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

Abstract

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 β-glycosides. Aglycones, the active moieties, are absorbed slowly and unevenly due to reduced water solubility and biotransformation from β-glycosides. NeoSol™RCL40 is a novel RCL isoflavone aglycones preparation based on active solubilization technologies. In the present study, NeoSol™RCL40 was shown to induce solubilization of isoflavones and to increase estrogenic and antioxidative effects in comparison to a standard RCL extract (RCLE). NeoSol™RCL40 was prepared from RCLE using as host molecules either 2-pyrrolidone, 1-ethenyl homopolymer (PVP), γ-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™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™RCL40 to promote isoflavones solubilization leading to increased biological activity. NeoSol™RCL40 is therefore an interesting novel preparation providing improved availability of active isoflavones aglycones.