Plants are known to have numerous phytochemicals and other secondary metabolites with numerous pharmacological and biological properties. Among the various compounds, polyphenols, flavonoids, anthocyanins, alkaloids, and terpenoids are the predominant ones that have been explored for their biological potential. Among these, chalcones and bis-chalcones are less explored for their biological potential under in vitro experiments, cell culture models, and animal studies. In the present study, we evaluated six synthetic bis-chalcones that were different in terms of their aromatic cores, functional group substitution, and position of substitutions. The results indicated a strong antioxidant property in terms of DPPH and ABTS radical-scavenging potentials and ferric-reducing properties. In addition, compounds 1, 2, and 4 exhibited strong antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella enteritidis. The disc diffusion assay values were indicative of the antibacterial properties of these compounds. Overall, the study indicated the antioxidant and antimicrobial properties of the compounds. Our preliminary studies point to the potential of this class of compounds for further in vivo investigation.

Plant secondary metabolites are important sources of biologically active compounds with wide pharmacological potentials. Among the different classes, the chalcones form integral pharmacologically active agents. Natural chalcones and bis-chalcones exhibit high antioxidant and anti-inflammatory properties in various experiments. Studies are also underway to explore more biologically active bis-chalcones by chemical synthesis of these compounds. In this study, the effects of six synthetic bis-chalcones were evaluated in intestinal epithelial cells (IEC-6); further, the anti-inflammatory potentials were studied in lipopolysaccharide-induced cytokine production in macrophages. The synthesized bis-chalcones differ from each other first of all by the nature of the aromatic cores (functional group substitution, and their position) and by the size of a central alicycle. The exposure of IEC-6 cells to peroxide radicals reduced the cell viability; however, pre-treatment with the bis-chalcones improved the cell viability in these cells. The mechanism of action was observed to be the increased levels of glutathione and antioxidant enzyme activities. Further, these bis-chalcones also inhibited the LPS-stimulation-induced inflammatory cytokine production in RAW 264.7 macrophages. Overall, the present study indicated the cytoprotective and anti-inflammatory abilities of synthetic bis-chalcones.

Aims: In this paper, we report on the synthesis and liquid crystalline properties of some low molecular weight bis-chalcone compounds derived from acetone, cyclopentanone and cyclohexanone mesogenic cores. Background: Structurally bis-chalcones belong to a broader family of chalcone compounds. Chalcone is a compound that consists of two aromatic rings linked by an unsaturated α, β-ketone. Objective: Liquid crystalline chalcones are prepared by aliphatic chain substituents on two aromatic rings. Chalcones are well studied for their mesomorphic properties. Compared to a large number of chalcone based LCs reported, only a few articles have been published on the mesomorphic properties of bis-chalcone compounds. The target compounds of the present study varied not only in their central core but also in number and position of terminal aliphatic chain substitution-a key structural unit in deciding the liquid crystalline properties of a compound. Methods: All target compounds were synthesized in good yield by base catalyzed Claisen-Schmidt condensation reaction. Molecular structures were confirmed by FT-IR, ¹H NMR, ¹³C NMR, and mass spectroscopic methods. Liquid crystalline property of these compounds was evaluated using polarizing optical microscopy and differential scanning calorimetry. Results: Although none of the acetone based compounds exhibited mesomorphism, cyclopentanone and cyclohexanone based compounds with octyloxy chain at para position on either side of the dibenzylidine ring stabilized liquid crystalline smectic (SmA and SmC) and nematic (N) phases. The observed structure-liquid crystalline property relationship was explained by structural analysis of molecules using DFT calculations. Considering the inherent photoluminescence nature of the chalcone moiety, a preliminary study was carried out on a selected compound to reveal its fluorescence property. Conclusion: Our study brings about an important structure-liquid crystalline property relationship in a relatively unexplored class of bis-chalcone liquid crystals.

The present work describes the synthesis of two cholesterol appended cyanostyryl thiophene positional isomers CS-1 and CS-2 and their stimuli responsive solid state emission and liquid crystalline properties. Both compounds showed enhanced emission in the solid state due to their aggregation-induced emission (AIE). Interestingly, CS-1 and CS-2 showed emission switching under the influence of thermal and/or mechanical stimuli. The difference in emission properties of pristine CS-1 and its melt processed sample CS-1M is attributed to the formation of two different crystalline phases. The powder X-ray diffractogram simulated from the single crystal X-ray diffraction data of CS-1 and CS-1M showed similar features indicating that the molecules in the melt cooled phase adopt a packing similar to the one observed in the single crystal. In addition to heat-induced changes in fluorescence properties, compound CS-2 showed mechanofluorochromism and methanol vapour-induced reversible emission switching. The observed emission switching in CS-2 under thermal and shear stress was due to crystalline to amorphous transition. The emission recovery from the ground sample of CS-2 under methanol vapours was attributed to the reversible transition from amorphous to a crystalline phase similar to pristine CS-2. A detailed analysis of various photophysical parameters of the compounds under different stimuli is reported. The liquid crystalline properties of the compounds were studied using polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements. Both CS-1 and CS-2 showed the formation of an enantiotropic cholesteric (N*) liquid crystalline phase. Interestingly, the N* phase in CS-1 and CS-2 was stabilized down to room temperature in a glassy state.

Herein, we report the synthesis and self-assembly of a new class of amphiphilic azo dyes derived from a plant-based phenol, cardanol.