Ex vivo effects of ibogaine on the activity of antioxidative enzymes in human erythrocytes

Abstract

Ethnopharmacological relevance: Ibogaine is a naturally occurring alkaloid with psychotropic and metabotropic effects, derived from the bark of the root of the West African Tabernanthe iboga plant. The tribes of Kongo basin have been using iboga as a stimulant, for medicinal purposes, and in rite of passage ceremonies, for centuries. Besides, it has been found that this drug has anti-addictive effects. Aim of the study: Previous studies have demonstrated that ibogaine changed the quantity of ATP and energy related enzymes as well as the activity of antioxidant enzymes in cells thus altering redox equilibrium in a time manner. In this work, the mechanism of its action was further studied by measuring the effects of ibogaine in human erythrocytes in vitro on ATP liberation, membrane fluidity and antioxidant enzymes activity. Materials and methods: Heparinized human blood samples were incubated with ibogaine (10 and 20 mu M) at 37 degrees C for 1 h. Blood plasma was separated by centrifugation and the levels of ATP and uric acid were measured 10 mm after the addition of ibogaine using standard kits. The activity of copper zinc superoxide dismutase (SOD1), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) were measured in erythrocytes after incubation period. The stability of SOD1 activity was further tested through in vitro incubation with H2O2 and scanning of its electrophoretic profiles. Membrane fluidity was determined using an electron paramagnetic resonance spin-labelling method. Results: Results showed that ibogaine treatment of erythrocytes in vitro increased ATP concentration in the blood plasma without changes in neither erythrocytes membrane fluidity nor uric acid concentration. lbogaine also increased SOD1 activity in erythrocytes at both doses applied here. Treatment with 20 mu M also elevated GR activity after in vitro incubation at 37 degrees C. Electrophoretic profiles revealed that incubation with ibogaine mitigates H2O2 mediated suppression of SOD1 activity. Conclusion: Some of the effects of ibogaine seem to be mediated through its influence on energy metabolism, redox active processes and the effects of discrete fluctuations of individual reactive oxygen species on different levels of enzyme activities. Overall, ibogaine acts as a pro-antioxidant by increasing activity of antioxidative enzymes and as an adaptagene in oxidative distress.