Current Medicinal Chemistry - Volume 23, Issue 32, 2016

Xanthone derivatives have been described as compounds with a privileged scaffold exhibiting diverse biological/pharmacological activities, what directed the interest to pursue the development of these derivatives into drug candidates. Nevertheless, to achieve this purpose it is crucial to study their pharmacokinetics and toxicity (PK/tox) properties as decision endpoints to continue or interrupt the development investment. This review aims to expose the most relevant analytical methods used in the physicochemical and PK/tox studies in order to detect, quantify, and identify different bioactive xanthones. Analyzing the main results from in vitro and in vivo systems towards ADME properties such as solubility, lipophilicity, pKa, chemical and metabolic stability, permeability, transporters modulation, and plasma protein binding, it is possible to uncover some threats governing the PK properties and to understand the bioavailability and drugability of xanthone derivatives. The last section of this review focuses on a case-study of the development of the drug candidate DMXAA, which has reached clinical trials, to provide the paths and the importance of PK/tox parameters of this scaffold. The data assembled in this review intends to guide for tackling issues in the design of potential lead compounds and drug candidates with a xanthone scaffold.

Aberrant epigenetic reprogramming occurs frequently in the development of tumors. Histone H3 lysine 27 trimethylation (H3K27me3) exerts a repressive epigenetic mark on a large number of genes. UTX and JMJD3 are the only two histone demethylases which activate gene expression via demethylating H3K27me3 to H3K27me2 or H3K27me1. Current studies show that dysregulation of these two proteins are heavily linked to oncogenesis in various tissue types. Accumulating evidence suggested that there is remarkable therapeutic potential of targeting JMJD3 or UTX in different types of cancer. Herein, we shall give a brief review on the functional roles of JMJD3 and UTX in cancers and evaluate the available compounds and agents targeting UTX and JMJD3. Finally, we also discuss the several modalities that target UTX and JMJD3 for cancer therapy. This review will help to develop novel strategies to abolish or restore effects of UTX and JMJD3 in the pathogenesis of cancer.

Skin cancer in humans represents about 30% of all new cancers and is by far the most common malignancy in the Caucasian population. Exposure to radiations especially ultraviolet-B (UV-B) radiation is the major cause for development of skin cancers along with other chemical or biological factors. The growing incidence rates of skin cancer around the world, demand the need for new treatment options. Understanding the etiology and pathogenesis of skin cancer is therefore crucial for developing an effective drug against this prevailing disease. Medicinal plants are rich with numerous secondary metabolites such as flavonoids, which are now known to treat various chronic diseases, including inflammations and cancers. Flavonoids are sub-classified in to flavones, flavonols, iosflavones, flavanones, flavanols and anthocyanidins. They act on different targets including scavenging reactive oxygen species (ROS), regulation of the cell cycle, and initiation of DNA repair mechanisms, apoptotic induction and inhibition of metastasis. Innumerable evidence suggested that an increased consumption of flavonoid-rich fruits and vegetables rendered DNA protection to normal skin exposed to carcinogens such as UV-B radiation. Flavonoids also showed the potential to induce cell death mechanisms in melanoma, the most dreadful form of skin cancer. This comprehensive review presents flavonoids and their mechanism of action in relation to inflammation and skin cancer management.

In the last decade, drug resistant invasive mycoses have become significantly more common and new antifungal drugs and ways to specifically deliver them to the fungal cell are being looked for. One of the biggest obstacles in finding such comes from the fact that fungi share essential metabolic pathways with humans. One significant difference in the metabolism of those two cells that can be challenged when looking for possible selective therapeutics is the uptake of zinc, a nutrient crucial for the fungal survival and virulence. This work summarizes the recent advances in the biological inorganic chemistry of zinc metabolism in fungi. The regulation of zinc uptake, various types of its transmembrane transport, storage and the maintenance of intracellular zinc homeostasis is discussed in detail, with a special focus on the concept of a constant ‘tug of war’ over zinc between the fungus and its host, with the host trying to withhold essential Zn(II), and the fungus counteracting by producing high-affinity zinc binding molecules.

A vast amount of research on nanoparticles has been conducted in recent years with versatile applications in the field of drug delivery systems. Nanoparticles are designed as a carrier molecule to deliver drugs in a sustained and stimuli response manner. Recent advances in nanotechnology have led to the development of long circulating nanoparticles with high encapsulation efficiency. This article focuses on the properties such as biocompatibility and biodegradability, which are considered as essential criteria for nanoparticles to be successfully used as a carrier molecule in drug delivery systems. Physicochemical characterization of the nanoparticles such as size and size distribution, surface morphology, zeta potential and surface chemistry has a significant role in the successful formulation and applications in drug delivery systems. Mostly, the size and surface characteristics of nanoparticles enable enhanced intracellular accumulation in tumor cells through passive targeting mechanisms and rapid development of nanoengineering, and aid towards attaining active targeting delivery by co-functionalization of nanoparticles using appropriate targeting ligands. This article reviews the recent progress and development of employing different biocompatible and biodegradable nanoparticles in drug delivery systems. It also briefly recaps the important methods available to evaluate its biocompatibility, the mechanism of biodegradability and clearance properties of NPs.