Cytotoxic activities of Mannich bases of chalcones and related compounds

Bioreduction of 4'-Hydroxychalcone in Deep Eutectic Solvents: Optimization and Efficacy with Various Yeast Strains

4'-dihydrochalcones are secondary metabolites isolated from many medicinal plants and from the resin known as 'dragon's blood'. Due to their biological potential, our research objective was to determine the possibilities of using biocatalysis processes carried out in deep eutectic solvents (DESs) to obtain 4'-dihydrochalcones as a model compound. The processes were carried out in a culture of the yeast Yarrowia lipolytica KCh 71 and also in cultures of strains of the genera Rhodotorula and Debaryomyces. Based on the experiments carried out, an optimum process temperature of 35 °C was chosen, and the most suitable DES contained glycerol as a hydrogen bond donor (HBD). For a medium with 30% water content (DES 11), the conversion observed after 24 h exceeded 70%, while increasing the amount of water to 50% resulted in a similar level of conversion after just 1 h. A fivefold increase in the amount of added substrate resulted in a reduction in conversion, which reached 30.3%. Of the other yeast strains tested, Rhodotorula marina KCh 77 and Rhodotorula rubra KCh 4 also proved to be good biocatalysts for the bioreduction process. For these strains, the conversion reached 95.4% and 95.1%, respectively. These findings highlight the potential of yeast as a biocatalyst for the selective reduction of α,β-unsaturated ketones and the possibility of using a DESs as a reaction medium in this process.

Synthesis, Antimicrobial Activities, and Molecular Modeling Studies of Agents for the Sortase A Enzyme

Sortase A (SrtA) is an attractive target for developing new anti-infective drugs that aim to interfere with essential virulence mechanisms, such as adhesion to host cells and biofilm formation. Herein, twenty hydroxy, nitro, bromo, fluoro, and methoxy substituted chalcone compounds were synthesized, antimicrobial activities and molecular modeling strategies against the SrtA enzyme were investigated. The most active compounds were found to be T2, T4, and T19 against Streptococcus mutans (S. mutans) with MIC values of 1.93, 3.8, 3.94 μg/mL, and docking scores of -6.46, -6.63, -6.73 kcal/mol, respectively. Also, these three active compounds showed better activity than the chlorohexidine (CHX) (MIC value: 4.88 μg/mL, docking score: -6.29 kcal/mol) in both in vitro and in silico. Structural stability and binding free energy analysis of S.mutans SrtA with active compounds were measured by molecular dynamic (MD) simulations throughout 100 nanoseconds (ns) time. It was observed that the stability of the critical interactions between these compounds and the target enzyme was preserved. To prove further, in vivo biological evaluation studies could be conducted for the most promising precursor compounds T2, T4, and T19, and it might open new avenues to the discovery of more potent SrtA inhibitors.

Synthesis of Novel Heterocyclic Ferrocenyl Chalcones and Their Biological Evaluation

Breast cancer is currently the most commonly diagnosed cancer, with 287,850 new cases estimated for 2022 as reported by the American Cancer Society. Therefore, finding an effective treatment for this disease is imperative. Chalcones are α,β-unsaturated systems found in nature. These compounds have shown a wide array of biological activities, making them popular synthetic targets. Chalcones consist of two aromatic substituents connected by an enone bridge; this arrangement allows for a large number of derivatives. Given the biological relevance of these compounds, novel ferrocene-heterocycle-containing chalcones were synthesized and characterized based on a hybrid drug design approach. These heterocycles included thiophene, pyrimidine, thiazolyl, and indole groups. Fourteen novel heterocyclic ferrocenyl chalcones were synthesized and characterized. Herein, we also report their cytotoxicity against triple-negative breast cancer cell lines MDA-MB-231 and 4T1 and the noncancer lung cell line MRC-5. System 3 ferrocenyl chalcones displayed superior anticancer properties compared to their system 1 analogues. System 3 chalcones bearing five-membered heterocyclic substituents (thiophene, pyrazole, pyrrole, and pyrimidine) were the most active toward the MDA-MB-231 cancer cell line with IC50 values from 6.59 to 12.51 μM. Cytotoxicity of the evaluated compounds in the 4T1 cell line exhibited IC50 values from 13.23 to 213.7 μM. System 3 pyrazole chalcone had consistent toxicity toward both cell lines (IC50 ∼ 13 μM) as well as promising selectivity relative to the noncancer MRC-5 control. Antioxidant activity was also evaluated, where, contrary to anticancer capabilities, system 1 ferrocenyl chalcones were superior to their system 3 analogues. Antioxidant activity comparable to that of ascorbic acid was observed for thiophene-bearing ferrocenyl chalcone with EC50 = 31 μM.

Antileishmanial Activity of Cinnamic Acid Derivatives against Leishmania infantum

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in South America, the Mediterranean basin, and West and Central Asia. The most affected country, Brazil, reported 4297 VL cases in 2017. L. infantum is transmitted by female phlebotomine sand flies during successive blood meals. There are no validated vaccines to prevent the infection and the treatment relies on drugs that often present severe side effects, which justify the efforts to find new antileishmanial drugs. Cinnamic acid derivatives have shown several pharmacological activities, including antiparasitic action. Therefore, in the present study, the biological evaluation of cinnamic acid and thirty-four derivatives against L. infantum is reported. The compounds were prepared by several synthesis methods and characterized by spectroscopic techniques and high-resolution mass spectrometry. The results revealed that compound 32 (N-(4-isopropylbenzyl)cinnamamide) was the most potent antileishmanial agent (IC₅₀ = 33.71 μM) with the highest selectivity index (SI > 42.46), followed by compound 15 (piperonyl cinnamate) with an IC₅₀ = 42.80 μM and SI > 32.86. Compound 32 was slightly less potent and nineteen times more selective for the parasite than amphotericin B (MIC = 3.14 uM; SI = 2.24). In the molecular docking study, the most likely target for the compound in L. infantum was aspartyl aminopeptidase, followed by aldehyde dehydrogenase, mitochondrial. The data obtained show the antileishmanial potential of this class of compounds and may be used in the search for new drug candidates against Leishmania species.

Synthetic Cinnamides and Cinnamates: Antimicrobial Activity, Mechanism of Action, and In Silico Study

The severity of infectious diseases associated with the resistance of microorganisms to drugs highlights the importance of investigating bioactive compounds with antimicrobial potential. Therefore, nineteen synthetic cinnamides and cinnamates having a cinnamoyl nucleus were prepared and submitted for the evaluation of antimicrobial activity against pathogenic fungi and bacteria in this study. To determine the minimum inhibitory concentration (MIC) of the compounds, possible mechanisms of antifungal action, and synergistic effects, microdilution testing in broth was used. The structures of the synthesized products were characterized with FTIR spectroscopy, ¹ H-NMR, ¹³ C-NMR, and HRMS. Derivative 6 presented the best antifungal profile, suggesting that the presence of the butyl substituent potentiates its biological response (MIC = 626.62 μM), followed by compound 4 (672.83 μM) and compound 3 (726.36 μM). All three compounds were fungicidal, with MFC/MIC ≤ 4. For mechanism of action, compounds 4 and 6 directly interacted with the ergosterol present in the fungal plasmatic membrane and with the cell wall. Compound 18 presented the best antibacterial profile (MIC = 458.15 μM), followed by compound 9 (550.96 μM) and compound 6 (626.62 μM), which suggested that the presence of an isopropyl group is important for antibacterial activity. The compounds were bactericidal, with MBC/MIC ≤ 4. Association tests were performed using the Checkerboard method to evaluate potential synergistic effects with nystatin (fungi) and amoxicillin (bacteria). Derivatives 6 and 18 presented additive effects. Molecular docking simulations suggested that the most likely targets of compound 6 in C. albicans were caHOS2 and caRPD3, while the most likely target of compound 18 in S. aureus was saFABH. Our results suggest that these compounds could be used as prototypes to obtain new antimicrobial drugs.

Pharmacokinetic evaluation of Chalcone derivatives with antimalarial activity in New Zealand White Rabbits

Objective

Malaria is a major global health concern with the urgent need for new treatment alternatives due to the alarming increase of drug-resistant Plasmodium strains. Chalcones and its derivatives are important pharmacophores showing antimalarial activity. Determination of the pharmacokinetic variables at the preliminary step of drug development for any drug candidates is an essential component of in vivo antimalarial efficacy tests. Substandard pharmacokinetic variables are often responsible for insufficient therapeutic effect. Therefore, three chalcone derivatives, 1, 2, and 3, having antimalarial potency were studied further for potential therapeutic efficacy.

Results

In vivo pharmacokinetic studies of these three derivatives were performed on New Zealand White rabbits. The three derivatives were administered intra-peritoneally or orally at effective dose concentration and blood samples at different time points were collected. The determination of drug concentration was done through reverse phase-high performance liquid chromatography. The peak plasma concentration of derivative 1, 2, and 3 were 1.96 ± 0.46 µg/mL (intraperitoneal route), 69.89 ± 5.49 µg/mL (oral route), and 3.74 ± 1.64 µg/mL (oral route). The results indicate a very low bioavailability of these derivatives. The present study gives a benchmark to advance the investigation of more derivatives in order to revamp the pharmacokinetic variables while maintaining both potency and metabolic constancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05684-8.

Synthesis and structure of (E)-N-(4-meth-oxy-phen-yl)-2-[4-(3-oxo-3-phenyl-prop-1-en-1-yl)phen-oxy]acetamide

The title compound N-(4-meth-oxy-phen-yl)-2-[4-(3-oxo-3-phenyl-prop-1-en-1-yl)phen-oxy]acetamide, C24H21NO4, was prepared from reaction of N-(4-meth-oxy-phen-yl)-2-chloro-acetamide and (E)-3-(4-hy-droxy-phen-yl)-1-phenyl-prop-2-en-1-one, which was obtained from the reaction of 4-hy-droxy-benzaldehyde and aceto-phenone. The structure of the title compound was determined by IR, 1H-NMR, 13C-NMR and HR-MS spectroscopic data and further characterized by single-crystal X-ray diffraction. The asymmetric unit contains four mol-ecules, each displaying an E-configuration of the C=C bond. The dihedral angle between the phenyl rings in each mol-ecule varies between 14.9 (2) and 45.8 (2)°. In the crystal, C-H⋯O hydrogen-bonding inter-actions link the mol-ecules into chains running along the [001] direction. In addition, C-H⋯π inter-actions further stabilize the crystal packing. A Hirshfeld analysis indicates that the most important contributions to the surface contacts are from H⋯H (43.6%), C⋯H/H⋯C (32.1%) and O⋯H/H⋯O (18.1%) inter-actions.

Study on the Interaction of 4'-Hydroxychalcones and their Mannich Derivatives with Calf Thymus DNA by TLC and Spectroscopic Methods, a DNA Cleavage Study

Background:

Phenolic Mannich bases derived from hydroxychalcones show remarkable cytotoxic potencies towards cancer cell lines. However, the exact mechanism of action is still partially uncleared.

Objective:

Interaction of two hydroxychalcones and their Mannich derivatives with calf thymus DNA (ctDNA) has been investigated.

Methods:

Thin-layer chromatography and UV-Vis spectroscopic method were used for studying the interaction. The binding constant has been determined by UV-Vis spectrophotometric titration. The DNA cleavage activity of the compounds was studied by agarose gel electrophoresis.

Results:

Interaction of the compounds with ctDNA exhibited relatively high intrinsic binding constant (4-5x104 M-1). The results indicate existence of weak, non-covalent interactions between the investigated derivatives with ctDNA. Some compounds showed a slight DNA cleavage activity with pBR322.

Conclusion:

The obtained results provide additional knowledge on the previously documented cytotoxicity against tumor cell lines of the hydroxychalcones and their Mannich-derivatives.

Microwave-assisted synthesis of 1-(4-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one and its activities as an antioxidant, sunscreen, and antibacterial

Chalcone analogs have been reported to have a variety of exciting biological activities, such as anticancer, anti-inflammatory, antioxidant, photoprotective, antibacterial, and antidiabetic activities. Therefore, analogs of these compounds have been widely synthesized as intermediate compounds or target molecules in the discovery of bioactive compounds to be applied in the pharmaceutical field. The purpose of this study is to synthesize chalcone analog compounds (E)-1-(4-hydroxyphenyl)-3-(4-methoxyphenyl) prop-2-en-1-on with the microwave irradiation method and explore some of the biological activities of these compounds, including testing the antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method, in vitro sunscreen activity by microplate method, and antibacterial activity by disk diffusion method. DPPH test results indicate that the compound has weak antioxidant activity, with an IC50 value of 300.43 µg/mL. However, the compound showed excellent potential as a UV B and UV A filter at a concentration of 150 µg/mL with a value of %Te of 0.73±0.10% (sunblock), %Tp of 0.07±0.00% (sunblock), SPF value of 21.10±1.46 (ultra-protection) and potentially better than benzophenone-3 as a standard sunscreen. Then, disk diffusion testing showed that the compound had weak antibacterial activity against Staphylococcus aureus and did not show antibacterial activity against Escherichia coli bacteria at test concentrations of 30, 60, and 120 µg/disk.

COX-1/COX-2 inhibition activities and molecular docking study of newly designed and synthesized pyrrolo[3,4-c]pyrrole Mannich bases

In the present paper we describe the biological activity of newly designed and synthesized series of pyrrolo[3,4-c]pyrrole Mannich bases (7a-n). The Mannich bases were obtained in good yields by one-pot, three-component condensation of pyrrolo[3,4-c]pyrrole scaffold (6a-c) with secondary amines and an excess of formaldehyde solution in C₂H₅OH. The chemical structures of the compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR, and elemental analysis. Moreover, single crystal X-ray diffraction has been recorded for compound 7l. All synthesized derivatives were investigated for their potencies to inhibit COX-1 and COX-2 enzymes by colorimetric inhibitor screening assay. In order to analyse the intermolecular interactions between theligands and cyclooxygenase, experimental data were supported with the results of molecular docking simulations. According to the results, all of the tested compounds inhibited the activity of COX-1 and COX-2.

Synthesis and biological evaluation of some new mono Mannich bases with piperazines as possible anticancer agents and carbonic anhydrase inhibitors

New mono Mannich bases, (2-(4-hydroxy-3-((4-substituephenylpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one), were prepared to evaluate their cytotoxic/anticancer properties and also their inhibitory effects on human carbonic anhydrase I and II isoenzymes (hCA I and II). Amine part was changed as [N-phenylpiperazine (1), N-benzylpiperazine (2), 1-(2-fluorophenyl)piperazine (3), 1-(4-fluorophenyl)piperazine (4), 1-(2-methoxyphenyl)piperazine (5)]. The structure of the synthesized compounds was characterized by ¹H NMR, ¹³C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compound 4 had the highest tumor selectivity value (TS: 59.4) possibly by inducing necrotic cell death in series. Additionally, all compounds synthesized showed a good inhibition profile towards hCA I and II isoenzymes with the Ki values between 29.6 and 58.4 nM and 38.1-69.7 nM, respectively. These values were lower than the reference compound AZA. However, it seems that the compounds 4 and 2 can be considered as lead compounds of CA studies with the lowest Ki values in series for further designs.

Investigation of anti-inflammatory, nitric oxide donating, vasorelaxation and ulcerogenic activities of 1, 3-diphenylprop-2-en-1-one derivatives in animal models

The main aim of this work is to find out novel chemical moieties with potent anti-inflammatory and vasorelaxant activities with reduced gastric toxicities. For fulfilling the above aim, here we investigated novel chalcones (1, 3-diphenylprop-2-en-1-one derivatives) with nitric oxide (NO) and hydrogen sulphide (H₂ S) donating potency for anti-inflammatory activity by carrageenan-induced rat paw oedema. These molecules then further evaluated for in-vitro NO-releasing potency and vasorelaxation effect on isolated adult goat aortic tissue. The promising molecules were further screened for ulcerogenic activity in the rat model. The tested compounds produced % inhibition in paw oedema ranging from 29.16% to 79.69% and standard drug Diclofenac sodium produced 85.30% reduction in paw oedema after 5 hours. Out of this dataset, compounds AI1, AI7, Ca1, B2, B10, D2, and E8 showed 73.01%, 79.69%, 75.02%, 75.46%, 74.35%, 73.9% and 74.35% reduction in paw oedema respectively, which is approximately 80%-90% to that of standard Diclofenac sodium. The compound Ca1 was found to release 0.870 ± 0.025 mol/mol of NO and standard Glyceryl trinitrate (GTN) was found to release 0.983 ± 0.063 mol/mol of NO. The compound Ca1 produced 950.2 μmol/L of EC₅₀ whereas standard GTN produced 975.8 μmol/L of EC₅₀ for aortic smooth relaxation. The compounds Ca1 produced 0.1117 of ulcer index which is far less than that of standard Diclofenac sodium (1.148). The potent lead molecules were further evaluated to understand the mechanism of vasorelaxation by using specific antagonists or blockers of NO and H₂ S.

Small Multitarget Molecules Incorporating the Enone Moiety

Chalcones represent a class of small drug/druglike molecules with different and multitarget biological activities. Small multi-target drugs have attracted considerable interest in the last decade due their advantages in the treatment of complex and multifactorial diseases, since "one drug-one target" therapies have failed in many cases to demonstrate clinical efficacy. In this context, we designed and synthesized potential new small multi-target agents with lipoxygenase (LOX), acetyl cholinesterase (AChE) and lipid peroxidation inhibitory activities, as well as antioxidant activity based on 2-/4- hydroxy-chalcones and the bis-etherified bis-chalcone skeleton. Furthermore, the synthesized molecules were evaluated for their cytotoxicity. Simple chalcone b4 presents significant inhibitory activity against the 15-human LOX with an IC50 value 9.5 µM, interesting anti-AChE activity, and anti-lipid peroxidation behavior. Bis-etherified chalcone c12 is the most potent inhibitor of AChE within the bis-etherified bis-chalcones followed by c11. Bis-chalcones c11 and c12 were found to combine anti-LOX, anti-AchE, and anti-lipid peroxidation activities. It seems that the anti-lipid peroxidation activity supports the anti-LOX activity for the significantly active bis-chalcones. Our circular dichroism (CD) study identified two structures capable of interfering with the aggregation process of Aβ. Compounds c2 and c4 display additional protective actions against Alzheimer's disease (AD) and add to the pleiotropic profile of the chalcone derivatives. Predicted results indicate that the majority of the compounds with the exception of c11 (144 Å) can cross the Blood Brain Barrier (BBB) and act in CNS. The results led us to propose new leads and to conclude that the presence of a double enone group supports better biological activities.

Novel Conjugated Unsaturated Ketones with Submicromolar Potencies Towards some Leukemic and Colon Cancer Cells

BACKGROUND

Cancer continues to be the major health burden worldwide. There is an urgent need for the development of novel antineoplastic compounds to treat this devastating condition. Various alkylating anticancer drugs have been employed in the clinic for treating cancers. Unsaturated conjugated ketones are a group of alkylators which are of significant interest as potent antineoplastic agents.

OBJECTIVE

The goal of this study is to discover unsaturated conjugated ketones which are novel potent cytotoxins displaying growth-inhibitory properties towards neoplasms and also to serve as cytotoxic warheads in drug development.

METHODS

A variety of 3,5-bis (benzylidene)-4-piperidones 2a-n were synthesized and evaluated against a number of neoplastic cell lines. The short-term neurotoxicity of 2a-k, n was evaluated in mice by i.p. administration using doses level of 30, 100 and 300 mg/kg. Statistical correlations for determining structure-activity relationships were performed using an SPSS software.

RESULTS

A number of compounds display cytotoxic potencies in the region of 10-7 to 10-8 M and some of the structural features contributing to the cytotoxicity were identified. Compounds 2a-d, 2h demonstrated substantially higher cytotoxic potencies compared to melphalan and 5- fluorouracil against a panel of leukemic and colon cancer cell lines. These lead cytotoxins comply with drug-likeness properties. In general, the antineoplastics 2 are well tolerated in mice using a short-term neurotoxicity screening.

CONCLUSION

In general, this group of compounds comprises excellent cytotoxic agents, which warrant their further development as cytotoxic warheads.

Facile synthesis of some pyrazoline-based compounds with promising anti-inflammatory activity

Aim: Search for new anti-inflammatory agents with higher efficacy and lower toxicity is an urgent demand in drug discovery era. Methodology: Different pyrazoline derivatives 4a,b, 5a,b, 6a–h and 7a–f were prepared from the condensation reactions of 1,5-bis(5-methylfuran/thiophen-2-yl)penta-1,4-dien-3-ones 3a,b with different hydrazine derivatives. All compounds were screened for their anti-inflammatory activity using the carrageenan-induced paw edema method in rats and TNF-α inhibition assay. Results: Many compounds revealed promising anti-inflammatory activity relative to indomethacin especially compounds 4a, 5a, 5b, 6b, 6d, 6f and 7b. They were safe to the gastric mucosa and did not cause toxicity up to tenfolds the anti-inflammatory dose, in addition, all compounds inhibited TNF-α with IC50 values of 1.7–100 nM.

Designing, synthesis and bioactivities of 4-[3-(4-hydroxyphenyl)-5-aryl-4,5-dihydro-pyrazol-1-yl]benzenesulfonamides

In this study, 4-[3-(4-hydroxyphenyl)-5-aryl-4,5-dihydro-pyrazol-1-yl]benzenesulfonamide (1-9) types compounds were synthesized and their chemical structures were confirmed by 1H NMR, 13C NMR and HRMS spectra. Cytotoxic and carbonic anhydrase (CA) inhibitory effects of the compounds were investigated. Cytotoxicity experiments pointed out that compound 4, (4-[5-(4-chlorophenyl)-3-(4-hydroxyphenyl)-4,5-dihydro-pyrazol-1-yl]benzenesulfonamide), exerting the highest tumor selectivity (TS) and potency selectivity expression (PSE) values, can be considered as a lead compound of this study in terms of development of novel anticancer agents. All synthesized sulfonamides showed a good inhibition profile on hCA IX and XII in the range of 53.5-923 nM and 6.2-95 nM, respectively. These compounds were 2.5-13.4 times more selective for the inhibition of hCA XII versus hCA IX, except compound 2 which had similar inhibitory action towards both isoenzymes.

Microwave-assisted synthesis and bioevaluation of new sulfonamides

In this study, 4-[5-(4-hydroxyphenyl)-3-aryl-4,5-dihydro-1H-pyrazol-1-yl]benzenesulfonamide derivatives (8-14) were synthesized for the first time by microwave irradiation and their chemical structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. Cytotoxic activities and inhibitory effects on carbonic anhydrase I and II isoenzymes of the compounds were investigated. The compounds 9 (PSE = 4.2), 12 (PSE = 4.1) and 13 (PSE = 3.9) with the highest potency selectivity expression (PSE) values in cytotoxicity experiments and the compounds 13 (Ki = 3.73 ± 0.91 nM toward hCA I) and 14 (Ki = 3.85 ± 0.57 nM toward hCA II) with the lowest Ki values in CA inhibition studies can be considered as leader compounds for further studies.

Synthesis and bioactivity studies on new 4-(3-(4-Substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides

A series of new 4-(3-(4-substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides (7-12) was synthesized starting from 2-(4-substitutedbenzylidene)-2,3-dihydro-1H-inden-1-one (1-6) and 4-hydrazinobenzenesulfonamide. The substituted benzaldehydes from which the key intermediate was prepared by introducing 2- or 4-substituents such as fluorine, hydroxy, methoxy, or the 3,4,5-trimethoxy moieties. The compounds were tested for their cytotoxicity, tumor-specificity and potential as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The 3,4,5-trimethoxy and the 4-hydroxy derivatives showed interesting cytotoxic activities, which may be crucial for further anti-tumor activity studies, whereas some of these sulfonamides strongly inhibited both human (h) cytosolic isoforms hCA I and II.

Synthesis, carbonic anhydrase I and II inhibition studies of the 1,3,5-trisubstituted-pyrazolines

4-(3-(4-Substituted-phenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl) benzenesulfonamides (9-16) were successfully synthesized and their chemical structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS spectra. Carbonic anhydrase I and II inhibitory effects of the compounds were investigated. K_i values of the compounds were in the range of 316.7 ± 9.6-533.1 ± 187.8 nM towards hCA I and 412.5 ± 115.4-624.6 ± 168.2 nM towards hCA II isoenzymes. While K_i values of the reference compound Acetazolamide were 278.8 ± 44.3 nM and 293.4 ± 46.4 nM towards hCA I and hCA II izoenzymes, respectively. Compound 14 with bromine and compound 13 with fluorine substituents can be considered as the leader compounds of the series because of the lowest K_i values in series to make further detailed carbonic anhydrase inhibiton studies.

Synthesis and carbonic anhydrase inhibitory activities of new thienyl-substituted pyrazoline benzenesulfonamides

A series of new thienyl-substituted pyrazoline benzenesulfonamides were synthesized and their carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activities were tested on the human (h) isoforms hCA I and hCA II. The inhibition constant (Ki) of these sulfonamides were in the range of 232.16-637.70 nM toward the slow cytosolic isozyme hCA I, and in the range of 342.07-455.80 nM toward hCA II. Many of these compounds showed comparable inhibition with the reference sulfonamide acetazolamide, a clinically used drug. As the sulfonamide CA inhibitors (CAIs) show many therapeutic uses, these derivatives represent interesting examples of a novel class of such derivatives.

Niacin esters of chalcones with tumor-selective properties

Novel series of niacin esters of chalcones 2, 4 and 6 were designed as antineoplastic agents that have the potential to release the chemoprotectant niacin. These enones are cytotoxic to human CD4(+ )T-lymphocyte Molt 4/C8 and CEM and murine leukemia L1210 cells. Quantitative structure-activity relationship (QSAR) studies of the biodata in series 4 revealed that cytotoxic potency was enhanced by placing electron-repelling groups in one of the aryl rings. The compounds are lethal to HL-60, HSC-2, HSC-3 and HSC-4 neoplasms but less toxic to nonmalignant hepatocyte growth factor, hematopoietic progenitor cell and human periodontal ligament fibroblast cells. Hence, the compounds display tumor-selective toxicity. These chalcones are well tolerated in mice and no overt toxicity was noted. The results establish that in general the compounds in series 2, 4 and 6 have positive characteristics which warrant further studies.

Recent advances of cytotoxic chalconoids targeting tubulin polymerization: Synthesis and biological activity

Since microtubules have an important role in mitosis and other vital cellular functions, tubulin-targeting chemotherapy has been received growing attention in anticancer drug design and development. It was found that a number of naturally occurring compounds including distinct chalcones exert their effect by inhibition of tubulin polymerization. After the identification of tubulin polymerization as potential target for chalcone-type compounds, extensive researches have been made to design and synthesis of new anti-tubulin chalconoids. Although diverse chalcones have found to be potent anticancer agents but in the present review, we focused on the recently reported tubulin polymerization inhibitors from chalcone origin and related synthetic compounds, and their detailed synthetic methods and biological activities.

Crystal structure of 1-{4-hy-droxy-3-[(pyrrolidin-1-yl)meth-yl]phen-yl}-3-phenyl-prop-2-en-1-one

In the title compound, C20H21NO2, the pyrrolidine ring adopts an envelope conformation with the N atom at the flap position. The central benzene ring makes dihedral angles of 21.39 (10) and 80.10 (15)° with the phenyl ring and the mean plane of the pyrrolidine ring, respectively. The mol-ecular conformation is stabilized by an intra-molecular O-H⋯N hydrogen bond, which closes an S(6) ring. A weak C-H⋯π inter-action is observed in the crystal.

A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions andcis-transisomerization in theα,β-unsaturated ketone moiety. Despite this limitation, we found a way to improve the luminescent efficiency of our bis-chalcone derivative. In this project, two series of bis-chalcone compounds have been synthesized through Claisen-Schmidt condensation by reacting terephthaldehyde or 2,5-dimethoxyterephthaldehyde with the respective R-acetophenone [where R = H (1aand2a) andortho-hydroxy (1band2b)] in 1 : 2 mole ratio. The presence of a methoxy (OMe) substituent on the central phenyl ring of bis-chalcone has weakened the C=C bond at theα,β-unsaturated ketone moiety of2aand2b. Interestingly, the OMe group has improved the emission efficiency of the bis-chalcone; that is, the quantum yield of1ain DCM solution was not able to be determined due to poor luminescence, but the quantum yield of2ain DCM solution was improved to 0.57. In addition, compound2aalso shows solvatochromism effect where theλmaxemission shifted from 499 nm in nonpolar solvents (benzene) to 523 nm in polar solvents (acetonitrile). This work provides another way to improve the emission efficiency of chalcone related compounds apart from using the complexation method which has been reported before.

Pharmacogenomic study using bio- and nanobioelectrochemistry: Drug-DNA interaction

Small molecules that bind genomic DNA have proven that they can be effective anticancer, antibiotic and antiviral therapeutic agents that affect the well-being of millions of people worldwide. Drug-DNA interaction affects DNA replication and division; causes strand breaks, and mutations. Therefore, the investigation of drug-DNA interaction is needed to understand the mechanism of drug action as well as in designing DNA-targeted drugs. On the other hand, the interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases. For this purpose, electrochemical methods/biosensors can be used toward detection of drug-DNA interactions. The present paper reviews the drug-DNA interactions, their types and applications of electrochemical techniques used to study interactions between DNA and drugs or small ligand molecules that are potentially of pharmaceutical interest. The results are used to determine drug binding sites and sequence preference, as well as conformational changes due to drug-DNA interactions. Also, the intention of this review is to give an overview of the present state of the drug-DNA interaction cognition. The applications of electrochemical techniques for investigation of drug-DNA interaction were reviewed and we have discussed the type of qualitative or quantitative information that can be obtained from the use of each technique.

Synthesis of mono Mannich bases of 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one and evaluation of their cytotoxicities

Chalcones and Mannich bases are a group of compounds known for their cytotoxicities. In this study restricted chalcone analogue, compound 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one MT1, was used as a starting compound to synthesize new mono Mannich bases since Mannich bases may induce more cytotoxicity than chalcone analogue that they are derived from by producing additional alkylating center for cellular thiols. In this study, cyclic and acyclic amines were used to synthesize Mannich bases. All compounds were tested against Ca9-22 (gingival carcinoma), HSC-2, HSC-3 and HSC-4 (oral squamous cell carcinoma) as tumour cell lines and HGF (gingival fibroblasts), HPC (pulp cells) and HPLF (periodontal ligament fibroblasts) human normal oral cells as non tumour cell lines. Cytotoxicity, selectivity index (SI) values and potency selectivity expression (PSE) values expressed as a percentage were determined for the compounds. According to data obtained, the compound MT8 with the highest PSE value bearing N-methylpiperazine moiety seems to be a good candidate to develop new cytotoxic compounds and is suited for further investigation.

Anti-cancer chalcones: Structural and molecular target perspectives

Chalcone or (E)-1,3-diphenyl-2-propene-1-one scaffold remained a fascination among researchers in the 21st century due to its simple chemistry, ease of synthesis and a wide variety of promising biological activities. Several natural and (semi) synthetic chalcones have shown anti-cancer activity due to their inhibitory potential against various targets namely ABCG2/P-gp/BCRP, 5α-reductase, aromatase, 17-β-hydroxysteroid dehydrogenase, HDAC/Situin-1, proteasome, VEGF, VEGFR-2 kinase, MMP-2/9, JAK/STAT signaling pathways, CDC25B, tubulin, cathepsin-K, topoisomerase-II, Wnt, NF-κB, B-Raf and mTOR etc. In this review, a comprehensive study on molecular targets/pathways involved in carcinogenesis, mechanism of actions (MOAs), structure activity relationships (SARs) and patents granted have been highlighted. With the knowledge of molecular targets, structural insights and SARs, this review may be helpful for (medicinal) chemists to design more potent, safe, selective and cost effective anti-cancer chalcones.

Simple chalcones and bis-chalcones ethers as possible pleiotropic agents

The synthesis, the antioxidative properties and the lipoxygenase (LOX) and acetylcholinesterase (AChE) inhibition of a number of 4-hydroxy-chalcones diversely substituted as well as of a series of bis-chalcones ether derivatives are reported. The chalcones derivatives were readily produced using a Claisen-Schmidt condensation in a ultra sound bath in good yields. The structures of the synthesized compounds were confirmed by spectral and elemental analysis. Their lipophilicity is experimentally determined by reversed-phase thin-layer chromatography method. Most of them are potent in vitro inhibitors of lipid peroxidation and of LOX. Compounds b2 and b3 were found to be the most potent LOX and AChE inhibitors among the tested derivatives with a significant anti-lipid peroxidation profile. The results led us to propose these enone derivatives as new multifunctional compounds against Alzheimer's disease. The results are discussed in terms of structural and physicochemical characteristics of the compounds. Moreover, the pharmacokinetic profile of these compounds was investigated using computational methods.

Mannich bases in medicinal chemistry and drug design

The biological activity of Mannich bases, a structurally heterogeneous class of chemical compounds that are generated from various substrates through the introduction of an aminomethyl function by means of the Mannich reaction, is surveyed, with emphasis on the relationship between structure and biological activity. The review covers extensively the literature reports that have disclosed Mannich bases as anticancer and cytotoxic agents, or compounds with potential antibacterial and antifungal activity in the last decade. The most relevant studies on the activity of Mannich bases as antimycobacterial agents, antimalarials, or antiviral candidates have been included as well. The review contains also a thorough coverage of anticonvulsant, anti-inflammatory, analgesic and antioxidant activities of Mannich bases. In addition, several minor biological activities of Mannich bases, such as their ability to regulate blood pressure or inhibit platelet aggregation, their antiparasitic and anti-ulcer effects, as well as their use as agents for the treatment of mental disorders have been presented. The review gives in the end a brief overview of the potential of Mannich bases as inhibitors of various enzymes or ligands for several receptors.

Design, synthesis and structure-activity relationship of novel semi-synthetic flavonoids as antiproliferative agents

Various flavonoid scaffold based derivatives viz furochalcones (3a-e, 6a-d and 9a-d), furoflavones (10a-d, 11a-d, 12a-d, 18a&b), flavones (21a-d), furoaurones (13a,b, 14a-d and 15a-d) and 7-styrylfurochromones (22a-d and 25a-e) were designed and synthesized. The novel compounds were evaluated for their antiproliferative activity against a panel of 60 cancer cell lines comprising 9 types of tumors. Ten compounds belonging to the major subgroups of flavonoids viz furochalcones (3a, 3d, 6b, 9a and 9b), furoflavones (12a and 12c), furoaurones (15d), styrylfurochromones (25b and 25e) showed very promising activity. These active compounds were also evaluated in vitro as kinase inhibitors against CDK2/cyclin E1, CDK4/cyclin D1 and GSK-3β and the best inhibition was displayed against GSK-3β with the allylfurochalcone derivative 9b exhibiting 80% decrease in GSK-3β catalytic activity. On the other hand, the styrylfurochromone 25e interestingly showed a 13% enhancement of GSK-3β catalytic power and a 12% reduction in CDK4/cyclin D1 activity. Finally, the in vivo anti-tumor activity of 25e was evaluated against breast cancer induced in mice. The results showed a profound anti-tumor effect of 25e that accompanies a significant increase and decrease in the levels of GSK-3β and cyclin D1, respectively.

Rational approaches, design strategies, structure activity relationship and mechanistic insights for anticancer hybrids

A Hybrid drug which comprises the incorporation of two drug pharmacophores in one single molecule are basically designed to interact with multiple targets or to amplify its effect through action on another bio target as one single molecule or to counterbalance the known side effects associated with the other hybrid part(.) The present review article offers a detailed account of the design strategies employed for the synthesis of anticancer agents via molecular hybridization techniques. Over the years, the researchers have employed this technique to discover some promising chemical architectures displaying significant anticancer profiles. Molecular hybridization as a tool has been particularly utilized for targeting tubulin protein as exemplified through the number of research papers. The microtubule inhibitors such as taxol, colchicine, chalcones, combretasatin, phenstatins and vinca alkaloids have been utilized as one of the functionality of the hybrids and promising results have been obtained in most of the cases with some of the tubulin based hybrids exhibiting anticancer activity at nanomolar level. Linkage with steroids as biological carrier vector for anticancer drugs and the inclusion of pyrrolo [2,1-c] [1,4]benzodiazepines (PBDs), a family of DNA interactive antitumor antibiotics derived from Streptomyces species in hybrid structure based drug design has also emerged as a potential strategy. Various heteroaryl based hybrids in particular isatin and coumarins have also been designed and reported to posses' remarkable inhibitory potential. Apart from presenting the design strategies, the article also highlights the structure activity relationship along with mechanistic insights revealed during the biological evaluation of the hybrids.