Synthesis, antihyperglycemic activity and computational studies of antioxidant chalcones and flavanones derived from 2,5 dihydroxyacetophenone

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.

Synthesis, antioxidant, in silico and computational investigation of 2,5-dihydroxyacetophenone derived chloro-substituted hydroxychalcones, hydroxyflavanones and hydroxyflavindogenides

An imbalance between reactive oxygen species (ROS) and their elimination by antioxidants damages the cell and infect whole organism. The biological defence system against oxidative stress injury is Kelch-like ECH associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response elements (ARE) pathways. Antioxidants activate the Nrf2-ARE-Keap1 pathway and suppress the oxidative stress. Flavonoids are well known medicinal compounds inheriting antioxidant efficacy and wide spectrum of pharmacological activities. The study is aimed to synthesise, characterize and evaluate pharmacological activities of synthesized chloro-derivatives of flavonoids. Chloro-derivatives of flavonoids were synthesized and characterized by IR, ¹H NMR and ¹³C NMR. Antioxidant potential of each synthesized compound was evaluated and then subjected to molecular docking with Keap1 (PDB ID: 2FLU) for the activation of Nrf2 and computational studies were performed by using DFT approach. Among the synthesized compounds compound 1a exhibited lower IC₅₀ value. While docking and computational studies infer that compound 3c is a good Nrf2 activator and radical scavenger with highest docking score and lower energy gaps and IP values compared to references. Hence, it might be considered for further molecular studies for the treatment of inflammatory diseases through Nrf2-ARE-Keap1 pathway. Communicated by Ramaswamy H. Sarma.HighlightsChloro-substituted hydroxychalcones, hydroxyflavanones and hydroxyflavindogenides were synthesized.Antioxidant potential was accessed, compound 1a exhibited good antioxidant potential.In silico study was performed with Keap1, compound 3c have shown highest docking score with Keap1.DFT approach was used to explore the structure activity relationship.

Synthesis, Conformational Analysis and ctDNA Binding Studies of Flavonoid Analogues Possessing the 3,5-di-tert-butyl-4-hydroxyphenyl Moiety

Flavanones and their biochemical precursors, chalcones, are naturally occurring compounds and consist of privileged scaffolds used in drug discovery due to their wide range of biological activities. In this work, two novel flavanones (3 and 4), the arylidene flavanone 5, and the chalcone 6, displaying structural analogies with butylated hydroxytoluene (BHT), were synthesized via an aldol reaction. According to the antioxidant activity studies of the synthesized flavanones, the arylidene flavanone 5 was the most potent antioxidant (70.8% interaction with DPPH radical and 77.4% inhibition of lipid peroxidation). In addition, the ability of the synthesized compounds to bind with ctDNA was measured via UV-spectroscopy, revealing that chalcone 6 has the strongest interaction with DNA (Kb = 5.0 × 10−3 M−1), while molecular docking was exploited to simulate the compound-DNA complexes. In an effort to explore the conformational features of the novel synthetic flavanones (3 and 4), arylidene flavanone 5, and chalcone 6, theoretical calculations were applied and the calculation of their physicochemical properties was also performed.

Recent advances in the antioxidant activity and mechanisms of chalcone derivatives: a computational review

In this review, we have reported the antioxidant mechanisms and structure-antioxidant activity relationship of several chalcone derivatives, investigated in the recent past, based on the density functional theory (DFT) calculations, considering free radical scavenging and metal chelation ability. The antioxidant mechanisms include hydrogen atom transfer (HAT), sequential proton loss electron transfer (SPLET), single electron transfer followed by proton transfer (SET-PT), sequential proton loss hydrogen atom transfer (SPLHAT), sequential double proton loss electron transfer (SdPLET), sequential triple proton loss double electron transfer (StPLdET), sequential triple proton loss triple electron transfer (StPLtET), double HAT, double SPLET, double SET-PT, triple HAT, triple SET-PT, triple SPLET, proton-coupled electron transfer (PCET), single electron transfer (SET), radical adduct formation (RAF) and radical adduct formation followed by hydrogen atom abstraction (RAF-HAA). Furthermore, solvent effects have also been considered using different solvation models. The feasibility of scavenging different reactive oxygen and nitrogen species (ROS/RNS) has been discussed considering various factors such as the number and position of hydroxyl as well as methoxy groups present in the antioxidant molecule, stability of the species formed after scavenging reactive species, nature of substituent, steric effects, etc. This review opens new perspectives for designing new compounds with better antioxidant potential.

Synthesis, Spectroscopic and Biological Investigation of a New Ca(II) Complex of Meloxicam as Potential COX-2 Inhibitor

Drug development on basis of coordination compounds provides versatile structural and functional properties as compared to other organic compounds. In the present study, a new Ca(II) complex of meloxicam was synthesized and characterized by elemental analysis, FT-IR, UV–Vis, ¹³C NMR, SEM–EDX, powder XRD and thermal analysis (TGA). The Ca(II) complex was investigated for its in vitro, in vivo biological activities and in silico docking analysis against COX-1 and COX-2. The spectral analysis indicates that the meloxicam acts as a deprotonated bidentate ligand (coordinated to the metal atom through the amide oxygen and the nitrogen atom of the thiazolyl ring) in the complex. SEM–EDX and powder XRD analysis depicted crystalline morphology of Ca(II) complex with a crystalline size of 32.86 nm. The in vitro biological activities were evaluated by five different antioxidant methods and COX inhibition assay, while in vivo activities were evaluated by carrageenan-, histamine- and PGE₂-induced paw edema methods and acetic acid-induced writhing test. The Ca(II) complex showed prominent antioxidant activities and was found to be more selective toward COX-2 (43.77) than COX-1 as compared to meloxicam. It exhibited lower toxicity (LD₅₀ 1000 mg/Kg) and significantly inhibited carrageenan- and PGE₂-induced inflammation at 10 mg/Kg (P < 0.05), but no significant effect was observed on histamine-induced inflammation. Moreover, Ca(II) complex significantly reduced the number of writhes induced by acetic acid (P < 0.05). The in silico molecular docking data revealed that Ca(II) complex obstructed COX-2 (dock score 6438) more effectively than COX-1 (dock score 5732) as compared to meloxicam alone.

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.