Isolation and identification of quorum sensing antagonist from Cinnamomum verum leaves against Pseudomonas aeruginosa.

PURPOSE: The study aimed at isolating and identifying potential anti-quorum sensing (QS) compounds from Cinnamomum verum leaves against Pseudomonas aeruginosa. METHODOLOGY: Isolation of anti-QS compounds from C. verum leaf ethanol extract was carried out by column chromatography. The bioactive fraction was analysed by UV, IR, and GCMS spectroscopy. Various virulence assays were performed to assess the QS quenching ability of the purified compounds. In vivo toxicity of the purified compounds was examined in zebrafish model. The expression of the virulence genes was evaluated by qPCR analysis and in silico assessment was accomplished to check the binding ability of the compounds with the autoinducer molecule. KEY FINDINGS: The QS inhibitors isolated and identified showed a remarkable ability in reducing the production of elastase, pyocyanin, swarming motility and biofilm formation in P. aeruginosa. In the presence of the characterized compounds, the expression of virulence genes of P. aeruginosa was significantly reduced. Toxicity studies in zebrafish model indicated no effects on development and organogenesis at a concentration below 100 mg/l. Further, in silico analysis demonstrated the binding efficiency of the anti-QS compounds to AHL molecules, thus proving the QS quenching ability of the isolated compounds. SIGNIFICANCE: To the best of our knowledge this is the first report of isolation of anti-QS compounds from C. verum leaves against P. aeruginosa. The identified compounds qualify as potential QS antagonists. Further studies on these compounds can pave way for an effective and attractive anti-pathogenic therapy, to overcome the emergence of antibiotic resistance in bacteria.

Synthesis, In Vitro Anticancer, Anti-Inflammatory and DNA Binding Activity of Thiazolidinedione Derivatives.

BACKGROUND: Cancer is the second leading cause of mortality worldwide. Despite several advances made in the treatment strategies, the cure for cancer remains still a challenge. Currently used treatment modalities pose several side effects and remain ineffective in the later stages. Thiazolidinediones (TZDs) have been shown to possess anti-cancer activity in several in vitro models. OBJECTIVES: The objective of this study was to assess the effect of novel synthesized thiazolidinedione derivatives on three selected cancer cell lines viz., human breast adenocarcinoma cell line (MCF-7), lung adenocarcinoma (A549) and colorectal carcinoma (HT29). This study also aimed to evaluate the anti-inflammatory and DNA binding activity of the synthesized derivatives. METHODS: The synthesized thiazolidinedione derivatives were screened for their in vitro anti-cancer activity on the human breast adenocarcinoma cell line (MCF-7), lung adenocarcinoma (A549) and colorectal carcinoma (HT29) using the Methyl Thaizolyl Tetrazolium (MTT) Assay. They were also evaluated for in vitro antiinflammatory activity using albumin denaturation method, DNA binding activity and hemocompatibility. RESULTS: Compounds 5a, 5b, 5d, 6c and 6d showed IC50 of 30.19, 41.56, 65.97, 60.16 and 50.41µM respectively on breast adenocarcinoma (MCF-7), IC50 of 49.75, 51.42, 65.43, 61.94 and 56.80µM on lung adenocarcinoma (A549) and 38.11, 45.58, 71.24, 53.15 and 51.25µM on colorectal carcinoma (HT29). In the hemolysis assay, compounds 5a and 5b were found to be nontoxic and nonhemolytic to human erythrocytes. Five compounds possessed significant anticancer and anti-inflammatory activity. Three of them are Mannich bases, whereas the remaining two are aryl acyl derivatives. CONCLUSION: The in vitro results (anticancer and anti-inflammatory) showed that the 4-chloro anilinomethyl substitution at third position and thiophenoethenyl at the fifth position of thiozolidinedione (5a) emerged as the most effective derivative on all the tested cancer cell lines. A higher DNA binding affinity of the test compounds was also found.

Spectroscopic, single crystal X-ray, Hirshfeld, in vitro and in silico biological evaluation of a new series of potent thiazole nucleus integrated with pyrazoline scaffolds.

In the present study, the spectroscopic characterization of a new series of substituted thiazole linked pyrazoline scaffolds 4a-l was performed. The formation of 4a-l from the intermediate 3-(4-chlorophenyl)-5-[4-(propan-2-yl)phenyl]-4,5-dihydro-1H-pyrazole-1-carbothioamide 2 and substituted 2-bromo-1-phenylethanone 3a-l was evidenced through the changes in FTIR, 1H NMR, 13C NMR, LCMS data. The X-ray diffraction studies revealed that compound 2 and 4g crystallized in monoclinic crystal system with P21/n space group. Compound 4j crystallized in triclinic system, P1̄ space group with Z=4. The percentage of intermolecular contacts and distribution of electrostatic potential of molecular crystal structures was resolved by Hirshfeld surface analysis with 2D finger plots and electrostatic potential map. The newly synthesized derivatives were screened for their in vitro antioxidant and antimicrobial activity. The single crystal studies revealed that, for compounds 2, 4g and 4j the isopropyl phenyl ring is positioned at near right angle with the other rings. Due to the lack of planarity of bulkier group substituted to phenyl ring (ring B), all the synthesized molecules showed weak to moderate radical scavenging capacity owing to the destabilization of the radical formed during oxidation. Also, on performing molecular docking studies to explore the interactions of ligand with the target pyrimidine nucleoside hydrolase YbeK with bound ribose complex (PNH, PDB ID-3GHW), disclosed that active compounds emerged for in vitro studies also bound to PNH more efficiently. The compounds with polar group substitution interacted through hydrogen bonding while other molecules with non-covalent interactions.

Crystal structure of ethyl (1RS,6SR)-4-(2-methyl-1H-imidazol-4-yl)-2-oxo-6-(2,3,5-tri-chloro-phen-yl)cyclo-hex-3-ene-1-carboxyl-ate.

The title compound, C19H17Cl3N2O3, has been prepared in a cyclo-condensation reaction between 2,3,5-tri-chloro-benzaldehye and 4-acetyl-2-methyl-1H-imidazole. The cyclo-hexenone ring adopts an envelope conformation with the C atom substituted by the tri-chloro-phenyl ring as the flap. The mutually trans ester and aryl substituents both occupy equatorial sites. In the crystal, a combination of N-H⋯O and C-H⋯N hydrogen bonds links the mol-ecules into ribbons of edge-fused centrosymmetric rings, which enclose R 2 (2)(14) and R 4 (4)(16) alternate ring motifs, propagating along the b-axis direction.

Crystal structure of (RS)-(4-chloro-phen-yl)(pyridin-2-yl)methanol.

In the title racemic compound, C12H10ClNO, the dihedral angle between the benzene and pyridine rings is 74.34 (6)°. In the crystal, the mol-ecules are linked by O-H⋯N hydrogen bonds, forming zigzag C(5) [001] chains in which alternating R- and S-configuration mol-ecules are related by c-glide symmetry. In addition, inversion-related pairs of mol-ecules are linked into dimers by pairs of weak C-Cl⋯π(pyrid-yl) inter-actions, which link the hydrogen-bonded chains into (100) sheets. Structural comparisons are drawn with a number of related compounds.

The crystal structures of three 3-methyl-1H-1,2,4-triazole-5-thio-nes, including a second polymorph of 4-[(E)-(5-bromo-2-hy-droxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione and a redetermination of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione.

The structures of three 3-methyl-1H-1,2,4-triazole-5-thione derivatives are reported. The structure of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C3H6N4S, (I), has been redetermined with an improved model for the H atoms: the non-H atoms of (I) all lie on mirror planes in space group Pbcm, and the H atoms of the methyl group are disordered over two sets of reflection-related atomic sites having occupancy 0.5: two independent N-H⋯S hydrogen bonds link the mol-ecules of compound (I) into complex sheets. The non-H atoms in the mol-ecules of 4-[(E)-(3,4-di-meth-oxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-tri-azol-5(4H)-thione, C12H14N4O2S, (II), despite lying in general positions are close to planar, with a dihedral angle between the two rings of 6.31 (10)°: the mol-ecules of compound (II) are linked by a three-centre N-H⋯(O)2 hydrogen bond into a C(10)C(11)[R 1 (2)(5)] chain of rings. A second polymorph of 4-[(E)-(5-bromo-2-hy-droxy-5-bromo-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C10H9BrN4OS, (III), has been identified; the non-H atoms are nearly co-planar with a dihedral angle between the two rings of 1.9 (4)°. There is an intra-molecular O-H⋯N hydrogen bond and the mol-ecules are linked by N-H⋯S hydrogen bonds, forming centrosymmetric R 2 (2)(8) dimers. Comparisons are made with some related structures.

Ethyl (4-benzyloxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate and a redetermination of ethyl (4RS)-4-(4-methoxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate, as its 0.105-hydrate, both at 200†K: subtly different hydrogen-bonded ribbons.

Two sulfanylidene-1,2,3,4-tetrahydropyrimidine derivatives have been synthesized using acid-catalysed cyclocondensation reactions between thiourea, ethyl 3-oxobutanoate and substituted benzaldehydes. In each of ethyl (4RS)-4-(4-benzyloxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate, C21H22N2O3S, (I), where Z' = 2, and ethyl (4RS)-4-(4-methoxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate 0.105-hydrate, C15H18N2O3S·0.105H2O, (II), the reduced pyrimidine ring adopts a conformation intermediate between the boat, screw-boat and twist-boat forms. In (I) and (II), a combination of N-H...O and N-H...S hydrogen bonds links the organic molecules into ribbons containing alternating R2(2)(8) and R4(4)(20) rings. In (I), the ribbon contains three types of ring, viz. two different R2(2)(8) rings which are both centrosymmetric and R4(4)(20) rings which are not centrosymmetric. In (II), the ribbon contains two types of ring, both of which are centrosymmetric. In compound (II), the ribbons enclose continuous channels which run along the twofold rotation axes in the space group C2/c, and the partial-occupancy water molecules lie within these channels. Structural comparisons are made with a number of related compounds.

(2E)-1-(4-Chloro-phen-yl)-3-[4-(propan-2-yl)phen-yl]prop-2-en-1-one.

In the title compound, C18H17ClO, the dihedral angle between the benzene rings is 53.5 (1)°. The mean plane of the prop-2-en-1-one group is twisted by 24.5 (8) and 33.5 (3)° from the chloro- and propanyl-substituted rings, respectively.

4-[(4-Acetyl-phen-yl)amino]-2-methyl-idene-4-oxo-butanoic acid.

In the title compound, C13H13NO4, the N-C(=O) bond length of 1.354 (2) Šis indicative of amide-type resonance. The dihedral angle between the mean planes of the benzene ring and oxo-amine group is 36.4 (3)°, while the mean plane of the 2-methyl-idene group is inclined by 84.2 (01)° from that of the oxo-amine group. In the crystal, classical O-H⋯O hydrogen bonds formed by the carb-oxy-lic acid groups and weak N-H⋯O weak inter-actions formed by the amide groups and supported by weak C-H⋯O inter-actions between the 2-methyl-idene, phenyl and acetyl groups with the carb-oxy-lic acid, oxo-amine and acetyl O atoms, together link the mol-ecules into dimeric chains along [010]. The O-H⋯O hydrogen bonds form R 2 (2)(8) graph-set motifs.

1-{3-(4-Chloro-phen-yl)-5-[4-(propan-2-yl)phen-yl]-4,5-di-hydro-1H-pyrazol-1-yl}butan-1-one.

In the title compound, C22H25ClN2O, the pyrazole ring exhibits an envelope conformation with the methine C atom as the flap. The benzene rings are twisted by 3.3 (5) and 84.6 (5)° from the pyrazole mean plane, and are inclined to each other by 81.4 (4)°. In the crystal, pairs of weak C-H⋯O hydrogen bonds form centrosymmetric dimers with an R 2 (2)(16) graph-set motif. C-H⋯π inter-actions link the dimers into columns propagating in [100].

1-{3-(4-Chloro-phen-yl)-5-[4-(propan-2-yl)phen-yl]-4,5-di-hydro-1H-pyrazol-1-yl}propan-1-one.

In the title compound, C21H23ClN2O, the dihedral angle between the benzene rings is 83.2 (6)°, while the mean plane of the pyrazole ring [r.m.s. deviation = 0.043 (1) Å] makes dihedral angles of 3.4 (3) and 86.2 (1)° with the benzene rings. In the crystal, a pair of weak C-H⋯O inter-actions between the benzene ring and the propan-1-one group link the mol-ecules into an inversion dimer with an R 2 (2)(16) graph-set motif. In addition, a weak π-π stacking inter-action [centroid-centroid distance = 3.959 (4) Å] connects the dimers into a tape running along [201].

4-[(4-Bromo-phenyl)amino]-2-methyl-idene-4-oxo-butanoic acid.

In the title compound, C11H10BrNO3, two independent mol-ecules (A and B) crystallize in the asymmetric unit. The dihedral angles between the mean planes of the 4-bromo-phenyl ring and amide group are 24.8 (7) in mol-ecule A and 77.1 (6)° in mol-ecule B. The mean plane of the methyl-idene group is further inclined by 75.6 (4) in mol-ecule A and 72.5 (6)° in mol-ecule B from that of the amide group. In the crystal, N-H⋯O hydrogen bonds formed by amide groups and O-H⋯O hydrogen bonds formed by carb-oxy-lic acid groups are observed and supported additionally by weak C-H⋯O inter-actions between the methyl-idene and amide groups. Together, these link the mol-ecules into chains of dimers along [110] and form R 2 (2)(8) graph-set motifs.

1-{3-(4-Chloro-phen-yl)-5-[4-(propan-2-yl)phen-yl]-4,5-di-hydro-1H-pyrazol-1-yl}ethanone.

In the title compound, C20H21ClN2O, the dihedral angles between the pyrazole ring (r.m.s. deviation = 0.049 Å) and the benzene and chloro-benzene rings are 84.65 (10) and 3.35 (10)°, respectively. In the crystal, inversion dimers linked by pairs of weak C-H⋯O inter-actions generate R 2 (2)(16) loops. Weak π-π stacking inter-actions [centroid-centroid distance = 3.8490 (11) Å] are also observed.

2-(2-Methyl-phen-yl)-N-(1,3-thia-zol-2-yl)acetamide.

In the title compound, C12H12N2OS, the dihedral angle between the benzene and thia-zole rings is 83.5 (7)°. The acetamide group is almost coplanar with the thia-zole ring, being twisted from it by 4.2 (9)°. In the crystal, pairs of N-H⋯N hydrogen bonds link mol-ecules into inversion dimers, generating R 2 (2)[8] loops; the dimers are stacked along [001].

4-[(E)-(4-Hy-droxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione.

The title compound, C10H10N4OS, is nearly planar with the mean planes of the hy-droxy-benzyl and triazole rings inclined at an angle of only 3.2 (7)°. In the crystal, O-H⋯N hydrogen bonds between the hy-droxy group and the triazole ring in concert with weak N-H⋯S inter-molecular inter-actions between the triazole ring and thione group form chains along [-210] enclosing R 2 (2)(8) graph-set motifs. A weak intra-molecular C-H⋯S inter-action and inter-molecular π-π inter-actions [centroid-centroid distance = 3.5990 (15) Å] are also observed.

3-(4-Fluoro-benzo-yl)-4-(4-fluoro-phen-yl)-4-hy-droxy-2,6-di-phenyl-cyclo-hexane-1,1-dicarbo-nitrile.

In the title compound, C33H24F2N2O2, the cyclo-hexane ring adopts a slightly distorted chair conformation. The dihedral angle between the planes of the phenyl rings is 71.80 (9)°, while the planes of the fluoro-phenyl and fluoro-benzoyl rings are inclined to one another by 31.04 (10)°. The dihedral angles between the planes of the phenyl ring adjacent to the 4-hydroxy group and those of the the fluoro-phenyl and fluoro-benzoyl rings are 51.64 (10) and 34.31 (10)°, respectively, while the corresponding angles for the phenyl ring adjacent to the 3-(4-fluorobenzoyl) group are 57.51 (9) and 85.02 (10)°, respectively. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked via pairs of O-H⋯N hydrogen bonds, forming inversion dimers. The dimers are linked via C-H⋯N and C-H⋯O hydrogen bonds, forming chains along the c-axis direction. C-H⋯F hydrogen bonds link the chains into sheets lying parallel to the bc plane.

3-Chloro-4-fluoro-anilinium picrate.

In the title picrate salt of a dihalogenated aniline derivative, C(6)H(6)ClF(+)·C(6)H(2)N(3)O(7) (-), the intra-cyclic C-C-C angles in the picrate anion cover a broad range [111.95 (12)-125.38 (13)°], while those in the aromatic cation span a much narrower range [118.25 (14)-122.33 (13)°]. In the crystal, classical N-H⋯O hydrogen bonds, as well as C-H⋯O contacts, connect the ions into layers parallel to (001).

2,2'-(Disulfanedi-yl)bis-[4,6-(4-fluoro-phen-yl)pyrimidine].

The title compound, C(32)H(18)F(4)N(4)S(2), is a disulfide symmetric-ally substituted with two diaza-meta-terphenyl groups. In the crystal, the mol-ecule adopts a twisted conformation with a C-S-S-C torsion angle of -91.82 (7)°. One of the 4,6-(4-fluoro-phen-yl)pyrimidine groups is virtually planar, with dihedral angles between the pyrimidine and benzene groups of 4.00 (8) and 5.44 (8)°, wheares the other is non-planar with analogues dihedral angles of 18.69 (8) and 26.60 (8)°. The planar 4,6-(4-fluoro-phen-yl)pyrimidine groups are involved in π-π stacking inter-actions via their 4-fluoro-phenyl groups [centroid-centroid distances of 3.8556 (11) and 3.9284 (11) Å] that assemble the mol-ecules into columns extended along the a axis. In addition, the structure is stabilized by C-F⋯π [F⋯centroid = 3.4017 (16) Å], C-H⋯F and C-H⋯π inter-actions.

(2E)-1-(4,4''-Difluoro-5'-meth-oxy-1,1':3',1''-terphenyl-4'-yl)-3-(4-fluoro-phen-yl)prop-2-en-1-one.

In the title compound, C(28)H(19)F(3)O(2), the C=C double bond has an E configuration. In the crystal, C-H⋯F contacts link the mol-ecules into chains along [111]. The shortest centroid-centroid distance between two π systems is 3.8087 (8) Šand is apparent between the para-fluoro-phenyl group attached to the Michael system and its symmetry-generated equivalent.