Synthesis of some novel chalcones, flavanones and flavones and evaluation of their anti-inflammatory activity

Halogen substituted aurones as potential apoptotic agents: synthesis, anticancer evaluation, molecular docking, ADMET and DFT study

A series of halogen-substituted aurone derivatives (2a-k) were synthesized and evaluated for an anti-proliferative study against NCI 60 cancer cell line panel and showed that most of the compounds predominantly exhibited promising activity against MCF-7. Compound 2e exhibited promising anticancer activity against the MCF-7 cancer cell line with 84.98% percentage growth inhibition in a single dose assay of 10 μM with an IC50 value of 8.157 ± 0.713 μM. In apoptotic assay, the effect of compound 2e on the cell cycle progression indicated that exposure of MCF-7 cells to compound 2e induced a significant disruption in the cell cycle profile including a time-dependent decrease in the cell population at G0/G1 and G2/M phase and arrests the cell cycle at the S phase. In silico, molecular docking ADME and toxicity studies of all compounds were also carried out. The docking study revealed that all the aurone derivatives displayed good docking scores ranging from -7.066 to -8.573. The results of Molecular Electrostatic Potential Mapping (MESP) and Density Functional Theory (DFT) studies of the most active compound 2e and least active compound 2k also favoured the experimental results.

Protective Effects of Trans-Chalcone on Myocardial Ischemia and Reperfusion Challenge through Targeting Phosphoinositide 3-kinase/Akt-inflammosome Interaction

Ischemia-reperfusion (IR) injury remains a pivotal contributor to myocardial damage following acute coronary events and revascularization procedures. Phosphoinositide 3-kinase (PI3K), a key mediator of cell survival signaling, plays a central role in regulating inflammatory responses and cell death mechanisms. Trans-chalcone (Tch), a natural compound known for its anti-inflammatory activities, has shown promise in various disease models. The aim of the current study was to investigate the potential protective effects of Tch against myocardial injury induced by ischemia and reperfusion challenges by targeting the PI3K-inflammasome interaction. Experimental models utilizing male rats subjected to an in vivo model of IR injury and myocardial infarction were employed. Administration of Tch (100 μg/kg, intraperitoneally) significantly reduced myocardial injury, as indicated by limited infarct size and decreased levels of the myocardial enzyme troponin. Mechanistically, Tch upregulated PI3K expression, thereby inhibiting the activity of the NOD-like receptor protein 3 inflammasome followed by the activation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Moreover, it mitigated oxidative stress and suppressed vascular-intercellular adhesion molecules, contributing to its cardioprotective effects. The PI3K/Akt pathway inhibitor LY294002 considerably attenuated the beneficial effects of Tch. These findings highlight the therapeutic potential of Tch in ameliorating myocardial injury associated with IR insults through its modulation of the PI3K/Akt-inflammasome axis. The multifaceted mechanisms underlying its protective effects signify Tch as a promising candidate for further exploration in developing targeted therapies aimed at mitigating ischemic heart injury and improving clinical outcomes in cardiovascular diseases characterized by IR injury.

Design and Development of COX-II Inhibitors: Current Scenario and Future Perspective

Innate inflammation beyond a threshold is a significant problem involved in cardiovascular diseases, cancer, and many other chronic conditions. Cyclooxygenase (COX) enzymes are key inflammatory markers as they catalyze prostaglandins production and are crucial for inflammation processes. While COX-I is constitutively expressed and is generally involved in "housekeeping" roles, the expression of the COX-II isoform is induced by the stimulation of different inflammatory cytokines and also promotes the further generation of pro-inflammatory cytokines and chemokines, which affect the prognosis of various diseases. Hence, COX-II is considered an important therapeutic target for drug development against inflammation-related illnesses. Several selective COX-II inhibitors with safe gastric safety profiles features that do not cause gastrointestinal complications associated with classic anti-inflammatory drugs have been developed. Nevertheless, there is mounting evidence of cardiovascular side effects from COX-II inhibitors that resulted in the withdrawal of market-approved anti-COX-II drugs. This necessitates the development of COX-II inhibitors that not only exhibit inhibit potency but also are free of side effects. Probing the scaffold diversity of known inhibitors is vital to achieving this goal. A systematic review and discussion on the scaffold diversity of COX inhibitors are still limited. To address this gap, herein we present an overview of chemical structures and inhibitory activity of different scaffolds of known COX-II inhibitors. The insights from this article could be helpful in seeding the development of next-generation COX-II inhibitors.

Antimicrobial Activities and Mode of Flavonoid Actions

The emergence of antibiotics-resistant bacteria has been a serious concern for medical professionals over the last decade. Therefore, developing new and effective antimicrobials with modified or different modes of action is a continuing imperative. In this context, our study focuses on evaluating the antimicrobial activity of different chemically synthesized flavonoids (FLAV) to guide the chemical synthesis of effective antimicrobial molecules. A set of 12 synthesized molecules (4 chalcones, 4 flavones and 4 flavanones), bearing substitutions with chlorine and bromine groups at the C6' position and methoxy group at the C4' position of the B-ring were evaluated for antimicrobial activity toward 9 strains of Gram-positive and Gram-negative bacteria and 3 fungal strains. Our findings showed that most tested FLAV exhibited moderate to high antibacterial activity, particularly against Staphylococcus aureus with minimum inhibitory concentrations (MIC) between the range of 31.25 and 125 μg/mL and that chalcones were more efficient than flavones and flavanones. The examined compounds were also active against the tested fungi with a strong structure-activity relationship (SAR). Interestingly, leakage measurements of the absorbent material at 260 nm and scanning electron microscopy (SEM) demonstrated that the brominated chalcone induced a significant membrane permeabilization of S. aureus.

Chalcones: Promising therapeutic agents targeting key players and signaling pathways regulating the hallmarks of cancer

The need for innovative anticancer treatments with high effectiveness and low toxicity is urgent due to the development of malignancies that are resistant to chemotherapeutic agents and the poor specificity of existing anticancer treatments. Chalcones are 1,3-diaryl-2-propen-1-ones, which are the precursors for flavonoids and isoflavonoids. Chalcones are readily available from a wide range of natural resources and consist of very basic chemical scaffolds. Because the ease with which the synthesis it allows for the production of several chalcone derivatives. Various in-vitro and in-vivo studies indicate that naturally occurring and synthetic chalcone derivatives exhibit promising biological activities against cancer hallmarks such as proliferation, angiogenesis, invasion, metastasis, inflammation, stemness, and regulation of cancer epigenetics. According to their structure and functional groups, chalcones derivatives and their hybrid compounds exert a broad range of biological activities through targeting key elements and signaling molecules relevant to cancer progression. This review will provide valuable insights into the latest updates of chalcone groups as anticancer agents and extensively discuss their underlying molecular mechanisms of action.

Nontraditional Aldol Condensation Performance of Highly Efficient and Reusable Cs+ Single Sites in β-Zeolite Channels

Aldol reactions (self- and cross-aldol condensations) for conjugated enone synthesis were efficiently performed on large-sized Cs⁺ single sites (1 wt %) confined in β-zeolite channels in toluene, which showed the highest level of catalytic aldol condensation activity among reported zeolite catalysts. In general, aldol condensation reactions for C-C bond synthesis can proceed by acids (e.g., H⁺), bases (e.g., OH^-), enolate species, and acidic or basic solid catalysts. However, the Cs⁺ single site/β sample without significant acid-base property showed unprecedented, efficient, and reusable catalysis for self-aldol and cross-aldol condensations. Intrinsically inactive Cs⁺ single sites due to the noble-gas electronic structure were transformed to active Cs⁺ single sites in β-zeolite channels. Cs⁺/β has many advantages such as broad substrate scope, eco-friendliness, high product selectivity and yield, and simple work-up procedure. Thus, the Cs⁺ single site/β provides an attractive and useful methodology for practical C-C bond synthesis. On the basis of the Cs⁺/β characterization by X-ray photoelectron spectroscopy (XPS), in situ X-ray absorption fine structure (XAFS) (X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)), and temperature-programmed desorption (TPD), density functional theory (DFT) calculations of the self- and cross-aldol condensation reaction pathways involving the transition states on the Cs⁺ single site in β-zeolite channel revealed nontraditional concerted interligand bond rearrangement mechanisms.

Synthesis and Evaluation of Galloyl Conjugates of Flavanones as BMP-2 Upregulators with Promising Bone Anabolic and Fracture Healing Properties

The molecular hybridization concept led us to design a series of galloyl conjugates of flavanones that have potent osteoblast differentiation ability in vitro and promote bone formation in vivo. An array of in vitro studies, especially gene expression of osteogenic markers, evinced compound 5e as the most potent bone anabolic agent, found to be active at 1 pM, which was then further assessed for its osteogenic potential in vivo. From in vivo studies on rat calvaria and a fracture defect model, we inferred that compound 5e, at an oral dose of 5 mg/(kg day), increased the expression of osteogenic genes (RUNX2, BMP-2, Col1, and OCN) and the bone formation rate and significantly promoted bone regeneration at the fracture site, as evidenced by the increased bone volume/tissue fraction compared with vehicle-treated rats. Furthermore, structure-activity relationship studies and pharmacokinetic studies suggest 5e as a potential bone anabolic lead for future osteoporosis drug development.

Synthesis and crystal structure of (2E,2′E)-3,3′-(1,3-phenylene)bis(1-(3-bromophenyl)prop-2-en-1-one), C24H16Br2O2

C24H16Br2O2, orthorhombic, Pnma (no. 62), a = 7.407(3) Å, b = 44.336(16) Å, c = 6.046(2) Å, V = 944.8(3) Å3, Z = 4, R gt (F) = 0.0602, wR ref (F 2) = 0.1315, T = 293 K.

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.

Metabolic Engineering of Microorganisms for the Production of Flavonoids

Flavonoids are a class of secondary metabolites found in plant and fungus. They have been widely used in food, pharmaceutical, and nutraceutical industries owing to their significant biological activities, such as antiaging, antioxidant, anti-inflammatory, and anticancer. However, the traditional approaches for the production of flavonoids including chemical synthesis and plant extraction involved hazardous materials and complicated processes and also suffered from low product titer and yield. Microbial synthesis of flavonoids from renewable biomass such as glucose and xylose has been considered as a sustainable and environmentally friendly method for large-scale production of flavonoids. Recently, construction of microbial cell factories for efficient biosynthesis of flavonoids has gained much attention. In this article, we summarize the recent advances in microbial synthesis of flavonoids including flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanins. We put emphasis on developing pathway construction and optimization strategies to biosynthesize flavonoids and to improve their titer and yield. Then, we discuss the current challenges and future perspectives on successful strain development for large-scale production of flavonoids in an industrial level.

Discovery and Development of Inflammatory Inhibitors from 2-Phenylchromonone (Flavone) Scaffolds

Flavonoids are compounds based on a 2-phenylchromonone scaffold. Flavonoids can be divided into flavonoids, flavonols, dihydroflavones, anthocyanins, chalcones and diflavones according to the oxidation degree of the central tricarbonyl chain, the connection position of B-ring (2-or 3-position), and whether the tricarbonyl chain forms a ring or not. There are a variety of biological activities about flavonoids, such as anti-inflammatory activity, anti-oxidation and anti-tumor activity, and the antiinflammatory activity is apparent. This paper reviews the anti-inflammatory activities and mechanisms of flavonoids and their derivatives reported in China and abroad from 2011 till date (2011-2020), in order to find a good drug scaffold for the study of anti-inflammatory activities.

Anti-Inflammatory, Antinociceptive, and Antioxidant Properties of Anacardic Acid in Experimental Models

Anacardic acid (AA), a compound extracted from cashew nut liquid, exhibits numerous pharmacological activities. The aim of the current investigation was to assess the anti-inflammatory, antinociceptive, and antioxidant activities of AA in mouse models. For this, Swiss albino mice were pretreated with AA (10, 25, 50 mg/kg, intraperitoneally, ip) 30 min prior to the administration of carrageenan, as well as 25 mg/kg of prostaglandin E2, dextran, histamine, and compound 48/80. The antinociceptive activity was evaluated by formalin, abdominal, and hot plate tests, using antagonist of opioid receptors (naloxene, 3 mg/kg, ip) to identify antinociceptive mechanisms. Results from this study revealed that AA at 25 mg/kg inhibits carrageenan-induced edema. In addition, AA at 25 mg/kg reduced edema and leukocyte and neutrophilic migration to the intraperitoneal cavity, diminished myeloperoxidase activity and malondialdehyde concentration, and increased the levels of reduced glutathione. In nociceptive tests, it also decreased licking, abdominal writhing, and latency to thermal stimulation, possibly via interaction with opioid receptors. Taken together, these results indicate that AA exhibits anti-inflammatory and antinociceptive actions and also reduces oxidative stress in acute experimental models, suggesting AA as a promising compound in the pharmaceutical arena.

Influence on the reactivity properties of the substitution by different halogens on the conjugated backbone of the 1,3,5-triaryl-2-pyrazoline skeleton in relation to the increasing alkyloxy chain length: a conceptual density functional theory study

A series of non-substituted 1,3,5-triaryl-2-pyrazolines and pyrazolines substituted with Fluoro (-F), Chloro (-Cl) and Bromo (-Br) groups at the 3-aryl position were studied. All calculations were done using the conceptual framework of density functional theory. The geometries and reactivity properties were analyzed according to an increase from one to twelve alkyl units in the 5-aryl of 2-pyrazoline ring. In order to be able to apply the particular methodology named KID procedure (for Koopmans in DFT), the KID descriptors were calculated and the results showed that the use of this approximation (Koopmans' theorem in DFT studies) is feasible. The results for the geometries determined that the increase of the chain with alkyl units does not affect the geometry of the systems. However, the solvation energy also calculated is affected by this increase in the allyl chain length. Due to this, as the chains increases, the solubility of the molecular systems diminishes. The chemical reactivity properties were determined by calculating the descriptors that arise from conceptual DFT and it could be demonstrated that they are not affected by the chain growth. Slight differences were found due to the different halogen substitutions. Finally, it could be observed that all the pyrazolines present an important electrophilic behavior. Graphical Abstract Properties changes in relation to the increasing alkyloxy chain length and halogens presence.

Ultrasounds-mediated 10-seconds synthesis of chalcones as potential farnesyltransferase inhibitors

A broad range of chalcones and derivatives were easily and rapidly synthesized, following Claisen-Schmidt condensation of (hetero)aryl ketones and (hetero)aryl aldehydes using a ultrasound probe. A comparison was made with classical magnetic stirring experiments, and an optimization study was realized, showing lithium hydroxide to be the best basic catalyst of the studied condensations. By-products of the reactions (β-hydroxy-ketone, diketones, and cyclohexanols) were also isolated. All compounds were evaluated in vitro for their ability to inhibit human farnesyltransferase, a protein implicated in cancer and rare diseases and on the NCI-60 cancer cell lines panel. Molecules showed inhibitory activity on the target protein and cytostatic effect on different cell lines with particular activity against MCF7, breast cancer cells.

Synthesis, Structure and In Vitro Anti-Trypanosomal Activity of Non-Toxic Arylpyrrole-Based Chalcone Derivatives

With an intention of identifying chalcone derivatives exhibiting anti-protozoal activity, a cohort of relatively unexplored arylpyrrole-based chalcone derivatives were synthesized in moderate to good yields. The resultant compounds were evaluated in vitro for their potential activity against a cultured Trypanosoma brucei brucei 427 strain. Several compounds displayed mostly modest in vitro anti-trypanosomal activity with compounds 10e and 10h emerging as active candidates with IC50 values of 4.09 and 5.11 µM, respectively. More importantly, a concomitant assessment of their activity against a human cervix adenocarcinoma (HeLa) cell line revealed that these compounds are non-toxic.

Polyphenols, Vitamin C, in Vitro Antioxidant Capacity, α-Amylase and COX-2 Inhibitory Activities of Citrus Samples from Aceh, Indonesia

Abstract. This study was conducted to analyse antioxidant potencies, vitamin C contents, polyphenol profiles, antidiabetic and anti-inflammatory potencies of citrus fruits from Indonesia. Total phenolics contents (TPC) of seven citrus fruits from northern Aceh, Indonesia, were measured using Folin-Ciocalteu (FC) and Fast Blue BB (FBBB) methods. Total flavonoid content (TFC) test showed for peel and pulp extracts of calung and jeruk takengon (local mandarin) the highest values. H-TEAC (hydrophilic trolox equivalent antioxidant capacity) and H-ORAC (hydrophilic oxygen reactive absorbance capacity) antioxidant capacity were highest for peel and pulp of jeruk takengon, calung and kruet mameh. Interestingly, peel extracts showed no α-amylase inhibition activity whilst pulp showed weak inhibitory activity. Polyphenol composition was dominated by flavanones, with hesperidin and neohesperidin as main flavanones (hesperidin: 131–5433 mg/100 g DW, neohesperidin: 431–4131 mg/100 g DW). Vitamin C contents were highly correlated with antioxidant capacities in pulp (R2 = 0.95 and R2 = 0.94 at p < 0.01 for H-TEAC and H-ORAC, respectively), and TPC and TFC were highly correlated with antioxidant capacities (R2 = 0.99 and R2 = 0.98 for TPC FC in pulp and R2 = 0.93 and R2 = 0.84 in peel for H-TEAC and H-ORAC, respectively; R2 = 0.88 and R2 = 0.80 in pulp, and R2 = 0.68 and R2 = 0.75 for TFC in peel for H-TEAC and H-ORAC at p < 0.01). In-vitro COX-2 inhibitory activity tests resulted in higher activity for pulp compared to the corresponding peel extracts except for calung. Pulp extract of jeruk takengon showed the highest activity. In general, local citrus fruits from Aceh, Indonesia, are potential sources of polyphenols and vitamin C.

Discovery of novel (+)-Usnic acid derivatives as potential anti-leukemia agents with pan-Pim kinases inhibitory activity

Usnic acid (UA) is the main secondary metabolite isolated from lichens, with moderate anticancer activity. A small group of (+)-UA derivatives characterized with flavanone moiety was designed and synthesized, and their anticancer activities were evaluated in leukemia cells. It was demonstrated that (+)-UA derivatives 6a-6g inhibited the proliferation of leukemia cells HL-60 and K562 with low micromolar IC₅₀ values. Mechanisms of action were investigated to find that 6g induced apoptosis in HL-60 and K562 cell lines, and affected the expression of MNK/eIF4E axis-related proteins, such as Mcl-1, p-eIF4E, p-4E-BP1. Finally, kinase inhibition assay suggested 6g was a potential inhibitor of pan-Pim kinases. Meanwhile, the blocking of phosphorylation of BAD and 4E-BP1 by 6g, together with the proposed binding mode of 6g with Pim-1 further confirmed its Pim inhibition effects. Our finding provides the sight towards the potential mechanism of (+)-UA derivatives 6g as anti-leukemia agents.

Lipophilicity as a Central Component of Drug-Like Properties of Chalchones and Flavonoid Derivatives

Lipophilcity is an important physico-chemical parameter that influences membrane transport and binding ability to action. Migration distance following complete elution of compounds was used to calculate different lipophilicity-related parameters. The aim of this study is to show that lipophilicity is a central component of thiazole chalcones and flavonoid derivatives regarding their drug-like properties. Experimental and computational methods were used. This study considers 44 previously synthesized compounds (thiazole chalcones, flavanones, flavones, 3-hydroxyflavones, and their acetylated derivatives). The concerned compounds have shown antitumoral hallmarks and antibacterial activity in vitro. The experimental method used to determine compounds’ lipophilicity was the reverse-phase thin layer chromatography (RP-TLC). Lipophilicity related parameters—isocratic retention factor (R_M), relative lipophily (R_M⁰), slope (b), chromatographic hydrophobic index (φ₀), scores of principal components (PC1/R_M)—were determined based on reverse-phase chromatography results.

Promising anti-inflammatory effects of chalcones via inhibition of cyclooxygenase, prostaglandin E2, inducible NO synthase and nuclear factor κb activities

Chalcones (1, 3-Diphenyl-2-propen-1-one) consist of a three carbon α, β-unsaturated carbonyl system and act as precursors for the biosynthesis of flavonoids in plants. However, laboratory synthesis of various chalcones has also been reported. Both natural and synthetic chalcones are known to exhibit a variety of pharmacological activities such as anti-inflammatory, antitumor, antibacterial, antifungal, antimalarial and antituberculosis. These promising activities, ease of synthesis and simple chemical structure have awarded chalcones considerable attraction. This review focuses on the anti-inflammatory effects of chalcones, caused by their inhibitory action primarily against the activities and expressions of four key inflammatory mediators viz., cyclooxygenase, prostaglandin E₂, inducible NO synthase, and nuclear factor κB. Various methodologies for the synthesis of chalcones have been discussed. The potency of recently synthesized chalcones is given in terms of their IC₅₀ values. Structure-Activity Relationships (SARs) of a variety of chalcone derivatives have been discussed. Computational methods were applied to calculate the ideal orientation of a typical chalcone scaffold against three enzymes, namely, cyclooxygenase-1, cyclooxygenase-2 and inducible NO synthase for the formation of stable complexes. The global market of anti-inflammatory drugs and its expected growth (from 2018 to 2026) have been discussed. SAR analysis, docking studies, and future prospects all together provide useful clues for the synthesis of novel chalcones of improved anti-inflammatory activities.

Discovery of a Prenylated Flavonol Derivative as a Pin1 Inhibitor to Suppress Hepatocellular Carcinoma by Modulating MicroRNA Biogenesis

Peptidyl-prolyl cis-trans isomerase Pin1 plays a crucial role in the development of human cancers. Recently, we have disclosed that Pin1 regulates the biogenesis of miRNA, which is aberrantly expressed in HCC and promotes HCC progression, indicating the therapeutic role of Pin1 in HCC therapy. Here, 7-(benzyloxy)-3,5-dihydroxy-2-(4-methoxyphenyl)-8-(3-methylbut-2-en-1-yl)-4H-chromen-4-one (AF-39) was identified as a novel Pin1 inhibitor. Biochemical tests indicate that AF-39 potently inhibits Pin1 activity with an IC₅₀ values of 1.008 μm, and also displays high selectivity for Pin1 among peptidyl prolyl isomerases. Furthermore, AF-39 significantly suppresses cell proliferation of HCC cells in a dose- and time-dependent manner. Mechanistically, AF-39 regulates the subcellular distribution of XPO5 and increases miRNAs biogenesis in HCC cells. This work provides a promising lead compound for HCC treatment, highlighting the therapeutic potential of miRNA-based therapy against human cancer.

Synthesis and in vitro evaluation of substituted 3-cinnamoyl-4-hydroxy-pyran-2-one (CHP) in pursuit of new potential antituberculosis agents

Tuberculosis is an ever-evolving infectious disease that urgently needs new drugs. In the search for new antituberculosis agents, a library of 3-cinnamoyl-4-hydroxy-6-methyl-2H-pyran-2-ones (CHPs) (2a-2y) was synthesized and evaluated against a standard virulent laboratory strain of Mycobacterium tuberculosis H37Rv. Out of 25 compounds, 11, 5, 7 and 2 (2a and 2u) showed least, moderate, good and appreciable activities, respectively, based on minimum inhibitory concentrations (MICs). Both 2a and 2u exhibited an MIC value of 4 μg ml^-1, which was close to those of standard antituberculosis drugs ethambutol, streptomycin and levofloxacin. Neither 2a nor 2u showed any activity against Gram-positive or Gram-negative bacteria and even against non-tuberculous mycobacterium, i.e. Mycobacterium smegmatis. Thus, like the antituberculosis drugs rifampicin, isoniazid and pretomanid, they are highly TB specific. All the pyrone-based chalcones showed no recognizable level of cytotoxicity against normal human kidney cell line (HEK-293) up to 80 μM concentration and 11 exhibited an IC₅₀ ≤ 100 μM (highest tested concentration). On further investigation, both 2a and 2u proved to be nontoxic against four human cell lines but 2a proved to be a better choice as it did not reach IC₅₀ even at 100 μM (highest tested concentration) while the IC₅₀ of 2u was around 80 μM. In conclusion, our results demonstrate that 2a is specific against M. tuberculosis with no appreciable toxicity; its activity matches that of some clinically approved antituberculosis drugs and it therefore merits further evaluation.

Novel Structurally Related Flavones Augment Cell Death Induced by rhsTRAIL

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) was identified as a powerful activator of apoptosis in tumor cells and one of the most promising candidates for cancer therapy with no toxicity against normal tissues. However, many tumor cells are resistant to TRAIL-induced apoptosis. The aim of this work was to analyze the improvement of the anticancer effect of rhsTRAIL (recombinant human soluble TRAIL) by nine flavones: 5-Hydroxyflavone, 6-Hydroxyflavone, 7-Hydroxyflavone and their new synthetic derivatives 5-acetoxyflavone, 5-butyryloxyflavone, 6-acetoxyflavone, 6-butyryloxyflavone, 7-acetoxyflavone and 7-butyryloxyflavone. We examined the cytotoxic and apoptotic effects of rhsTRAIL enhanced by novel structurally-related flavones on SW480 and SW620 colon cancer cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, the lactate dehydrogenase assay and annexin V-FITC fluorescence staining. We observed a slight difference in the activities of the flavones that was dependent on their chemical structure. Our study indicates that all nine flavones significantly augment cell death by rhsTRAIL (cytotoxicity range 36.8 ± 1.7%–91.4 ± 1.7%; apoptosis increase of 33.0 ± 0.7%–78.5 ± 0.9%). Our study demonstrates the potential use of tested flavones in TRAIL-based anticancer therapy and prevention.

Microwave Assisted Synthesis, Optical Properties and Physicochemical Investigations on the Powerful Fluorophore: Donor (D) -π-Acceptor (A) Chalcone

(2E)-3-[4-(dimethylamino)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one (DPHP) was synthesized by the reaction 4(dimethylamino) benzaldehyde with 1-(2-hydroxyphenyl) ethanone under microwave irradiation. Structure of DPHP was conformed by ¹H and ¹³C NMR, FT-IR, EI-MS spectral studies and elemental analysis. The electronic absorption and fluorescence spectra of DPHP have been studied in solvents of different polarities, and the data were used to study the solvatochromic properties such as extinction coefficient, stokes shift, oscillator strength, transition dipole moment, fluorescence quantum yield and photochemical quantum yield. The absorption maximum and fluorescence emission maximum was observed red shift when increase solvent polarity n-Hexane to DMF. DPHP undergoes solubilization in different micelles and may be used as a probe and quencher to determine the critical micelle concentration (CMC) of CTAB and SDS.

The Plant-Derived Chalcone 2,2',5'-Trihydroxychalcone Provides Neuroprotection against Toll-Like Receptor 4 Triggered Inflammation in Microglia

Chalcones are plant metabolites with potential for therapeutic exploitation as antioxidant, anti-inflammatory, and antiproliferative agents. Here we explored the neuroprotective effects of 2,2',5'-trihydroxychalcone (225THC), a potent antioxidant with radical-scavenging properties. 225THC was found to be a potent inhibitor of apoptosis in stimulated primary rat neuronal cultures. This was likely mediated by an anti-inflammatory effect on microglial cells since 225THC inhibited LPS-stimulated TNF-α and IL-6 secretion from primary rat microglia and modulated the cytokine/chemokine profile of BV2 microglial cells. Additionally, 225THC inhibited LPS-evoked inducible nitric oxide synthase expression but did not influence endogenous superoxide generation. Microglial flow cytometric analyses indicated the 225THC treatment induced a shift from an M1-like phenotype to a more downregulated microglial profile. Taken together these data suggest that the chalcone 2,2',5'-trihydroxychalcone can modulate neuroinflammatory activation in brain-derived microglia and holds promise as a therapeutic in neuroinflammatory conditions.

Synthesis, biological evaluation and docking study of maleimide derivatives bearing benzenesulfonamide as selective COX-2 inhibitors and anti-inflammatory agents

A series of maleimide analogs bearing benzenesulfonamide were synthesized (4a-r). The anti-inflammatory activity of synthesized derivatives was evaluated using carrageenan induced rat paw edema model. COX-1 and COX-2 potency was evaluated through in vitro cyclooxygenase assays. The results revealed that, compounds 4a, 4h, 4 j, 4 k and 4r had potent COX-2 percentage inhibition as well as in vivo anti-inflammatory activity. The potent compound 4 j was docked into the COX-2 active site to determine the probable binding model. The results of in vivo and in vitro studies demonstrate that phenyl ring with electron withdrawing groups on maleimide ring would generate more potent anti-inflammatory agents. Thus, these compounds can serve as potential leads for further anti-inflammatory studies.

Synthesis, characterization and antiamoebic activity of chalcones bearing N-substituted ethanamine tail

A series of chalcones (4-21) possessing N-substituted ethanamine were synthesized by the aldol condensation reaction of 1-(4-(2-substituted ethoxy)phenyl)ethanones with different aldehydes preceded by the reaction of 2-chloro N-substituted ethanamine hydrochloride and 4-hydroxy acetophenone. The structure of all the synthesized compounds was elucidated by various spectral and X-ray diffraction studies. The compounds were screened against HM1: IMSS strain of Entamoeba histolytica and cytotoxicity was performed on A549 (non-small cell lung cancer cell line) cells by MTT assay. Out of eighteen compounds twelve showed better activity then the standard drug metronidazole. The compound 9, 14 and 19 showed good cell viability, hence were least toxic.

Antimycobacterial and anti-inflammatory activities of substituted chalcones focusing on an anti-tuberculosis dual treatment approach

Tuberculosis (TB) remains a serious public health problem aggravated by the emergence of M. tuberculosis (Mtb) strains resistant to multiple drugs (MDR). Delay in TB treatment, common in the MDR-TB cases, can lead to deleterious life-threatening inflammation in susceptible hyper-reactive individuals, encouraging the discovery of new anti-Mtb drugs and the use of adjunctive therapy based on anti-inflammatory interventions. In this study, a series of forty synthetic chalcones was evaluated in vitro for their anti-inflammatory and antimycobacterial properties and in silico for pharmacokinetic parameters. Seven compounds strongly inhibited NO and PGE₂ production by LPS-stimulated macrophages through the specific inhibition of iNOS and COX-2 expression, respectively, with compounds 4 and 5 standing out in this respect. Four of the seven most active compounds were able to inhibit production of TNF-α and IL-1β. Chalcones that were not toxic to cultured macrophages were tested for antimycobacterial activity. Eight compounds were able to inhibit growth of the M. bovis BCG and Mtb H37Rv strains in bacterial cultures and in infected macrophages. Four of them, including compounds 4 and 5, were active against a hypervirulent clinical Mtb isolate as well. In silico analysis of ADMET properties showed that the evaluated chalcones displayed satisfactory pharmacokinetic parameters. In conclusion, the obtained data demonstrate that at least two of the studied chalcones, compounds 4 and 5, are promising antimycobacterial and anti-inflammatory agents, especially focusing on an anti-tuberculosis dual treatment approach.

Discovery of 2'-hydroxychalcones as autophagy inducer in A549 lung cancer cells

A series of 2'-hydroxychalcone derivatives was synthesized and the effects of all the compounds on growth of A549 lung cancer cell were investigated. The results showed that all compounds had inhibitory effects on the growth of A549 lung cancer cells and compound possessed the highest growth inhibitory effect and induced autophagy of A549 lung cancer cells.

Synthesis, characterization and biological evaluation of novel 4'-fluoro-2'-hydroxy-chalcone derivatives as antioxidant, anti-inflammatory and analgesic agents

In an effort to develop safe and potent anti-inflammatory agents, a series of novel 4'-fluoro-2'-hydroxychalcones 5a-d and their dihydropyrazole derivatives 6a-d was prepared. It was synthesized via aldol condensation of 4'-fluoro-2'-hydroxyacetophenone with appropriately substituted aldehydes followed by cyclization with hydrazine hydrate. All the synthesized compounds were evaluated for their antioxidant, anti-inflammatory, cyclooxygenase inhibition selectivity and analgesic activities. The dimethoxychalcone 5a and its dihydropyrazole derivative 6a showed the highest antioxidant activity, while the monomethoxychalcone 5d and its dihydropyrazole derivative 6d showed the highest analgesic and anti-inflammatory activities. It was also found that there is a close correlation between 4'-fluoro-2'-hydroxychalcones 5a-d and their dihydropyrazole derivatives 6a-d in the screened biological activities. To explain the correlation between the synthesized chalcones and their dihydropyrazole derivatives, especially for the anti-inflammatory activity, docking studies were performed.

Recent developments in biological activities of chalcones: a mini review

Chalcones represent key structural motif in the plethora of biologically active molecules including synthetic and natural products. Synthetic manipulations of chalcones or their isolation from natural sources are being investigated worldwide for the development of more potent and efficient drugs for the treatment of several dreadful diseases such as cancer, diabetes, HIV, tuberculosis, malaria etc. Over the past few years, a large volume of research papers and review articles highlighting the significance of chalcone derivatives has been compiled in the literature. The present review article focuses on the recent developments (2010-2014) on various pharmacological and medicinal aspects of chalcones and their analogues.