Abstract

Natural lead is a chemical compound derived from living organism. Nature provides a vast set of structurally diverse compounds that can be used as a medicine. Traditional knowledge of natural medicine will remain as an important source of future medicine and therapeutics. A lead compound in drug discovery possesses some therapeutic applicability, but it may require a series of structural changes to serve as a drug. The chemical structure of the lead molecule is used as a starting point for chemical modifications in order to improve its selectivity, potency, pharmacodynamics and pharmacokinetic parameters. The high-throughput screening (HTS) techniques are used to screen thousands of compounds to identify potential drug candidates for a given drug target. The structure-activity relationship (SAR) and absorption, distribution, metabolisms, excretion and toxicity (ADMET) parameters and other related druglikeness properties of a lead can be optimized to discover a potential drug. ADMET assays measure and define the properties such as the rate of metabolism, non-specific and plasma-protein binding, permeability, liver and kidney toxicity, LogP and solubility. Furthermore, the process of lead optimization improves the poor druglikeness of the lead and a new candidate drug can be recommended for in vitro or clinical testing.