橙黄决明素的制备及其与牛血清白蛋白的相互作用

采用硅胶真空液相层析从决明子(Cassia obtusifolia L.)中分离制备了橙黄决明素,以UPLC-QTOF-MS和C13-NMR、H1-NMR鉴定了其化学结构。采用荧光光谱和紫外光谱法研究了橙黄决明素与牛血清白蛋白的相互作用。结果表明,橙黄决明素对牛血清白蛋白有明显的荧光猝灭作用,在25、37、47℃3种温度下的荧光猝灭常数KSV变化不明显,猝灭速率Kq为1.412×1013 L/(mol.s),说明橙黄决明素对BSA的荧光猝灭属于静态猝灭。橙黄决明素与牛血清白蛋白作用的紫外光谱变化进一步确认了其属于静态猝灭。热力学计算表明,橙黄决明素与牛血清白蛋白的结合位点数为1,与BSA之间的结合主要是以疏水作用力相结合的自发过程。橙黄决明素与牛血清白蛋白的酪氨酸的疏水性结合可能引起了蛋白质构象的变化,但牛血清白蛋白分子的大小并未有明显的变化。

Preparation of aurantio-obtusin and its interaction with bovine serum albumin

Aurantio-obtusin was separated from Cassia obtusifolia L.and its chemical structure was identified using UPLC-QTOF-MS and C~13-NMR,H~1-NMR.The interaction and binding properties between aurantio-obtusin and bovine serum albumin showed that the fluorescence quenching effect of aurantio-obtusin to bovine serum albumin was obvious,aurantio-obtusin on BSA fluorescence quenching constants K_SV did not change significantly at 25,37,47 ℃.The fluorescent quenching rate Kq was 1.412×10~13 L/(mol·s).The thermodynamic calculation results indicate: The number of binding site of aurantio-obtusin and bovine serum albumin was 1.The interaction between aurantio-obtusin and bovine serum albumin was mainly to hydrophobic forces combined with spontaneous process.