Root decoctions of anthraquinone-containing plants are often taken as postpartum tonic and aphrodisiac. Anthraquinones are known for their diverse biological activities, especially antioxidant and anticancer. A series of 35 anthraquinones was generated by isolation from Rubiaceae plants and synthesis. Their UV/vis spectrum depends on the nature and relative positions of auxochromic substituents on the basic skeleton. To predict the maximum absorption bands for the current series of anthraquinones, excited sate calculations were performed using TD-DFT, CIS, ZINDO methods. The results showed that the use of PBE0 or its combination with B3LYP and B3P86 hybrid functionals are the most suitable to reproduce accurately the experimental λMAX. The structure–property relationships (SPRs) were established based on structural and electronic properties of the anthraquinones and showed (i) the importance of the number and position of OH groups and (ii) the positive contribution of the electrophilicity and hardness as electronic descriptors on position and amplitude of the maximum absorption bands.
Anthraquinones; UV/vis; TD-DFT; IEFPCM; Excited states
The title phenylhydrazine derivative, C16H16N2O4, has a crystallographically imposed centre of symmetry. Except for the methyl group, all non-H atoms are almost coplanar (r.m.s. deviation = 0.0095 Å). Intramolecular O—H⋯N hydrogen bonds are observed, generating S(6) graph-set ring motifs.
In the title compound, C16H16N2O3·H2O, the dihedral angle between the benzene rings is 30.27 (7)°. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O interactions into a three-dimensional network.
In the title benzoylhydrazide derivative, C17H18N2O, the dihedral angle between the benzene rings is 88.45 (8)° and the azomethine double bond adopts an E conformation. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming a chain along the b axis.
In the title hydrazone derivative, C15H13ClN2O2, the dihedral angle between the benzene rings is 2.36 (2)°. An intramolecular N—H⋯O hydrogen bond is present. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link the molecules into chains running parallel to the b axis.
In the title hydrazone derivative, C15H14N2O5, the benzene rings are twisted by 7.55 (8)° with respect to each other. The azomethine double bond adopts an E conformation. The molecular structure is stabilized by intramolecular O—H⋯N and N—H⋯O hydrogen bonds, generating S6 ring motifs. In the crystal, molecules are linked into a three-dimensional network by O—H⋯O hydrogen bonds.
In the title compound, C29H21O3P, a coumarin-substitued ylid, the P atom is linked to three benzene rings and a planar coumarin moiety via a methylenecarbonyl group. The bond lengths in the P=C–C=O fragment clearly indicate a delocalized system involving the olefinic and carbonyl bonds. The molecular structure is stabilized by an intramolecular C—H⋯O interaction that results in an S7 graph-set ring motif. In the crystal, molecules are linked into a three-dimensional framework by C—H⋯O hydrogen bonds.
The molecule of the title compound, C16H16N2O4, adopts an E conformation about the azomethine C=N double bond. The dihedral angle formed by the benzene rings is 18.88 (9)°. The molecular conformation is stabilized by an intramolecular O—H⋯N hydrogen bond, which forms an S(6) ring. In the crystal, the molecules are linked into chains parallel to  by N—H⋯O hydrogen bonds. The chains are further connected into a three-dimensional network by π–π stacking interactions with centroid–centroid distances of 3.6538 (10) and 3.8995 (11) Å.
The title compound, C15H14N2O4 adopts an E conformation about the azomethine double bond. Intramolecular N—H⋯O and O—H⋯N hydrogen bonds generate S(6) rings and help to establish the molecular conformation. The dihedral angle between the benzene rings is 17.84 (10)°. In the crystal, molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds into a two-dimensional network with a herring-bone pattern arranged parallel to the bc plane.
The title compound, C15H14N2O5·CH3OH, displays an E conformation about the azomethine double bond [C=N = 1.277 (2) Å] and the benzene rings are inclined to one another by 18.28 (9)°. An intramolecular O—H⋯O hydrogen bond occurs between the para-OH group and one of the meta-O atoms of the 3,4,5-trihydroxybenzylidene group. In the crystal, the components are linked into a three dimensional network by O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds.
In the title compound, C14H13N3O2·H2O, the azomethine double bond adopts an E conformation and the N—N=C—C torsion angle is 178.37 (19)°. The dihedral angle between the benzene and pyridine rings is 5.58 (12)° and the C atom of the methoxy group is roughly coplanar with its attached ring [deviation = 0.157 (3) Å]. In the crystal, the components are linked by O—H⋯O, O—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds, forming (001) sheets. The water O atom accepts one N—H⋯O and two C—H⋯O interactions from the adjacent organic molecule.
In the title compound, C17H18N2O4, the azomethine double bond adopts an E conformation with an N—N—C—C torsion angle of −178.3 (3)°. The benzene rings are almost coplaner, with a dihedral angle of 2.98 (14)° between their mean planes. In the crystal, the molecules are linked by N—H⋯O hydrogen bonds, resulting in chains of molecules lying parallel to the b axis. The structure is further consolidated by rather weak C—H⋯O hydrogen-bonding interactions, resulting in six-membered rings about inversion centers linked into chains arranged parallel to the b axis.
In the title compound, C19H20N2O6, the azomethine [C=N = 1.269 (2) Å] double bond adopts an E conformation and the dihedral angle between the planes of the benzene rings is 17.41 (11)°. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R
2(16) loops. The dimers are connected by C—H⋯O and C—H⋯N hydrogen bonds, forming sheets lying parallel to (100).
This study was aimed to isolate and evaluate neuroprotective compounds from the hexane extract of the bark of Mesua kunstleri (Clusiaceae) on H2O2-induced apoptosis in NG108-15 cells. Five 4-phenylcoumarins were isolated by using various chromatographic techniques via neuroprotective activity-guided fractionation and isolation from the active hexane extract. The chemical structures of the isolated compounds were confirmed by NMR spectroscopic data interpretation and comparison with literature values. Cell viability data demonstrated that mesuagenin C 3 significantly increased cell viability. Hoechst 33342/PI staining illustrated mesuagenin C 3 was able to abate the nuclear shrinkage, chromatin condensation and formation of apoptotic bodies. Pretreatment with mesuagenin C 3 reduced total annexin V positive cells and increased the level of intracellular glutathione (GSH). Mesuagenin C 3 attenuated membrane potential (Δψm), reduced Bax/Bcl-2 ratio and inactivated of caspase-3/7 and -9. These results indicated that mesuagenin C 3 could protect NG108-15 cells against H2O2-induced apoptosis by increasing intracellular GSH level, aggrandizing Δψm, and modulating apoptotic signalling pathway through Bcl-2 family and caspase-3/7 and -9. These findings confirmed the involvement of intrinsic apoptotic pathway in H2O2-induced apoptosis and suggested that mesuagenin C 3 may have potential therapeutic properties for neurodegenerative diseases.
The title co-crystal, C30H34O5·C30H34O5, comprises a 1:1 mixture of two mostly superimposed molecules with the same chemical formula that differ in the nature of the substituent (2-methylbutanoyl or 3-methylbutanoyl) bound at the exocyclic ketone. The lactone ring is close to planar (r.m.s. deviation = 0.058 Å) and the phenyl ring is twisted out of this plane [dihedral angle = 60.08 (9)°]. The geranyl substituent is almost normal to benzene ring to which it is connected [C—C—Car—Car (ar = aromatic) torsion angle = −87.8 (2)°]. Intramolecular O—H⋯O and O—H⋯π interactions are formed. In the crystal, supramolecular chains are formed along the a axis owing to C—H⋯O contacts, with the lactone carbonyl atom accepting two such bonds.
The non-H atoms of the title compound, C16H12O3, lie approximately in a common plane (r.m.s. deviation = 0.032 Å). The methyl C atom is forced away from the carbonyl O atom which can be seen by the widened Cfused ring–Cbenzene–Cmethyl angle of 125.8 (2)°.
The title pentacyclic oxindole alkadoid, isolated from Uncaria longiflora, crystallizes as a methanol solvate, C20H22N2O4·CH4O. The five-membered ring comprising the indole fused ring is nearly planar [maximum atomic deviation = 0.031 (2) Å], whereas the five-membered ring having alphatic C atoms adopts an envelope shape (with the tertiary N atom representing the flap). The six-membered ring that shares an N atom with the envelope-shaped ring adopts a chair shape; the six-membered ring having an O atom is sofa-shaped. The carboxylic acid group acts as a hydrogen-bond donor to a methanol molecule; this, in turn, acts as a hydrogen-bond donor to the double-bond carboxyl O atom of an adjacent molecule, generating a chain. Adjacent chains are linked by N—H⋯O hydrogen bonds, forming a layer motif.
The asymmetric unit of the title compound, C19H12O5, contains two independent molecules, both slightly buckled along an axis passing through the C=O bonds of the anthraquinone ring system (r.m.s. deviation of non-H atoms = 0.082 and 0.148 Å): the benzene rings are twisted to each other by 4.3 (3)°in one molecule and 10.6(3)° in the other. In both molecules, the hydroxy group forms an intramolecular O—H⋯O hydrogen bond. The two independent molecules interact by π–π stacking with a centroid–centroid distance of 3.539 (2) Å between hydroxybenzene rings of adjacent molecules.
The title compound, C16H12O5, common name: lucidin ω-methyl ether, exists as a planar molecule (r.m.s. deviation = 0.04 Å). Within the molecule, the 1-hydroxy group forms a hydrogen bond to the adjacent carbonyl O atom, and the 3-hydroxy group forms a hydrogen bond to the adjacent methoxy O atom. The methoxy O atom is disordered over two positions of equal occupancy.
The title compound, C16H12O4, exists as planar molecules in the solid state (r.m.s. deviation of 0.02 Å in one molecule and 0.07 Å in the second independent molecule comprising the asymmetric unit). In each molecule, the 1-hydroxy group forms an intramolecular hydrogen bond to the adjacent carbonyl O atom.
The molecule of the title compound, C15H8O4, is approximately planar. An intramolecular O—H⋯O hydrogen bond is observed between the hydroxy and formyl groups. The crystal used was a nonmerohedral twin, with a minor twin component of 15.9%.
The title compound, C15H8O5, also known as nordamnacanthal, was isolated from the Malaysian Morinda citrifolia L. The 20 non-H atoms are coplanar. The structure is stabilized by intramolecular O—H⋯O hydrogen bonds and intermolecular O—H⋯O and C—H⋯O hydrogen bonds, forming bilayers of molecular tapes with alternating stacking directions along the a axis.