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A new dicationic ring [(water)-(ammonium)] was found as a building block for a 3D supramolecular assembly of the compound [(CH)NCHNH](NH)[VO]·8HO, 1, where (CH)NCHNH = 4-( N, N-(dimethylamino)pyridinium) (DMAP). The title compound was synthesized and characterized by single crystal X-ray diffraction at 100 K, infrared spectroscopy and thermogravimetric analysis. Compound 1 crystallizes in space group P-1 in the triclinic system with cell parameters: a = 11.1296(4) Å, b = 11.4790(4) Å, c = 11.8691(4) Å, α = 109.631(1)°, β = 100.601(1)°, γ = 92.909(1)° and R( F) = 0.021. The three-dimensional supramolecular structure is driven by intermolecular hydrogen bonds O···H-N and O···H-O from decavanadate anion with NH and [(CH)NCHNH] cations, as well as those formed between water molecules and decavanadate ions. The embedded rings consist of two sets of water-water-water-ammonium chains joint together in a twisted chair conformation, in which water-ammonium pairs are at the top and bottom sites. The ring is hydrogen bond stabilized and represents to our knowledge, the first example of building block with this composition for a supramolecular structure to be reported. [ABSTRACT FROM AUTHOR]

Epaltes mexicana is a plant widely used in traditional medicine and as a food in Mexico; however, its phytochemical and pharmacological studies are limited. This study aimed to identify the active secondary metabolites of Epaltes mexicana and determine its cytotoxic activity on cancer cell lines. Three organic extracts were obtained by maceration using n -hexane, dichloromethane, and methanol. The n -hexane extract was fractioned by simple column chromatography. Eight terpenes were annotated in collection 6 (C6) by LC-QTOF-MS using a gradient elution and Electrospray Ionization (ESI) in positive ion mode: 1) Gibberellin A15, 2) farfugin A, 3) dehydromyodesmone, 4) eremopetasitenin A1, 5) hydroxyisonobilin, 6) anhydrocinnzeylanine, 7) nigakilactone H and 8) taxodione. On the other hand, C6 showed a concentration-dependent cytotoxic effect on cancer cell lines MCF-7 (E max = 74.69 ± 6.19 % and IC 50 = 6.31 μg/mL), MDA-MB-231 (E max = 79.28 ± 12.12 % and IC 50 = 124.21 μg/mL), and SiHa (E max = 82.96 ± 6.02 % and IC 50 = 124.31 μg/mL). The C6 did not show a cytotoxic effect against DU-145 and non-cancerous cells from the mammary glands MCF-10A. These results indicate cytotoxic specificity on cancer cell lines and support the hypothesis that terpenes identified in E. mexicana must be investigated and developed for non-clinical and clinical trials as potential anti-cancer drugs. [Display omitted] • Eight terpenes were annotated in the active collection of Epaltes mexicana. • Eight terpenes were found in positive ion mode by LC-QTOF-MS analysis. • The terpenes showed cytotoxic activity on MCF-7, MDA-MB-231 and SIHa. • E. mexicana showed selective cytotoxic activity in breast and cervical cancer cell lines. [ABSTRACT FROM AUTHOR]

The kinetics of cyclization of 2-hydroxypropyl p-nitrophenyl phosphate (1) promoted by two mononuclear Zn(II) catalytic complexes of bis(2-pyridylmethyl)benzylamine (4) and bis(2-methyl 6-pyridylmethyl)benzylamine (5) in methanol were studied under (s)(s)pH-controlled conditions (where (s)(s)pH refers to [H(+)] activity in methanol). Potentiometric titrations of the ligands in the absence and presence of Zn(2+) and a non-reactive model for 1 (2-hydroxylpropyl isopropyl phosphate (HPIPP, 6)) indicate that the phosphate is bound tightly to the 4:Zn(II) and 5:Zn(II) complexes as L:Zn(II):6(-), and that each of these undergoes an additional ionization to produce L:Zn(II):6(-):((-)OCH(3)) or a bound deprotonated form of the phosphate, L:Zn(II):6(2-). Kinetic studies as a function of [L:Zn(II)] indicate that the rate is linear in [L:Zn(II)] at concentrations well above those required for complete binding of the substrate. Plots of the second order rate constants (defined as the gradient of the rate constant vs. [complex] plot) vs. (s)(s)pH in methanol are bell-shaped with rate maxima of 23 dm mol(-1) s(-1) and 146 dm mol(-1) s(-1) for 4:Zn(II) and 5:Zn(II), respectively, at their (s)(s)pH maxima of 10.5 and 10. A mechanism is proposed that involves binding of one molecule of complex to the phosphate to yield a poorly reactive 1 : 1 complex, which associates with a second molecule of complex to produce a transient cooperative 2 : 1 complex within which the cyclization of 1 is rapid. The observations support an effect of the reduced polarity solvent that encourages the cooperative association of phosphate and two independent mononuclear complexes to give a reactive entity.