Antioxidant, antimicrobial and anticancer activity of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis

<p>Abstract</p> <p>Background</p> <p>The aim of this study is to investigate in vitro antioxidant, antimicrobial and anticancer activity of the acetone extracts of the lichens <it>Cladonia furcata, Lecanora atra </it>and <it>Lecanora muralis</it>.</p> <p>Methods</p> <p>Antioxidant activity was evaluated by five separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method against six species of bacteria and ten species of fungi. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method.</p> <p>Results</p> <p>Of the lichens tested, <it>Lecanora atra </it>had largest free radical scavenging activity (94.7% inhibition), which was greater than the standard antioxidants. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. Extract of <it>Cladonia furcata </it>was the most active antimicrobial agent with minimum inhibitory concentration values ranging from 0.78 to 25 mg/mL. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀values ranging from 8.51 to 40.22 μg/mL.</p> <p>Conclusions</p> <p>The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial and anticancer effects. That suggest that lichens may be used as as possible natural antioxidant, antimicrobial and anticancer agents to control various human, animal and plant diseases.</p

(E)-2-[(2-chlorophenyl)iminomethyl]-5-methoxyphenol: X-ray and

The crystal structures of the title 4-chlorophenyl, (I), and 2-chlorophenyl, (II), compounds, both C14H12ClNO2, have been determined using X-ray diffraction techniques and the molecular structures have also been optimized at the B3LYP/6-31 G(d, p) level using density functional theory (DFT). The X-ray study shows that the title compounds both have strong intramolecular O-H center dot center dot center dot N hydrogen bonds and that the crystal networks are primarily determined by weak C-H center dot center dot center dot pi and van der Waals interactions. The strong intramolecular O-H center dot center dot center dot N hydrogen bond is evidence of the preference for the phenol-imine tautomeric form in the solid state. The IR spectra of the compounds were recorded experimentally and also calculated for comparison. The results from both the experiment and theoretical calculations are compared in this study

Coordination Mode

A novel Cu(II) coordination polymer of general empirical formula {[Cu(mu-HC(2)O(4))(2)(H(2)O)(2)][Cu(HC(2)O(4))(2)]a (TM) 6H(2)O} (n) (1) has been synthesized and characterized by single-crystal X-ray diffraction technique. The complex (1) crystallizes in the triclinic form with P-1 space group. It is quite surprising that single crystal X-ray analysis of 1 illustrates the presence of hydrogen oxalate ligand in the coordination environment of Cu(II) ion. Because oxalate is not present in the starting reaction mixture, it may be derived from the reduction of squarate ligand. In 1, Cu(II) ions exhibit two different coordination environments, forming a distorted octahedral geometry. The Cu1 is coordinated with six oxygen atoms from two bidentate HC(2)O(4) (-) and two aqua ligands, while Cu2 is coordinated with six oxygen atoms from four HC(2)O(4) (-) ligands. The HC(2)O(4) (-) ligand acts in two different coordination modes, as a bidentate and an unprecedented tridentate bridging coordination mode

(E)-5-Methoxy-2-((4-methoxyphenylimino)methyl)phenol

The title compound, (E)-5-methoxy-2-((4-methoxyphenylimino)methyl)phenol (C(15)H(15)NO(3)), crystallizes in monoclinic, space group P2(1)/(c) with a = 9.4361(6), b = 10.6212(5), c = 12.9338(9) angstrom,beta = 93.064(5)degrees, V= 1294.41(14) angstrom(3), Z = 4, D(c) = 1.320 g/cm(3), F(000) = 544, R(int) = 0.116, T= 296 K, mu = 0.09 mm(-1), the final R = 0.051 and wR = 0.148 for 1836 observed reflections with I > 2 sigma(I). An extensive two-dimensional network of C-H center dot center dot center dot O hydrogen bonds and pi-ring interactions are responsible for the crystal stabilization. Intermolecular hydrogen bonds and C-H center dot center dot center dot pi interactions produce R(2)(2)(14), R(4)(4)(30) and R(4)(4)(31) rings. In addition to the molecular geometry from X-ray experiment, the molecular geometry of the title compound in the ground state has been calculated using the semi-empirical (AM1 and PM3) and density functional theory method (DFT) (B3LYP) with 6-31G(d) basis set. To determine the conformational flexibility, molecular energy profile of the title compound was obtained by semi-empirical (PM3 and AM1) and DFT/B3LYP calculations with respect to the selected degree of torsional freedom, which varied from 180 to +180 degrees in a step of 10 degrees

(E)-5-Methoxy-2-((4-methoxyphenylimino)methyl)phenol

The title compound, (E)-5-methoxy-2-((4-methoxyphenylimino)methyl)phenol (C(15)H(15)NO(3)), crystallizes in monoclinic, space group P2(1)/(c) with a = 9.4361(6), b = 10.6212(5), c = 12.9338(9) angstrom,beta = 93.064(5)degrees, V= 1294.41(14) angstrom(3), Z = 4, D(c) = 1.320 g/cm(3), F(000) = 544, R(int) = 0.116, T= 296 K, mu = 0.09 mm(-1), the final R = 0.051 and wR = 0.148 for 1836 observed reflections with I > 2 sigma(I). An extensive two-dimensional network of C-H center dot center dot center dot O hydrogen bonds and pi-ring interactions are responsible for the crystal stabilization. Intermolecular hydrogen bonds and C-H center dot center dot center dot pi interactions produce R(2)(2)(14), R(4)(4)(30) and R(4)(4)(31) rings. In addition to the molecular geometry from X-ray experiment, the molecular geometry of the title compound in the ground state has been calculated using the semi-empirical (AM1 and PM3) and density functional theory method (DFT) (B3LYP) with 6-31G(d) basis set. To determine the conformational flexibility, molecular energy profile of the title compound was obtained by semi-empirical (PM3 and AM1) and DFT/B3LYP calculations with respect to the selected degree of torsional freedom, which varied from 180 to +180 degrees in a step of 10 degrees

one 0.25-hydrate

The title compound, C14H12ClNO3 center dot 0.25H(2)O, exists in the keto-amine form, and the aromatic rings are oriented at a dihedral angle of 7.24 (7)degrees. Bifurcated intramolecular N-H center dot center dot center dot(O,O) hydrogen bonds result in the formation of planar six- and five-membered rings. In the crystal structure, intermolecular O-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds link the molecules into chains. pi-pi contacts between benzene rings [centroid-centroid distance = 3.5065 (9) angstrom] may further stabilize the structure. There also exists a weak C-H center dot center dot center dot pi interaction

(E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino)phenyl]ethanone: X-ray and

The isomeric structures of (E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)phenyl] ethanone (I) and (E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino)phenyl]ethanone (II), both C(16)H(15)NO(3), have been determined using X-ray diffraction techniques and characterized by IR, and their molecular structures have also been optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G(d,p) basis set by applying the polarizable continuum model (PCM). The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition, DFT calculations of the title compounds' molecular electrostatic potentials (MEP) were performed at the B3LYP/6-31G(d,p) level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H center dot center dot center dot N hydrogen bonds. The molecules of! are linked into a one-dimensional framework structure by C-H center dot center dot center dot pi interactions, while in II, intermolecular pi center dot center dot center dot pi interactions result in the formation of infinite chains running along the [010]

'-Azobispyridine (abpy), (mu-abpy)[Cd(HsaI)(2)(abpy)](2)

mu-2,2'-Azobispyridinebis[2,2'-azobispyridinesalicylato(O)-salicylato(O,O') cadmium(II), (mu-abpY)[Cd(HsaI)(2)(abpy)](2) (I) was synthesized and characterized by IR and UV/Vis spectroscopy, thermal analysis, and X-ray diffraction techniques. Two abpy ligands and two salicylato ligands coordinate to the Cd2+ ion in a monocapped trigonal-prismatic arrangement. The capping atom is the N3 atom. One of the two abpy ligands behaves as a "s-frame" bridging ligand and adopts a s-cis/E/s-cis conformation, whereas the other one adopts as a s-cis/E/s-trans conformation. One of the two salicylato ligands acts as a monodentate ligand, which coordinates with the carboxylate oxygen atom, whereas the other one adopts bidentate coordination through two carboxylate oxygen atoms. The hydroxy groups of salicylato ligands, which coordinate in a monodentate fashion, are disordered over two positions, with occupancies of 0.52 for group A and 0.48 for group B. The decomposition reaction takes place in the temperature range 20-1000 degrees C under nitrogen. Thermal decomposition of the title complex proceeds in two stages