丁香精油抗LDL糖基化活性及其主要成分—丁香酚与牛血清白蛋白的相互作用

Antiglycation Activity on LDL of Clove Essential Oil and the Interaction of Its Most Abundant Component—Eugenol With Bovine Serum Albumin

实验室前期研究结果表明,在国家规定的药食两用物品名单中,丁香抗氧化活性最强。前人发现天然产物的抗氧化功能与抗糖基化活性息息相关。因此,目的是在此基础上进一步对丁香精油(clove essential oil,CEO)的抗糖基化活性及其中含量最高的组分—丁香酚(Eugenol)与牛血清白蛋白(bovine serum albumin,BSA)的相互作用进行研究。在低密度脂蛋白(low density lipoprotein,LDL)的非酶糖基化孵育体系中,光谱测定结果表明CEO对LDL糖基化早期、中期和末期产物的生成均具有显著的抑制效果,且对末期产物的抑制作用最强。采用气相色谱-质谱联用技术(gas chromatography mass spectrometry,GC-MS)对CEO分析发现,CEO中含量最多的组分是丁香酚。通过多光谱和分子对接对丁香酚与BSA的相互作用研究发现,紫外-可见(ultraviolet-visible,UV-Vis)光谱表明丁香酚与BSA之间存在相互作用;在荧光发射光谱中,随着丁香酚浓度增加,BSA的荧光强度逐渐增强且发生蓝移,进一步证明了二者之间存在相互作用。通过计算不同温度下的结合常数发现,丁香酚与BSA产生相互作用过程中有热力学过程参与,热力学参数和位点标记竞争试验表明丁香酚通过氢键和范德华力与BSA在位点Ⅰ结合。随着丁香酚浓度增加,丁香酚与BSA混合体系的同步荧光(synchronous fluorescence,SF)、三维荧光(three-dimensional,3D)和傅里叶变换红外(Fourier transform infrared,FTIR)光谱的信号强度在发生变化的同时也发生了位移,表明丁香酚的添加使BSA构象发生了改变。通过分子对接技术进一步验证了丁香酚与BSA间相互作用的试验结果。该研究为丁香进一步开发应用提供理论支持。

The previous research results of our laboratory showed that clove had the strongest antioxidant activity in the state’s list of food-medicine herbs promulgated.It has been found that the antioxidant activity of natural products is closely related to antiglycation activity.Therefore,this study aimed to investigate further the antiglycation activity of clove essential oil(CEO)and the interaction between eugenol the component with the highest content in CEO and bovine serum albumin(BSA).The spectral results showed that in the non-enzymatic glycation incubation system of low-density lipoprotein(LDL),CEO had significant inhibition effects on forming the early,intermediate and late products of LDL glycation and had the strongest inhibition effect on the late product.The composition analysis of CEO by gas chromatography-mass spectrometry(GC-MS)indicated that eugenol was the most abundant component in CEO.Multispectral and molecular docking were applied to investigate the interaction between eugenol and BSA.The result of ultraviolet-visible(UV-Vis)absorption spectroscopy indicated an interaction between eugenol and BSA.In fluorescence emission spectroscopy,with the increase of eugenol concentration,the fluorescence intensity of BSA gradually increased with the blue shift,which further proved the interaction between them.The calculated results of binding parameters at different temperatures confirmed that the thermodynamic processes were involved in the interaction between eugenol and BSA.Thermodynamic parameters and the site marker competitive experiments showed that eugenol particularly bonds to BSA at the siteⅠthrough hydrogen bond and vander Waals force.In synchronous fluorescence(SF),three-dimensional(3D)fluorescence,and Fourier transform infrared(FTIR)spectroscopy,the signal strengths changed with the increase of eugenol concentration,and the shifts also occurred,which indicated that the conformation of BSA changed with the addition of eugenol.The results of the interaction between eugenol and BSA were further verified by molecular docking technology.The findings can provide theoretical support for the further development of clove.