Neuroprotective Actions of Tannins from Myracrodruon urundeuva on 6-Hydroxydopamine-Induced Neuronal Cell Death

Abstract

ABSTRACT In the present work we studied the neuroprotective effect of a tannin-enriched fraction (TEF) on rat primary mesencephalic cells culture, before (preventive protocol) and after (curative protocol) exposure to the neurotoxin 6-hydroxydopamine (6-OHDA). TEF was isolated from the stem bark of Myracrodruoun urundeuva, a Brazilian medicinal plant, largely used as a female genital tract antiinflammatory. The results showed that TEF (0.1 to 100 μg/ml) significantly reversed 6-OHDA-induced toxicity on neuronal cells as measured by the MTT assay, which expresses the degree of cell viability and integrity, in both protocols. Although the reversion was only partial, it was observed even at the lowest TEF concentration, and MTT absorbance returned to values close to those of controls. TEF was also very effective when added to cells culture before and after the neurotoxin, and reversed completely the 6-OHDA-induced lipid peroxidation, indicated by the formation of thiobarbituric acid reactive substances (TBARS). However, TEF did not reverse the increase in nitrite concentration observed in the cell culture in the presence of 6-OHDA. The neuroprotective mechanism of TEF seems to be related with mitochondrial protection and antioxidant activity exhibited by tannins presented in the stem bark from M. urundeuva.