The isoflavones mixture from Trifolium pratense L. protects HCN 1-A neurons from oxidative stress.

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.

The phytoestrogenic isoflavones from Trifolium pratense L. (Red clover) protects human cortical neurons from glutamate toxicity.

The endogenous steroid estrogen has been shown to affect neuronal growth, differentiation and survival. Genistein, daidzein and other isoflavones have been shown to mimic the pharmacological actions of the gonadal steroid estrogen with which they have structural similarities. Several studies have looked at the effect of isoflavones in the brain. In the present study, human cortical cell line HCN 1-A maintained in culture was used to test the neuroprotective efficacy of a natural mixture of phytoestrogenic isoflavones (genistein, daidzein, biochanin A and formononetin) from Red clover against glutamate toxicity. Neuronal viability was determined by MTT or trypan blue test and neuronal membrane damage was quantitatively measured by lactate dehydrogenase (LDH). The results obtained indicate that exposure of HCN 1-A cell cultures to glutamate resulted in concentration-dependent decreases in neuron viability. Concentration of glutamate ranging from 0.01 to 5 mM was toxic to these cultures. A 24-h pretreatment with 0.5, 1 and 2 microg/ml isoflavones enriched fraction (IEF) significantly increased cell survival and significantly decreased cellular lactate dehydrogenase release from differentiated cortical neurons, indicating that neurons treated with isoflavones were protected from the cell death induced by glutamate exposure. Moreover, the pretreatment with IEF prevented the morphological disruption caused by glutamate as shown by microscopical inspection. These findings indicate that IEF has a neuroprotective effect in human cortical neurons and that this effect might be resulted from his antioxidant and estrogenic actions.