Recent developments in biological activities of chalcones: a mini review

The Antioxidant, Anti-Inflammatory, and Neuroprotective Properties of the Synthetic Chalcone Derivative AN07

Chalcones belong to a class of biologically active polyphenolic natural products. As a result of their simple chemical nature, they are easily synthesized and show a variety of promising biological activities. 2-Hydroxy-4′-methoxychalcone (AN07) is a synthetic chalcone derivate with potential anti-atherosclerosis effects. In this study, we demonstrated the novel antioxidant, anti-inflammatory, and neuroprotective effects of AN07. In RAW 264.7 macrophages, AN07 attenuated lipopolysaccharide (LPS)-induced elevations in reactive oxygen species (ROS) level and oxidative stress via down-regulating gp91^phox expression and stimulating the antioxidant system of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) pathways, which were accompanied by increased glutathione (GSH) levels. Additionally, AN07 attenuated LPS-induced inflammatory factors, including NO, inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and phosphorylated inhibitor of nuclear factor kappa B-alpha (p-IκBα) in RAW 264.7 macrophages. However, the effects of AN07 on promoting nuclear Nrf2 levels and decreasing COX-2 expressions were significantly abrogated by the peroxisome proliferator-activated receptor-γ (PPARγ) antagonist GW9662. In human dopaminergic SH-SY5Y cells treated with or without methylglyoxal (MG), a toxic endogenous by-product of glycolysis, AN07 up-regulated neurotrophic signals including insulin-like growth factor 1 receptor (IGF-1R), p-Akt, p-GSK3β, glucagon-like peptide 1 receptor (GLP-1R), and brain-derived neurotrophic factor (BDNF). AN07 attenuated MG-induced apoptosis by up-regulating the B-cell lymphoma 2 (Bcl-2) protein and down-regulating the cytosolic expression of cytochrome c. AN07 also attenuated MG-induced neurite damage via down-regulating the Rho-associated protein kinase 2 (ROCK2)/phosphorylated LIM kinase 1 (p-LIMK1) pathway. Moreover, AN07 ameliorated the MG-induced down-regulation of neuroprotective Parkinsonism-associated proteins parkin, pink1, and DJ-1. These findings suggest that AN07 possesses the potentials to be an anti-inflammatory, antioxidant, and neuroprotective agent

Salvia miltiorrhiza-Derived Sal-miR-58 Induces Autophagy and Attenuates Inflammation in Vascular Smooth Muscle Cells

Autophagy is associated with the cytoprotection of physiological processes against inflammation and oxidative stress. Salvia miltiorrhiza possesses cardiovascular protective actions and has powerful anti-oxidative and anti-inflammatory effects; however, whether and how Salvia miltiorrhiza-derived microRNAs (miRNAs) protect vascular smooth muscle cells (VSMCs) by inducing autophagy across species are unknown. We first screened and identified Sal-miR-58 from Salvia miltiorrhiza as a natural autophagy inducer. Synthetic Sal-miR-58 suppresses chronic angiotensin II (Ang II) infusion-induced abdominal aortic aneurysm (AAA) formation in mice, as well as induces autophagy in VSMCs and attenuates the inflammatory response elicited by Ang II in vivo and in vitro. Mechanistically, Sal-miR-58 downregulates Krüppel-like factor 3 (KLF3) expression through direct binding to the 3' UTR of KLF3, which in turn relieves KLF3 repression of E3 ubiquitin ligase neural precursor cell-expressed developmentally downregulated 4-like (NEDD4L) expression, whereas NEDD4L upregulation increases the ubiquitination and degradation of the platelet isoform of phosphofructokinase (PFKP), subsequently leading to a decrease in the activation of Akt/mammalian target of rapamycin (mTOR) signaling and facilitating VSMC autophagy induced by Sal-miR-58 in the context of chronic Ang II stimulation and aneurysm formation. Our results provide the first evidence that plant-derived Sal-miR-58 induces autophagy and attenuates inflammation in VSMCs through cross-species modulation of the KLF3/NEDD4L/PFKP regulatory pathway.

β-Lactams as promising anticancer agents: Molecular hybrids, structure activity relationships and potential targets

β-Lactam, commonly referred as azetidin-2-one, is a multifunctional building block for synthesizing β-amino ketones, γ-amino alcohols, and other compounds. Besides its well known antibiotic activity, this ring system exhibits a wide range of activities, attracting the attention of researchers. However, the structurally diverse β-lactam analogues as anticancer agents and their different molecular targets are poorly discussed. The purpose of this review is 3-fold: (1) to explore the molecular hybridization approach to design β-lactams hybrids as anticancer agents; (2) the structure activity relationship of the most active anticancer β-lactams and (3) to summarize their antitumor mechanisms.

Antiproliferative and Apoptotic Effects of Cardamonin against Hepatocellular Carcinoma HepG2 Cells

Liver cancer is the sixth most common cancer in terms of incidence and the fourth in terms of mortality. Hepatocellular carcinoma (HCC) represents almost 90% of primary liver cancer and has become a major health problem globally. Cardamonin (CADMN) is a natural bioactive chalcone found in several edible plants such as cardamom and Alpinia species. Previous studies have shown that CADMN possesses anticancer activities against breast, lung, prostate and colorectal cancer. In the present study, the mechanisms underlying the anti-hepatocellular carcinoma effects of CADMN were investigated against HepG2 cells. The results demonstrated that CADMN has anti-proliferative effects and apoptotic action on HepG2 cells. CADMN showed potent cytotoxicity against HepG2 cells with an IC₅₀ of 17.1 ± 0.592 μM at 72 h. Flow cytometry analysis demonstrated that CADMN arrests HepG2 cells in G1 phase and induces a significant increase in early and late apoptosis in a time-dependent manner. The mechanism by which CADMN induces apoptotic action was via activation of both extrinsic and intrinsic pathways. Moreover, the findings of this study showed the involvement of reactive oxygen species (ROS), which inhibit the NF-κB pathway and further enhance the apoptotic process. Together, our findings further support the potential anticancer activity of CADMN as an alternative therapeutic agent against HCC.

(E)-2-(3,5-Di-meth-oxy-benzyl-idene)indan-1-one

The title chalcone, C18H16O3, was prepared by a solventless base-promoted Claisen-Schmidt condensation and, upon recrystallization from ethanol, obtained in 56% yield. The dihedral angle between the indanone ring system and the benzene ring is 2.54 (4) ° and the C atoms of the methoxy groups deviate from the benzene ring by 0.087 (1) and 0.114 (1) Å. In the crystal, π-stacking is the predominant inter-molecular force, with the mol-ecules stacking into columns running parallel to the b axis of the unit cell.

Advanced Mechanochemistry Device for Sustainable Synthetic Processes

Mechanochemistry is an alternative for sustainable solvent-free processes that has taken the big step to become, in the near future, a useful synthetic method for academia and the fine chemical industry. The apparatus available, based on ball milling systems possessing several optimizable variables, requires too many control and optimization experiments to ensure reproducibility, which has limited its widespread utilization so far. Herein, we describe the development of an automatic mechanochemical single-screw device consisting of an electrical motor, a drill, and a drill chamber. The applicability and versatility of the new device are demonstrated by the implementation of di- and multicomponent chemical reactions with high reproducibility, using mechanical action exclusively. As examples, chalcones, dihydropyrimidinones, dihydropyrimidinethiones, pyrazoline, and porphyrins, were synthesized with high yields. The unprecedented sustainability is demonstrated by comparison of EcoScale and E-factor values of these processes with those previously described in the literature.

Novel Class of Chalcone Oxime Ethers as Potent Monoamine Oxidase-B and Acetylcholinesterase Inhibitors

Previously synthesized novel chalcone oxime ethers (COEs) were evaluated for inhibitory activities against monoamine oxidases (MAOs) and acetylcholinesterase (AChE). Twenty-two of the 24 COEs synthesized, except COE-17 and COE-24, had potent and/or significant selective inhibitory effects on MAO-B. COE-6 potently inhibited MAO-B with an IC₅₀ value of 0.018 µM, which was 105, 2.3, and 1.1 times more potent than clorgyline, lazabemide, and pargyline (reference drugs), respectively. COE-7, and COE-22 were also active against MAO-B, both had an IC₅₀ value of 0.028 µM, which was 67 and 1.5 times lower than those of clorgyline and lazabemide, respectively. Most of the COEs exhibited weak inhibitory effects on MAO-A and AChE. COE-13 most potently inhibited MAO-A (IC₅₀ = 0.88 µM) and also significantly inhibited MAO-B (IC₅₀ = 0.13 µM), and it could be considered as a potential nonselective MAO inhibitor. COE-19 and COE-22 inhibited AChE with IC₅₀ values of 5.35 and 4.39 µM, respectively. The selectivity index (SI) of COE-22 for MAO-B was higher than that of COE-6 (SI = 778.6 vs. 222.2), but the IC₅₀ value (0.028 µM) was slightly lower than that of COE-6 (0.018 µM). In reversibility experiments, inhibitions of MAO-B by COE-6 and COE-22 were recovered to the levels of reference reversible inhibitors and both competitively inhibited MAO-B, with K_i values of 0.0075 and 0.010 µM, respectively. Our results show that COE-6 and COE-22 are potent, selective MAO-B inhibitors, and COE-22 is a candidate of dual-targeting molecule for MAO-B and AChE.

Coumarin-containing hybrids and their antibacterial activities

Infections caused by Gram-positive and -negative bacteria are one of the foremost causes of morbidity and mortality globally. Antibiotics are the mainstay of therapy for bacterial infections, but the emergence and wide spread of drug-resistant pathogens have already become a huge issue for public healthcare systems. The coumarin moiety, which is ubiquitous in nature, could bind to the B subunit of DNA gyrase in bacteria and inhibit DNA supercoiling by blocking the ATPase activity; hence, coumarin derivatives possess potential antibacterial activity. Several coumarin-containing hybrids such as coumermycin A1, clorobiocin, and novobiocin have already been used in clinical practice for the treatment of various bacterial infections; thus, it is conceivable that hybridization of the coumarin moiety with other antibacterial pharmacophores may provide opportunities for the development of novel antibiotics. This review outlines the advances in coumarin-containing hybrids with antibacterial potential in the recent 5 years and the structure-activity relationships are also discussed.

Natural Chalcones in Chinese Materia Medica: Licorice

Licorice is an important Chinese materia medica frequently used in clinical practice, which contains more than 20 triterpenoids and 300 flavonoids. Chalcone, one of the major classes of flavonoid, has a variety of biological activities and is widely distributed in nature. To date, about 42 chalcones have been isolated and identified from licorice. These chalcones play a pivotal role when licorice exerts its pharmacological effects. According to the research reports, these compounds have a wide range of biological activities, containing anticancer, anti-inflammatory, antimicrobial, antioxidative, antiviral, antidiabetic, antidepressive, hepatoprotective activities, and so on. This review aims to summarize structures and biological activities of chalcones from licorice. We hope that this work can provide a theoretical basis for the further studies of chalcones from licorice.

Discovery of thiazole-based-chalcones and 4-hetarylthiazoles as potent anticancer agents: Synthesis, docking study and anticancer activity

The crucial need for novel antitumor agents with high selectivity toward cancer cells has promoted us to synthesize new series of thiazole-based chalcones and 4-hetarylthiazoles (rigid chalcones). The synthesis of thiazolyl chalcones and 4-hetarylthiazoles and the assertion of their structure are described. Their anti-proliferative activity was estimated against three human cancer cell lines; HepG-2, A549 and MCF-7. 3-(4-Methoxyphenyl)-1-(5-methyl-2-(methylamino)thiazol-4-yl)prop-2-en-1-one (chalcone derivative 3a) showed significant and broad antitumor activity that was more potent than Doxorubicin. In addition, compounds 3d, 3e and 7a displayed potent activity compared to Doxorubicin. Additionally, these compounds were less toxic on normal lung cells WI-38 with high selectivity index. Further study on 3a regarding its effect on the normal cell cycle profile in A549 cells demonstrated cell cycle arrest at the G2/M phase together with rise in the percentage of the apoptotic pre-G1 cells. CDK1/CDK2/CDK4 inhibition assays were carried out on 3a, 3d, 3e and 7a and the results revealed non selective inhibition on the tested CDKs with IC₅₀ values of 0.78-1.97 µM. Moreover, docking study predicted that 3a, 3d, 3e and 7a can fit in the ATP binding site of CDK1 enzyme. The apoptosis induction potential of 3a, 3d, 3e and 7a was also estimated against some apoptosis markers. Interestingly, they elevated the level of Bax by 6.36-10.12 folds and reduced the expression of Bcl-2 by 1.94-4.12 folds compared to the control. Furthermore, they increased both active caspase-3 and p53 levels by 8.76-10.56 and 6.85-10.36 folds, respectively higher than the control which indicates their potential to induce apoptosis.

Soybean isoflavones prevent atrazine-induced neurodegenerative damage by inducing autophagy

Atrazine (ATR) is a widely used herbicide with documented dopaminergic (DAergic) neurotoxicity that can lead to a Parkinson's disease (PD)-like motor syndrome. However, there have been few studies on preventative interventions. The aim of the present study was to investigate the neuroprotective efficacy of soybean isoflavones (SI) and associated molecular mechanisms in a rat model of ATR-induced DAergic toxicity. Male Sprague-Dawley rats (6 weeks old) received daily intraperitoneal injection of SI (10, 50, or 100 mg/kg) or vehicle followed 1 h later by oral gavage of ATR (50 mg/kg) for 45 consecutive days. Open field and grip-strength tests indicated no differences in motor function among treatment groups. Alternatively, histopathology revealed neuronal damage in the striatum of rats receiving vehicle plus ATR that was ameliorated by SI pretreatment. SI attenuate ATR-induced oxidative stress (indicated by MDA accumulation and GSH depletion) and inflammatory damage (as evidenced by TNF-α and IL-6 elevation) in the substantia nigra. ATR increased expression of the pro-apoptotic factor Bax and reduced expression levels of the DA synthesis enzyme tyrosine hydroxylase (TH) and the anti-apoptotic factor Bcl-2 in the substantia nigra and striatum. All of these effects were reversed by SI pretreatment, suggesting that SI can inhibit ATR-induced apoptosis of DAergic neurons. ATR also inhibited autophagy in the substantial nigra as evidenced by LC3-II and Beclin-1 downregulation and increased expression of p62, whereas SI pretreatment reversed these effects, indicating autophagy induction. Furthermore, ATR increased the expression of mTOR and reduced the expression of phosphorylated S6 (p-S6) and BEX2 in the substantia nigra. Collectively, these findings suggest that SI can prevent ATR-mediated degeneration of DAergic neurons by inducing autophagy through an mTOR-dependent signaling pathway.

Structure based modification of chalcone analogue activates Nrf2 in the human retinal pigment epithelial cell line ARPE-19

Oxidative stress-induced degeneration of retinal pigment epithelial (RPE) cells is known to be a key contributor to the development of age-related macular degeneration (AMD). Activation of the nuclear factor-(erythroid-derived 2)-related factor-2 (Nrf2)-mediated cellular defense system is believed to be a valid therapeutic approach. In the present study, we designed and synthesized a novel chalcone analogue, 1-(2,3,4-trimethoxyphenyl)-2-(3,4,5-trimethoxyphenyl)-acrylketone (Tak), as a Nrf2 activator. The potency of Tak was measured in RPE cells by the induction of the Nrf2-dependent antioxidant genes HO-1, NQO-1, GCLc, and GCLm, which were regulated through the Erk pathway. We also showed that Tak could protect RPE cells against oxidative stress-induced cell death and mitochondrial dysfunction. Furthermore, by modifying the α, β unsaturated carbonyl entity in Tak, we showed that the induction of antioxidant genes was abolished, indicating that this unique feature in Tak was responsible for the Nrf2 activation. These results suggest that Tak is a potential candidate for clinical application against AMD.

Chalcones, stilbenes and ketones have anti-infective properties via inhibition of bacterial drug-efflux and consequential synergism with antimicrobial agents

With antimicrobial resistance creating a major public health crisis, the designing of novel antimicrobial compounds that effectively combat bacterial infection is becoming increasingly critical. Interdisciplinary approaches integrate the best features of whole-cell phenotypic evaluation to validate novel therapeutic targets and discover new leads to combat antimicrobial resistance. In this project, whole-cell phenotypic evaluation such as testing inhibitors on bacterial growth, viability, efflux pump, biofilm formation and their interaction with other drugs were performed on a panel of Gram-positive, Gram-negative and acid-fast group of bacterial species. This enabled additional antimicrobial activities of compounds belonging to the flavonoid family including ketones, chalcones and stilbenes, to be identified. Flavonoids have received renewed attention in literature over the past decade, and a variety of beneficial effects of these compounds have been illuminated, including anti-cancer, anti-inflammatory, anti-tumour as well as anti-fungal and anti-bacterial. However, their mechanisms of action are yet to be identified. In this paper, we found that the compounds belonging to the flavonoid family exerted a range of anti-infective properties being identified as novel efflux pump inhibitors, whilst offering the opportunity to be used in combination therapy. The compound 2-phenylacetophenone displayed broad-spectrum efflux pump inhibition activity, whilst trans-chalcone, displayed potent activity against Gram-negative and mycobacterial efflux pumps causing inhibition higher than known potent efflux pump inhibitors, verapamil and chlorpromazine. Drug-drug interaction studies also highlighted that 2-phenylacetophenone not only has the potential to work additively with known antibacterial agents that affect the cell-wall and DNA replication but also trans-chalcone has the potential to work synergistically with anti-tubercular agents. Overall, this paper shows how whole-cell phenotypic analysis allows for the discovery of new antimicrobial agents and their consequent mode of action whilst offering the opportunity for compounds to be repurposed, in order to contribute in the fight against antimicrobial resistance.

Privileged Scaffold Chalcone: Synthesis, Characterization and Its Mechanistic Interaction Studies with BSA Employing Spectroscopic and Chemoinformatics Approaches

Chalcone, a privileged structure, is considered as an effective template in the field of medicinal chemistry for potent drug discovery. In the present study, a privileged template chalcone was designed, synthesized, and characterized by various spectroscopic techniques (NMR, high-resolution mass spectrometry, Fourier transform infrared (FT-IR) spectroscopy, UV spectroscopy, and single-crystal X-ray diffraction). The mechanism of binding of chalcone with bovine serum albumin (BSA) was determined by multispectroscopic techniques and computational methods. Steady-state fluorescence spectroscopy suggests that the intrinsic fluorescence of BSA was quenched upon the addition of chalcone by the combined dynamic and static quenching mechanism. Time-resolved spectroscopy confirms complex formation. FT-IR and circular dichroism spectroscopy suggested the presence of chalcone in the BSA molecule microenvironment and also the possibility of rearrangement of the native structure of BSA. Moreover, molecular docking studies confirm the moderate binding of chalcone with BSA and the molecular dynamics simulation analysis shows the stability of the BSA-drug complex system with minimal deformability fluctuations and potential interaction by the covariance matrix. Moreover, pharmacodynamics and pharmacological analysis show good results through Lipinski rules, with no toxicity profile and high gastrointestinal absorptions by boiled egg permeation assays. This study elucidates the mechanistic profile of the privileged chalcone scaffold to be used in therapeutic applications.

Therapeutic significance of β-glucuronidase activity and its inhibitors: A review

The emergence of disease and dearth of effective pharmacological agents on most therapeutic fronts, constitutes a major threat to global public health and man's existence. Consequently, this has created an exigency in the search for new drugs with improved clinical utility or means of potentiating available ones. To this end, accumulating empirical evidence supports molecular target therapy as a plausible egress and, β-glucuronidase (βGLU) - a lysosomal acid hydrolase responsible for the catalytic deconjugation of β-d-glucuronides has emerged as a viable molecular target for several therapeutic applications. The enzyme's activity level in body fluids is also deemed a potential biomarker for the diagnosis of some pathological conditions. Moreover, due to its role in colon carcinogenesis and certain drug-induced dose-limiting toxicities, the development of potent inhibitors of βGLU in human intestinal microbiota has aroused increased attention over the years. Nevertheless, although our literature survey revealed both natural products and synthetic scaffolds as potential inhibitors of the enzyme, only few of these have found clinical utility, albeit with moderate to poor pharmacokinetic profile. Hence, in this review we present a compendium of exploits in the present millennium directed towards the inhibition of βGLU. The aim is to proffer a platform on which new scaffolds can be modelled for improved βGLU inhibitory potency and the development of new therapeutic agents in consequential.

A novel chalcone derivative has antitumor activity in melanoma by inducing DNA damage through the upregulation of ROS products

Background

Melanoma is one of the most aggressive tumors with the remarkable characteristic of resistance to traditional chemotherapy and radiotherapy. Although targeted therapy and immunotherapy benefit advanced melanoma patient treatment, BRAFi (BRAF inhibitor) resistance and the lower response rates or severe side effects of immunotherapy have been observed, therefore, it is necessary to develop novel inhibitors for melanoma treatment.

Methods

We detected the cell proliferation of lj-1-59 in different melanoma cells by CCK 8 and colony formation assay. To further explore the mechanisms of lj-1-59 in melanoma, we performed RNA sequencing to discover the pathway of differential gene enrichment. Western blot and Q-RT-PCR were confirmed to study the function of lj-1-59 in melanoma.

Results

We found that lj-1-59 inhibits melanoma cell proliferation in vitro and in vivo, induces cell cycle arrest at the G2/M phase and promotes apoptosis in melanoma cell lines. Furthermore, RNA-Seq was performed to study alterations in gene expression profiles after treatment with lj-1-59 in melanoma cells, revealing that this compound regulates various pathways, such as DNA replication, P53, apoptosis and the cell cycle. Additionally, we validated the effect of lj-1-59 on key gene expression alterations by Q-RT-PCR. Our findings showed that lj-1-59 significantly increases ROS (reactive oxygen species) products, leading to DNA toxicity in melanoma cell lines. Moreover, lj-1-59 increases ROS levels in BRAFi -resistant melanoma cells, leading to DNA damage, which caused G2/M phase arrest and apoptosis.

Conclusions

Taken together, we found that lj-1-59 treatment inhibits melanoma cell growth by inducing apoptosis and DNA damage through increased ROS levels, suggesting that this compound is a potential therapeutic drug for melanoma treatment.

DBU-promoted ring-opening reactions of multi-substituted donor–acceptor cyclopropanes: access to functionalized chalcones with a quaternary carbon group

A strategy to synthesize highly stereoselective chalcones with alkylcyanoacetate subunits via DBU-promoted ring-opening reactions of multi-substituted D–A cyclopropanes has been developed without the requirement of a transition metal catalyst and extra solvent.

Synthesis of Hydroxybenzofuranyl-pyrazolyl and Hydroxyphenyl-pyrazolyl Chalcones and Their Corresponding Pyrazoline Derivatives as COX Inhibitors, Anti-inflammatory and Gastroprotective Agents

Five new series of hydroxybenzofuranyl-pyrazolyl chalcones 3a,b, hydroxyphenyl-pyrazolyl chalcones 6a-c and their corresponding pyrazolylpyrazolines 4a, d, 7a-c and 8a-f have been synthesized and evaluated for their in vitro cyclooxygenase (COX)-1 and COX-2 inhibitory activity. All the synthesized compounds exhibited dual COX-1 and COX-2 inhibitory activity with obvious selectivity against COX-2. The pyrazolylpyrazolines 4a-d and 8a-f bearing two vicinal aryl moieties in the pyrazoline nucleus showed more selectivity towards COX-2. Within these two series, derivatives 4c, d and 8d-f bearing the benzenesulfonamide group were the most selective. Compounds 4a-d and 8a-f were further subjected to in vivo anti-inflammatory screening, ulcerogenic liability and showed good anti-inflammatory activity with no ulcerogenic effect. In addition compounds 4c and 8d as examples showed prostaglandin (PG)E2 inhibition % 44.23 and 51.4 respectively, tumor necrosis factor α (TNFα) inhibition % 33.48 and 41.41 respectively and gastroprotective effect in ethanol induced rodent gastric ulcer model. In addition, to explore the binding mode and selectivity of our compounds, 8d and celecoxib were docked into the active site of COX-1 and COX-2. It was found that compound 8d exhibited a binding pattern and interactions similar to that of celecoxib with COX-2 active site, while bitter manner of interaction than celecoxib to COX-1 active site.

Herbicidal Activity of Flavokawains and Related trans-Chalcones against Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv

Flavokawains have a broad spectrum of biological activities; however, the herbicidal activity of these naturally occurring chalcones has been less investigated. Flavokawains and their analogues were prepared by the Claisen-Schmidt condensation reaction between xanthoxyline (or aromatic ketones) and a variety of aromatic and heteroaromatic aldehydes. These compounds were then evaluated for their inhibitory effect against representative dicot and monocot plants. Among 45 synthetic chalcones, derivatives containing phenoxyacetic acid, 4-(N,N-dimethylamino)phenyl, N-methylpyrrole, or thiophenyl groups inhibited the germination and growth of Chinese amaranth (Amaranthus tricolor L.) with moderate to high degrees compared to commercial butachlor. For barnyardgrass (Echinochloa crus-galli (L.) Beauv.), most of the thiophenyl chalcones interrupted shoot and root emergence. This finding highlighted the importance of functional groups on the herbicidal activity of chalcones. The level of inhibition also depended on the applied concentrations, plant species, and plant organs. (E)-2-(2-(3-Oxo-3-(thiophen-2-yl)prop-1-enyl)phenoxy)acetic acid (14f) was the most active compound among 45 derivatives. This chalcone could be a promising structure for controlling the germination and growth of weeds. The structure-activity relationship results provide useful information about the development of active chalconoids as novel natural product-like herbicides.

Crystal structure of (E)-3-(3-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl)-1-phenylprop-2-en-1-one, C27H21N5O

C27H21N5O, triclinic, P1̄ (no. 2), a = 8.1464(7) Å, b = 10.3861(8) Å, c = 13.2507(9) Å, α = 84.898(6)°, β = 89.413(6)°, γ = 80.351(7)°, V = 1100.88(15) Å3, Z = 2, R gt(F) = 0.0648, wR ref(F 2) = 0.1726, T = 296(2) K.

Antimicrobial, antioxidant and cytotoxic evaluation of diazenyl chalcones along with insights to mechanism of interaction by molecular docking studies

BACKGROUND

In continuation of our work, new diazenyl chalcones scaffolds (C-18 to C-27) were efficiently synthesized from substituted acetophenone azo dyes (A-E) by base catalyzed Claisen-Schmidt condensation with different substituted aromatic/heteroaromatic aldehydes.

METHODOLOGY

The synthesized chalcones were assessed for their in vitro antimicrobial potential towards several pathogenic microbial strains by tube dilution method and further evaluated for antioxidant potential by DPPH assay. These derivatives were also assessed for the cytotoxicity towards the human lung cancer cell line (A549) and normal cell line (HEK) by MTT assay. The most active antimicrobial compounds were docked using Schrodinger v18.1 software with the various potential bacterial receptors to explore the mechanism of interaction.

RESULTS

The derivative C-22 exhibited high antibacterial activity with very low MIC (1.95-3.90 µg ml-1) and MBC (3.90-7.81 µg ml-1) values. The derivatives C-23, C-24 and C-27 have demonstrated good antioxidant potential (IC50 = 7-18 µg ml-1) correlated to the ascorbic acid (IC50 = 4.45 µg ml-1). The derivative C-25 had shown comparable cytotoxicity to camptothecin against A549 cell line. The docking studies predicted the bacterial dihydrofolate reductase (PDB ID: 3SRW) and bacterial DNA gyrase (PDB ID: 4ZVI) as the possible targets for most of the active antimicrobial compounds. These derivatives affirmed their safety by presenting less cytotoxicity towards HEK cells. Further the ADME prediction by qikprop module of the Schrodinger proved that these compounds exhibited drug-like attributes.

CONCLUSION

Hence, these compounds have shown their potential as lead for future expansion of novel antimicrobial and cytotoxic drugs.

Flurbiprofen-chalcone hybrid Mannich base derivatives as balanced multifunctional agents against Alzheimer's disease: Design, synthesis and biological evaluation

The complex pathogenesis of Alzheimer's disease (AD) calls for multitarget approach for disease management. Herein, a series of novel flurbiprofen-chalcone hybrid Mannich base derivatives were designed and synthesized. The biological screening results indicated that most of the derivatives exhibited potent multi-target effects involved in AD. In particular, compound 6c bearing a pyrrolidine group showed the highest activities against self- and Cu²⁺-induced Aβ_1-42 aggregation (70.65% and 54.89% at 25.0 µM, respectively), highly selective inhibition towards AChE and MAO-B (IC₅₀ = 7.15 μM and 0.43 μM respectively), good antioxidant ability and metal-chelating property. Moreover, 6c displayed excellent anti-neuroinflammatory activity and appropriate BBB permeability in vitro. These outstanding results qualified compound 6c as a promising multifunctional agent for further development of disease-modifying treatment of AD.

Synthesis and Biological Evaluation of Novel Aminochalcones as Potential Anticancer and Antimicrobial Agents

A series of 18 aminochalcone derivatives were obtained in yields of 21.5-88.6% by applying the classical Claisen-Schmidt reaction. Compounds 4-9, 14 and 16-18 with 4-ethyl, 4-carboxy-, 4-benzyloxy- and 4-benzyloxy-3-methoxy groups were novel, not previously described in the scientific literature. To determine the biological properties of the synthesized compounds, anticancer and antimicrobial activity assays were performed. Antiproliferative potential was evaluated on four different human colon cancer cell lines-HT-29, LS180, LoVo and LoVo/DX -using the SRB assay and compared with green monkey kidney fibroblasts COS7. Anticancer activity was described as the IC50 value. The best results were observed for 2'-aminochalcone (1), 3'-aminochalcone (2) and 4'-aminochalcone (3) (IC50 = 1.43-1.98 µg·mL-1) against the HT-29 cell line and for amino-nitrochalcones 10-12 (IC50 = 2.77-3.42 µg·mL-1) against the LoVo and LoVo/DX cell lines. Moreover, the antimicrobial activity of all derivatives was evaluated on two strains of bacteria: Escherichia coli ATCC10536 and Staphylococcus aureus DSM799, the yeast strain Candida albicans DSM1386 and three strains of fungi: Alternaria alternata CBS1526, Fusarium linii KB-F1 and Aspergillus niger DSM1957. In the case of E. coli ATCC10536 almost all derivatives hindered the bacterial growth (∆OD = 0). Furthermore, the best results were observed in the presence of 4'-aminochalcone (3), that completely limited the growth of all tested strains at the concentration range of 0.25-0.5 mg·mL-1. The strongest bacteriostatic activity was exhibited by novel 3'-amino-4-benzyloxychalcone (14), that prevented the growth of E. coli ATCC10536 with MIC = 0.0625 mg·mL-1.

Synthesis of Chalcone Derivatives: Inducing Apoptosis of HepG2 Cells via Regulating Reactive Oxygen Species and Mitochondrial Pathway

Chalcone derivatives, as a hot research field, exhibit a variety of physiological bioactivities and target multiple biological receptors. Based on the skeleton of (E)-1,3-diphenyl-2-propene-1-one, 14 chalcone derivatives were designed and synthesized, and evaluated as the antitumor candidates agents against four human cancer cell lines (A549, Hela, HepG2, and HL-60) as well as one normal cell line (WI-38). Among the title compounds, compound a14 showed better inhibitory activity against HepG2 cells (IC₅₀ = 38.33 µM) and had relatively weak cytotoxicity towards normal cells WI-38 (IC₅₀ = 121.29 µM). In this study, apoptosis, cycle arrest, assessment of reactive oxygen species (ROS) level, and measurement of mitochondrial membrane potential were adopted to explore the inhibitory mechanism of a14 towards HepG2. Compound a14 could effectively block the division of HepG2 cell lines in the G2/M phase and robustly induced generation of ROS, demonstrating that the generation of ROS induced by a14 was the main reason for resulting in the apoptosis of HepG2 cells. Moreover, the mitochondrial membrane potential (MMP) of HepG2 cells treated with a14 was significantly decreased, which was closely related to the enhanced ROS level. Furthermore, based on Western blot experiment, cell apoptosis induced by a14 also involved the expression of B-cell lymphoma-2 (Bcl-2) family and Caspase 3 protein. In summary, compound a14 could contribute to the apoptosis of HepG2 cells through regulating ROS-mitochondrial pathway, which provides valuable hints for the discovery of novel anti-tumor drug candidates.

Microwave Assisted Green Synthesis of Benzimidazole Derivatives and Evaluation of Their Anticonvulsant Activity

Background:

Benzimidazole is the fused heterocyclic aromatic compound. It is an essential pharmacophore and privileged structure for the development of new drug molecules. These are bioactive molecules present in various anthelmintic drugs such as albendazole, mebendazole, parbendazole, triclabendazole etc.

Methods:

Benzimidazole derivatives are synthesized by reaction between orthophenylene diamine and anthranillic acid followed by acetylation in the presence of acetic anhydride. Finally, the acetylated products undergo Claisen-Schimdt condensation with various substituted benzaldehydes to produce corresponding benzimidazole derivatives or chalcones. Both conventional and microwave irradiation technology are followed to get the titled compounds. The titled compounds are screened for their anticonvulsant and neurotoxicity activity.

Results:

By the help of microwave synthesis, the yield of product was increased in less reaction time. So, it follows Green chemistry approach by making above reactions eco-friendly. Some of the compounds exhibited significant anticonvulsant activity as compared to standard drug.

Conclusion:

In the present investigation, we have synthesized novel benzimdazole derivatives with chalone moiety to improve the biological activity. The compounds were obtained under microwave reaction with high yield in a short reaction time.

Cyclization of flavokawain B reduces its activity against human colon cancer cells

Chalcones are naturally occurring compounds exhibiting biological activity through multiple mechanisms. Flavokawain B is one of chalcones found in kava plant. In our studies, we focused on the anticancer activity of flavokawain B in colorectal cancer cells LoVo and its resistant to doxorubicin subline-LoVo/Dx. Strong cytotoxic activity of flavokawain B and its ability to inhibit the proliferation in both cell lines was detected. These effects accompanied with induction cell cycle arrest in G2/M phase and the presence of SubG1 fraction. Flavokawain B at low concentration led to increase of caspase-3 activity. The chalcone-induced apoptosis was also confirmed by DNA fragmentation. In our work, the conversion of flavokawain B to corresponding flavanone-5,7-dimetoxyflavanone-was shown to be more extensive in cancer than in non-cancer cells. We found that the cyclization of the chalcone was related to the significant decrease in the cytotoxicity. Cell proliferation and cell cycle progression were not impaired significantly in the studied cancer cells incubated with 5,7-dimethoxyflavanone. We did not observe apoptosis in the cells incubated with flavanone. The results from biological studies agreed with the theoretical activity that emerges from structural parameters.

Sofalcone, a gastroprotective drug, covalently binds to KEAP1 to activate Nrf2 resulting in anti-colitic activity

Sofalcone is a synthetic chalcone being used as a gastric mucosa protective agent in Japan. Sofalcone contains a 1,3-diaryl-2-propen-1-one moiety, which is a common chemical scaffold in naturally occurring chalcones. The α,β-unsaturated carbonyl group (Michael reaction acceptor) has electrophilic properties. We investigated the biochemical mechanisms by which sofalcone activated the cytoprotective and anti-inflammatory nuclear factor-erythroid 2 (NF-E2) p45-related factor 2 (Nrf2)-heme oxygenase (HO)-1 pathway. Furthermore, we investigated whether the activation of this pathway was involved in sofalcone -mediated protective effects in an experimental colitis model. Sofalcone induced HO-1 protein expression, which was dependent on increased nuclear accumulation of Nrf2 in human colon carcinoma cells. In addition, Sofalcone reacted with nucleophilic thiol compounds to form Michael adducts. A reduced form of sofalcone (SFCR) in which the Michael reaction acceptor was deactivated, did not exert biological or chemical activity. Biotin-tagged sofalcone bound to Kelch-like ECH-associated protein 1 (KEAP1), a cytosolic repressor of Nrf2. This binding was prevented by pretreatment with sofalcone and a thiol compound but not with SFCR. Furthermore, sofalcone treatment induced dissociation of the Nrf2-KEAP1 complex. Rectal administration of sofalcone alleviated colon damage and inflammation and increased colon nuclear accumulation of Nrf2 and HO-1 levels in a dinitrobenzene sulfonic acid-induced rat colitis model. The protective effects of sofalcone against colon damage and inflammation were significantly inhibited by co-administration of an HO-1 inhibitor. In conclusion, sofalcone activated the Nrf2-HO-1 pathway by covalently binding to KEAP1 via Michael addition, and may confer anti-colitic effects by inducing Nrf2 activation.