X-ray crystallographic structures of two lamotrigine analogues: (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine water solvate and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine methanol solvate

The X-ray crystal structures of two lamotrigine derivatives (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine, C9H8ClN5, (465BL) as a hydrate, and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine, C9H7Cl2N5, (469BR) as a methanol solvate, have been carried out at liquid nitrogen temperature and room temperature, respectively. A detailed comparison of the two structures is given. Both are centrosymmetric with (I) in the orthorhombic space group Pbca, a = 12.2507(3), b = 15.7160(6), c = 21.71496(9) angstrom, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) angstrom, beta = 111.59(1)degrees, Z = 8. Final R indices [I > 2sigma(I)] for (I) are R1 = 0.0670, wR2 = 0.1515 and for (II) R1 = 0.0434, wR2 = 0.1185. Structure (I) has water of crystallization in the lattice and (II) includes a solvated CH3OH. Structure (I) is characterized by having two crystallographically independent molecules, A and B, of 465BL, per asymmetric unit. Molecule B has a very unusual feature in that the 2-chlorophenyl ring is statistically disordered, occupying site (1) in 87.5% of the structure and site (2) in 12.5% of the structure. Sites (1) and (2) are related by an exact 180 degrees pivot of the phenyl ring about the ring linkage bond. The presence of two independent molecules per asymmetric unit provides an ideal opportunity for the conformational flexibility of the molecule 465BL to be studied. Structure (I) also includes a further unusual feature in that the lattice contains one fully occupied water molecule and an additional solvated water which is only 33% occupied.

Antioxidant and cytoprotective activity of leaves of Peltiphyllum peltatum (Torr.) Engl.

The antioxidant potential of fresh leaves of Peltiphyllum peltatum (Torr.) Engl. (Saxfragaceae) was analysed by measuring scavenging potential against l,l'-diphenyl-2-picrylhydrazyl (DPPH center dot) and hydroxyl radicals (W), reducing power, inhibition of lipid peroxidation and protection of cultured cells from a lethal dose of hydrogen peroxide (H2O2). In all chemical assays used, the crude ethanolic extract of leaves of P. peltatum, which contained 21.8 +/- 1.7% (w/w, n = 3) of total phenols, was as effective as the standard antioxidant compound, rutin. Fractionation of the crude extract with solvent of increasing polarity (namely, petroleum ether, chloroform, ethyl acetate, butanol and water) led to identification of the active fractions (ethyl acetate and butanol fractions). The crude extract and its active fractions, but not rutin, protected cultured RAW 264.7 macrophages from a lethal dose Of H2O2.