Inorganic complexes are increasingly used for biological and medicinal applications and the question of the cell-penetration and of the cell-distribution of metal-lodrugs is key to understand their biological activity. Oxi-dative stress is known to be involved in inflammation and in Inflammatory Bowel Diseases for which antioxidative defenses are weakened. We report here the study of a Mn-complex Mn1 mimicking superoxide dismutase, a protein involved in the cell protection against oxidative stress, using an approach in inorganic cellular chemistry combining investigation of Mn1 intracellular speciation using mass spectrometry, of its quantification and distribution using electron paramagnetic resonance and spatially-resolved X-ray fluorescence with evaluation of its biological activity. More precisely, we have looked for and find the MS-signature of Mn1 in cell lysates and quantified the overall Mn-content. Intestinal epithelial cells activated by bacterial lipopolysaccharide were taken as a cellular model of oxidative stress and inflammation. Mn1 exerts an intra-cellular anti-inflammatory activity, remains at least partially coordinated, with a diffuse distribution over the whole cell and functionally complements mitochondrial MnSOD.