6-(Propan-2-yl)-3-methyl-morpholine-2,5-dione, a novel cyclodidepsipeptide with modulatory effect on rat thymocytes

A study has been carried out on the potential effect of a novel cyclodidepsipeptide, 6-(propan-2-yl)-3-methyl-morpholine-2,5-dione (PMMD), on rat thymocytes. Rat thymocytes were cultivated with increasing PMMD concentrations (0.1, 1, 10 μg/well), for 24 h, and evaluated for proliferative activity, viability, reactive oxygen species and mitochondrial membrane potential. The higher PMMD concentrations inhibited thymocytes proliferative activity mainly through induction of oxidative stress and resulting cytotoxicity, without any mitochondrial membrane potential alterations in thymocytes. The obtained results are correlated with previously published data on effects of 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones on rat thymocytes. The presence of methyl group in position 4 or/and the length of alkyl chain in position 3 of 6-(propan-2-yl)-morpholine-2,5-dione core plays a role for the obtained differences in the biological response between PMMD and two previously tested 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones.