Preparation and antioxidant activity of albumin binding Salen Schiff-base metal complexes

Abstract

A kind of novel biopolymer antioxidant (BSA/HOSalenM, M=Co, Mn, Zn) is prepared with conjugation, which increases the antioxidant activity of the bovine serum albumin (BSA). The conjugations have been characterized by IR spectra, UV-Vis spectra, Fluorescence spectra, Circular dichroism (CD) spectra and Native-PAGE. The BSA is used as a biopolymer scaffold, and the insoluble Salen Schiff-base metal complexes HOSalenM make axial coordination with the amino acid residues of the BSA. The structure of the BSA is unchanged when the binding rate of HOSalenCo is less than 10. The HOSalenCo conjugations show an excellent hydroxyl radical (·OH) scavenging activity, and the activity (EC 50 ) of BSA/HOSalenCo(10) (BSA : HOSalenCo=1 : 10) is improved by two orders of magnitude compared with the BSA, while the activity of the BSA/HOSalenMn is weak and the BSA/HOSalenZn shows no scavenging activity. The reactive oxygen species (ROSs) are associated with the carcinogenesis, the coronary heart disease and many health problems which are related to advancing age [1][2][3]. The hydroxyl radical (·OH) is one of the most damaging radicals produced under the physiological conditions. Epidemiological and clinical studies indicate that the effective antioxidants can protect the human body from the free radicals and retard the progress of many chronic diseases [4,5]. Many ROS-scavenging materials, including natural and synthetic antioxidants, are used to reduce the damage to the human body [6,7]. As synthetic antioxidants, Schiff-base metal complexes have been widely studied as the effective scavengers of the ROS [8][9][10][11]. However, the majority of Schiffbase metal complexes are insoluble in the aqueous solutions, which limits their applications.The serum albumin is a versatile protein, principally characterized by its remarkable ability of binding a wide range of insoluble endogenous and exogenous compounds [12][13][14][15]. Since the serum albumin was considered to be nonantigenic and biodegradable, and was readily available [16], the albumin has been used as a bio-material, such as drug delivery and novel hydrophilic carriers [17][18][19][20]. However, the bovine serum albumin (BSA) has not been used for ROS-scavenging materials because the ROS-scavenging activity of the BSA is very weak [21]. Recently, the macromolecules conjugation has been proved to be an effective method to improve their bioactivity [22]. In this paper, a biopolymer BSA and Salen Schiff-base metal complexes were integrated together, which afforded a new kind of water-soluble biopolymer conjugation. The specific affinity between the small molecule and the protein was proved to be one of the most straightforward and applicable approaches

Bovine Serum Albumin Metal Complexes for Mimic of SOD

“…27 Although antioxidative capacity of BSA was fairly weak, 28 it can be dramatically improved after combining with amino acid Schiff base compounds. 29 Based on the fact that BSA is a natural polymer, great efforts have been made to investigate the O •− 2 scavenging using BSA-M as antioxidant. Transition metal ions (Cu II , Mn II , Co II ) were combined into BSA, which afforded bovine serum albumin metal complexes (BSA-M).…”

Albumin Conjugating Amino Acid Schiff-Base Metal Complexes for Scavenging Superoxide Anion Radical

“…Our group found that the amino acid Schiff-base complexes could be easily prepared with amino acid, salicylaldehyde and metal salts in alcohol, and it could effectively activate O 2 , which being applied to oxidize olefins [18]. The BSA is a versatile protein, which can easily bind with a wide range of insoluble endogenous and exogenous compounds [19]. Since BSA is considered to be non-antigenic, biodegradable, and readily available, it has been used as a bio-material, such as drug delivery and novel hydrophilic carriers [20].…”

Albumin as a promiscuous biocatalyst in organic synthesis

“…Moreover, BSA was used as a supporter for binding Schiffbase metal complexes with oxidative radical scavenging activity in order to generate novel water-soluble metalloprotein conjugates. 23,24 The non-covalent binding of porphyrins, phthalocyanines and corroles to albumins was also investigated. 25,26 2.1 Hydroformylation Rh(CO) 2 (acac)/(HSA) complexes were employed in the hydroformylation reaction of several alkenes in a water/pentane biphasic system, at 40-60 C and 50-80 atm (CO/H 2 ¼ 1, Scheme 1).…”