oa Editorial [Hot Topic: Small Molecule Drug Agents (Guest Editor: Sanjay V. Malhotra)]

Discovery of a new drug is a long, arduous, and expensive process due to the challenges underlying the understanding of disease pathogenesis, and the design of interventions that target the disease process while sparing normal cells or processes. A promising new molecule identified in drug discovery has to go through complex and laborious testing involving expertise from various disciplines, and has to meet the current standards of scientific rigor, before it becomes available for the treatment of patients. Thus, designing or finding such a molecule which selectively modulates the disease process is not an easy task. Natural products have long been recognized as a thriving source for innovation in drug discovery due to the high chemical diversity, biochemical specificity, and other molecular properties that make them favorable as ‘lead’ structures for discovery of drugs, and which also differentiates them from libraries of synthetic and combinatorial compounds. The articles selected in this issue give us a glimpse of the richness of natural products and complimentary strength of medicinal chemistry in discovery of drugs. The introductory article is an extensive review on Prunus, which is a genus of trees and shrubs, with around 500 species spread throughout the northern temperate regions of the globe. Prunus are considered valuable as food and ornamental plants, while extracts from the tree have been used to alleviate some of the discomfort caused by inflammation in patients suffering from benign prostatic hyperplasia. A detailed account of the extensive work done on Puruns i.e. the chemical constituents of Genus Prunus and their medicinal properties, has been nicely described by Prof. Parmar et al. Dr. Sharma's team has delved into the chemistry of chromones, discussing the current status, their natural occurrence and biological activities. Podophyllotoxin (PPT) is a non-alkaloid toxin lignan extracted from the roots and rhizomes of Podophyllum species. Podophyllotoxin displays a range of activities such as a cathartic, purgative, antiviral, vesicant, and antihelminthic agent and also presents potentially exciting leads as an anti-tumor agent. Dr. Kumar and colleagues discuss the chemistry and anti-cancer activity of the aza-analogs of PPT, as potential alternative scaffolds of Podophyllotoxins. Prof. Fruzi and colleagues provide a unique perspective on the antioxidant therapy, analyzing the limitations of the past, the current status and its future prospects. Prof. Rawat et al. have reviewed the utility of Trioxane and Tetraoxane moieties, which are commonly found in compounds from plants such as Artemisia arnica. Such compounds have shown promising anti-malarial, anti-cancer, and antibacterial activity. The medicinal potential of these moieties has been presented in this article. The concluding article is a review on Coumarins- an old class of naturally occurring benzopyrene derivatives which have served as valuable leads for further design and synthesis of more active analogs. Dr. Kostova and colleagues discuss the antioxidant application of these natural compounds. I am grateful to all authors for their contribution of extensive reviews on their respective areas of expertise. I hope the readers will find this issue highly informative.