Evaluation of estrogenic activity of red clover (Trifolium pratense L.) sprouts cultivated under different conditions by content of isoflavones, calorimetric study and molecular modelling

Isoflavones have an affinity for estrogen receptors (ERs) including beneficial affinity for ER beta. Widely used soy is a source of poorly absorbed isoflavones glycosides. Red clover contains mostly easily absorbed free aglycones. Red clover sprouts were cultivated under different conditions (white light, UVA or UVB for 12 or 24 h a day at 18 or 25 degrees C) to maximise the content of isoflavones, especially of high affinity for ER beta. The affinity of isoflavones to ERs was evaluated by molecular modelling and isothermal titration calorimetry (ITC). The richest source of isoflavones, especially formononetin were sprouts cultivated for 10 days under continuous white light and at 25 degrees C (562 mg/100 g of fresh mass). Formononetin and the above sprouts has been shown to have a high affinity for ER beta. Red clover sprouts can be considered as a source of phytoestrogens with high biological activity and as a dietary supplement reducing menopausal symptoms.