Transition metal complexes of symmetrical and asymmetrical Schiff bases as antibacterial, antifungal, antioxidant, and anticancer agents: progress and prospects

2015 ◽  
Vol 35 (4) ◽  
pp. 191-224 ◽  
Author(s):  
Ikechukwu P. Ejidike ◽  
Peter A. Ajibade

AbstractThe huge research on Schiff base coordination complexes in the past few decades has given rise to several new molecules that have been of biological importance. The ease with which the Schiff base ligands are designed and prepared and their pattern is elucidated have made them to be referred to as “fortunate ligands” possessing azomethine derivatives, the C=N linkage that is essential for biological activity, including antibacterial, antifungal, antioxidant, anticancer, and diuretic activities. A variety of Schiff base and its complexes have been studied as model molecules for biological oxygen carrier systems. The uses of Schiff bases as DNA-cleaving agents and its mode of interaction and free-radical scavenging properties are described. The review encapsulates the applications of Schiff bases and their complexes.

2016 ◽  
Author(s):  
Elżbieta Hejchman ◽  
Barbara Sowirka ◽  
Magdalena Tomczyk ◽  
Dorota Maciejewska

Based on World Health Organization (WHO) report, it was estimated that one in five people before age 75 will suffer from cancer during their lifetime, and more than 13 million cancers death will happen in 2030. Chemotherapy is a basic approach for the treatment of cancer diseases. However, because of drug resistance and considerable side effects drug-induced toxicity, the discovery of new metal analogs with promising activity and high therapeutic index is an urgent need. The fundamental role of copper and the recognition of its complexes as important bioactive compounds in vitro and in vivo aroused an ever-increasing interest in these agents as potential drugs for therapeutic intervention in various diseases. Schiff bases are a critical class of compounds in medical chemistry that have demonstrated significant chemotherapeutic and antibacterial application. Schiff base Cu(II) complexes revealed great potential for antiproliferative, antibacterial, and gastroprotective activity. Coumarins are a wide class of natural and synthetic compounds that showed diverse pharmacological activities including anticancer activity. Among the wide variety of coumarins, 7-hydroxycoumarin derivatives have been shown to possess desirable antiproliferative activities. In particular, their antibacterial, antifungal and anticancer activities make the compounds attractive for further derivatization and screening as novel therapeutic agents. Taking these compounds as lead, we have designed and synthesized a series of new copper(II) complexes with coumarin-derived Schiff base ligands. Two series of Schiff bases were prepared by condensation of 8-formyl-7-hydroxy-4-methylcoumarin and 8-acetyl-7-hydroxy-4-methylcoumarin with p-substituted aniline derivatives. These compounds were used as ligands in the synthesis of copper(II) complexes. The obtained Schiff bases as well as copper complexes are mostly novel molecules. Only the products of condensation 8-formyl-7-hydroxy-4-methylcoumarin with p-toluidine and 8-acetyl-7-hydroxy-4-methylcoumarin with p-toluidine and its copper(II) complex were synthesized, but the anticancer activity of these compounds was not determined. The assay of their cytotoxic activity is in progress. Preliminary, we have identified two copper(II) coordination compounds of 7-hydroxy-8-[1-(4-methoxyphenyl imino)ethyl]-4-methyl-2H-chromen-2-one and 7-hydroxy-8-[1-(4-hydroxyphenyloimino)ethyl]-4-methyl-2H- chromen-2-one having dose-dependent antiproliferative activity on HeLa cancer cell line. Additionally, the Schiff bases – derivatives of substituted salicylaldehydes and 2-hydroxyacetophenones condensed with appropriate anilines were prepared. Such compounds have been reported in scientific papers, their copper complexes have not been assayed yet, and may serve as an useful tool in QSAR investigation.


2016 ◽  
Author(s):  
Elżbieta Hejchman ◽  
Barbara Sowirka ◽  
Magdalena Tomczyk ◽  
Dorota Maciejewska

Based on World Health Organization (WHO) report, it was estimated that one in five people before age 75 will suffer from cancer during their lifetime, and more than 13 million cancers death will happen in 2030. Chemotherapy is a basic approach for the treatment of cancer diseases. However, because of drug resistance and considerable side effects drug-induced toxicity, the discovery of new metal analogs with promising activity and high therapeutic index is an urgent need. The fundamental role of copper and the recognition of its complexes as important bioactive compounds in vitro and in vivo aroused an ever-increasing interest in these agents as potential drugs for therapeutic intervention in various diseases. Schiff bases are a critical class of compounds in medical chemistry that have demonstrated significant chemotherapeutic and antibacterial application. Schiff base Cu(II) complexes revealed great potential for antiproliferative, antibacterial, and gastroprotective activity. Coumarins are a wide class of natural and synthetic compounds that showed diverse pharmacological activities including anticancer activity. Among the wide variety of coumarins, 7-hydroxycoumarin derivatives have been shown to possess desirable antiproliferative activities. In particular, their antibacterial, antifungal and anticancer activities make the compounds attractive for further derivatization and screening as novel therapeutic agents. Taking these compounds as lead, we have designed and synthesized a series of new copper(II) complexes with coumarin-derived Schiff base ligands. Two series of Schiff bases were prepared by condensation of 8-formyl-7-hydroxy-4-methylcoumarin and 8-acetyl-7-hydroxy-4-methylcoumarin with p-substituted aniline derivatives. These compounds were used as ligands in the synthesis of copper(II) complexes. The obtained Schiff bases as well as copper complexes are mostly novel molecules. Only the products of condensation 8-formyl-7-hydroxy-4-methylcoumarin with p-toluidine and 8-acetyl-7-hydroxy-4-methylcoumarin with p-toluidine and its copper(II) complex were synthesized, but the anticancer activity of these compounds was not determined. The assay of their cytotoxic activity is in progress. Preliminary, we have identified two copper(II) coordination compounds of 7-hydroxy-8-[1-(4-methoxyphenyl imino)ethyl]-4-methyl-2H-chromen-2-one and 7-hydroxy-8-[1-(4-hydroxyphenyloimino)ethyl]-4-methyl-2H- chromen-2-one having dose-dependent antiproliferative activity on HeLa cancer cell line. Additionally, the Schiff bases – derivatives of substituted salicylaldehydes and 2-hydroxyacetophenones condensed with appropriate anilines were prepared. Such compounds have been reported in scientific papers, their copper complexes have not been assayed yet, and may serve as an useful tool in QSAR investigation.


2016 ◽  
Vol 81 (10) ◽  
pp. 1111-1119 ◽  
Author(s):  
Fatemeh Bagheri ◽  
Abolfazl Olyaei

A novel method was developed for synthesizing a series of new three dentate Schiff base ligands starting from hydroxynaphthalidene pyrimidinyl amines with o-phenylenediamines or o-aminophenol or 2-amino-3-hydroxy-pyri-dine in the presence of formic acid catalyst under solvent-free conditions. In these reactions [1+1] condensation product as half-unit ligand was obtained. Moreover, the reaction of hydroxynaphthalidene pyrimidinyl amines with 3,4-diamino-pyridine and 1,8-naphthalenediamine lead to the formation of C2-naphthylated imidazopyridine and dihydropyrimidine, respectively. The attractive features of this protocol are: use of inexpensive catalyst, operationally simple, short reaction times, easy handling, and good yields.


2018 ◽  
Vol 42 (6) ◽  
pp. 4646-4652 ◽  
Author(s):  
Hua Zhang ◽  
Junyang Xing ◽  
Yanhong Dong ◽  
Shangqing Xie ◽  
Shishuai Ren ◽  
...  

The sp2 C–H bond activation of the HCN moiety in diphenylphosphino benzalimines was realized using CoMe(PMe3)4 with the elimination of methane.


2019 ◽  
Vol 48 (33) ◽  
pp. 12496-12511 ◽  
Author(s):  
G. Kalaiarasi ◽  
S. Dharani ◽  
V. M. Lynch ◽  
R. Prabhakaran

Three tetranuclear (1–3) complexes and a mononuclear (4) palladium(ii) complex were synthesized from 3-acetyl-chromen-2-one Schiff base ligands [H2-3MAC-Rtsc] (where R = H; CH3; C2H5[H2-3MAC-etsc] or C6H5) and potassium tetrachloropalladate.


1999 ◽  
Vol 77 (12) ◽  
pp. 2095-2098 ◽  
Author(s):  
Simon J Coles ◽  
Michael B Hursthouse ◽  
David G Kelly ◽  
Andrew J Toner ◽  
Neil M Walker

TiBz4 reacts with N-2-fluorenyl(salicylideneimine) to afford a crystallographically characterized titanium(IV) complex containing two conventional bidentate Schiff base ligands and two O-bound ligands in which the imine function has been reduced by the addition of benzyl and hydrogen moieties.Key words: insertion, nucleophilic additions, Schiff bases, titanium


2015 ◽  
Vol 51 ◽  
pp. S17-S18
Author(s):  
R. Alexandrova ◽  
T. Zhivkova ◽  
A. Abudalleh ◽  
L. Dyakova ◽  
D. Dinev ◽  
...  

1988 ◽  
Vol 43 (5) ◽  
pp. 611-615 ◽  
Author(s):  
T. Sogo ◽  
J. Romero ◽  
A. Sousa ◽  
A. de Blas ◽  
M. L. Durán ◽  
...  

Abstract The electrochemical synthesis and physico-chemical properties of neutral zinc(II) complexes of bidentate Schiff bases derived from salicylaldehydes are presented together with the X-ray structure of bis[N-(4-methylphenyl)salicylaldiminato]zinc(II). The crystal is monoclinic, a = 21.877(3), b = 8.801(2), c = 12.027(5) Å, β = 96.55(3)°, space group C2/c. The complex is a monomer, and the zinc atom is tetrahedrally coordinated.


1973 ◽  
Vol 26 (7) ◽  
pp. 1459 ◽  
Author(s):  
WW Fee ◽  
JD Pulsford ◽  
PD Vowles

The kinetics of copper(II)-promoted solvolyses of two series of nickel(II) complexes containing polydentate Schiff bases with various remote substituents, in dimethyl sulphoxide (dmso), are discussed from the viewpoints of rate constants and of enthalpies and entropies of activation. Appearance of an isokinetic relation for the tridentate (ONS donors) reactants may indicate a common mechanism operative within this reactant series. Rate constants appear related to σp values in such a way that a dissociative mechanism appears important for the tridentate reactants, while characterization in terms of associative behaviour is indicated for the tetradentates.


2019 ◽  
Vol 19 (13) ◽  
pp. 1060-1067 ◽  
Author(s):  
Arokia V.A. Mariadoss ◽  
Ramachandran Vinyagam ◽  
Vinothkumar Rajamanickam ◽  
Vijayalakshmi Sankaran ◽  
Sathish Venkatesan ◽  
...  

Over the past two decades, many researchers have concluded that a diet rich in polyphenolic compounds plays an important therapeutic role in reducing the risk of cancer, cardiovascular disease, inflammation, diabetes, and other degenerative diseases. Polyphenolic compounds have been reported to be involved in neutralization of reactive oxygen species and charged radicals, and have anticarcinogenic effects, hepatoprotective effects, low-glycaemic response, and other benefits. The benefits of fruits and vegetables may be partly attributable to polyphenolic compounds, which have antioxidant and free radical scavenging properties. Fruits such as apples contain a variety of phytochemicals, including (+)-catechin and (-)-epicatechin, phlorizin, phloretin quercetin, cyanidin-3-Ogalactoside, chlorogenic acid, and p-coumaric acid, all of which are strong antioxidants. Phloretin, a natural phenolic compound, is a dihydrochalcone, which is present in the apple. It exhibits a wide variety of activities such as antioxidative, anti-inflammatory, anti-microbial, anti-allergic, anticarcinogenic, anti-thrombotic, and hepatoprotective, besides being involved in the activation of apoptotic associated gene expression and signal transduction in molecular pathways. Despite a multitude of clinical studies, new efforts are needed in clinical research to determine the complete therapeutic potential of phloretin.


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