Solution Equilibrium Study of Divalent Metal Ions with Phenylpropanoid Derivatives and Acetylcysteine Ligands

Abstract

Solution equilibrium of divalent metal ions (M Mn21) Redox-inert metals such as mercury (Hg), lead (Pb) and cadmium (Cd) are toxic agents, exposure to these and other essential metals may cause negative effects on health.2) Metals are known to be able to bind with proteins in human body which may lead to various detrimental effects on human health. For instance, high exposure of zinc results in respiratory and gastrointestinal toxicity, clinical changes and copper deficiency.3) Excess amount of copper can cause serious diseases including cancers, liver and kidney damage.4) Cobalt exposure leads to ailment such as vision problem, lung problem, heart problem and thyroid damage. Exposure to manganese can cause disorders such as Parkinson, schizophrenia and dullness. Although nickel appears to be essential for plants and bacteria, however for human this metal was found to be difficult to elucidate and may cause severe health problems such as cancer. 5)Chelation therapy is known as an effective treatment to reduce the harmful effects of metal ions by utilizing the metal binding ability of organic ligand.6-10) Therefore to prevent metal intoxication, the ligand used should have stronger binding ability than the proteins. Phenylpropanoid derivatives, currently considered as promising chelating agents, are classified as phenolic acids that are known to function as natural antioxidant, free radical scavenger, anti-carcinogenic, and chemoprevention agent. [11][12][13][14] In this work, caffeic acid and dihydrocaffeic acid were chosen as the phenylpropanoid derivatives. Caffeic acid (denoted as ligand C) is an important anti-oxidative compound which can be extracted from natural sources such as coffee bean, potatoes, grains and vegetables. 15)This compound has beneficial pharmacological effects such as inhibit cancer cell in human HT-1080 fibro sarcoma cell line. 16,17) Dihydrocaffeic acid (denoted as ligand D) is a degradation product of caffeic acid, this compound is one of the critical phenolic antioxidants commonly present in olives, 18) and in blood or urine as the result of secondary metabolism of various polyphenols.19) The ortho-dihydroxyl structure of ligand D is also known to act as an active radical-scavenger. 15)On the other hand, acetylcysteine is an organic compound which has been approved as one of the essential medicines for basic health system by World Health Organization (WHO). 20)Acetylcysteine is known as a precursor for glutathione, the antioxidant which prevents formation of oxidative species in tissue. 21,22) . 22,24,25) The mixed ligand combination of acetylcysteine and ligands C or D is expected to improve the stability of the chelate complex.Recently, the complexation of ligands C and D with metal ion has gained attention of some researchers. [26][27][28][29][30] To the best of our knowledge, very few literatures are available for the complexation study of ligand D with essential divalent metal ions. Therefore, in order to gain primary understanding on the complexation of ligands C and D, potenti...

Complex formation constant of ferric ion with Gly, Pro-Hyp and Gly-Pro-Hyp

“…The Hyperquad 2008 program is more simple and accurate in determining the complex formation constant compared to several non-linear-square algorithm computer programs. 16 The refined formation constants of each complex species at different temperatures were introduced to the HySS2009 program. 20 HySS2009 was used to obtain the speciation diagrams that could be used to depict the distributions of various complex species in the observed pH ranges and at different temperatures.…”

“…The Hyperquad 2008 program is more simple and accurate in determining the complex formation constant compared to several non-linear-square algorithm computer programs. 16 The rened formation constants of each complex species at NaCl and 25 C (a), 37 C (b) and 40 C (c). Carbonate-free NaOH (0.1 mol dm À3 ) was used to titrate the solutions.…”

“…The complex formation was studied at three different temperatures, and the ionic strength was maintained with 0.15 mol dm À3 NaCl. 16,17 The three temperatures of 25 C, 37 C, and 40 C were chosen since they are the standard room temperature, normal body temperature, and fever temperature, respectively. The stabilities of the complexes were presented as the complex formation constants (log b).…”

Preparation of nanocrystalline cellulose-montmorillonite composite via thermal radiation for liquid-phase adsorption

“…1a, an inflection point is occurring at pH 5.0. This inflection point occurs when the mol base added is adequate to deprotonate H atom of the NCC [29,30]. Based on the structure of NCC, the deprotonation more likely occurred at the H atom of CH 2 OH group (C6, Fig.…”