The most common type of osteoporosis is bone loss associated with ovarian hormone deficiency at menopause. There is evidence that diets which contain high levels of phytoestrogenic isoflavones are associated with a low incidence of osteoporosis and menopausal symptoms. Plant extracts, which contain high levels of isoflavones, such as Red clover (Trifolium pratense L.), have been used to reduce menopausal symptoms.The objective of this study was to evaluate the preventive effects of Red clover total isoflavones on the progression of bone loss induced by estrogens deficiency (ovariectomy) in rats. Bilateral ovariectomy was performed on female Wistar rats. One week after the operation the rats were treated with an oral dose of 20 and 40 mg of total isoflavones daily for 14 weeks. The results from this study showed that the ovariectomy reduced bone mineral content, femoral weight, femoral density, mechanical strength of the tibia and increased the levels of bone specific alkaline phosphatase in the serum and the number of osteoclasts in the femur sections compared with sham operated controls. Treatment with isoflavones significantly increased bone mineral content, mechanical strength of the tibia, femoral weight, femoral density and prevented the rise of serum alkaline phosphatase levels. In addition, the treatment with isoflavones significantly reduced the number of osteoclasts compared with the ovariectomized control rats. These findings suggest that Red clover isoflavones are effective in reducing bone loss induced by ovariectomy, probably by reducing of the bone turnover via inhibition of bone resorption.

Since ancient times, extracts of plants have been used for women's health to prevent menopausal symptoms. The symptoms of menopause have been attributed to a reduction in the amount of estrogen produced by the ovaries. In this study the estrogenic activity of a commercial standardized extract of the roots of Angelica sinensis, used to relieve climacteric symptoms was evaluated using in vivo tests such as the degree of cornification of vaginal epithelium, uterotrophic assays and serum LH concentration in ovariectomized rats. Furthermore, the effects on the estrous cycle in rat were investigated. The results obtained have shown that the administration of a standardized ethanol extract in ovariectomized rats exhibited a stimulation of the uterine histoarchitecture, a significant cornification in the vaginal epithelium and a reduction of serum LH concentration showing the estrogenic nature of the extract. Furthermore, the administration of the extract in intact female rats provoked a significant modification of the vaginal smear in 67% of treated rats. The estrous cycle thus modified was characterized by a prolonged estrus stage with a temporary reduction of the regular cyclicity.

The aim of this study was to investigate the neuroprotective effects of a titolated extract from Rhodiola rosea L. (RrE) and of salidroside (Sa), one of the major biologically active compounds extracted from this medicinal plant, against oxidative stressor hydrogen peroxide (H₂O₂) and glutamate (GLU)-induced cell apoptosis in a human cortical cell line (HCN 1-A) maintained in culture. The results obtained indicate that exposure of differentiated HCN 1-A neurons to GLU or H₂O₂ resulted in concentration-dependent cell death. A 24 h pre-treatment with RrE significantly increased cell survival and significantly prevented the plasma membrane damage and the morphological disruption caused by GLU or H₂O₂, indicating that neurons treated with RrE were protected from the neurotoxicity induced by the oxidative stressor used. In addition, RrE significantly reduced H₂O₂ or GLU-induced elevation of intracellular free Ca²⁺ concentration. The results obtained have also shown that Sa caused similar effects in all experimental models used; however, the potency of the action was lower than that of the extract containing corresponding quantities of Sa. These findings indicate that RrE has a neuroprotective effect in cortical neurons and suggest that the antioxidant activity of the RrE, due to the structural features of the synergic active principles they contain, may be responsible for its ability to stabilize cellular Ca²⁺ homeostasis.

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.