1.0         INTRODUCTION

1.1         NATURAL PRODUCTS AND MEDICINAL CHEMISTRY

A natural product is a chemical compound or a substance produced by a living organism that is found in nature1.Within the field of organic chemistry, the definition of natural products is usually restricted to mean purified organic compounds isolated from natural sources.2 Natural products sometimes have pharmacological or biological activity that can be of therapeutic benefit in treating diseases. As such, natural products are active components not only for most traditional medicines but also for many modern medicines.3

A significant number of anti-infectives are based on natural products. The first antibiotic to be discovered is Penicillin [1].

A large number of currently prescribed drugs have been directly derived from natural products. For example the bark of the Willow tree has been known from antiquity to have pain relieving properties4; this is due to the presence of the natural product salicin [2] which in turn may be hydrolyzed to salicylic acid [3], a synthetic derivative acetylsalicylic acid [4] better known as aspirin widely usedas a pain reliever was obtained when salicylic acid is treated with acetic anhydride (scheme 1)……