Synthesis, crystal structures and antioxidant activities of water-soluble salicylaldehyde Schiff base complexes.

Graphical abstract Seven new water-soluble chiral/achiral SOD-mimicking metal complexes were synthesized and fully characterized. The antioxidant activity of all complexes and their corresponding hybrid proteins were determined. The results show that the water-solubility played a role in improving the antioxidant activity, and the activity was higher when combined with BSA. Abstract Seven new water-soluble chiral/achiral SOD-mimicking metal complexes: NaK[Mn(R -L1)(C 2 H 5 OH) 4 ] (Mn - 1a), NaK[Mn(S -L1)(C 2 H 5 OH) 4 ] (Mn - 1b), NaK[Co(R -L1)]·3H 2 O (Co - 2a), NaK[Co(S -L1)]·3H 2 O (Co - 2b), NaK[(VO)(R -L1)(OH)]·5H 2 O (V - 3a), NaK[(VO)(S -L1)(OH)]·5H 2 O (V - 3b) and [MnL2]·[(CH 3 CH 2) 3 NH] 2 ·5H 2 O (Mn - 4) were synthesized and fully characterized. Furthermore, hybrid protein, binding with complexes and bovine serum albumin (BSA) to enhance the antioxidant activity, were synthesized and evaluated by multispectroscopic techniques. The SOD activities of all complexes and their corresponding hybrid proteins were tested by xanthine/xanthine oxidase method, the antioxidant activity of them were determined by ABTS method. The results show that the SOD activities of the hybrid proteins are higher than that of the corresponding complexes. From the values of the antioxidant activity we obtained, there seems to be some connection between the configuration and antioxidant activity. [ABSTRACT FROM AUTHOR]