Caridad N. Perez

Genotoxic, Cytotoxic, Antigenotoxic, and Anticytotoxic Effects of Sulfonamide Chalcone Using the Ames Test and the Mouse Bone Marrow Micronucleus Test

Chalcones present several biological activities and sulfonamide chalcone derivatives have shown important biological applications, including antitumor activity. In this study, genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activities of the sulfonamide chalcone N-{4-[3-(4-nitrophenyl)prop-2-enoyl]phenyl} benzenesulfonamide (CPN) were assessed using the Salmonella typhimurium reverse mutation test (Ames test) and the mouse bone marrow micronucleus test. The results showed that CPN caused a small increase in the number of histidine revertant colonies in S. typhimurium strains TA98 and TA100, but not statistically significant (p > 0.05). The antimutagenicity test showed that CPN significantly decreased the number of His+ revertants in strain TA98 at all doses tested (p < 0.05), whereas in strain TA100 this occurred only at doses higher than 50 μg/plate (p < 0.05). The results of the micronucleus test indicated that CPN significantly increased the frequency of micronucleated polychromatic erythrocytes (MNPCE) at 24 h and 48 h, revealing a genotoxic effect of this compound. Also, a significant decrease in polychromatic/normochromatic erythrocyte ratio (PCE/NCE) was observed at the higher doses of CPN at 24 h and 48 h (p < 0.05), indicating its cytotoxic action. CPN co-administered with mitomycin C (MMC) significantly decreased the frequency of MNPCE at almost all doses tested at 24 h (p < 0.05), showing its antigenotoxic activity, and also presented a small decrease in MNPCE at 48 h (p > 0.05). Additionally, CPN co-administered with MMC significantly increased PCE/NCE ratio at all doses tested, demonstrating its anticytotoxic effect. In summary, CPN presented genotoxic, cytotoxic, antigenotoxic, and anticytotoxic properties.

Absence of genotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one) and its potential chemoprevention against DNA damage using in vitro and in vivo assays

The chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one), or 2HMC, displays antileishmanial, antimalarial, and antioxidant activities. The aim of this study was to investigate the cytotoxic, genotoxic, mutagenic, and protective effects of 2HMC using the Ames mutagenicity test, the mouse bone marrow micronucleus test, and the comet assay in mice. In the assessment using the Ames test, 2HMC did not increase the number of His+ revertants in Salmonella typhimurium strains, demonstrating lack of mutagenicity. 2HMC showed no significant increase in micronucleated polychromatic erythrocyte frequency (MNPCE) in the micronucleus test, or in DNA strand breaks using the comet assay, evidencing absence of genotoxicity. Regarding cytotoxicity, 2HMC exhibited moderate cytotoxicity in mouse bone marrow cells by micronucleus test. 2HMC showed antimutagenic action in co-administration with the positive controls, sodium azide (SA) and 4-nitroquinoline-1-oxide (4NQO), in the Ames test. Co-administered and mainly pre-administered with cyclophosphamide (CPA), 2HMC caused a decrease in the frequency of MNPCE using the micronucleus test and in DNA strand breaks using the comet assay. Thus, 2HMC exhibited antimutagenic and antigenotoxic effects, displaying a DNA-protective effect against CPA, SA, and 4NQO carcinogens. In conclusion, 2HMC presented antimutagenic, antigenotoxic and moderate cytotoxic effects; therefore it is a promising molecule for cancer prevention.

Study of Reactions of Two Mannich Bases Derived of 4'-Hydroxychalcones with Glutathione by RP-TLC, RP-HPLC and RP-HPLC-ESI-MS Analysis

4’-Hydroxychalcones have been reported to possess several beneficial biological effects. Several lines of evidence accumulated to demonstrate increased biological activities of the Mannich base derivatives of the parent 4’-hydroxychalcones. Bioactivities of chalcones and related α,β-unsaturated ketones are frequently associated with their reactivity with cellular thiols, such as GSH. For comparison of GSH reactivity, two bis Mannich bases of two 4’-hydroxychalcones were synthesized and reacted with GSH under non-cellular conditions. Reversed-phase thin layer chromatography (RP-TLC) and reversed-phase high performance liquid chromatography (RP-HPLC) analysis showed formation of two polar products which structures were confirmed by RP-HPLC-ESI-MS (RP-HPLC-electrospray ionization mass spectrometry) as 1:1 chalcone-GSH adducts in each case. At pH values below 8.0, the two bis Mannich bases showed higher GSH reactivity than two 4’-hydroxychalcones. Influence of the nature of the amino groups, the ring-B substituents and pH of the medium on reactivity was also investigated. The findings could serve as useful structure-activity information for subsequent molecular modification of thiol-reactive 4’-hydroxychalcones.

Structural insights into a novel anticancer sulfonamide chalcone

Natural products have stood out due to their wide range of biological activities. Among the various naturally occurring classes, we can highlight chalcones, sulfonamides and hybrid compounds formed by both. Although many pharmacological activities of these classes of compounds are known, new ones have arisen lately and require detailed structural and biological analyses. Herein, we report the synthesis and structural elucidation of a novel sulfonamide chalcone 2,5-dichloro-N-{3-[(2E)-3-(4-nitrophenyl)prop-2-enoyl]phenyl}benzenesulfonamide (BSC) by Single Crystal X-ray Diffraction and spectroscopy analysis (Infrared, NMR and Mass Spectroscopy). Topology was determined through Hirshfeld surface analysis and the electrostatic potential map, while the energy of frontier molecular orbitals was used to evaluate the stability of BSC. Additionally, the cytotoxicity of the title compound was evaluated through the MTT colorimetric method. We show that the BSC compound has a planar conformation in its chalcone portion, which is further corroborated by the low angle between the aromatic rings (5.23°). In addition, intermolecular interactions of type C–H⋯O and N–H⋯O make up a dimeric supramolecular arrangement. An inverse virtual screening approach allowed identifying potential biological applications for BSC, which indicated that BSC might interact with the binding sites of RARα and RARβ. Consequently, BSC was experimentally evaluated against three cancer cell lines, and was shown to hold potent anticancer activity. In addition, a cytotoxic effect was observed for all strains, which was more pronounced for HCT-116, a colon cancer cell line.

Presence of antigenotoxic and anticytotoxic effects of the chalcone 1E,4E-1-(4-chlorophenyl)-5-(2,6,6-trimethylcyclohexen-1-yl)penta-1,4-dien-3-one using in vitro and in vivo assays

Abstract Chalcones are chemically defined as α,β–unsaturated ketones with a 1,3-diphenyl-2-propen-1-one nucleus. These compounds occur naturally in plants and are considered precursors of flavonoids. Given that evaluating genetic toxicology tests is essential in investigating the safe use and chemopreventive potential of different natural and synthetic compounds, this study aimed to assess the genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activity of the chalcone 1E,4E-1-(4-chlorophenyl)-5-(2,6,6-trimethylcyclohexen-1-yl)penta-1,4-dien-3-one (CAB7β). The CAB7β was synthesized via Claisen–Schmidt reaction. The Ames test was applied using the co-treatment model as well as a micronucleus assay of mouse bone marrow with co-, pre- and post-treatment models. Our results indicate no genotoxic effect for CAB7β in any of the tests applied. At all the concentrations used, CAB7β showed a significant DNA protective effect against the mutagenic action of 4-nitroquinoline-1-oxide and sodium azide according to the Ames test, and against doxorubicin in the co-, pre- and post-treatment models of the micronucleus assay. CAB7β alone displayed cytotoxic activity in the micronucleus test. At concentrations of 12,5 and 50 µg/plate, CAB7β showed a moderate cytotoxic profile only in Salmonella typhimurium strain TA98. However, an anticytotoxic effect was observed against S. typhimurium strain TA100 for all the concentrations tested and during co-, pre- and post-treatment in the micronucleus assay. It was concluded that CAB7β exhibited a slightly cytotoxic effect in S. typhimurium strain TA98 and significant antigenotoxic and anticytotoxic effects in cells of mouse, making it a promising candidate in chemoprevention and possibly in the development of new cancer treatments.

Reagent-induced asymmetric induction in addition reaction of reduced glutathione onto bis-Mannich chalcones

The stereochemistry of non‐enzyme catalyzed nucleophilic addition of GSH to 4′‐hydroxychalcone 1 and its bis‐Mannich derivative 2 was investigated at different pH values (pH 3.2, 6.1, 7.4, and 8.0). The stereochemical outcome of the reactions was evaluated by HPLC‐UV‐Vis method. Under strongly acidic conditions (pH 3.2), an unexpected diastereoselective addition of GSH onto the bis‐Mannich derivative 2 was observed. Such a selectivity could not be observed in the similar reaction of 2 with N‐acetylcysteine. The observed stereoselectivity can be rationalized by ion‐pair formation between the protonated Mannich nitrogens and the deprotonated GSH(glutamate)‐carboxylate. To the best of our knowledge, this is the first example of reagent‐induced asymmetric induction in Michael‐type additions of thiols.

Mutagenicity and antimutagenicity of Salacia crassifolia (mart. Ex. Schult.) G. Don. evaluated by Ames test

Salacia crassifolia (Mart. Ex. Schult.) G. Don. is a bush which belongs to Celastraceae family and occurs specially in Brazilian Cerrado. Its leaves, stem, seeds and fruits are popularly used for several medicinal purposes, such as antitumoral, antirheumatic, anti-inflammatory and antimicrobial. In this study, the mutagenic and antimutagenic activities of S. crassifolia stem bark fractions (hexane, ethyl acetate and hydroalcoholic) were evaluated by the Ames mutagenicity assay in Salmonella typhimurium TA98 and TA100 strains. By the obtained results, all S. crassifolia fractions did not significantly increase the number of prototrophic revertants for histidine (His+) in both S. typhimurium strains tested (p > 0.05), suggesting absence of mutagenicity. Regarding antimutagenicity, the fractions ethyl acetate and hydroalcoholic significantly decreased the number of His+ revertants colonies induced by positive control for strain TA98 (p < 0.05), demonstrating protection against mutagenicity induced by 4-nitroquinolile1-oxide, whereas the hexane fraction did not show antimutagenic effect in this strain. In the TA100 strain, all fractions of S. crassifolia protected DNA against the harmful action of sodium azide, and the hexane fraction exhibited the greatest protection in this work. Thus, its possible conclude that the fractions of S. crassifolia tested in this study could be used in chemoprevention.

Structural investigation of a novel sulfonamide chalcone hybrid

Sulfonamides are important organic molecules to study regarding their wide range of reported biological activities1. In this way, hybrid compounds such as sulfonamide chalcones (a fusion of sulfonamide and chalcone moieties) conserve or even increase their biological activities1–3. The synthesis and structural analysis of a new sulfonamide chalcone (2,5-dichloro-N-{3-[(2E)-3-(4-nitrophenyl)prop-2-enoyl]phenyl}benzene-1-sulfonamide) (SCH) are reported in this work. Single crystal X-ray diffraction of SCH was collected on Bruker APEX II CCD diffractometer. The refinement of the structure (R1 = 5.79% and Goof = 1.068) was made by SHELX suit programs and indicates the centrosymmetric monoclinic space group C2/c, obtained after squeeze by Platon software. Figure 1(a) shows an ortep representation of SCH. The quasi planarity of the chalcone portion is confirmed by the angle of 5.23° formed between the planes of its aromatic rings, whereas the sulfonamide moiety is almost perpendicular to it (85.72°). Hydrogen bonded dimers are linked in a chain by C-H⋯O interaction, involving the nitrobenzene aromatic ring. These chains form a layer associated by interactions around sulfone and nitro groups. Finally, the crystal packing is obtained by stacking these dimeric chains, intercalating chalcone moieties and sulfonamides aromatic rings. The solvent accessible voids were found with 13.2% of unit cell volume, as shown in Figure 1(b). Hirshfeld surface analysis were performed before SQUEEZE and indicates that crystal packing is also stabilized by both π⋯π and C-H⋯π interactions.

The effect of propanone molecule on supramolecular arrangement of solvatomorphs of a novel anticancer sulfonamide chalcone

Sulfonamide chalcones are hybrid compounds formed by sulfonamide and chalcone moieties, with various biological activities1–3. A new sulfonamide chalcone C24H20CL2N2O6S was synthesized and its biological tests indicate activities against prostate and colon cancer tumor cells [PC-3 = 97.51± 0.65 and HCT116 = 100.00±1.83]. Two single crystals of solvatomorphs (SFV-SV and SFC) were obtained by different crystallization experiments and were collected on Bruker APEX II CCD diffractometer. Both structures crystallized in the centrosymmetric P-1 space group and were refined by SHELXL [R1 = 0.0597 and S = 1.023 for SFC-SV; R1 = 0.0695 and S = 1.053]. The SFC-SV structure has one propanone molecule in the asymmetric unit and the values of dihedral angles indicate the planarity throughout the chalcone moiety. The SFC structure has two independent molecules in asymmetric unit (SFC-α and SFC-β) and its residual electronic density was refined by SQUEEZE routine by PLATON. Both crystal forms can be obtained by rotations around σ bonds and the planarity decreases following the order SFC-SV > SFC-β > SFC-α. The crystal packing of both molecules are stabilized by interactions of type C-H··· O, N-H···O and C-H···Cl . In SFC-SV, propanone molecules are responsible for binding two dimmer chains, while in SFC the solvent space is substituted by voids on refinement. The Figure 1 shows the supramolecular arrangements of SFC-SV, with solvent molecules in black, and SFC. In addition, the packing is stabilized by C-H··· π and π··· π, as described on the Hirshfeld surface dnorm and Hirshfeld surface shape index.