Synthesis, Characterization and Antibacterial Activities of New Fluorinated Chalcones

Synthesis, antibacterial, antibiofilm, and docking studies of chalcones against multidrug resistance pathogens

The escalating threat of drug-resistant microbes underscores the urgent need for novel antimicrobial agents. In response, considerable research effort has been directed towards developing innovative frameworks and strategies to address this challenge. Chalcones, known for their broad-spectrum biological activities, have emerged as promising candidates for combating drug resistance. In this study, a series of 2'-Hydroxychalcones (5a, 5b, 5c, and 5d) with varying electron withdrawing and donating groups were synthesized via Claisen Schmidt condensation. FT-IR, 1H NMR, and 13C NMR analyses were employed to confirm the structure of the synthesized compounds. Subsequent evaluation of the synthesized compounds revealed their potential as antibacterial and antibiofilm agents. Notably, compounds 5a and 5d exhibited potent antibacterial activity against multidrug-resistant (MDR) bacteria E. coli, P. aeruginosa, K. pneumoniae, and S. aureus, surpassing the reference drug Ciprofloxacin (30 μg/mL) and other synthesized compounds. Compound 5d showed a notable 19.5 mm zone of inhibition against K. pneumoniae. Furthermore, 5a (at a concentration of 30 μg) and 5d (at a concentration of 50 μg) exhibited statistically significant (P > 0.05) biofilm inhibition efficacy compared to Ciprofloxacin (30 μg/mL). The synthesized chalcones 5a-5d were also docked via PachDock molecular docking software for Glucosamine-6-phosphate (GlcN-6-P) synthase inhibition and showed that ligand 5a exhibited outstanding results with score 4238 and ACE value -160.89 kcal/mol, consistent with the observed antibacterial activity. These findings underscore the potential of chalcones, particularly 5a and 5d, as promising candidates for the development of new antimicrobial agents targeting drug-resistant microbes and biofilm formation.

Furan-based Chalcone Annihilates the Multi-Drug-Resistant Pseudomonas aeruginosa and Protects Zebra Fish Against its Infection

The emergence of carbapenem-resistant Pseudomonas aeruginosa, a multi-drug-resistant bacteria, is becoming a serious public health concern. This bacterium infects immunocompromised patients and has a high fatality rate. Both naturally and synthetically produced chalcones are known to have a wide array of biological activities. The antibacterial properties of synthetically produced chalcone were studied against P. aeruginosa. In vitro, study of the compound (chalcone derivative named DKO1), also known as (2E)-1-(5-methylfuran-2-yl)-3-(4-nitrophenyl) prop-2-en-1-one, had substantial antibacterial and biofilm disruptive action. DKO1 effectively shielded against P. aeruginosa-induced inflammation, oxidative stress, lipid peroxidation, and apoptosis in zebrafish larvae. In adult zebrafish, the treatment enhanced the chances of survivability and reduced the sickness-like behaviors. Gene expression, biochemical analysis, and histopathology studies found that proinflammatory cytokines (TNF-α, IL-1β, IL-6, iNOS) were down regulated; antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) levels increased, and histoarchitecture was restored in zebrafish. The data indicate that DKO1 is an effective antibacterial agent against P. aeruginosa demonstrated both in vitro and in vivo.

Antiviral and antimicrobial applications of chalcones and their derivatives: From nature to greener synthesis

Chalcones and their derivatives have been widely studied due to their versatile pharmacological and biological activities, such as anti-inflammatory, antibacterial, antiviral, and antitumor effects. These compounds have shown suitable antiviral effects through the selective targeting of a variety of viral enzymes, including lactate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fumarate reductase, protein tyrosine phosphatase, topoisomerase-II, protein kinases, integrase/protease, and lactate/isocitrate dehydrogenase, among others. Chalcones and their derivatives have displayed excellent potential for combating pathogenic bacteria and fungi (especially, multidrug-resistant bacteria). However, relevant mechanisms should be further explored, focusing on inhibitory effects against DNA gyrase B, UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), and efflux pumps (e.g., NorA), among others. In addition, the antifungal and antiparasitic activities of these compounds (e.g., antitrypanosomal and antileishmanial properties) have prompted additional explorations. Nonetheless, systematic analysis of the relevant mechanisms, biosafety issues, and pharmacological properties, as well as clinical translation studies, are vital for practical applications. Herein, recent advancements pertaining to the antibacterial, antiviral, antiparasitic, and antifungal activities of chalcones and their derivatives are deliberated, focusing on the relevant mechanisms of action, crucial challenges, and future prospects. Furthermore, due to the great importance of greener and more sustainable synthesis of these valuable compounds, especially on an industrial scale, the progress made in this field has been briefly discussed. Hopefully, this review can serve as a catalyst for researchers to delve deeper into the exploration and designing of novel chalcone compounds with medicinal properties, especially against pathogenic viruses and multidrug-resistant bacteria as major causes of concern for human health.

Chalcones: Synthetic Chemistry Follows Where Nature Leads

Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest groups of bioactive natural products. The potential anticancer, anti-inflammatory, antimicrobial, antioxidant, and antiparasitic properties of naturally occurring chalcones, and their unique chemical structural features inspired the synthesis of numerous chalcone derivatives. In fact, structural features of chalcones are easy to construct from simple aromatic compounds, and it is convenient to perform structural modifications to generate functionalized chalcone derivatives. Many of these synthetic analogs were shown to possess similar bioactivities as their natural counterparts, but often with an enhanced potency and reduced toxicity. This review article aims to demonstrate how bioinspired synthesis of chalcone derivatives can potentially introduce a new chemical space for exploitation for new drug discovery, justifying the title of this article. However, the focus remains on critical appraisal of synthesized chalcones and their derivatives for their bioactivities, linking to their interactions at the biomolecular level where appropriate, and revealing their possible mechanisms of action.

Pharmacological Properties of Chalcones: A Review of Preclinical Including Molecular Mechanisms and Clinical Evidence

Chalcones are among the leading bioactive flavonoids with a therapeutic potential implicated to an array of bioactivities investigated by a series of preclinical and clinical studies. In this article, different scientific databases were searched to retrieve studies depicting the biological activities of chalcones and their derivatives. This review comprehensively describes preclinical studies on chalcones and their derivatives describing their immense significance as antidiabetic, anticancer, anti-inflammatory, antimicrobial, antioxidant, antiparasitic, psychoactive, and neuroprotective agents. Besides, clinical trials revealed their use in the treatment of chronic venous insufficiency, skin conditions, and cancer. Bioavailability studies on chalcones and derivatives indicate possible hindrance and improvement in relation to its nutraceutical and pharmaceutical applications. Multifaceted and complex underlying mechanisms of chalcone actions demonstrated their ability to modulate a number of cancer cell lines, to inhibit a number of pathological microorganisms and parasites, and to control a number of signaling molecules and cascades related to disease modification. Clinical studies on chalcones revealed general absence of adverse effects besides reducing the clinical signs and symptoms with decent bioavailability. Further studies are needed to elucidate their structure activity, toxicity concerns, cellular basis of mode of action, and interactions with other molecules.

Design, Synthesis, and Antibacterial and Antifungal Activities of Novel Trifluoromethyl and Trifluoromethoxy Substituted Chalcone Derivatives

Despite the availability of many drugs to treat infectious diseases, the problems like narrow antimicrobial spectrum, drug resistance, hypersensitivities and systemic toxicities are hampering their clinical utility. Based on the above facts, in the present study, we designed, synthesized and evaluated the antibacterial and antifungal activity of novel fluorinated compounds comprising of chalcones bearing trifluoromethyl (A1-A10) and trifluoromethoxy (B1-B10) substituents. The compounds were characterized by spectroscopic techniques and evaluated for their antimicrobial activity against four pathogenic Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Bacillus subtilis) bacterial and fungal (Candida albicans and Aspergillus niger) strains. In this study, the compounds with trifluoromethoxy group were more effective than those with trifluoromethyl group. Among the 20 fluorinated chalcones, compound A3/B3 bearing an indole ring attached to the olefinic carbon have been proved to possess the most antimicrobial activity compared to the standard drugs without showing cytotoxicity on human normal liver cell line (L02). Further, the minimum inhibitory concentration (MIC) for A3/B3 was determined by serial tube dilution method and showed potential activity. These results would provide promising access to future study about the development of novel agents against bacterial and fungal infections.

Direct antibacterial and antibiotic resistance modulatory activity of chalcones synthesized from the natural product 2-hydroxy-3,4,6-trimethoxyacetophenone

Antibiotic for clinical use lose its effectiveness over time due to bacterial resistance. In this work, four chalcones with modifications in their ligands were synthesized from the natural product 2-hydroxy-3,4,6-trimethoxyacetophenone, characterized by nuclear magnetic resonance (NMR) and infrared spectroscopy, and tested in bacterial models to investigate the direct and modifiers effects of the antibiotic activity of these four novel chalcones. The tests followed the broth microdilution methodology to obtain the Minimum Inhibitory Concentration (MIC). The MIC/8 of the products were used in the resistance reversion test. The chalcone 2 showed the best result in terms of direct activity, with MIC 645 μg/mL for Staphylococcus aureus and 812 μg/mL for Escherichia coli. While, for the bacterial resistance reversal test, the chalcones presented several synergistic interactions, being that chalcone 4 had the best interaction with the tested antibiotics. It was found that the type of ligand, as well as its position in the ring, interferes in the modulation of the antibiotic activity. Our results show that chalcones are strong candidates to be used as antibacterial drug or in combination with antibiotics for the treatment of infections caused by multidrug-resistant (MDR) strains.