Synthesis, Characterization and Antioxidant Activity of Some Transition Metal Complexes With Terpenoid Derivatives

Abstract

A series of transition metal complexes of Fe(III), Co(II) and Cu(II) containing the bidentate N,O and N,S donor ligand, camphor semicarbazone (1,7,7-trimethylbicyclo [2,2,1]heptanesemicarbazone, TBHSC) and camphor thiosemicarbazone (1,7,7-trimethylbicyclo (1:2). The free radical scavenging activity of newly synthesized ligands (TBHSC, TBHTSC) and their metal complexes have been determined at the concentration range of 50-1000 µg/ml by means of their interaction with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). All the compounds have shown encouraging antioxidant activities. The least IC 50 value (111.0 µg/ml) for compound (5) showed the potent scavenging property compared to other test compounds.

Spectroscopic Characterization,In VitroCytotoxicity, and Antioxidant Activity of Mixed Ligand Palladium(II) Chloride Complexes Bearing Nucleobases

“…The increased antioxidant activity of these complexes can be attributed to the downfield shift of the 1 H-NMR signals ( Table 3). As reported [12,13], this phenomenon is as a result of the electron withdrawing effect of the Pd(II) ion which facilitates the release of hydrogen to reduce the DPPH radical. These proton shifts were very profound in cis-[PdCl 2 (Ad)(Gua)] with the H-1 proton of guanine absorbing at a chemical shift of 14.06 ppm.…”

“…In view of the strong electron withdrawing ability of these metal ions, there is a drift of electron density onto the metal centre and in effect ligand hydrogens are easily lost in the presence of a free radical. This makes these metal complexes act as better antioxidants as compared to the free ligand [12,13].…”

“…From Table 4, cis-[PdCl 2 (Ad)(Gua)] was the most cytotoxic against both cell lines with IC 50 values of 11.45 ± 2.91 and 8.31 ± 1.44 M on the respective cell lines. It was more cytotoxic than the positive control (curcumin) [12,13,46]. This assay is based on the measurement of the decrease in molar absorptivity of DPPH at 517 nm after reaction with the test compound.…”

“…An effective antioxidant, however, should be able to terminate the attack of reactive species like free radicals and prevent them from attacking body cells. The antioxidant activity of a synthetic compound can be measured using the scavenging ability of that compound to trap free radicals [13]. Although some palladium(II) complexes of pyrimidine and pyridine derivatives have been synthesized and characterized [1,29], not much has been reported about the antioxidant activity as well as the in vitro cytotoxicity of these complexes.…”

Antioxidant Effects of Muehlenbeckia Hastulata J. (Polygonaceae) Extracts

“…The importance of natural product in medicine, is not based only on their pharmacological or chemotherapeutic effects, but they offer the possibility to develop the new drugs structures 1,3 . Thus, phytochemicals and biochemistry of medicinal plant are of particular interest to many scientists, since they are widely used as nutrients, and the role they can play in the fight against diseases of the modern age (malignant tumors, cardiovascular disease, diabetes, rheumatism, Alzheimer's disease) and aging processes, are often connected with oxidative stress, reactive oxygen species (ROS) and lipid peroxidation (LP) [2][3][4][5][6][7][8] . A reactive oxygen species is effectively eliminated with the help of antioxidant compounds within which polyphenols are included 10 .…”