Protective effect of ovalbumin-flavonoid hydrogel on thrombolytic activity and stability of nattokinase

The protective effect of ovalbumin-flavonoids (naringenin, genistein, naringin, puerarin, and daidzein) hydrogels on the thrombolytic activity and stability of nattokinase were investigated. The results suggested that flavonoids promoted the gelation of ovalbumin solution, which was not able to form hydrogel at the same concentration upon heating. The nattokinase/ovalbumin-naringenin hydrogel had the strongest hardness and springiness. All nattokinase/ovalbumin-flavonoids hydrogels were more elastic than viscous. After in vitro digestion, the thrombolytic capacities of all nattokinase/ovalbumin-flavonoids hydrogels were significantly higher than that of free nattokinase. Moreover, nattokinase/ovalbumin-flavonoids hydrogels showed higher thermal and pH stability than free nattokinase. Fluorescence spectroscopy and molecular docking analysis revealed that the main interactions between nattokinase and daidzein, nattokinase and genistein were mainly hydrogen bond, while the main interactions between nattokinase and naringin, nattokinase and puerarin, nattokinase and naringenin were hydrophobic interaction. This research suggested that nattokinase/ovalbumin-flavonoids had great potential for applications in the treatment of thrombus.