Antitubercular and antioxidant activities of hydroxy and chloro substituted chalcone analogues: Synthesis, biological and computational studies

Transition Metal-Catalyzed Transformations of Chalcones

Chalcones are a class of naturally occurring flavonoid compounds associated to a variety of biological and pharmacological properties. Several reviews have been published describing the synthesis and biological properties of a vast array of analogues. However, overviews on the reactivity of chalcones has only been explored in a few accounts. To fill this gap, a systematic survey on the most recent developments in the transition metal-catalyzed transformation of chalcones was performed. The chemistry of copper, palladium, zinc, iron, manganese, nickel, ruthenium, cobalt, rhodium, iridium, silver, indium, gold, titanium, platinum, among others, as versatile catalysts will be highlighted, covering the literature from year 2000 to 2023, in more than 380 publications.

The significance of persisters in tuberculosis drug discovery: Exploring the potential of targeting the glyoxylate shunt pathway

The significant challenge in confronting TB eradication is the discursive treatment that results in the disease reactivation, patient non compliance and drug resistance. The presently available drug regimen for TB largely targets the active bacilli and thus remains inadequate against the dormant or persistent subpopulation of Mtb that results in latent TB affecting a quarter of the global population. The crucial pathways that are particularly essential for the survival of dormant Mtb demand better apprehension. Novel drugs are needed to specifically address these persisters in order to enhance treatment effectiveness. Among such pathways, the glyoxylate bypass plays a critical role in the persistence and latent infection of Mtb, making it a promising target for drug development in recent years. In this review, we have compiled the attributes of bacterial subpopulations liable for latent TB and the pathways indispensable for their survival. Specifically, we delve into the glyoxylate shunt pathway and its key enzymes as potential drug targets.

Photophysical and biological aspects of α, β-unsaturated ketones: Experimental and in silico approach

In this work, four fluorinated α, β-unsaturated ketones named as 3-(3-bromophenyl)-1-(3-(trifluoromethyl)phenyl)prop-2-en-1-one (1), 3-(4-methoxyphenyl)-1-(3-(trifluoromethyl)phenyl) prop-2-en-1-one (2), 3-(3-bromo-5-chloro-2-hydroxyphenyl)-1-(3-(trifluoromethyl)phenyl) prop-2-en-1-one (3) and 3-(2-hydroxy-5-methylphenyl)-1-(3-(trifluoromethyl)phenyl)prop-2-en-1-one (4) were synthesized by Claisen-Schmidt reaction. The synthesized molecules were then characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FTIR), 1 H-NMR, 13 C-NMR, and mass spectrometry. The antioxidant potential, Urease inhibition, and interaction of compounds 1-4 with Salmon sperm DNA were experimentally explored and supported by molecular docking studies. The synthesized compounds strongly interact with SS-DNA through intercalative mode. It was noticed that compound 1 served as potent Urease inhibitor while compound 4 as better antioxidant among synthesized compounds. Moreover, frontier molecular orbitals, nonlinear optical (NLO) properties, natural bond orbitals, molecular electrostatic potential, natural population analysis, and photophysical properties of synthesized compounds were accomplished through density functional theory and time-dependent density functional theory. The band gap of all the compounds have been worked out using Taucs method. In addition to that, a precise comparative account of UV and IR data obtained from theoretical and experimental findings showed good agreement between theoretical and experimental data. The findings of our studies reflected that compounds 1-4 possess better NLO properties than Urea standard and the band gap data also reflected their prospective use towards optoelectronic materials. The better NLO behavior of compounds was attributed to the noncentrosymmetric structure of synthesized compounds.

Chalcones reloaded: an integration of network pharmacology and molecular docking for type 2 diabetes therapy

Chalcones have various biological effects, from immune boosting to anti-cancer and anti-diabetic. Structurally modified chalcones (SMC) are clinically relevant for diabetes and cardiometabolic complications. From the original research articles, a structurally proven and biologically outstanding 14 structurally modified chalcones were screened and inducted in this study. This study evaluated the effects of SMC towards diabetes via network pharmacology analysis. The network data shows compounds S2, S3, S5, S9 &S12 suit the diabetes target. Especially Compounds S5 and S9 have a higher binding affinity towards the targets of TNF, PI3K, MAPK1 and AKT1 active sites. Compound S9 [(E)-3-(4-(1H-imidazol-1-yl)phenyl)-1-(4-(2,4-difluorobenz-yloxy)phenyl)prop-2-en-1-one] have identified with stronger binding affinities towards the active sites of MAPK3 (PDB:4QTB) -10.5(Kcal/mol). To provide a more effective mechanism for demonstrating protein-ligand interaction, one of the molecular docking complex (ERK2 kinase-S5) was subjected to a molecular dynamic at 300K for 100 ns. In term of structural stability, structure compactness, residual flexibility and hydrogen bond interaction of the complex was evaluated Integrating network pharmacology, in silico virtual screening, and molecular docking analysis shows that structurally modified compounds are effective and may help identify lead compounds towards glycemic control.Communicated by Ramaswamy H. Sarma.

Hydroxy Chalcones and Analogs with Chemopreventive Properties

The aim of this review is to highlight the chemopreventive properties of hydroxy-substituted natural and synthetic chalcones along with a number of their analogs. These products display various biological activities, and have many applications against various diseases. Antioxidant and anti-inflammatory properties of chalcones bearing hydroxy substituents are underlined. The influence of hydroxy substituents located on ring A, B, or both are systematized according to the exhibited biological properties.

Promising Antimycobacterial Activities of Flavonoids against Mycobacterium sp. Drug Targets: A Comprehensive Review

Tuberculosis (TB) caused by the bacterial pathogen Mycobacterium tuberculosis (Mtb) remains a threat to mankind, with over a billion of deaths in the last two centuries. Recent advancements in science have contributed to an understanding of Mtb pathogenesis and developed effective control tools, including effective drugs to control the global pandemic. However, the emergence of drug resistant Mtb strains has seriously affected the TB eradication program around the world. There is, therefore, an urgent need to develop new drugs for TB treatment, which has grown researchers’ interest in small molecule-based drug designing and development. The small molecules-based treatments hold significant potential to overcome drug resistance and even provide opportunities for multimodal therapy. In this context, various natural and synthetic flavonoids were reported for the effective treatment of TB. In this review, we have summarized the recent advancement in the understanding of Mtb pathogenesis and the importance of both natural and synthetic flavonoids against Mtb infection studied using in vitro and in silico methods. We have also included flavonoids that are able to inhibit the growth of non-tubercular mycobacterial organisms. Hence, understanding the therapeutic properties of flavonoids can be useful for the future treatment of TB.

Structural modification and antibacterial property studies of natural chalcone sanjuanolide

Clinical infections arise from multidrug-resistant bacteria and pose a serious threat to human and global public health. Moreover, due to very few antibiotics being discovered, there is an urgent need to develop new antibacterial agents to combat antimicrobial resistance challenges. In this study, a series of new chalcone derivatives bearing a 3′-hydroxyisoprenyl moiety were prepared to employ Claisen–Schmidt condensation as a key step by combinatorial chemistry, and overall yields of these novel derivatives are in the range of 28–68% in the two-step reaction. Sanjuanolide and the synthesized derivatives have been investigated for their expected antibacterial activities against Gram-positive bacteria (Staphylococcus aureus CMCC 26003) and Gram-negative bacteria (Escherichia coli CMCC 44102). Among these compounds, only 4c (MIC = 12.5 μg/ml) and 4d (MIC = 25 μg/ml) exhibited antibacterial activity comparable to sanjuanolide (MIC = 12.5 μg/ml, against S. aureus CMCC 26003), and the results of subsequent in vivo experiments on sanjuanolide suggest that sanjuanolide exhibits bacteriostatic and bactericidal effects by altering the cellular structure, disrupting the integrity of cell membranes, and reducing the outer membrane potential.

Synthesis, Structure, and Biologic Activity of Some Copper, Nickel, Cobalt, and Zinc Complexes with 2-Formylpyridine N4-Allylthiosemicarbazone

A series of zinc(II) ([Zn(H₂O)(L)Cl] (1)), copper (II) ([Cu(L)Cl] (2), [Cu(L)Br] (3), [Cu₂(L)₂(CH₃COO)₂]·4H₂O (4)), nickel(II) ([Ni(HL)₂]Cl₂·H₂O (5)), and cobalt(III) ([Co(L)₂]Cl (6)) complexes were obtained with 2-formylpyridine N⁴-allylthiosemicarbazone (HL). In addition another two thiosemicarbazones (3-formylpyridine N⁴-allylthiosemicarbazone (HL^a) and 4-formylpyridine N⁴-allylthiosemicarbazone (HL^b)) have been obtained. The synthesized thiosemicarbazones have been studied using ¹H and ¹³C NMR spectroscopy, IR spectroscopy, and X-ray diffraction analysis. The composition and structure of complexes were studied using elemental analysis, IR and UV-Vis spectroscopies, molar conductivity, and magnetic susceptibility measurements. Single crystal X-ray diffraction analysis elucidated the structure of thiosemicarbazones HL, HL^a, and HL^b, as well as complexes 4 and 5. The antiproliferative properties of these compounds toward a series of cancer cell lines (HL-60, HeLa, BxPC-3, RD) and a normal cell line (MDCK) have been investigated. The nickel complex shows high selectivity (SI > 1000) toward HL-60 cell line and is the least toxic. The zinc complex shows the highest selectivity toward RD cell line (SI = 640). The copper complexes (2–4) are the most active molecular inhibitors of proliferation of cancer cells, but exhibit not such a high selectivity and are significantly more toxic. Zinc and copper complexes manifest high antibacterial activity. It was found that calculated at B3LYP level of theory different reactivity descriptors of studied compounds strongly correlate with their biological activity.

Synthesis and in vitro studies for structure-based design of novel chalcones as antitubercular agents targeting InhA

Background: The authors aimed to estimate the therapeutic potential of novel chalcones against tuberculosis. Methods: 11 synthesized compounds were tested for in vitro antimycobacterial activity against Mycobacterium tuberculosis (H37RV; American Type Culture Collection number: 27294) using the microplate alamarBlue assay. Molecular docking and pharmacokinetic parameter analyses were then performed. Results: The most potent compounds, (2E)-1-(4-bromophenyl) (2E)-1-(2-nitrophenyl) prop-2-en-1-one, -3-(2-nitrophenyl) prop-2-en-1-one (4-bromophenyl) (2E)-1-(3-phenoxyphenyl)prop-2-en-1-one, 3-(phenoxyphenyl)prop-2-en-1-one (4-bromophenyl) prop-2-en-1-one and (2E)-1-(4-bromophenyl)-3-(5-chloro-2-hydroxyphenyl)-prop-2-en-1-one, showed in vitro activity, with a minimum inhibitory concentration (MIC) of 6.25 μg/ml. Conclusion: Compounds LSD2, LSD12, LSD13 and LSD15 showed strong in vitro antimycobacterial activity at a concentration of 6.25 μg/ml.

Hybrid Catalysts from Copper Biosorbing Bacterial Strains and Their Recycling for Catalytic Application in the Asymmetric Addition Reaction of B2(pin)2 on α,β-Unsaturated Chalcones

The recycling of heavy metal contaminants from wastewater as a source of valuable products perfectly fits with the principles of a Circular Economy system in view of restoring pollutants back into the system endowed with new social and economic benefits. Heavy metals are often present in such a low concentration that it makes the removal efficiency difficult to realize through the conventional physicochemical methods with high selectivity. Biosorption, conversely, by EPSs (extracellular polymeric substances) produced by several bacterial cells’ strains, is gaining a great deal of attention as an economic, efficient and sustainable depolluting process of wastewater from metal cations such as copper. Metal coordination to EPS components was thus deeply investigated by 1H NMR titration experiments. The 1,10–Phenanthroline–copper complex was exploited for quantifying the ability of different strains to sequester copper by a practical UV-Vis spectrophotometric method. The obtained data distinguished Serratia plymuthica strain SC5II as the bacterial strain displaying copper-adsorbing properties higher than any other, with Stenotrophomonas sp. strain 13a resulting in the worst one. Different analytical techniques, i.e., Dynamic Light Scattering (DLS), FT-IR analysis and SEM spectroscopy were thus employed to rationalize these results. Finally, the obtained copper chelates were successfully employed as hybrid catalysts in the asymmetric boron addition to α,β-unsaturated chalcones for the synthesis of valuable pharmaceutical intermediates, thus placing waste management in a new circular perspective.