Abstract

INHIBITORY EFFECTS AND MECHANISM OF FLAVONOIDS FROM XANTHOCERAS SORBIFOLIA BUNGE ON TYROSINASE

*Quan-Cheng Zhou, Hong-Mei Zhang, Jie Geng

ABSTRACT

Background: Xanthoceras sorbifolia Bunge (XSB) kernel was waste after extraction process in oil industrial. This study aimed to determine inhibitory effects of flavonoids from XSB on tyrosinase and elucidate its mechanism. RESULTS: The inhibition rate of the flavonoids toward the activity of tyrosinase presented non-linear changes with the concentrations. The inhibition rate was 42.6% when the flavonoids concentration was 0.960 mg mL-1 and it slowed down with the time increasing. FX was not a pure uncompetitive or competitive inhibitor of tyrosinase. The inhibitory mechanism of FX on the tyrosinase indicated that FX acts as a static quenching agent during its interaction with tyrosinase through nearly 2 binding site; the FX decreased the content of α-helix, β-turn and random coil in tyrosinase, but significantly increased the contents of β-sheet, which showed FX make the tyrosinase structure loosens and inhibit tyrosinase activity. Conclusions: These result showed the effects and mechanism of FX as the tyrosinase inhibitor and structure loosens. It is a good inhibitor of tyrosinase.

Keywords: xanthoceras sorbifolia bunge, flavonoids, tyrosinase, fluorescence, CD.