CHAPTER ONE

INTRODUCTION AND LITERATURE REVIEW

1.1       Introduction

Plants have long served mankind as sources of food, shelter and medical agents. The medicinal plants have been used for many years in daily life to treat diseases all over the world (Ates and Erzdogrul, 2003). According to reports of the World Health Organisation, 80% of the world’s population relies mainly on traditional therapies for their primary health care (WHO, 1993) because of better cultural acceptability, fewer side effects and a steady rise in antibiotic resistance of bacteria due to indiscriminate use of commercial drugs (Ahmed et al., 1998) and  these urgently calls for the discovery of alternative therapeutic agents by using medicinal plants, which involve the use of plant extracts or their active substance. Secondary plant metabolites (phytochemicals) have been extensively investigated as sources of medicinal agents (Krishnaraju et al., 2005). The medicinal value of plants lies in some chemical substances that produce definite physiological action on the human body and the most important of these bioactive compounds of plants are alkaloids, flavonoids, tannins and phenolic compounds, they have defence mechanism and protection from various diseases (Chidambara et al., 2003). Knowledge of the chemical constituents of plants is very important not only for the discovery of drugs and other therapeutics agents but also in disclosing new sources of such economic materials as tannins, oils, gums and precursors for the synthesis of complex chemical substances (Mojab et al., 2003).