Improved solubility and increased biological activity of NeoSol (TM) RCL40, a novel Red Clover Isoflavone Aglycones extract preparation

Red clover (Trifolium pratense L., Fabaceae; RCL), a perennial plant rich in isoflavones, is a natural alternative for menopausal symptoms, as well as antiaging and antioxidant. Isoflavone preparations usually contain aglycones and beta-glycosides. Aglycones, the active moieties, are absorbed slowly and unevenly due to reduced water solubility and biotransformation from beta-glycosides. NeoSol (TM) RCL40 is a novel RCL isoflavone aglycones preparation based on active solubilization technologies. In the present study, NeoSol (TM) RCL40 was shown to induce solubilization of isoflavones and to increase estrogenic and antioxidative effects in comparison to a standard RCL extract (RCLE). NeoSol (TM) RCL40 was prepared from RCLE using as host molecules either 2-pyrrolidone, 1-ethenyl homopolymer (PVP), gamma-cyclodextrin, or maltodextrin. Solubilisation assays, performed by means of HPLC-UV, showed that solubilization of isoflavone aglycones was highest with RCLE processed with PVP, which was therefore selected for functional assays. In comparison to RCLE, NeoSol (TM) RCL40 containing the same amount of isoflavone aglycones displayed 3.4 times higher estrogenicity in MCF-7 cell, 1.9-2.0 higher antioxidant activity in the DPPH and in the FRAP assay, and was cytoprotective in PC12 cells. As a whole, results support the ability of NeoSol (TM) RCL40 to promote isoflavones solubilization leading to increased biological activity. NeoSol (TM) RCL40 is therefore an interesting novel preparation providing improved availability of active isoflavones aglycones.