Chalcone Structure Research Articles

Synthesis of some acylated 2-pyrazoline and chalcone derivatives

α-Haloesters containing the chalcone structure and α-haloamides containing the pyrazoline ring have been synthesized by reaction of substituted hydroxy chalcones and pyrazoline derivatives (prepared as reported elsewhere; J Chem 8(4):1574–1581, 2011) with chloroacetyl chloride in dry THF in the presence of Et3N. The structures of the synthesized compounds were confirmed by IR, 1H NMR, and (for some compounds) 13C NMR spectroscopy.

Novel Cyclopentadienyl Tricarbonyl Complexes of 99mTc Mimicking Chalcone as Potential Single-Photon Emission Computed Tomography Imaging Probes for β-Amyloid Plaques in Brain

Rhenium and technetium-99m cyclopentadienyl tricarbonyl complexes mimicking the chalcone structure were prepared. These complexes were proved to have affinity to β-amyloid (Aβ) in fluorescent staining on brain sections of Alzheimer's Disease (AD) patient and binding assay using Aβ(1-42) aggregates, with K(i) values ranging from 899 to 108 nM as the extension of conjugated π system. In vitro autoradiograpy on sections of transgenic mouse brain confirmed the affinity of [(99m)Tc]5 (K(i) = 108 nM). In biodistribution, all compounds showed good initial uptakes into the brain and fast blood clearance, while the decreasing of initial brain uptakes correspond to increasing of conjugation length, from 4.10 ± 0.38% ID/g ([(99m)Tc]3) to 1.11 ± 0.34% ID/g ([(99m)Tc]5). These small technetium-99m complexes (<500 Da) designed by an integrated approach provide encouraging evidence that development of a promising (99m)Tc-labeled agent for imaging Aβ plaques in the brain may be feasible.

Isoliquiritigenin showed strong inhibitory effects towards multiple UDP-glucuronosyltransferase (UGT) isoform-catalyzed 4-methylumbelliferone (4-MU) glucuronidation

Isoliquiritigenin, a herbal ingredient with chalcone structure, has been speculated to be able to inhibit one of the most drug-metabolizing enzymes (DMEs) UDP-glucuronosyltransferase (UGT). Therefore, the aim of the present study was to investigate the inhibition of isoliquiritigenin towards important UGT isoforms in the liver and intestine, including UGT1A1, 1A3, 1A6, 1A7, 1A8, 1A9 and 1A10. The recombinant UGT-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used as probe reactions. The results showed that 100μM of isoliquiritigenin inhibited the activity of UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, and UGT1A10 by 95.2%, 76.1%, 78.9%, 87.2%, 67.2%, 94.8%, and 91.7%, respectively. The data fitting using Dixon plot and Lineweaver–Burk plot showed that the inhibition of UGT1A1, UGT1A9 and UGT1A10 by isoliquiritigenin was all best fit to the competitive inhibition, and the second plot using the slopes from the Lineweaver–Burk plot versus isoliquiritigenin concentrations was used to calculate the inhibition kinetic parameter (Ki) to be 0.7μM, 0.3μM, and 18.3μM for UGT1A1, UGT1A9, and UGT1A10, respectively. All these results indicated the risk of clinical application of isoliquiritigenin on the drug–drug interaction and other possible diseases induced by the inhibition of isoliquiritigenin towards these UGT isoforms.

Synthesis and anti Methicillin resistant Staphylococcus aureus activity of substituted chalcones alone and in combination with non-beta-lactam antibiotics

A total of 30 chalcone analogues was synthesized via a base catalyzed Claisen Schmidt condensation and screened for their in vitro antibacterial activity against Methicillin-sensitive Staphylococcus aureus (MSSA) and Methicillin-resistant Staphylococcus aureus (MRSA) alone or in combination with non beta-lactam antibiotics namely ciprofloxacin, chloramphenicol, erythromycin, vancomycin, doxycycline and gentamicin. In the checkerboard technique, fractional inhibitory concentration indices (FICI) show that the following combinations like ciprofloxacin with 25 (4′-bromo-2-hydroxychalcone); doxycycline with 21 (4-hydroxychalcone); doxycycline with 25; and doxycycline with 4 (2′,2-dihydroxychalcone) were synergistic against MRSA. In term SAR study, the relationship between chalcone structure and their antibacterial activity against S. aureus and synergy with tested antibiotics were discussed. Possible mechanisms for antibacterial activity of chalcones alone as well as the synergistic effect in combinations were proposed by molecular modeling studies, respectively. Combinations of chalcones with conventional antibiotics could be an effective alternative in the treatment of infection caused by MRSA.

Xanthohumol, a prenylated chalcone from Humulus lupulus L., inhibits cholesteryl ester transfer protein

High density lipoprotein (HDL)-cholesterol levels are correlated with a low risk of atherosclerosis. The inhibition of cholesteryl ester transfer protein (CETP), which catalyses cholesterol transfer between lipoproteins, leads to an increase in HDL-cholesterol and is expected to be the next anti-atherogenic target. This study revealed that xanthohumol, a prenylated chalcone, showed the highest inhibition against CETP from screening of natural products in various plants. We investigated the inhibitory activity of some chalcones and flavanones. Naringenin chalcone showed weak CETP inhibition compared with xanthohumol. In addition, isoxanthohumol and naringenin drastically decreased the inhibitory activity. These results suggest that the prenyl group and chalcone structure of xanthohumol were responsible for the CETP inhibitory activity.

Investigation of chalcones and benzochalcones as inhibitors of breast cancer resistance protein

Breast cancer resistance protein (BCRP/ABCG2) belongs to the ATP binding cassette family of transport proteins. BCRP has been found to confer multidrug resistance in cancer cells. A strategy to overcome resistance due to BCRP overexpression is the investigation of potent and specific BCRP inhibitors. The aim of the current study was to investigate different multi-substituted chalcones for their BCRP inhibition. We synthesized chalcones and benzochalcones with different substituents (viz. OH, OCH3, Cl) on ring A and B of the chalcone structure. All synthesized compounds were tested by Hoechst 33342 accumulation assay to determine inhibitory activity in MCF-7 MX and MDCK cells expressing BCRP. The compounds were also screened for their P-glycoprotein (P-gp) and Multidrug resistance-associated protein 1 (MRP1) inhibitory activity in the calcein AM accumulation assay and were found to be selective towards inhibition of BCRP. Substituents at position 2′ and 4′ on chalcone ring A were found to be essential for activity; additionally there was a great influence of substituents on ring B. Presence of 3,4-dimethoxy substitution on ring B was found to be optimal, while presence of 2- and 4-chloro substitution also showed a positive effect on BCRP inhibition.

New, High Efficiency Nonlinear Optical Chalcone Co-Crystal and Structure–Property Relationship

In our present study, we attempted to grow the single crystals of (2E)-1-(4-chlorophenyl)-3-[4-(methylsulfanyl)phenyl]prop-2-en-1-one by making use of the slow evaporation solution growth technique at room temperature. But the single crystal X-ray diffraction technique revealed that the grown crystal was a co-crystal with molecular formula C16H13Br0.66Cl0.34OS (4Br4MSP/4Cl4MSP). The presence of functional groups in the molecular structure is confirmed by Fourier transform infrared (FT-IR) spectroscopy. The UV–vis–NIR absorption spectrum shows that this co-crystal has a good transparency window for optical application. Second harmonic generation (SHG) analysis was done to explore nonlinear optical (NLO) characteristics of the material, and the co-crystal was found to have the highest SHG efficiency when compared with all the co-crystals reported in the literature.

Synthesis and anti-bacterial activities of some novel pyrazolobenzothiazine-based chalcones and their pyrimidine derivatives

A novel series of fifteen pyrimidine derivatives was prepared from pyrazolobenzothiazine-based chalcones by refluxing with guanidine hydrochloride. The starting materials 4-(3,4-dimethyl-5,5-dioxidobenzo[4,3-c][1,2]thiazin-2(4-H)yl)phenyl)ethanone (2) or 4-(3,4-dimethyl-5,5-dioxidobenzo[4,3-c][1,2]thiazin-2(4-H)yl)benzaldehyde (3) were obtained by N-arylation of 3,4-dimethyl-2,4-dihydrobenzo[e]pyrazolo[4,3-c][1,2]thiazine 5,5-dioxide (1) with 4-fluoroacetophenone or 4-fluorobenzaldehyde, respectively, using phase transfer catalyst, hexadecyl-tri-n-butylphsophonium bromide. The N-arylated product (2) or (3) was reacted in MeONa/MeOH with diversified aromatic aldehydes or ketones to furnish two series of new chalcones 4 and 5. Refluxing of 4 or 5 with guanidine hydrochloride in KOH(aq) and H2O2/EtOH yielded the 2-(4-(2-amino-6-arylpyrimidin-4-yl)phenyl)3,4-dimethyl-2,4-dihydrobenzo[e]pyrazolo[4,3-c][1,2]thiazine-5,5-dioxide (6). The structures of chalcones (4 or 5) and corresponding pyrimidines (6) were confirmed with spectral data and elemental analysis. Several chalcones as well as pyrimidines showed marked activity against E. coli and S. aureus.

(2E,4E)-1-(2-Hydroxyphenyl)-5-phenylpenta-2,4-dien-1-one

In the structure of the title chalcone, C17H14O2, derived from cinnamaldehyde, the olefine group has a trans configuration. The mol­ecular conformation is stabilized by an intra­molecular O—H⋯O hydrogen-bond inter­action with graph-set motif S(6).

Isoliquiritigenin (4,2′,4′-trihydroxychalcone): A new matrix-assisted laser desorption/ionization matrix with outstanding properties for the analysis of neutral oligosaccharides

A novel matrix of isoliquiritigenin (ISL), a flavonoid with a chalcone structure (4,2′,4′-trihydroxychalcone), was demonstrated to be advantageous in the analysis of neutral oligosaccharides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). With ISL as a matrix, adequate signal for an analyte can be obtained in much lower matrix concentrations and laser intensity compared to commonly used MALDI matrices. Four different sample preparation methods were tested, and the dried droplet method exhibited the best performance on MALDI-TOF-MS analysis of oligosaccharides with ISL as a matrix. For the analysis of carbohydrates, compared with popular matrices such as 2,5-dihydroxybenzoic acid (DHB) and 2,4,6-trihydroxyacetophenone (THAP), ISL exhibited outstanding matrix properties as follows: (1) higher homogeneity of crystallization thus allowing automatic data acquisition, (2) better spectral quality in terms of resolution and signal to noise ratio (S N −1), (3) better salt tolerance, (4) higher sensitivity, and (5) enough fragmentation yield to use LIFT-TOF/TOF MS to get richer structural information. In addition, reliable quantitative analysis of oligosaccharides with a good linearity over two concentration orders (1–100 pmol μL −1) and good reproducibility of the signal intensity (RSD less than 15%) were achieved using this matrix. These results give a new outlook on high-speed analysis of neutral carbohydrates by MALDI-TOF MS.

MD-2 as the Target of Nonlipid Chalcone in the Inhibition of Endotoxin LPS-Induced TLR4 Activity

Myeloid differentiation 2 (MD-2) recognizes endotoxin lipopolysaccharide (LPS), which is required for Toll-like receptor 4 (TLR4) activity. MD-2 represents a more attractive therapeutic target than TLR4 for intervention in severe inflammatory disorders due to microbial infection. Here, we suggest MD-2 as a molecular target of nonlipid chalcone in the inhibition of LPS-induced cellular inflammation. A chalcone derivative, 2',4-dihydroxy-6'-isopentyloxychalcone (JSH) competitively displaced LPS from MD-2, and was fitted into the ligand-binding site on the crystal structure of MD-2 under the most energetically favorable simulation. JSH nullified TLR4 activation mechanism and sequentially inhibited nuclear factor-κB (NF-κB) activation that involves the phosphorylation and degradation of inhibitory κBs and the nuclear import and transcriptional activity of NF-κB in LPS-activated macrophages. Moreover, JSH suppressed NF-κB-target inflammatory genes such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-1β (IL-1β) and IL-6. Taken together, this study assigns the chalcone structure as an LPS antagonist binding to MD-2 with therapeutic potential against inflammatory conditions.

Inhibitors and promoters of tubulin polymerization: Synthesis and biological evaluation of chalcones and related dienones as potential anticancer agents

A series of dihalogenated chalcones and structurally related dienones were synthesized and evaluated for their antiproliferative activity in 10 different cancer cell lines and for their effect on microtubule assembly. All compounds showed cytotoxic activity, with IC 50 values in the 5–280 μM range depending on the chalcone structure and the cell line. Five of the compounds were found to be tubulin polymerization inhibitors. In contrast, one of the compounds was found to stabilize tubulin to the same extent as the anticancer drug docetaxel. Molecular modeling suggested that the tubulin inhibitors bind to the colchicine binding site of β-tubulin while the novel tubulin stabilization agent seems to interact with the paclitaxel binding site.

Synthesis and crystal structure of chalcones as well as on cytotoxicity and antibacterial properties

A series of chalcones derivatives were synthesized and evaluated for cytotoxic and antibacterial activities in vitro. These modifications changed their bioactivity profile and indicated a combination of SAR analysis toward the substituents in rings A and B of chalcones. Compounds 2, 6–8, 14–17, and 32 exhibited good cytotoxic properties against two human cancer cell lines HT29 and SGC7901. Compounds 16 and 17 showed high antibacterial activity toward 14 clinically isolated multidrug-resistant strains. Subsequently, the structure of bi-bioactive compound 16 was determined using single-crystal X-ray diffraction. This study presents a few novel leading compounds for the development of potential antitumor and antibacterial agents. A series of chalcones derivatives were synthesized and evaluated for cytotoxic and antibacterial activities in vitro. Subsequently, the structure of bi-bioactive compound 16 was determined using single-crystal X-ray diffraction.

Core structure of flavonoids precursor as an antihyperglycemic and antihyperlipidemic agent: an in vivo study in rats.

trans-Chalcone is the core structure of naringenin chalcone, located halfway in the biosynthesis pathway of flavonoids. Flavonoids have been reported as mammalian alpha-amylase inhibitors, a property which could be useful in the management of postprandial hyperglycemia in diabetes and related disorders. As a mammalian alpha-amylase inhibitor in vitro, the putative beneficial effect of trans-chalcone on diabetes was tested in a streptozotocin-induced rat model of diabetes type 1, and the results analyzed with commonly used statistical methods. Significant reduction of blood glucose levels and beneficial effect on dyslipidemia were observed in diabetic rats, as well as reduction of disturbing consequences of diabetes such as high urine volume and water intake. trans-chalcone was observed to have a weight loss-inductive effect, alongside with a reduction in food intake, which is suggestive of a therapeutic potential of this compound in overweight and obese patients.

Synthesis and Pharmacological Evaluation of Some Phenylpyrazolo Indoquinoxaline Derivatives

Indoloquinoxalin was fused with 2,3 diphenyl quinoxaline by a methylene bridge which was then allowed for acetylation. The acetylated product was made to react with different aromatic aldehydes to give chalcones. Chalcones refluxed with substituted acid hydrazides to afford different indoloquinoxaline pyrazolines. The structure of chalcones and indoloquinoxaline pyrazolines were confirmed by M.P, TLC and spectral data. All the synthesized compounds were screened for their antioxidant, anti‐inflammatory and antihistamic activities.

Synthesis and calming activity of 2-amino-4-(4-β-d-allopyranoside-phenyl)-6-3(4)-substituted phenylpyrimidines

Using helicid as starting material, E-4-β-D-allopyranoside-cinnamic-4-substituted phenylketones (1a–1h) containing the structure of chalcones were synthesized; then these chalcones were reacted with guanidine hydrochloride through a 1,4-Michael reaction, giving 2-amino-4-(4-β-D-allopyranoside-phenyl)-6-3(4)substituted phenylpyrimidines (2a–2h), which were characterized by IR, 1 H NMR, and HR-MS. The target compounds were evaluated by the spontaneous locomotor activity test, showing that all of them had good calming activity; compound 2f was found to have the greatest.

Isoliquiritigenin extracted from licorice Glycyrrhiza uralensis roots by a facile conversion technique

Isoliquiritigenin (1), one of the major constituents of licorice, is a natural pigment with a simple chalcone structure 4,2,4-trihydroxychalcone. This study was performed to determine whether liquiritin, isoliquiritin, and liquiritigenin can be converted into isoliquiritigenin using alkaline conversion after acid hydrolysis. An orthogonal L 9 (3) 4 test design was used in the extraction mode and used for optimization of the extract conditions, and the yield from the conventional procedure and from the optimum procedure to extract 1 was compared. The results demonstrated that the yield of the novel procedure was increased about 27 times compared with the conventional procedure, which indicated that the novel procedure is powerful in separating and purifying isoliquiritigenin.

Emerging role of Garcinol, the antioxidant chalcone from Garcinia indica Choisy and its synthetic analogs

Garcinol, harvested from Garcinia indica, has traditionally been used in tropical regions and appreciated for centuries; however its biological properties are only beginning to be elucidated. There is ample data to suggest potent antioxidant properties of this compound which have been used to explain most of its observed biological activities. However, emerging evidence suggests that garcinol could be useful as an anti-cancer agent, and it is increasingly being realized that garcinol is a pleiotropic agent capable of modulating key regulatory cell signaling pathways. Here we have summarized the progress of our current research knowledge on garcinol and its observed biological activities. We have also provided an explanation of observed properties based on its chemical structure and provided an insight into the structure and properties of chalcones, the precursors of garcinol. The available data is promising but more detailed investigations into the various properties of this compound, particularly its anti-cancer activity are urgently needed, and it is our hope that this review will stimulate further research for elucidating and appreciating the value of this nature's wonder agent.

Synthesis of Some Phenylpyrazolo Benzimidazolo Quinoxaline Derivatives as Potent Antihistaminic Agents

2,3‐Diphenyl quinoxaline (NI) was fused with benzimidazole (NII) by a methylene bridge, which was then allowed for acetylation. The acetylated product (NIV) was made to react with different aromatic aldehydes to give chalcones (NV1‐NV5). Chalcones refluxed with substituted acid hydrazides to afford different phenyl pyrazolo benzimidazole quinoxaline derivatives (NVI 1‐NVI 15). The structure of chalcones and phenyl pyrazolo benzimidazole quinoxaline derivatives were confirmed by m.p, TLC and spectral data. All the synthesized compounds were screened for their antihistaminic activity. Compounds NVI‐3, NVI‐12, NVI‐13, NVI‐14 and NVI‐15 were shown good % protection of antihistamic activity.

Inhibitory activity of prostaglandin E 2 production by the synthetic 2′-hydroxychalcone analogues: Synthesis and SAR study

A series of 2′-hydroxychalcones has been synthesized and screened for their in vitro inhibitory activities of cyclooxygenase-2 catalyzed prostaglandin production from lipopolysaccharide-treated RAW 264.7 cells. Structure–activity relationship study suggested that inhibitory activity against prostaglandin E 2 production was governed to a greater extent by the substituent on B ring of the chalcone, and most of the active compounds have at least two methoxy or benzyloxy groups on B ring. The relationship between chalcone structures and their PGE 2 inhibitory activities was also interpreted by docking study on cyclooxygenase-2.