Spectroscopic and biological studies of new mononuclear metal complexes of a bidentate NN and NO hydrazone-oxime ligand derived from egonol.

A novel ligand, vicinal dioxime ligand (egonol-hydrazone glyoxime) (LH2) was synthesized and characterized using (1)H NMR, (13)C NMR, MS, AAS, infrared spectroscopy, and magnetic susceptibility measurements. Mononuclear nickel (II), copper (II) and cobalt (II) complexes with a metal:ligand ratio of 1:2 for LH2 were also synthesized. Zn(II) forms complex [Zn(LH)Cl2] with a metal to ligand ratio of 1:1. IR spectrum shows that the ligand act in a bidentate manner and coordinates N4 donor groups of the ligands to Ni(II), Cu(II), Co(II) and Zn(II) ions. The detection of H-bonding (OH⋯O) in the [M(LH)2] metal complexes by IR spectra supported the square-planar MN4 coordination of Ni(II), Cu(II) and Co(II) complexes. The antimicrobial activities of compounds LH2 and their Ni(II), Cu(II), Co(II) and Zn(II) complexes were evaluated using the disc diffusion method against 16 bacteria and 5 yeasts. The minimal inhibitory concentrations (MICs) against all the bacteria and yeasts were also determined. Among the attempted test compounds, it is showed that all the compounds (L, LH2, [Ni(LH)2], [Cu(LH)2], [Co(LH)2(H2O)2], [Zn(LH)Cl2]) were effective against used test microorganisms.

Synthesis, antimicrobial and cytotoxic activities, and structure-activity relationships of gypsogenin derivatives against human cancer cells.

A series of gypsogenin (1) derivatives (1a-i) was synthesized in good yields, and the derivatives' structures were established using UV, IR, (1)H NMR, (13)C NMR, and LCMS spectroscopic data. Among the tested compounds, 1a, 1b, 1d, 1e, and gypsogenin (1) showed antimicrobial activities against Bacillus subtilis and Bacillus thrungiensis, with inhibition zones of 10-14 mm. In addition, compounds 1b, 1d, and 1e showed antimicrobial activities against Bacillus cereus, with inhibition zones of 9-14 mm. Using six human cancer cell lines in vitro, the cytotoxic activities of all tested compounds were determined by calculating the IC50 values. Doxorubicin and paclitaxel were used as controls. Among the tested compounds, 1a, 1c, and 1d had inhibitory effects with IC50 values of 3.9 µM (HL-60 cells), 5.15 µM (MCF-7 cells), and 5.978 µM (HL-60), respectively. To determine the type of cell death, Hoechst 33258 (HO) and propidium iodide (PI) double staining was used. Especially, gypsogenin (1) and compound 1a triggered the apoptotic mechanism at a concentration of 20 µM. Thus, gypsogenin (1) and compounds 1a, 1c, and 1d possess varying degrees of biological activities and can be considered as potential antitumor agents.