A Comprehensive View on (-)-7-Oxo-ent-kaur-16-en-19-oic Acid, the Major Constituent of Xylopia sericea Leaves Extract: Complete NMR Assignments, X-Ray Crystallographic Structure, in Vitro Antimalarial Activity and Cytotoxicity.

Bioguided fractionation of Xylopia sericea antiplasmodial dichloromethane leaves extract led to the isolation of (-)-7-oxo-ent-kaur-16-en-19-oic acid (C20 H28 O3 ) that was identified by a combination of 1D and 2D NMR experiments (COSY, HMBC, HSQC, HSQC-TOCSY, HSQC-NOESY and NOESY) and by X-ray crystallography. A feature to be pointed out is its (4R) configuration that was inferred from the NOE experiments (HSQC-NOESY and NOESY) and X-ray crystallography. In vitro evaluation of this rare diterpene acid against the chloroquine-resistant strain Plasmodium falciparum W2 by the PfLDH method showed it disclosed a low antiplasmodial activity and was not cytotoxic to HepG2 cells (CC50 862.6±6.7 µm) by the MTT assay. The unequivocal NMR signals assignments, the X-ray crystallographic structure, the assessment to the bioactivities and the occurrence this diterpene in X. sericea are reported here for the first time.

Two polymorphs of 2-(prop-2-yn-1-yl-oxy)naphthalene-1,4-dione: solvent-dependent crystallization.

The title compound, C13H8O3, crystallizes in two polymorphs, namely the monoclinic (space group P21/c) and triclinic (space group Pi) forms, obtained from N,N-di-methyl-formamide and isopropyl alcohol solutions, respectively. The mol-ecular structures and conformations in the two forms are essentially the same as each other. The naphtho-quinone ring systems are essentially planar with r.m.s. deviations of 0.015 and 0.029 Šfor the monoclinic and triclinic forms, respectively. The O-propargyl groups are coplanar with the naphtho-quinone units with r.m.s deviations ranging from 0.04 to 0.09 Å. In the monoclinic crystal, mol-ecules are linked via pairs of C-H⋯O hydrogen bonds, forming a tape structure running along [120]. The tapes are further linked by a C-H⋯π inter-action into a layer parallel to the ab plane. Adjacent layers are linked by another C-H⋯π inter-action. In the triclinic crystal, mol-ecules are linked via C-H⋯O and π-π inter-actions, forming a layer parallel to the ab plane. Adjacent layers are linked by a C-H⋯π inter-action.

Crystal structure of 4-nitro-phenyl 6-O-ethyl-ß-d-galacto-pyran-oside monohydrate.

The synthesis and crystal structure of the title compound, C14H19NO8·H2O, prepared in three steps from 6-O-ethyl-1,2;3,4-di-O-iso-propyl-idene-α-d-galacto-pyran-ose using protecting-group strategies employed in carbohydrate chemistry, is reported. The asymmetric unit consists of a single galactoside mol-ecule, in which the pyran-oid ring has a 4C1 conformation and the 4-nitro-phenyl moiety is essentially planar. In the crystal, each carbohydrate is surrounded by other d-galactose residues and water mol-ecules, linked by O-H⋯O hydrogen bonds involving all hy-droxy groups, giving a two-dimensional substructure lying parallel to (100) and extended into three dimensions by C-H⋯O inter-actions.

Nanoparticle phosphate-based composites as vehicles for antimony delivery to macrophages: possible use in leishmaniasis.

Pentavalent antimonial drugs such as N-methylglucamine antimonate (Glucantime®) are used for treating leishmaniasis but produce severe side effects, including cardiotoxicity and hepatotoxicity. We characterized the physicochemical properties of 3 nanoparticle phosphate-based composites (NPCs; NPC0, NPC3, and NPC5) as Sb(v) carriers for specifically targeting macrophages and reducing systemic side effects. NPCs were synthesized in liquid media and sterilized at 25 kGy before use. Macrophage viability and NPC toxicity, independent of Sb uptake, were evaluated to assess NPC safety in visceral leishmaniasis treatment. NPC zeta potential, conductivity, diameter, Sb content, and crystallinity were determined using electrophoretic light scattering, scanning electron microscopy (SEM), conductance, graphite furnace atomic absorption spectrometry (GFAAS), and X-ray diffraction, respectively. In vitro NPC cytotoxicity against murine peritoneal macrophages was evaluated using MTT assays, and Sb amounts internalized by macrophages were determined using GFAAS. The rate of macrophage infection caused by Leishmania infantum was assayed in vitro, by using Glucantime® as a reference drug. NPCs featured negative zeta potentials (-15.5 to -19.5 mV), mean diameters around 180 nm, and a low dissolution constant in Milli-Q water (<0.0197 mS cm-1), and were prepared using 0.0 (NPC0) to 36.2 µg mL-1 Sb (NPC5). NPC5 exhibited characteristic crystalline peaks resembling mopungite, but other NPCs exhibited predominantly amorphous structures. Cell viability was not markedly affected at any NPC concentration tested. Light microscopy, SEM, and GFAAS data revealed NPC internalization and intracellular Sb retention. Amastigote infection was reduced by both Sb-containing NPC3 and Sb-lacking NPC0, but NPC3 was more effective. These data indicate the potential of NPCs as Sb nanocarriers for specifically targeting macrophages and lowering Sb dosage without reducing leishmanicidal activity.