Oxidative stress-induced neuronal cell death has been implicated in different
neurological disorders and
neurodegenerative diseases such as
Alzheimer's disease and Parkinson's. Using the
Alzheimer's disease-associated
hydrogen peroxide (H(2)O(2)), we investigated the neuroprotective efficacy of a natural mixture of phytoestrogenic
isoflavones (
genistein,
daidzein,
biochanin A and
formononetin) from Trifolium pratense L. (Red clover) against oxidative stress-induced cell death in human cortical cell line HCN 1-A maintained in culture. Neuronal viability was determined by MTT or
trypan blue test and neuronal integrity by morphological analysis.The results obtained indicate that exposure of HCN 1-A cell cultures to
hydrogen peroxide resulted in a concentration-dependent decrease in neuron viability. Concentration of H(2)O(2) ranging from 50 to 200 microg/ml were toxic to these cultures. A 24-hour pretreatment with 0.5, 1 and 2 microg/ml
isoflavones extract significantly increased cell survival as evidenced by MTT or
trypan blue test and significantly prevented the morphological disruption caused by H(2)O(2) as shown by microscopical inspection, indicating that neurons treated with
isoflavones were protected from the cell death induced by H(2)O(2) exposure. These findings imply that the
neuroprotective effect of
isoflavones extract is partly associated with its
antioxidant activity. Further, results of these investigations indicate that although
isoflavones extract exert a
neuroprotective effect, it do not promoted cortical neuron process outgrowth.