Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-2192, Japan.
Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori 680-8552, Japan.
Nutrients. 2020 Nov 13;12(11):3480. doi: 10.3390/nu12113480.
Neurological dementias such as Alzheimer's disease and Lewy body dementia are thought to be caused in part by the formation and deposition of characteristic insoluble fibrils of polypeptides such as amyloid beta (Aβ), Tau, and/or α-synuclein (αSyn). In this context, it is critical to suppress and remove such aggregates in order to prevent and/or delay the progression of dementia in these ailments. In this report, we investigated the effects of spearmint extract (SME) and rosmarinic acid (RA; the major component of SME) on the amyloid fibril formation reactions of αSyn, Aβ, and Tau proteins in vitro. SME or RA was added to soluble samples of each protein and the formation of fibrils was monitored by thioflavin T (ThioT) binding assays and transmission electron microscopy (TEM). We also evaluated whether preformed amyloid fibrils could be dissolved by the addition of RA. Our results reveal for the first time that SME and RA both suppress amyloid fibril formation, and that RA could disassemble preformed fibrils of αSyn, Aβ, and Tau into non-toxic species. Our results suggest that SME and RA may potentially suppress amyloid fibrils implicated in the progression of Alzheimer's disease and Lewy body dementia in vivo, as well.
神经退行性痴呆症，如阿尔茨海默病和路易体痴呆症，被认为部分是由淀粉样β（Aβ）、Tau 和/或α-突触核蛋白（αSyn）等多肽的形成和沉积引起的特征性不溶性纤维所致。在这种情况下，抑制和清除这些聚集体对于预防和/或延缓这些疾病的痴呆进展至关重要。在本报告中，我们研究了留兰香提取物（SME）和迷迭香酸（RA；SME 的主要成分）对αSyn、Aβ 和 Tau 蛋白体外淀粉样纤维形成反应的影响。将 SME 或 RA 添加到每种蛋白质的可溶性样品中，并通过硫黄素 T（ThioT）结合测定和透射电子显微镜（TEM）监测纤维的形成。我们还评估了 RA 是否可以溶解预先形成的纤维。我们的结果首次表明 SME 和 RA 均能抑制淀粉样纤维的形成，并且 RA 可以将预先形成的αSyn、Aβ 和 Tau 纤维解聚成无毒物质。我们的结果表明 SME 和 RA 可能潜在地抑制体内阿尔茨海默病和路易体痴呆症进展中涉及的淀粉样纤维。
