Fig. 1.

H₂S release by mitochondrial H₂S donors. A and B: The chemical structure of mitochondrial H₂S donors: the H₂S releasing groups anethole dithiolethione (ADT-OH) in AP39 (A) and 4-hydroxythiobenzamide (HTB) in AP123 (B) are bound by ester linkage to 10-carbon alkyl linker region and the triphenyl phosphonium mitochondrial targeting group. C-D: The total amount of H₂S released from non-mitochondrial (ADT-OH, HTB) and mitochondrial (AP39, AP123) H₂S donors (100–500 μM) was detected in cell culture medium (DMEM supplemented with 10% FBS) for 10 days. E-F: Daily H₂S release values are plotted with curve-fitting results to highlight the donor compound decomposition. G-H: The total amount of H₂S liberated from mitochondrial and respective non-mitochondrial H₂S donors over the first 3-day long period is shown.