Synthesis and antitumor activity evaluation of different 2,5-dialkyloxazolopyrano[3,2-c]quinolinone derivatives

Developing our knowledge of the quinolone scaffold and its value to anticancer drug design

INTRODUCTION

The quinolone scaffold is a bicyclic benzene-pyridinic ring scaffold with nitrogen at the first position and a carbonyl group at the second or fourth position. It is endowed with a diverse spectrum of pharmacological activities, including antitumor activity, and has progressed into various development phases of clinical trials for their target-specific anticancer activity.

AREAS COVERED

The present review covers both classes of quinolones, i.e. quinolin-2(H)-one and quinolin-4(H)-one as anticancer agents, along with their possible mode of binding. Furthermore, their structure-activity relationships, molecular mechanisms, and pharmacokinetic properties are also covered to provide insight into their structural requirements for their rational design as anticancer agents.

EXPERT OPINION

Synthetic feasibility and ease of derivatization at multiple positions, has allowed medicinal chemists to explore quinolones and their chemical diversity to discover newer anticancer agents. The presence of both hydrogen bond donor (-NH) and acceptor (-C=O) functionality in the basic scaffold at two different positions, has broadened the research scope. In particular, substitution at the -NH functionality of the quinolone motif has provided ample space for suitable functionalization and appropriate substitution at the quinolone's third, sixth, and seventh carbons, resulting in selective anticancer agents binding specifically with various drug targets.

Synthesis, characterization, anticancer, and antioxidant activities of chitosan Schiff bases bearing quinolinone or pyranoquinolinone and their silver nanoparticles derivatives

In this work, new chitosan-based Schiff bases were synthesized by the reaction of chitosan with quinolinone and pyranoquinolinone giving CSQ, and CSP, respectively. The novel Chitosan Schiff bases were grafted on silver nanoparticles providing CSQ/Ag, CSP/Ag structures. Characterization of isolated compounds was carried out by FT-IR, TGA, XRD, SEM, and TEM. The target compounds CSQ, CSP, CSQ/Ag, and CSP/Ag were evaluated as antitumor agents against three cancer cell lines, liver (HepG-2), colon (HCT-116), and breast (MCF-7). Compound CSQ/Ag disclosed potent cytotoxic effect with IC50 values in the range of 41.9–55.1 μg/ml in comparison with 5-fluorouracil against different cancer cell lines. Besides, the antioxidant activity of chitosan and its quinolinone and pyranoquinolinone analogues was assessed as radical scavengers versus 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH%). The compound CSQ/Ag emerged as the most active member in scavenging the DPPH radicals. The obtained findings proved that the new Schiff bases/silver nanoparticles of chitosan showed higher antiproliferative and antioxidant activities than the blank CS and would be highly applicable in biomedical fields.

Graphical abstract

A review on the synthesis of heteroannulated quinolones and their biological activities

The quinoline scaffold has become an important construction motif for the development of new drugs. The quinolones and their heteroannulated derivatives have high importance due to their diverse spectrum of biological activities as antifungal, anti-inflammatory, anti-diabetes, anti-Alzheimer's disease, antioxidant and diuretic activities. This review summarizes the various new, efficient and convenient synthetic approaches to synthesize diverse quinolone-based scaffolds and their biological activities. We also dealt with the important mechanism, the route and type of reactions of the obtained products. The biological activities of some heteroannulated quinolones were also discussed.

Exploring quinolone scaffold: Unravelling the chemistry of anticancer drug design

Globally, cancer is considered as the major leading cause in decreasing the patient health care system of human beings. The growing threat from drug-resistant cancers makes heterocyclic moieties as an urgent need to develop more successful candidates for anti-cancer therapy. In view of outstanding pharmacological activities Quinolone and its derivatives have attracted more attention towards drug designing and biological evaluation in the search of new drug molecules. The inspired researchers attempted efforts in order to discover quinolone based analogs due to its wide range of biological activities. Due to immense pharmacological importance, distinct synthetic methods have been executed to attain new drug entities from quinolones and all the reported molecules have shown constructive anticancer activity. Some of the synthetic protocol like, one pot synthesis, post-Ugi-transformation, catalysed based synthesis, enzyme-based synthesis and nano-catalyst based synthetic procedures are also discussed as recent advancement in production of quinolone derivatives. In this review, recent synthetic approaches in the medicinal chemistry of quinolones and potent quinolone derivatives on the basis of structural activity relationship are outlined. Moreover, their major methods and modifications are discussed.

Anticancer activity of novel Schiff bases and azo dyes derived from 3-amino-4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione

New Schiff bases and azo dyes derivatives have been synthesized via appropriate conventional methods using pyranoquinolinone as a starting material. The compounds obtained were characterized by spectral analysis and evaluated for anticancer activity in several human tumor cell lines: MCF-7 breast cancer, HepG2 liver cancer and HCT-116 colon carcinoma. 5-fluorouracil was used as a reference drug. The in vitro cytotoxicity screening results revealed that all tested compounds showed promising activity against MCF-7 cells. In particular, compounds 6a, 6b, and 7b showed excellent activity against the three human tumor cell lines. Structure-activity relationship studies indicated that the azo derivative with a trifluoromethoxy group (compound 7b) was the most potent candidate against the three human tumor cell lines (IC50, 1.82-8.06 μg/mL). Our findings highlight pyranoquinolinone analogues as a promising class of compounds for new anticancer therapies.

Recent advances in the synthetic and medicinal perspective of quinolones: A review

In the modern scenario, the quinolone scaffold has emerged as a very potent motif considering its clinical significance. Quinolones possess wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiprotozoal, antiviral, anti-inflammatory, carbonic anhydrase inhibitory and diuretic activity etc. The versatile synthetic approaches have been successfully applied and several of the resulted synthesized compounds exhibit fascinating biological activities in numerous fields. This has prompted to discover quinolone-based analogues among the researchers due to its great diversity in biological activities. In the past few years, various new, efficient and convenient synthetic approaches (including green chemistry and microwave-assisted synthesis) have been designed and developed to synthesize diverse quinolone-based scaffolds which represent a growing area of interest in academic and industry as well as to explore their biological activities. In this review, an attempt has been made by the authors to summarize (1) One of the most comprehensive listings of quinolone-based drugs or agents in the market or under various stages of clinical development; (2) Recent advances in the synthetic strategies for quinolone derivatives as well as their biological implications including insight of mechanistic studies. (3) Further, the biological data is correlated with structure-activity relationship studies to provide an insight into the rational design of more active agents.