Antioxidant Studies of Thiazole Ring Bearing Chalcone Derivatives

Oxidative stress is one of the common problems seen in a variety of diseases. Chalcones and in particular heteroaryl chalcones had reported with promising antioxidant activities. Hence, in the present work, we reported the antioxidant activity of twenty thiazole ring bearing chalcone derivatives (1-20). Among the tested compounds, compounds 17, 19 and 20 containing 2-pyridinyl, 3-pyridinyl and 2-thiazolyl scaffolds showed superior antioxidant activity than the standard with their IC50 values 4±1µg/mL, 3±1 µg/mL and 5±1 µg/mL respectively. The compound 19 is an interesting lead for the development of newer antioxidant agents.

Chalcone Scaffolds, Bioprecursors of Flavonoids: Chemistry, Bioactivities, and Pharmacokinetics

Chalcones are secondary metabolites belonging to the flavonoid (C6-C3-C6 system) family that are ubiquitous in edible and medicinal plants, and they are bioprecursors of plant flavonoids. Chalcones and their natural derivatives are important intermediates of the flavonoid biosynthetic pathway. Plants containing chalcones have been used in traditional medicines since antiquity. Chalcones are basically α,β-unsaturated ketones that exert great diversity in pharmacological activities such as antioxidant, anticancer, antimicrobial, antiviral, antitubercular, antiplasmodial, antileishmanial, immunosuppressive, anti-inflammatory, and so on. This review provides an insight into the chemistry, biosynthesis, and occurrence of chalcones from natural sources, particularly dietary and medicinal plants. Furthermore, the pharmacological, pharmacokinetics, and toxicological aspects of naturally occurring chalcone derivatives are also discussed herein. In view of having tremendous pharmacological potential, chalcone scaffolds/chalcone derivatives and bioflavonoids after subtle chemical modification could serve as a reliable platform for natural products-based drug discovery toward promising drug lead molecules/drug candidates.

Computational and Spectral Discussion of Some Substituted Chalcone Derivatives

The substituted chalcone derivatives 1–7 have been synthesized, and spectroscopic characterization were done as done using the experimental FT-IR, UV-Vis, GC-MS, 1D NMR spectroscopy. The favored conformation of substituted chalcone 3 was predicted theoretically by geometry optimization structure selected geometrical parameters and molecular properties such as NBO, AIM, HOMO-LUMO, MEP surface, and atomic charges were derived from optimized structures. The 1H and 13C NMR spectral data had been additionally computed using the Gaussian-09 package and compared with the experimental values. The antibacterial and antifungal activity was derived by the disc diffusion method.

Inhibition of XPO-1 Mediated Nuclear Export through the Michael-Acceptor Character of Chalcones

The nuclear export receptor exportin-1 (XPO1, CRM1) mediates the nuclear export of proteins that contain a leucine-rich nuclear export signal (NES) towards the cytoplasm. XPO1 is considered a relevant target in different human diseases, particularly in hematological malignancies, tumor resistance, inflammation, neurodegeneration and viral infections. Thus, its pharmacological inhibition is of significant therapeutic interest. The best inhibitors described so far (leptomycin B and SINE compounds) interact with XPO1 through a covalent interaction with Cys528 located in the NES-binding cleft of XPO1. Based on the well-established feature of chalcone derivatives to react with thiol groups via hetero-Michael addition reactions, we have synthesized two series of chalcones. Their capacity to react with thiol groups was tested by incubation with GSH to afford the hetero-Michael adducts that evolved backwards to the initial chalcone through a retro-Michael reaction, supporting that the covalent interaction with thiols could be reversible. The chalcone derivatives were evaluated in antiproliferative assays against a panel of cancer cell lines and as XPO1 inhibitors, and a good correlation was observed with the results obtained in both assays. Moreover, no inhibition of the cargo export was observed when the two prototype chalcones 9 and 10 were tested against a XPO1-mutated Jurkat cell line (XPO1C528S), highlighting the importance of the Cys at the NES-binding cleft for inhibition. Finally, their interaction at the molecular level at the NES-binding cleft was studied by applying the computational tool CovDock.