Nickel(II) complexes of new polydentate carboxyamide: spectroscopic, kinetics of thermal decomposition and X-ray powder diffraction studies

Structure elucidation, protein profile and the antitumor effect of the biological active substance extracted from sea cucumber Holothuria polii

Holothuria polii (Delle Chiaje, 1823) (Holothuriidae) is a sea cucumber inhabiting Mediterranean Sea coast of Egypt. The bioactive compound of its tegument has antifungal, antibacterial and antiparasitic effects. The present study aims to elucidate the structure of the bioactive material of H. polii for pharmacological and chemotaxonomic purposes. Furthermore, the study demonstrates its efficacy as a cytotoxic agents against two tumor cell lines HCT116 (colon adenocarcinoma cell line) and MCF7 (breast adenocarcinoma cell line). The biological active compound of the ethanol extract has been characterized by means of infrared (IR), proton-nuclear magnetic resonance ((1)H NMR), ultraviolet-visible (UV-Vis) and mass spectra. Protein profile was carried out using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Cytotoxic activity was carried out according to sulforhodamine-B assay. IR, (1)H NMR, UV-Vis and mass spectra showed that the extracted bioactive material is a nonsulfated hexaosides called bivittoside. This glycoside is composed of aglycone and a glycosidic chain (carbohydrate chain) enclosed with six sugar units, including xylose, glucose, 3-O-methylglucose and quinovose. There were no traces of dissolved proteins. The preliminary cytotoxic assay of bivittoside exhibited significant cytotoxic activity against two types of cultured tumor cell lines of HCT116 and MCF7. The half-maximal inhibitory concentration was 17.4 µg/ml and 18 µg/ml for MCF7 and HCT116, respectively. Although H. polii belongs to the genus Holothuria, the lacking of sulfate group and the fact that it contains up to six monosaccharides make it different from this genus. The present study suggests separation of H. polii from its genus to a new one. On the other hand, results support the hypothesis that H. polii bioactive compound has an antitumor effect.

Copper(II) complexes with bioactive carboxyamide: synthesis, characterization and biological activity

Complexes of Cu(II) with bioactive carboxyamide ligands N',N''-bis(3-carboxy-1-oxoprop-2-enyl)2-amino-N-arylbenzamidine, N',N''-bis(3-carboxy-1-oxopropanyl)2-amino-N-arylbenzamidine and N',N''-bis(3-carboxy-1-oxophenelenyl)2-amino-N-arylbenzamidine have been synthesized and characterized by various physico-chemical techniques. Mass spectrum explains the successive degradation of the molecular species in solution and justifies ML complexes. Vibrational spectra indicate coordination of amide and carboxylate oxygen of the ligands along with water molecules. Electronic spectra and magnetic susceptibility measurements reveal octahedral geometry for Cu(II) complexes. The EPR of the reported complex show g( parallel)>g( perpendicular)>2.0023 and G value within the range 2.08-4.49 are consistent with d(x2-y2) ground state in an octahedral geometry. The voltammogram of the copper(II) complex shows a quasi-reversible redox process and a simple one electron process assignable to the Cu(II)/Cu(I) couple. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redfern method, which confirm first order kinetics. The bio-efficacy of the ligands and its copper complexes have been examined against the growth of bacteria and pathogenic fungi in vitro to evaluate their antimicrobial potential. The results indicate that the ligand and its metal complexes possess notable antimicrobial properties.