Li Dongpu, Yu Hongfei, Lin Qinxiong, Liu Yun
Tianjin Medical University General Hospital, Tianjin, China.
Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
PLoS One. 2017 Oct 30;12(10):e0186590. doi: 10.1371/journal.pone.0186590. eCollection 2017.
A bioactive chemical constituent, doliroside A, from Chinese traditional herbal medicine Dolichos falcata Klein was isolated, purified and identified by 60% ethanol extraction, thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectroscopy. Molecular interaction mechanism between doliroside and amyloid β42 protein was evaluated by thioflavin T fluorescence (ThT), circular dichroism (CD), atomic force microscope (AFM), and differential scanning calorimeter (DSC) from the aspects of kinetics, secondary structure, morphology, and thermodynamics, respectively. Results show that the purity of doliroside A is 99.9% by HPLC, and its chemical structure is identified by 1H- and 13C-NMR. Doliroside A is observed to be concentration-dependent inhibiting the fibrillation of Aβ42 with the IC50 value of 26.57 ± 1.6 μM. CD and DSC results imply that doliroside A can bind to the nuclei and oligomers of Aβ42 to form a stable complex and suppress Aβ42 fibrillation. AFM images show that doliroside A, after bound to the nuclei and oligomers, redirect Aβ42 into off-pathway, amorphous oligomers. These findings not only provide a full insight into the molecular interaction mechanisms between Aβ42 and doliroside A, but also facilitate the development of new native anti-AD drug of doliroside A compound.
从中国传统草药镰扁豆（Dolichos falcata Klein）中分离、纯化并鉴定了一种生物活性化学成分多利罗苷A，采用60%乙醇提取、薄层色谱（TLC）、高效液相色谱（HPLC）和核磁共振（NMR）光谱法进行。分别从动力学、二级结构、形态学和热力学方面，通过硫黄素T荧光（ThT）、圆二色性（CD）、原子力显微镜（AFM）和差示扫描量热仪（DSC）评估了多利罗苷与淀粉样β42蛋白之间的分子相互作用机制。结果表明，通过HPLC测得多利罗苷A的纯度为99.9%，并通过1H-和13C-NMR鉴定了其化学结构。观察到多利罗苷A呈浓度依赖性抑制Aβ42的纤维化，IC50值为26.57±1.6μM。CD和DSC结果表明，多利罗苷A可与Aβ42的核和寡聚体结合形成稳定的复合物并抑制Aβ42纤维化。AFM图像显示，多利罗苷A与核和寡聚体结合后，将Aβ42重定向到非途径的无定形寡聚体中。这些发现不仅全面深入地了解了Aβ42与多利罗苷A之间的分子相互作用机制，也促进了多利罗苷A化合物新型天然抗阿尔茨海默病药物的开发。
