Antioxidant action of SMe1EC2, the low-basicity derivative of the pyridoindole stobadine, in cell free chemical models and at cellular level

The aim of the study was to evaluate the antioxidant action of SMe1EC2, the structural analogue of the hexahydropyridoindole antioxidant stobadine. The antiradical activity of SMe1EC2 was found to be higher when compared to stobadine, as determined both in cell-free model systems of AAPH-induced oxidation of dihydrorhodamine 123 and 2',7'-dichloro-dihydrofluorescein diacetate, and in the cellular system of stimulated macrophages RAW264.7. Analysis of proliferation of HUVEC and HUVEC-ST cells revealed absence of cytotoxic effect of SMe1EC2 at concentrations below 100 µM. The antioxidant activity of SMe1EC2, superior to the parent drug stobadine, is accounted for by both the higher intrinsic free radical scavenging action and by the better bioavailability of the low-basicity SMe1EC2 relative to the high-basicity stobadine.