For ages, human beings have been using medicinal agents until the concept of

medicinal chemistry and DNA microarrays identify to them. A DNA microarray is a

powerful genomic tool for biomedical and clinical research, while medicinal

chemistry is a discipline at the intersection of numerous other disciplines such as,

synthetic organic chemistry, pharmacology, molecular biology, etc. DNA microarrays

and medicinal chemistry constitute the essential step in the discovery of a new drug

for disease and identification of the protein target that is the basis of disease.

The term drug is the fundamental and most long-standing debates related to the basic

concepts of health and disease. Its historic roots arguably date back to ancient times.

The phrase drug originated from the French word 'Drogue' and refers to a desiccated

herb, which sturdily recommends that primary drugs were isolated from plant origin

[Wadud et al, 2007]. On the contrary, the disease is any condition that impairs the

normal well being of the body. In particular, no study, to our knowledge, has

considered that provides the evidence to claim how old the concept of the disease and

drug is. Thus, it appears the terms drug and disease possibly come into fact at the

same time. The earnest attempt by leading researchers to manage and treat the

diseases has led to investigating new drug candidates or appropriate analogueues of

active drugs. Initially, the drugs were isolated from sources such as, plant, animal and

mineral sources, but due to some shortcomings e.g. the lack of potency and decisive

cure and occasionally more toxicity, the identification of new drugs that are improved

potency and reduced toxicity became crucial. The process of drug development turned

into an imperative part and is intended at revising the biological action of drugs,

predominantly to lessen the side effects and to enhance the potency of the drugs.

Subsequently, at present, > 60% drugs employed in clinics are synthetic analogueues

and the sphere of synthetic medicinal chemistry is broadening day-by-day.

A series of studies on pharmacophore approaches in facilitating drug discovery

process has been reported in recent years.Currently, pharmacophore modelling has

been extensively used in various ligand-based and structure-based methods and

successfully practised in essential screening, de novo architecture and lead

modification after the progress made in computational chemistry in the past two

decades [Yang, 2010]. Today, in modern medicinal chemistry a great diversity of

software tools is available to the researcher in the area of analogueue design/ligandbased

pharmacophore modelling.