Antiproliferative and pro-apoptotic activities of 2′- and 4′-aminochalcones against tumor canine cells

Insights of potential trypanocidal effect of the synthetic derivative (2E)-1-(4-aminophenyl)-3-(2,4-dichlorophenyl)prop-2-en-1-one: in vitro assay, MEV analysis, quantum study, molecular docking, molecular dynamics, MPO analysis, and predictive ADMET

This study aims to evaluate the antitrypanosomiasis activity of a synthetic dichloro-substituted aminochalcone via in vitro assays against infected cell cultures, as well as a theoretical characterization of pharmacokinetics and pharmacodynamics against the protein targets of the evolutionary cycle of T. cruzi. The in vitro evaluation of parasite proliferation inhibition was performed via cytotoxicity analysis on mammalian host cells, effect on epimastigote and trypomastigote forms, and cell death analysis, while computer simulations characterized the electronic structure of (2E)-1-(4-aminophenyl)-3-(2,4-dichlorophenyl)prop-2-en-1-one (DCl), the mechanism of action against the proteins of the evolutionary cycle of T. cruzi: Cruzain, Trypanothione reductase, TcGAPDH, and CYP51 by molecular docking and dynamics and predictive pharmacokinetics by MPO-based ADMET. The in vitro tests showed that the DCl LC50 in order of 178.9 ± 23.9 was similar to the BZN, evidencing the effectiveness of chalcone against Trypomastigotes. Molecular docking and dynamics simulations suggest that DCl acts on the active site of the CYP51 receptor, with hydrogen interactions that showed a high degree of occupation, establishing a stable complex with the target. MPO analysis and ADMET prediction tests suggest that the compound presents an alignment between permeability and hepatic clearance, although it presents low metabolic stability. Chalcone showed stable pharmacodynamics against the CYP51 target, but can form reactive metabolites from N-conjugation and C = C epoxidation, as an indication of controlled oral dose, although the estimated LD50 rate > 500 mg/kg is a indicative of low incidence of lethality by ingestion, constituting a promising therapeutic strategy.

Novel coumarin-6-sulfonamide-chalcone hybrids as glutathione transferase P1-1 inhibitors

Multidrug resistance (MDR) mechanisms in cancer cells are greatly influenced by glutathione transferase P1-1 (hGSTP1-1). The use of synthetic or natural compounds as hGSTP1-1 inhibitors is considered an effective approach to overcome MDR. Nine compounds consisting of coumarin-6-sulfonamide linked to chalcone derivatives were synthesized and evaluated for their ability to inhibit hGSTP1-1. Among the synthetic derivatives, compounds 5g, 5f, and 5a displayed the most potent inhibitory effect, with IC50 values of 12.2 ± 0.5 μΜ, 12.7 ± 0.7 and 16.3 ± 0.6, respectively. Kinetic inhibition analysis of the most potent molecule, 5g, showed that it behaves as a mixed-type inhibitor of the target enzyme. An in vitro cytotoxicity assessment of 5a, 5f, and 5g against the human prostate cancer cell lines DU-145 and PC3, as well as the breast cancer cell line MCF-7, demonstrated that compound 5g exhibited the most pronounced cytotoxic effect on all tested cell lines. Molecular docking studies were performed to predict the structural and molecular determinants of 5g, 5f, and 5a binding to hGSTP1-1. In agreement with the experimental data, the results revealed that 5g exhibited the lowest docking score among the three studied inhibitors as a consequence of shape complementarity, governed by van der Waals, hydrogen bonds and a π-π stacking interaction. These findings suggest that coumarin-chalcone hybrids offer new perspectives for the development of safe and efficient natural product-based sensitizers that can target hGSTP1-1 for anticancer purposes.

Synergistic activity between conventional antifungals and chalcone-derived compound against dermatophyte fungi and Candida spp

The scarce antifungal arsenal, changes in the susceptibility profile of fungal agents, and lack of adherence to treatment have contributed to the increase of cases of dermatomycoses. In this context, new antimicrobial substances have gained importance. Chalcones are precursors of the flavonoid family that have multiple biological activities, have high tolerability by humans, and easy synthesis. In this study, we evaluated the in vitro antifungal activity, alone and in combination with conventional antifungal drugs, of the VS02-4'ethyl chalcone-derived compound against dermatophytes and Candida spp. Susceptibility testing was carried out by broth microdilution. Experiments for determination of the target of the compound on the fungal cell, time-kill kinetics, and toxicity tests in Galleria mellonella model were also performed. Combinatory effects were evaluated by the checkerboard method. Results showed high activity of the compound VS02-4'ethyl against dermatophytes (MIC of 7.81-31.25 μg/ml). The compound targeted the cell membrane, and the time-kill test showed the compound continues to exert gradual activity after 5 days on dermatophytes, but no significant activity on Candida. Low toxicity was observed at 250 mg/kg. Excellent results were observed in the combinatory test, where VS02-4'ethyl showed synergistic interactions with itraconazole, fluconazole, terbinafine, and griseofulvin, against all isolates tested. Although further investigation is needed, these results revealed the great potential of chalcone-derived compounds against fungal infections for which treatments are long and laborious.

Phenolic chalcones as agents against Trichomonas vaginalis

Trichomonas vaginalis, a flagellated and anaerobic protozoan, is a causative agent of trichomoniasis. This disease is among the world's most common non-viral sexually transmitted infection. A single class drug, nitroimidazoles, is currently available for the trichomoniasis treatment. However, resistant isolates have been identified from unsuccessfully treated patients. Thus, there is a great challenge for a discovery of innovative anti-T. vaginalis agents. As part of our ongoing search for antiprotozoal chalcones, we designed and synthesized a series of 21 phenolic chalcones, which were evaluated against T. vaginalis trophozoites. Structure-activity relationship indicated hydroxyl group plays a role key in antiprotozoal activity. 4'-Hydroxychalcone (4HC) was the most active compound (IC50 = 27.5 µM) and selected for detailed bioassays. In vitro and in vivo evaluations demonstrated 4HC was not toxic against human erythrocytes and Galleria mellonella larvae. Trophozoites of T. vaginalis were treated with 4HC and did not present significant reactive oxygen species (ROS) accumulation. However, compound 4HC was able to increase ROS accumulation in neutrophils coincubated with T. vaginalis. qRT-PCR Experiments indicated that 4HC did not affect the expression of pyruvate:ferredoxin oxidoreductase (PFOR) and β-tubulin genes. In silico simulations, using purine nucleoside phosphorylase of T. vaginalis (TvPNP), corroborated 4HC as a promising ligand. Compound 4HC was able to establish interactions with residues D21, G20, M180, R28, R87 and T90 through hydrophobic interactions, π-donor hydrogen bond and hydrogen bonds. Altogether, these results open new avenues for phenolic chalcones to combat trichomoniasis, a parasitic neglected infection.

A Novel MDM2-Binding Chalcone Induces Apoptosis of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) represents ~90% of all oral cancers, being the eighth most common cancer in men. The overall 5-year survival rate is only 39% for metastatic cancers, and currently used chemotherapeutics can cause important side effects. Thus, there is an urgency in developing new and effective anti-cancer agents. As both chalcones and 1,2,3-triazoles are valuable pharmacophores/privileged structures in the search for anticancer compounds, in this work, new 1,2,3-triazole-chalcone hybrids were synthesized and evaluated against oral squamous cell carcinoma. By using different in silico, in vitro, and in vivo approaches, we demonstrated that compound 1f has great cytotoxicity and selectivity against OSCC (higher than carboplatin and doxorubicin) and other cancer cells in addition to showing minimal toxicity in mice. Furthermore, we demonstrate that induced cell death occurs by apoptosis and cell cycle arrest at the G2/M phase. Moreover, we found that 1f has a potential affinity for MDM2 protein, similar to the known ligand nutlin-3, and presents a better selectivity, pharmacological profile, and potential to be orally absorbed and is not a substrate of Pg-P when compared to nutlin-3. Therefore, we conclude that 1f is a good lead for a new chemotherapeutic drug against OSCC and possibly other types of cancers.

Application of Polyphenols and Flavonoids in Oncological Therapy

The use of naturally derived drugs in anti-cancer therapies has grown exponentially in recent years. Among natural compounds, polyphenols have shown potential therapeutic applications in treatment due to their protective functions in plants, their use as food additives, and their excellent antioxidant properties, resulting in beneficial effects on human health. Building more efficient cancer therapies with fewer side effects on human health can be achieved by combining natural compounds with conventional drugs, which are typically more aggressive than natural chemicals with polyphenols. This article reviews a wide variety of studies where polyphenolic compounds can play a key role as anticancer drugs, alone or in combination with other drugs. Moreover, the future directions of applications of various polyphenols in cancer therapy are shown.

Boron-Containing heterocycles as promising pharmacological agents

The incorporation of the "magic" boron atom has been established as an important new strategy in the field of medicinal chemistry as boron compounds have been shown to form various bonds with their biological targets. Currently, a number of boron-based drugs (e.g. bortezomib, crisaborole, and tavaborole) have been FDA approved and are in the clinic, and several other boron-containing compounds are in clinical trials. Boron-based heterocycles have an incredible potential in the ongoing quest for new therapeutic agents owing to their plethora of biological activities and useful pharmacokinetic profiles. The present perspective is intended to review the pharmacological applications of boron-based heterocycles that have been published. We have classified these compounds into groups exhibiting shared pharmacological activities and discussed their corresponding biological targets focusing mainly on the most potent therapeutic compounds.

Anticancer Activity of Natural and Synthetic Chalcones

Cancer is a condition caused by many mechanisms (genetic, immune, oxidation, and inflammatory). Anticancer therapy aims to destroy or stop the growth of cancer cells. Resistance to treatment is theleading cause of the inefficiency of current standard therapies. Targeted therapies are the most effective due to the low number of side effects and low resistance. Among the small molecule natural compounds, flavonoids are of particular interest for theidentification of new anticancer agents. Chalcones are precursors to all flavonoids and have many biological activities. The anticancer activity of chalcones is due to the ability of these compounds to act on many targets. Natural chalcones, such as licochalcones, xanthohumol (XN), panduretin (PA), and loncocarpine, have been extensively studied and modulated. Modification of the basic structure of chalcones in order to obtain compounds with superior cytotoxic properties has been performed by modulating the aromatic residues, replacing aromatic residues with heterocycles, and obtaining hybrid molecules. A huge number of chalcone derivatives with residues such as diaryl ether, sulfonamide, and amine have been obtained, their presence being favorable for anticancer activity. Modification of the amino group in the structure of aminochalconesis always favorable for antitumor activity. This is why hybrid molecules of chalcones with different nitrogen hetercycles in the molecule have been obtained. From these, azoles (imidazole, oxazoles, tetrazoles, thiazoles, 1,2,3-triazoles, and 1,2,4-triazoles) are of particular importance for the identification of new anticancer agents.

Design, synthesis and antibacterial activity of chalcones against MSSA and MRSA planktonic cells and biofilms

Staphylococcus aureus is the one of the most successful modern pathogens. The same bacterium that lives as a skin and mucosal commensal can be transmitted in health-care and community-settings and causes severe infections. Thus, there is a great challenge for a discovery of novel anti-Staphylococcus aureus compounds, which should act against resistant strains. Herein, we designed and synthesized a series of 17 chalcones, substituted by amino group on ring A, which were evaluated against methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus MRSA planktonic cells. The antibacterial potency was improved by substituents on ring B, which were designed according to Topliss' manual method. 4-bromo-3'-aminochalcone (5f) was the most active, demonstrating minimum inhibitory concentration (MIC) values of 1.9 μg mL^-1 and 7.8 µg mL^-1 against MSSA and MRSA, respectively. The association of 5f with vancomycin demonstrated synergistic effect against MSSA and MRSA, with Fractional Inhibitory Concentration Index (FICI) values of 0.4 and 0.3, respectively. Subinhibitory concentration of 5f inhibited the MSSA and MRSA adhesion to human keratinocytes. Chalcone 5f was able to reduce MSSA and MRSA biofilm formation, as well as acts on preformed biofilm in concentration-dependent mode. Scanning electron microscopy analyses confirmed severe perturbations caused by 5f on MSSA and MRSA biofilm architecture. The acute toxicity assay, using Galleria mellonella larvae, indicated a low toxic effect of 5f after 72 h, displaying lethality of 20% and 30% at 7.8 μg mL^-1 and 78.0 μg mL^-1, respectively. In addition, the antibacterial activity spectrum of 5f indicated action against planktonic cells of Enterococcus faecalis (MIC = 7.8 μg mL^-1), Acinetobacter baumannii (MIC = 15.6 μg mL^-1) and Mycobacterium tuberculosis (MIC = 5.7 μg mL^-1). Altogether, these results open new avenues for 5f as an anti-Staphylococcus aureus agent, with potential applications as antibacterial drug, adjunct of antibiotics and medical devices coating.

Synthesis and biological evaluation of chalcone-polyamine conjugates as novel vectorized agents in colorectal and prostate cancer chemotherapy

The aim of this study was to synthesize chalcone-polyamine conjugates in order to enhance bioavailability and selectivity of chalcone core towards cancer cells, using polyamine-based vectors. Indeed, it is well-known that polyamine transport system is upregulated in tumor cells. 3',4,4',5'-tetramethoxychalcone was selected as parent chalcone since it was found to be an efficient anti-proliferative agent on various cancer cells. A series of five chalcone-polyamine conjugates was obtained using the 4-bromopropyloxy-3',4',5'-trimethoxychalcone as a key intermediate. Chalcone core and polyamine tails were fused through an amine bond. These conjugates were found to possess a marked in vitro antiproliferative effect against colorectal (HT-29 and HCT-116) and prostate cancer (PC-3 and DU-145) cell lines. The most active conjugate (compound 8b) was then chosen for further biological evaluations to elucidate mechanisms responsible for its antiproliferative activity. Investigations on cell cycle distribution revealed that this conjugate can prevent the proliferation of human colorectal and prostate cancer cells by blocking the cell cycle at the G1 and G2 phase, respectively. Flow cytometry analysis revealed a sub-G1 peak, characteristic of apoptotic cell population and our inquiries highlighted apoptosis induction at early and later stages through several pro-apoptotic markers. Therefore, this chalcone-N1-spermidine conjugate could be considered as a promising agent for colon and prostatic cancer adjuvant therapy.

Progress in the medicinal chemistry of organoboron compounds

The review aims to draw attention to the latest advances in the organoboron chemistry and therapeutic use of organoboron compounds. The synthetic strategies towards boron-containing compounds with proven in vitro and/or in vivo biological activities, including derivatives of boronic acids, benzoxaboroles, benzoxaborines and benzodiazaborines, are summarized. Approaches to the synthesis of hybrid structures containing an organoboron moiety as one of the pharmacophores are considered, and the effect of this modification on the pharmacological activity of the initial molecules is analyzed. On the basis of analysis of the published data, the most promising areas of research in the field of organoboron compounds are identified, including the latest methods of synthesis, modification and design of effective therapeutic agents.

The bibliography includes 246 references.

Chalcones and their B-aryl analogues as myeloperoxidase inhibitors: In silico, in vitro and ex vivo investigations

In the present study, a series of chalcones and their B-aryl analogues were prepared and evaluate as inhibitors of myeloperoxidase (MPO) chlorinating activity, using in vitro and ex vivo assays. Among these, B-thiophenyl chalcone (analogue 9) demonstrated inhibition of in vitro and ex vivo MPO chlorinating activity, exhibiting IC₅₀ value of 0.53 and 19.2 µM, respectively. Potent ex vivo MPO inhibitors 5, 8 and 9 were not toxic to human neutrophils at 50 µM, as well as displayed weak 2,2-diphenyl-1-pycrylhydrazyl radical (DPPH•) and hypochlorous acid (HOCl) scavenger abilities. Docking simulations indicated binding mode of MPO inhibitors, evidencing hydrogen bonds between the amino group at 4'position (ring A) of chalcones with Gln91, Asp94, and Hys95 MPO residues. In this regard, the efficacy and low toxicity promoted aminochalcones and arylic analogues to the rank of hit compounds in the search for new non-steroidal anti-inflammatory compounds.

A Comprehensive Review of Aminochalcones

Chalcones, members of the flavonoid family, display a plethora of interesting biological activities including but not limited to antioxidant, anticancer, antimicrobial, anti-inflammatory, and antiprotozoal activities. The literature cites the synthesis and activity of a range of natural, semisynthetic, and synthetic chalcones. The current review comprehensively covers the literature on amino-substituted chalcones and includes chalcones with amino-groups at various positions on the aromatic rings as well as those with amino-groups containing mono alkylation, dialkylation, alkenylation, acylation, and sulfonylation. The aminochalcones are categorized according to their structure, and the corresponding biological activities are discussed as well. Some compounds showed high potency against cancer cells, microbes, and malaria, whereas others did not. The purpose of this review is to serve as a one-stop location for information on the aminochalcones reported in the literature in recent years.

Investigating the Modes of Action of the Antimicrobial Chalcones BC1 and T9A

Xanthomonas citri subsp. citri (X. citri) is an important phytopathogen and causes Asiatic Citrus Canker (ACC). To control ACC, copper sprays are commonly used. As copper is an environmentally damaging heavy metal, new antimicrobials are needed to combat citrus canker. Here, we explored the antimicrobial activity of chalcones, specifically the methoxychalcone BC1 and the hydroxychalcone T9A, against X. citri and the model organism Bacillus subtilis. BC1 and T9A prevented growth of X. citri and B. subtilis in concentrations varying from 20 µg/mL to 40 µg/mL. BC1 and T9A decreased incorporation of radiolabeled precursors of DNA, RNA, protein, and peptidoglycan in X. citri and B. subtilis. Both compounds mildly affected respiratory activity in X. citri, but T9A strongly decreased respiratory activity in B. subtilis. In line with that finding, intracellular ATP decreased strongly in B. subtilis upon T9A treatment, whereas BC1 increased intracellular ATP. In X. citri, both compounds resulted in a decrease in intracellular ATP. Cell division seems not to be affected in X. citri, and, although in B. subtilis the formation of FtsZ-rings is affected, a FtsZ GTPase activity assay suggests that this is an indirect effect. The chalcones studied here represent a sustainable alternative to copper for the control of ACC, and further studies are ongoing to elucidate their precise modes of action.

Current Perspectives of the Applications of Polyphenols and Flavonoids in Cancer Therapy

The development of anticancer therapies that involve natural drugs has undergone exponential growth in recent years. Among the natural compounds that produce beneficial effects on human health, polyphenols have shown potential therapeutic applications in cancer due to their protective functions in plants, their use as food additives, and their excellent antioxidant properties. The possibility of combining conventional drugs-which are usually more aggressive than natural compounds-with polyphenols offers very valuable advantages such as the building of more efficient anticancer therapies with less side effects on human health. This review shows a wide range of trials in which polyphenolic compounds play a crucial role as anticancer medicines alone or in combination with other drugs at different stages of cancer: cancer initiation, promotion, and growth or progression. Moreover, the future directions in applications of various polyphenols in cancer therapy are emphasized.

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.

Activity and mechanism of flavokawain A in inhibiting P-glycoprotein expression in paclitaxel resistance of lung cancer

Lung cancer is one of the most common cancers, which is the leading cause of cancer-related death among various cancers worldwide. Flavokawain A (FKA), a chalcone found in the kava plant, exerts potent anticancer activity. However, the activity and mechanisms of FKA in inhibiting the viability of paclitaxel (PTX)-resistant lung cancer A549 (A549/T) have not been investigated. In the present study, the effect of FKA on the viability of A549/T and hepatotoxicity in normal liver epithelial cells was detected by Cell Counting Kit-8 assay. Flow cytometry, western blot analysis and Annexin V-FITC/PI apoptosis detection kit were used to assess cell apoptosis. The effect of FKA on permeability-glycoprotein (P-gp) expression was measured by reverse transcription-PCR and western blot analysis. The results indicated that FKA dose-dependently inhibited cell proliferation and induced cell apoptosis in PTX-resistant A549/T cells, with an IC₅₀ value of ~21 µM, while the IC₅₀ value of A549/T cells to PTX was 34.64 µM. FKA had no hepatic toxicity in liver epithelial cells. P-gp, which contributes to the chemoresistant phenotype, was not expressed in A549 cells but was remarkably enhanced in A549/T cells. FKA (30 µM) decreased P-gp protein expression at 24 h by 3-fold. Furthermore, FKA downregulated P-gp expression by blocking the PI3K/Akt pathway. These findings suggest FKA as a potential candidate for the treatment of PTX-resistant lung cancer.

Influence of amide versus ester linkages on the anticancer properties of the new flavone-biotin conjugates

Novel biotinylated C-6 substituted flavones were synthesised by a one-step method that connects biotin to 6-hydroxyflavone and 6-aminoflavone by esterification and amidation of hydroxyl and amino groups, respectively. The obtained compounds, 6-O-biotinylflavone and 6-biotinylamidoflavone, are the bifunctional molecules composed of a flavone moiety as a fluorescent reporter and biotin as a cancer-targeting unit. Antiproliferative activity was evaluated using SRB assays in MCF-7, MCF-10A, HepG2, MDA-MB-231, 4T1, and Balb/3T3 cell lines. In vitro evaluation revealed that compounds with biotin moiety displayed better cell selectivity between the cancer and normal cells than the parental substrates. These results indicate that anticancer effect is not related to the position of biotin moiety, but it is related to the presence of ester or amide bond. 6-O-Biotinylflavone was more active than 6-hydroxyflavone against human breast (MDA-MB-231) and liver (HepG2) cancer cells with IC50 (concentration of tested agent that inhibits proliferation of the cell population by 50%) values equal to 78.5 ± 18.8 μM and 133.2 ± 14.2 μM, respectively. Non biotinylated 6-aminoflavone was more active than 6-biotinylamidoflavone against all tested cell lines, with IC50 values between 34.3 ± 9.1 μM (4T1) and 173.86 ± 24.3 μM (MCF-7).

Methoxychalcones: Effect of Methoxyl Group on the Antifungal, Antibacterial and Antiproliferative Activities

BACKGROUND

Chalcones substituted by methoxyl groups have presented a broad spectrum of bioactivities, including antifungal, antibacterial and antiproliferative effects. However, a clear and unambiguous investigation about the relevance of this substituent on the chalcone framework has not been described.

OBJECTIVE

The purpose of this work is to assess the antibacterial, antifungal and antiproliferative activities of the two series of seventeen synthesized regioisomeric methoxychalcones. Series I and II were constituted by chalcones substituted by methoxyl groups on rings A (5-12) and B (13-21), respectively. In addition, the library of methoxychalcones was submitted to in silico drug-likeness and pharmacokinetics properties predictions.

METHODS

Methoxychalcones were synthesized and their structures were confirmed by NMR spectral data analyses. Evaluations of antimicrobial activity were performed against five species of Candida, two Gram-negative and five Gram-positive species. For antiproliferative activity, methoxychalcones were evaluated against four human tumorigenic cell lines, as well as human non-tumorigenic keratinocytes. Drug-likeness and pharmacokinetics properties were predicted using Molinspiration and PreADMET toolkits.

RESULTS

In general, chalcones of series I are the most potent antifungal, antibacterial and antiproliferative agents. 3', 4', 5'-Trimethoxychalcone (12) demonstrated potent antifungal activity against Candida krusei (MIC = 3.9 μg/mL), eight times more potent than fluconazole (reference antifungal drug). 3'-Methoxychalcone (6) displayed anti-Pseudomonas activity (MIC = 7.8 μg/mL). 2',5'-Dimethoxychalcone (9) displayed potent antiproliferative effect against C-33A (cervix), A-431 (skin) and MCF-7 (breast), with IC50 values ranging from 7.7 to 9.2 μM. Its potency was superior to curcumin (reference antiproliferative compound), which exhibited IC50 values ranging from 10.4 to 19.0 μM.

CONCLUSION

Our studies corroborated the relevance of methoxychalcones as antifungal, antibacterial and antiproliferative agents. In addition, we elucidated influence of the position and number of methoxyl groups toward bioactivity. In silico predictions indicated good drug-likeness and pharmacokinetics properties to the library of methoxychalcones.

Antiproliferative activity and p53 upregulation effects of chalcones on human breast cancer cells

Chalcones are valuable structures for drug discovery due to their broad bioactivity spectrum. In this study, we evaluated 20 synthetic chalcones against estrogen-receptor-positive breast cancer cells (MCF-7 line) and triple-negative breast cancer (TNBC) cells (MDA-MB-231 line). Antiproliferative screening by MTT assay resulted in two most active compounds: 2-fluoro-4’-aminochalcone (11) and 3-pyridyl-4’-aminochalcone (17). Their IC₅₀ values ranged from 13.2 to 34.7 µM against both cell lines. Selected chalcones are weak basic compounds and maintained their antiproliferative activity under acidosis conditions (pH 6.7), indicating their resistance to ion-trapping effect. The mode of breast cancer cells death was investigated and chalcones 11 and 17 were able to induce apoptosis rather than necrosis in both lines. Antiproliferative target investigations with MCF-7 cells suggested 11 and 17 upregulated p53 protein expression and did not affect Sp1 protein expression. Future studies on chalcones 11 and 17 can define their in vivo therapeutic potential.

Anti-Trichomonas vaginalis activity of chalcone and amino-analogues

Trichomoniasis is the most common non-viral sexually transmitted disease worldwide and can lead to serious consequences in reproductive health, cancer, and HIV acquisition. The current approved treatment present adverse effects and drug resistance data on this neglected parasitic infection is underestimated. Chalcones are a family of molecules that present biological applications, such as activity against many pathogenic organisms including protozoan pathogens. Chalcone (1) and three amino-analogues (2-4) were synthesized by Claisen-Schmidt condensation reaction and had their activity evaluated against the parasitic protozoan Trichomonas vaginalis. This bioassay indicated the presence and position of the amino group on ring A was crucial for anti-T. vaginalis activity. Among these, 3'-aminochalcone (3) presented the most potent effect and showed high cytotoxicity against human vaginal cells. On the other hand, 3 was not able to exhibit toxicity against Galleria mellonella larvae, as well as the hemolytic effect on human erythrocytes. Trophozoites of T. vaginalis were treated with 3, and did not present significant reactive oxygen species (ROS) accumulation, but induced a significantly higher ROS accumulation in human neutrophils after co-incubation. T. vaginalis pyruvate:ferredoxin oxidoreductase (PFOR) and β-tubulin gene expression was not affected by 3.

Computational screening of chalcones acting against topoisomerase IIα and their cytotoxicity towards cancer cell lines

Targeted cancer therapy has become one of the high potential cancer treatments. Human topoisomerase II (hTopoII), which catalyzes the cleavage and rejoining of double-stranded DNA, is an important molecular target for the development of novel cancer therapeutics. In order to diversify the pharmacological activity of chalcones and to extend the scaffold of topoisomerase inhibitors, a series of chalcones was screened against hTopoIIα by computational techniques, and subsequently tested for their in vitro cytotoxicity. From the experimental IC₅₀ values, chalcone 3d showed a high cytotoxicity with IC₅₀ values of 10.8, 3.2 and 21.1 µM against the HT-1376, HeLa and MCF-7 cancer-derived cell lines, respectively, and also exhibited an inhibitory activity against hTopoIIα-ATPase that was better than the known inhibitor, salvicine. The observed ligand-protein interactions from a molecular dynamics study affirmed that 3d strongly interacts with the ATP-binding pocket residues. Altogether, the newly synthesised chalcone 3d has a high potential to serve as a lead compound for topoisomerase inhibitors.

Chalcone Derivatives 4'-Amino-1-Naphthyl-Chalcone (D14) and 4'-Amino-4-Methyl-1-Naphthyl-Chalcone (D15) Suppress Migration and Invasion of Osteosarcoma Cells Mediated by p53 Regulating EMT-Related Genes

Osteosarcoma (OS) is a primary malignant bone tumor that mainly affects children, adolescents, and young adults. The inhibition of metastasis is a main strategy of OS therapy since the development of metastatic disease due to drug resistance remains the most important cause of death from this cancer. Considering the severe side effects of current OS chemotherapy, the identification of anti-metastatic drugs with reduced toxicity is of great interest. Chalcones are polyphenols with a basic structure consisting of an α-, β-unsaturated carbonyl system linking two aryl rings. These compounds exhibit anticancer activity against a variety of tumor cell lines through multiple mechanisms, including the regulation of the tumor-suppressor protein p53 and its target genes. An important process regulated by p53 is epithelial-mesenchymal transition (EMT), which facilitates tumor metastasis by conferring migratory and invasive properties to cancer cells. The activation of p53 can revert EMT and reduce migration and invasion. This study aimed to examine the inhibitory effects of two 4′-aminochalcones on the migration/invasion of the U2OS (p53+/+) and SAOS-2 (p53−/−) OS cell lines as well as the underlying molecular mechanisms. Cell viability was examined by MTT assay. Transwell assays were used to evaluate the migratory and invasive ability of the cells. The two 4′-aminochalcones showed low capacity to inhibit the viability of OS cells independent of p53 status, but preferentially suppressed the migration of U2OS cells and of a SAOS-2 cell line expressing p53. Invasion was strongly inhibited by both chalcones independent of p53 status. RT-PCR, zymography, and Western blot were used to study the expression of matrix metalloproteinases and EMT markers after treatment with the chalcones. The results indicated that the 4′-aminochalcone-induced antimigratory and anti-invasive effects are potentially associated with the inhibition of extracellular matrix (ECM) enzymatic degradation in OS cells and with the modulation of EMT genes. These effects probably result from the induced increase of p53 protein expression by the two chalcones. In conclusion, chalcones D14 and D15 have potential anti-metastatic activity mediated by p53 that can be exploited for OS treatment.