The structural modification of natural products for novel drug discovery.

INTRODUCTION: Throughout history, natural products (NPs) have provided a rich source of compounds that have wide applications in the fields of medicine, health sciences, pharmacy and biology. Although naturally active substances are good lead compounds for the discovery of new drugs, most of them suffer from various deficiencies or shortcomings, such as complex structures, poor stability and solubility. Therefore, structural modification of NPs is needed to develop novel compounds with specific properties. Areas covered: This article presents an overview on the structural modifications of NPs in drug development. The application of multiple classes of NPs to the treatment of conditions such as cancers, infection, Alzheimer's and diabetes are discussed. This article also reveals that modification of NPs is a versatile approach to explore their mode of actions, which may lead to the discovery of novel drugs. Expert opinion: NPs are usually described by structural diversity and complexity. The use of isolated NPs as scaffolds for modification is a good approach to drug discovery and development. Despite many limitations associated with NPs, the total synthesis, semisynthetic modification, SAR-based modification, sometimes even a single atom alteration, may lead to the discovery of a novel drug.