金花茶花浸提物与消化蛋白酶的相互作用

为探讨金花茶花浸提物对消化蛋白酶活性的影响及其作用机理,首先研究了金花茶花浸提物对消化蛋白酶活性的影响以及抑制动力学,其次采用荧光光谱法、紫外光谱法和圆二色谱法研究浸提物抑制消化蛋白酶活性的机制。结果表明,醇提物和水提物对胃蛋白酶(IC₅₀分别为3.194和3.330 g/L;竞争抑制常数分别为4.518和7.641 g/L)和胰蛋白酶(IC₅₀分别为29.131和56.534 g/L;竞争抑制常数分别为74.571和175.832 g/L)有明显的抑制作用,且抑制类型为混合型抑制;金花茶花浸提物能降低胃蛋白酶(猝灭常数分别为1.522和1.205 L/g)和胰蛋白酶(猝灭常数分别为2.175和1.392 L/g)的内源荧光,改变消化蛋白酶的二级结构。因此,金花茶花浸提物可通过改变消化蛋白酶的结构抑制其活性,该研究为金花茶花功能性食品开发提供理论支撑。

Interaction properties between Camellia nitidissima Chi flower extract and digestive protease

To investigate the effect of Camellia nitidissima Chi flower on protein digestion and absorption,the effect of C.nitidissima Chi flower extract on the digestive protease activity and the inhibition kinetics of digestive protease were studied using fluorescence spectroscopy,ultraviolet spectroscopy,and circular dichroism.The results showed that both ethanol extract and aqueous extract of C.nitidissima Chi flower exhibited obvious inhibitory effect on pepsin(IC₅₀ were 3.194 and 3.330 g/L;competition inhibition constant was 4.518 and 7.641 g/L,respectively)and trypsin activity(IC₅₀ were 29.131 and 56.534 g/L;competition inhibition constant were 74.571 and 175.832 g/L,respectively),and the inhibition types were mixed manner.The spectrum experiment demonstrated that C.nitidissima Chi flower extract reduced the endogenous fluorescence of pepsin(quenching constant were 1.522 and 1.205 L/g,respectively)and trypsin(Quenching constant were 2.175 and 1.392 L/g,respectively),and further changed the secondary structure of digestive protease.Therefore,this study proved that the C.nitidissima Chi flower extracts could inhibit digestive protease activity by changing its structure,which provides theoretical support for the development of functional foods containing C.nitidissima Chi flower.