Synthesis, toxicities and bio-activities of manganese complexes with CO and H2S dual donors.

A series of H2SCO dual-donors [Mn(CO)4CS2NR1R2] was synthesized, and evaluated from toxicity and bioactivity. The COH2S measuring test showed all the complexes not only released CO, but released H2S. The resulting data of cytotoxicity showed all the complexes had activities against the cell proliferation; among them, complexes 1, 2 and 7 displayed higher activities than the others, and their potencies were close to cis-platinum (DDP); whereas the precursors A1-A22 had almost no activities against all five tumor cell lines and W138 cell line proliferation. It is worth noting that complex 1 displayed the highest activity to MCF-7, complex 2 displayed the highest activity to HePG2, and complex 7 showed selectivity inhibition to both A549 and HeLa. The developmental toxicities of the complex were assessed using zebrafish embryos. The results showed complexes 1 and 2 had effect on the mortality and hatching rate of zebrafish embryos in dose-dependent manner. They caused zebrafish malformations when they were over 10 μM. Meanwhile, they displayed dose-dependent toxicities to larval zebrafish. In the test of bio-activities, complexes 1 and 2 had strong anti-inflammatory activities; they not only down-regulated the expression levels of iNOS and TNF-α, up-regulated the expression of HO-1 and IL-10, but also up-regulated COX-2 levels. In contrast, the precursor compound (A1 or A2) displayed lower anti-inflammatory activity than the corresponding complex, which suggests both the CO and H2S from the complex took synergistic effects in the process of anti-inflammation. In addition, the complex showed antihypertensive effect and myocardial protection. This effect also possibly resulted from this synergistic effect. All these suggest the complexes have potential to be candidate medicines.