No abstract

Inhibition of xanthine oxidase (XO) is an effective and most prominent therapeutic approach for the management of gout. Discovery of its association in the pathophysiology of diabetes, cardiovascular disorders, etc., widened its therapeutic horizons. Limited drug candidates in clinical practice along with side effects forced researchers to develop more efficacious and safer XO inhibitors for the management of gout and other disorders associated with XO hyperactivity. In this regard, this review focus on (a) various drug candidates in clinical practice and under clinical trials, (b) Development of various heterocyclic motifs as XO inhibitors in last two decades and (c) various patented synthetic XO inhibitors.

Homeostasis between protein synthesis and degradation is a critical biological function involving a lot of precise and intricate regulatory systems. The ubiquitin-proteasome pathway (UPP) is a large, multi-protease complex that degrades most intracellular proteins and accounts for about 80% of cellular protein degradation. The proteasome, a massive multi-catalytic proteinase complex that plays a substantial role in protein processing, has been shown to have a wide range of catalytic activity and is at the center of this eukaryotic protein breakdown mechanism. As cancer cells overexpress proteins that induce cell proliferation, while blocking cell death pathways, UPP inhibition has been used as an anticancer therapy to change the balance between protein production and degradation towards cell death. Natural products have a long history of being used to prevent and treat various illnesses. Modern research has shown that the pharmacological actions of several natural products are involved in the engagement of UPP. Over the past few years, numerous natural compounds have been found that target the UPP pathway. These molecules could lead to the clinical development of novel and potent anticancer medications to combat the onslaught of adverse effects and resistance mechanisms caused by already approved proteasome inhibitors. In this review, we report the importance of UPP in anticancer therapy and the regulatory effects of diverse natural metabolites, their semi-synthetic analogs, and SAR studies on proteasome components, which may aid in discovering a new proteasome regulator for drug development and clinical applications.

The search for new heterocyclic compounds with potential bioactivities continues despite the fact that extensive work has already been done on pyranoquinolones. Researchers throughout the world have used the pyranoquinolone nucleus extensively to generate a wide variety of bioactive heterocycles that target a wide spectrum of biological targets. An in-depth investigation into possible pyranoquinolone derivatives and their pharmacological importance is the focus of this overview of synthetic techniques. Researchers and medicinal chemists can benefit from this review by developing new pyranoquinolone nucleus leads that are very effective and have fewer adverse effects than existing ones.