The potential protective effect of (±)-8-methoxy-1,3,4,4a,5,9b-hexahydro-pyrido[4,3-b]indole-2-carboxylic acid ethyl ester (II) was assessed against hydrogen peroxide (H2O2)-cytotoxicity in rat pancreatic INS-1E β cells and compared with the effect of the related pyridoindole, stobadine (I), a promising indole-type reference antioxidant. Only pre-treatment with the compound (II) led to a significant preservation of the metabolic and secretory functions of the cells exposed to H2O2. The caspase-9 and -3 activities, as well as the early apoptotic changes of plasma membrane, were suppressed in the cells pre-incubated with both of compounds tested. However, only pyridoindole (II) inhibited profoundly the time-delayed apoptotic changes, These results suggest that pyridoindole (II) characterized by enhanced intrinsic antioxidant efficiency, may protect β cells against cytotoxic effects of H2O2, involved in the development of both type 1 and type 2 diabetes.