title: Complexes of arabinogalactan of Pereskia aculeata and Co2+, Cu2+, Mn2+, and Ni2+.
abstract: The main interest in the biopolymer arabinogalactan is that it is edible. Complementing its high protein percentage, when complexed to essential metal ions, widens the use in food and pharmacology industries and technologies. The binding constants of Co2+, Cu2+, Mn2+ and Ni2+ with arabinogalactan, extracted from the leaves of Pereskia aculeata from Brazil were determined by potentiometric titrations and also the speciation according to pH values. The complexed species proposed by potentiometric titrations and the unique complexing ability of galacturonic acid groups towards Cu2+ and Ni2+ in the tridimensional web structure of arabinogalactan were confirmed by IR and EPR spectroscopies. The thermal stability of the complexed species also varied with the metal ion employed in the complexation when compared to the biopolymer alone. These complexes are new sources of additives for the food and pharmacology industries and carriers of essential metal ions to animal and vegetal biochemistry.
authors.affiliation: Departmento de Química Centro Politécnico, Universidade Federal do Poraná, Curitiba, Brazil. anamerce@quimica.ufpr.br
authors.forename: A L
authors.initials: AL
authors.lastname: Merce
authors.forename: J S
authors.initials: JS
authors.lastname: Landaluze
authors.forename: A S
authors.initials: AS
authors.lastname: Mangrich
authors.forename: B
authors.initials: B
authors.lastname: Szpoganicz
authors.forename: M R
authors.initials: MR
authors.lastname: Sierakowski
mesh_terms: D003035:Cobalt / Q000737:chemistry / Q000378:metabolism*; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D005685:Galactans / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry; D011485:Protein Binding; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D005685:Galactans; D011108:Polymers; D003035:Cobalt; D008345:Manganese; D003300:Copper; D009532:Nickel; C005653:arabinogalactan