, glycosides, flavonoids and alkaloids are found to be distributed in plants, yet these compounds were not well established due to the lack of knowledge and techniques  (Varghese and Pundir, 2010). The phytoconstituents which are phenols, anthraquinones, alkaloids, glycosides, flavonoids and saponins are antimicrobial principles of plants. Plants are now occupying important position in allopathic medicine, herbal medicine, homoeopathy and aromatherapy. Medicinal plants are the sources of many important drugs of the modern world. Many of these indigenous medicinal plants are used as spices and food plants; they are also sometimes added to foods meant for pregnant mothers for medicinal purpose (Varghese and Pundir, 2010). Many plants are cheaper and more accessible to most people especially in the developing countries than orthodox medicine, and there is lower incidence of adverse effects after use.