Enhancing genistein bioavailability by amylose complexes

Oral delivery systems for bioactive materials have long been of interest in food applications due to their contribution to the functional and sensory properties. Amylose complexes with hydrophobic molecules can be used as a delivery system to the intestine having the advantages of being readily available, cheap, nontoxic and biodegradable. In this study genistein, a major soy isoflavone possessing with various health promoting attributes, was used as a model polyphenol. The formation of the complexes was studied by X-ray diffraction (XRD). Light scattering analysis and atomic force microscopy were used to measure particles size and morphology. The stability of AGC was studied in-vitro in simulated gastro-intestine conditions and evaluating the influence of different temperatures and pH conditions on the complexes stability, simulating food matrix. The bioavailability of AGC was further studied in vivo. XRD of AGC suggesting genistein induces the formation of distinct supermolecular structures. The formed particles were in the nanometric scale, and tend to aggregate. In-vitro results showed that the complexes protected the guest molecule from heat and low pH in the food matrix. AGC have proved to be stable in the acidic environment in the stomach, and‎ release genistein slowly in simulated intestinal conditions which may increase genistein bioavailability. In vivo results showed that genistein concentration in the plasma was significantly higher and remained at higher level for a longer time in the experimental group that was given AGC. Genistein concentration in the urine was significantly higher in the experimental group, however, in the faeces, it was significantly higher in the control group. This research is trying to link between the structure of amylose-genistein complexes (AGC), to their functionality. The data obtained in this study demonstrate that complexation with amylose changes the bioavailability of genistein in the body.