Organometallic complexes with biological molecules. XIV. Biological activity of dialkyl and trialkyltin(IV) [meso‐tetra(4‐carboxy‐ phenyl)porphinate] derivatives

The effects of several organotin(IV) meso ‐tetra(4‐carboxyphenyl)porphinate] derivatives with the general formula (R 2 Sn) 2 TPPC and (R 3 Sn) 4 TPPC (R = Me, Bu, Ph) were tested in vivo on ascidian embryonic development. Embryos at the two‐cell stage were incubated in 1 × 10 −5 or 1 × 10 −7  M solutions of various compounds. The ligand, [ meso ‐tetra(4‐carboxyphenyl)porphine] (H 4 TPPC) was toxic at 1 × 10 −5   M , because development was blocked at an early gastrula stage, whereas 1 × 10 −7   M H 4 TPPC allowed the eggs to develop up to the larva stage. The most toxic among the tested compounds was tributyltin(IV) [ meso ‐tetra(4‐carboxyphenyl)porphinate], (Bu 3 Sn) 4 TPPC, since the fertilized eggs were unable to divide into two cells, even at a concentration of 1 × 10 −7   M . To correlate this embryonic arrest with the metabolic pathway, and especially to understand why cellular organelles first underwent chemical damage, 10 −5 and 10 −7   M (Bu 3 Sn) 4 TPPC‐cultured fertilized eggs were tested for DNA, RNA, protein, glucose, lipid and ATP contents, comparing the values obtained with those of control culture fertilized egg contents. The higher concentration (1 × 10 −5   M ) reduced the content of all the tested compounds, but the lower one (1 × 10 −7   M ), even if still unable to allow cleavage, reduced only the lipids and the ATP contents. A hypothesis concerning initial damage to mitochondrial membrane is proposed. Copyright © 2000 John Wiley & Sons, Ltd.