Synthesis, spectral characterization and in vitro microbiological evaluation of novel glyoxal, biacetyl and benzil bis-hydrazone macrocyclic Schiff bases and their Co(II), Ni(II) and Cu(II) complexes

A series of binuclear Co(II), Ni(II) and Cu(II) complexes were synthesized by the template condensation of glyoxal, biacetyl or benzil bis-hydrazide, 2,6-diformyl-4-methylphenol and Co(II), Ni(II) or Cu(II) chloride in a 2:2:2 M ratio in ethanol. These 22-membered macrocyclic complexes were characterized by elemental analyses, magnetic, molar conductance, spectral, thermal and fluorescence studies. Elemental analyses suggest the complexes have a 2:1 stoichiometry of the type M2LX2·nH2O and Ni2LX22H2O·nH2O (where M = Co(II) and Cu(II); L = H2L1, H2L 2 and H2L3; X = Cl; n = 2). From the spectroscopic and magnetic studies, it has been concluded that the Co(II) and Cu(II) complexes display a five coordinated square pyramidal geometry and the Ni(II) complexes have a six coordinated octahedral geometry. The Schiff bases and their metal complexes have also been screened for their antibacterial and antifungal activities by the MIC method. © 2011 Elsevier Ltd. All rights reserved

New glycosidic constituents from fruits of Lycium chinense and their antioxidant activities

Potential biologically active new constituents labd-3β, 9β-diol-3α-d-glucopyranosyl-(2a → 1b)-α-d-glucopyranosyl-(2b → 1c)-α-d-glucopyranosyl-(2c → 1d)-α-d-arabinofuranosyl-2d-p-hydroxybenzoate (1) and α-d-glucuronopyranosyl (2 → 1′)-α-d-glucuronopyranosyl (2′ → 1″)-α-d-glucopyranosyl-2″-n-octadec-9‴-enoate (2) along with β-sitosterol-β-d-glucoside were isolated from the fruits of Lycium chinense. Their chemical structures were elucidated using detailed spectroscopic studies. The structure assignments are based on two-dimensional (2D)-NMR techniques including COSY, HSQC, HMBC and NOESY experiments. Compounds 1 and 2 were evaluated for antioxidant activities with three assay protocols such as diphenylpicrylhydrazyl (DPPH) radical scavenging activity, reducing power and the phosphomolybdenum activity, compound 2 showed more potential as compared with 1