大黄素是自然界中发现的天然蒽醌衍生物,广为人知的草药。这里,隔板,location,大黄素与1,2-二肉豆蔻酰-sn-甘油-3-磷酸胆碱(DMPC)的脂质膜的相互作用进行了实验研究。我们的研究考虑了大黄素(EMH)的中性形式及其阴离子/去质子化形式(EM-),以及它们与越来越少的脂质膜的相互作用,凝胶和液相的DMPC,分别。虽然DSC结果表明这两个物种,EMH和EM-,类似地破坏DMPC双层的堆积,自旋标签清楚地表明,EMH会导致更强的双层破坏,在凝胶和液体DMPC中。荧光光谱显示EMH和EM-对DMPC都有很高的亲和力:发现EM-与凝胶和流体DMPC双层的结合非常相似,类似于EMH凝胶DMPC,Kp=(1.4±0.3)x103。然而,发现EMH与流体DMPC双层的结合强度提高了两倍,Kp=(3.2±0.3)x103。自旋标记和光学吸收光谱表明大黄素位于脂质双层表面附近,并表明EM-比EMH更接近脂质/水界面,如预期。本研究对目前对两种大黄素的影响的理解做出了相关贡献,EMH和EM-,存在于生物体的不同微区域,由于局部pH值可以显著变化,会导致中性脂质膜,或多或少的包装,喜欢凝胶和液体DMPC,分别,并可以扩展到生物膜的脂质结构域。
Emodin is a natural anthraquinone derivative found in nature, widely known as an herbal medicine. Here, the partition, location, and interaction of emodin with lipid membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are experimentally investigated with different techniques. Our studies have considered the neutral form of emodin (EMH) and its anionic/deprotonated form (EM-), and their interaction with a more and less packed lipid membrane, DMPC at the gel and fluid phases, respectively. Though DSC results indicate that the two species, EMH and EM-, similarly disrupt the packing of DMPC bilayers, spin labels clearly show that EMH causes a stronger bilayer disruption, both in gel and fluid DMPC. Fluorescence spectroscopy shows that both EMH and EM- have a high affinity for DMPC: the binding of EM- to both gel and fluid DMPC bilayers was found to be quite similar, and similar to that of EMH to gel DMPC, Kp = (1.4 ± 0.3)x103. However, EMH was found to bind twice more strongly to fluid DMPC bilayers, Kp = (3.2 ± 0.3)x103. Spin labels and optical absorption spectroscopy indicate that emodin is located close to the lipid bilayer surface, and suggest that EM- is closer to the lipid/water interface than EMH, as expected. The present studies present a relevant contribution to the current understanding of the effect the two species of emodin, EMH and EM-, present on different microregions of an organism, as local pH values can vary significantly, can cause in a neutral lipid membrane, either more or less packed, liked gel and fluid DMPC, respectively, and could be extended to lipid domains of biological membranes.