Potentiometric and Spectroscopic Studies on Aluminium(III) Complexes of Some Catechol Derivatives

Santoso

CHEMICAL & PHARMACEUTICAL BULLETIN

et al. 2016

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...

Section: Resultsmentioning

confidence: 96%

“…[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, potentiometry technique was conducted (at T=310.15 K and ionic strength I=0.15 mol·dm ).…”

Section: )mentioning

confidence: 99%

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

Santoso

CHEMICAL & PHARMACEUTICAL BULLETIN

et al. 2016

Front. Behav. Neurosci.

“…For example, the stimulation of NO-pathway decreases the effect of acute hypertension on BBB (Mayhan, 1995). Moreover, calcium signaling regulates tight junctions, as indirectly illustrated by the beneficial effects of dihydropyridine or PKC inhibitor treatments on hypertension related BBB damages (Turkel et al, 2004; Qi et al, 2008). In the same order of idea, antihypertensive AT1-R antagonists reduce the BBB alterations caused by acute hypertension in diabetic rat (Kaya et al, 2003).…”

Section: Blood Brain Barrier (Bbb) Cerebral Function and Gravitymentioning

confidence: 99%

Learning on Jupiter, learning on the Moon: the dark side of the G-force. Effects of gravity changes on neurovascular unit and modulation of learning and memory

Porte¹,

Morel²

2012

On earth, gravity vector conditions the development of all living beings by physically imposing an axis along which to build their organism. Thus, during their whole life, they have to fight against this force not only to maintain their architectural organization but also to coordinate the communication between organs and keep their physiology in a balanced steady-state. In space, astronauts show physiological, psychological, and cognitive deregulations, ranging from bone decalcification or decrease of musculature, to depressive-like disorders, and spatial disorientation. Nonetheless, they are confronted to a great amount of physical changes in their environment such as solar radiations, loss of light-dark cycle, lack of spatial landmarks, confinement, and obviously a dramatic decrease of gravity force. It is thus very hard to selectively discriminate the strict role of gravity level alterations on physiological, and particularly cerebral, dysfunction. To this purpose, it is important to design autonomous models and apparatuses for behavioral phenotyping utilizable under modified gravity environments. Our team actually aims at working on this area of research.

“…An approach toward better understanding of the HA-metal cation interactions is to use model compounds with well-known physicochemical properties. This approach, which has already provided important insight in the spectroscopic and structural properties of HA, consists in studying metal complexation of precursor compounds in the formation of soil organic matter [34][35][36][37][38][39][40][41][42][43]. The studied molecules are found essentially in the vegetable kingdom and consequently they present the same chemical functions as HA insofar as they are at the origin of its formation.…”

Section: Theoretical Determination Of Metal Binding Site In Multi-sitmentioning

confidence: 99%

Application of quantum chemical calculations to two non-trivial cases in the field of molecular spectroscopy

Lapouge

Cornard

2009

JCM

In this paper, we illustrate the contribution of the quantum chemical calculations to the simulation of two types of spectra. In a first part, the calculations of theoretical resonance Raman spectra of transient species are presented. The comparison of the theoretical and experimental spectra allows validating the methodology. From calculation results, the molecular structure and the spectra assignment of radicals have been deduced. In a second part, the TD-DFT methodology is applied to the determination of the preferential chelating site involved in the metal fixation by a ligand possessing several complexing functions in competition. We show that the use of UV-visible spectroscopy combined with quantum chemical calculations is well adapted to resolve the molecular structure of a complex. The reaction pathway calculations allow a better understanding of the regioselectivity of the complexation mechanism.