Antioxidants in Plants: A Valorization Potential Emphasizing the Need for the Conservation of Plant Biodiversity in Cuba.

Plants are phytochemical hubs containing antioxidants, essential for normal plant functioning and adaptation to environmental cues and delivering beneficial properties for human health. Therefore, knowledge on the antioxidant potential of different plant species and their nutraceutical and pharmaceutical properties is of utmost importance. Exploring this scientific research field provides fundamental clues on (1) plant stress responses and their adaptive evolution to harsh environmental conditions and (2) (new) natural antioxidants with a functional versatility to prevent and treat human pathologies. These natural antioxidants can be valorized via plant-derived foods and products. Cuba contains an enormously rich plant biodiversity harboring a great antioxidant potential. Besides opening new avenues for the implementation of sustainable agroecological practices in crop production, it will also contribute to new strategies to preserve plant biodiversity and simultaneously improve nature management policies in Cuba. This review provides an overview on the beneficial properties of antioxidants for plant protection and human health and is directed to the valorization of these plant antioxidants, emphasizing the need for biodiversity conservation.

Development, larvicide activity, and toxicity in nontarget species of the Croton linearis Jacq essential oil nanoemulsion.

In this study, the essential oil (EO) from leaves of Croton linearis Jacq was extracted and characterized by GC/MS. The EO hydrophilic-lipophilic balance required (rHLB) for nanoemulsion (NE) development was determined by the Griffin' method. For evaluating the larvicidal effect against Aedes aegypti, the preparation process of NE was optimized, using a central composite design. It was also evaluated the possible toxic effect of NE in nontarget species. The leaves of C. linearis contain 1.50% of EO, enclosing 61 volatile compounds, mainly eucalyptol (26.66%). The best surfactant, oil:water ratio (4.5-5.0-91.5; % w:w:w), allows to achieve the optimal NE, using a stirring speed of 800 rpm, the addition rate of 0.5 ml/min, and a stirring time of 30 min. NE (with particle size = 163 nm) showed a larvicide effect (LC50 = 17.86 µg/mL) more potent than the whole EO (LC50 = 64.24 µg/mL). NE showed neither hemolytic effect nor cytotoxicity, and it was classified as a nontoxic product, according to the OECD class toxicity test (IC50 > 2000 mg/kg). This product arises in a new green bio-larvicide that could be used for mosquito control.

Poly[diamminedi-µ3-dicyanamido-copper(II)].

The asymmetric unit of the title polymeric mononuclear Cu(II) complex, [Cu(C2N3)2(NH3)2] n , contains one half-mol-ecule, the complex being completed through inversion symmetry, with the Cu(II) atom situated on the centre of symmetry. The coordination polyhedron around Cu(II) is a Jahn-Teller-distorted [CuN6] octa-hedron. The terminal N atoms of two dicyanamide ligands and two ammine ligands form an approximate square plane, with N-Cu-N bite angles of 89.72 (5) and 90.28 (5)°. The coordination polyhedron is completed in the axial positions by the central amide-type N atoms of two additional dicyanamide ligands, with an elongated Cu-N distance of 2.548 (1) Å. In turn, each of the four dicyanamide ligands, acting as bidentate, link the Cu(II) ions into a two-dimensional polymeric structure parallel to (100). The ammine H atoms are involved in inter-molecular hydrogen bonding with the free terminal N atoms of neighbouring dicyanamide ligands, yielding a three-dimensional network.

Disodium tetra-aqua-bis(sulfato)iron(II).

In the title compound, [FeNa(2)(SO(4))(2)(H(2)O)(4)], the Fe(2+) cation is situated on a centre of inversion and is hexa-coordinated by four O atoms from water mol-ecules and two O atoms from two sulfate anions in an octa-hedral geometry. The coordination environment of Na(+) comprises six O atoms in a more distorted octa-hedral arrangement, with Na-O distances between 2.368 (1) and 2.612 (1) Å. The structure contains an extensive three-dimensional network of O-H⋯O hydrogen bonds.

Pseudo-merohedrally twinned tetrakis(1H-imidazole-kappaN3)bis(N-nitrocyanamidato-kappaN)copper(II).

Crystals of the title complex, [Cu(CN3O2)2(C3H4N2)4], the structure of which has been determined by single-crystal X-ray diffraction at 304 K, appear to be pseudo-merohedrally twinned. Transformation to a monoclinic C-centred cell was necessary in order to derive the twin law. Twin refinement in a triclinic unit cell significantly reduced the R value. The asymmetric unit of the triclinic cell consists of one molecule in a general position and two half entities with the Cu atom on a centre of inversion. The coordination of the Cu atom is quasi-octahedral, with four imidazole N-atom donors in the equatorial plane and two cyano N atoms from the N-nitrocyanamidate anion in axial positions. Owing to symmetry in the centrosymmetric molecules, the trans imidazole ligands are parallel, while those in the non-centrosymmetric molecule make angles of 22.8 (2) and 77.9 (2) degrees .