Further studies on anti-invasive chemotypes: An excursion from chalcones to curcuminoids

Galantamine-Curcumin Hybrids as Dual-Site Binding Acetylcholinesterase Inhibitors

Galantamine (GAL) and curcumin (CU) are alkaloids used to improve symptomatically neurodegenerative conditions like Alzheimer's disease (AD). GAL acts mainly as an inhibitor of the enzyme acetylcholinesterase (AChE). CU binds to amyloid-beta (Aβ) oligomers and inhibits the formation of Aβ plaques. Here, we combine GAL core with CU fragments and design a combinatorial library of GAL-CU hybrids as dual-site binding AChE inhibitors. The designed hybrids are screened for optimal ADME properties and BBB permeability and docked on AChE. The 14 best performing compounds are synthesized and tested in vitro for neurotoxicity and anti-AChE activity. Five of them are less toxic than GAL and CU and show activities between 41 and 186 times higher than GAL.

Vehicle development, pharmacokinetics and toxicity of the anti-invasive agent 4-fluoro-3',4',5'-trimethoxychalcone in rodents

Effective inhibitors of invasion and metastasis represent a serious unmet clinical need. We have recently identified 4-fluoro-3’,4’,5’-trimethoxychalcone or C16 as a potent anti-invasive molecule. In this paper, we report on the development of an optimized vehicle for oral administration of C16. We also explore its pharmacokinetic and toxicity profile in rodents as a prelude to a broad-scope evaluation as a pharmacological tool in animal models of disease. C16 showed suboptimal pharmacokinetics with limited oral bioavailability and whole blood stability. Rapid metabolism with elimination via glutathione conjugation was observed. An oral dosing routine using medicated gels was developed to overcome bioavailability issues and yielded sustained whole blood levels above the half maximal effective concentration (EC₅₀) in a 7-day study. The compound proved well-tolerated in acute and chronic experiments at 300 mg/kg PO dosing. The medicated gel formulation is highly suitable for evaluation of C16 in animal models of disease.

Novel synthetic chalcones induce apoptosis in the A549 non-small cell lung cancer cells harboring a KRAS mutation

A series of novel chalcones were synthesized by the Claisen-Schmidt condensation reaction of tetralones and 5-/6-indolecarboxaldehydes. Treatment of human lung cancer cell line harboring KRAS mutation (A549) with the chalcones induced dose-dependent apoptosis. Cell cycle analyses and Western blotting suggested the critical role of the chalcones in interrupting G2/M transition of cell cycle. SAR study demonstrated that substituent on the indole N atom significantly affects the anticancer activity of the chalcones, with methyl and ethyl providing the more active compounds (EC₅₀: 110-200nM), Compound 1g was found to be >4-fold more active in the A549 cells (EC₅₀: 110nM) than in prostate (PC3) or pancreatic cancer (CLR2119, PAN02) cells. Furthermore, compound 1l selectively induced apoptosis of lung cancer cells A549 (EC₅₀: 0.55μM) but did not show measurable toxicity in the normal lung bronchial epithelial cells (hBEC) at doses as high as 10μM, indicating specificity towards cancer cells.

Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5-10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its (1)H NMR spectrum.