Department of Anatomy, College of Medicine, Dongguk University, Gyeongju 38066, Republic of Korea.
Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea.
Int J Mol Sci. 2023 Aug 29;24(17):13386. doi: 10.3390/ijms241713386.
Garlic ( L.) is an aromatic herb known for its culinary and medicinal uses for centuries. Both unprocessed (white) and processed (black) garlic are known to protect against the pathobiology of neurological disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD), which has been attributed to their anti-inflammatory and antioxidant properties. The information on the effects of processed and unprocessed garlic on neuronal process outgrowth, maturation, and synaptic development is limited. This study aimed at investigating and comparing the effects of the ethanol extracts of unprocessed (white garlic extract, WGE) and processed (black garlic extract, BGE) garlic on the maturation of primary hippocampal neurons. Neurite outgrowth was stimulated in a dose-dependent manner by both WGE and BGE and the most effective doses were 15 μg/mL and 60 μg/mL, respectively, without showing cytotoxicity. At this optimal concentration, both extracts promoted axonal and dendritic growth and maturation. Furthermore, both extracts substantially increased the formation of functional synapses. However, the effect of WGE was more robust at every developmental stage of neurons. In addition, the gas chromatography and mass spectrometry (GC-MS) analysis revealed a chemical profile of various bioactives in both BGE and WGE. Linalool, a compound that was found in both extracts, has shown neurite outgrowth-promoting activity in neuronal cultures, suggesting that the neurotrophic activity of garlic extracts is attributed, at least in part, to this compound. By using network pharmacology, linalool's role in neuronal development can also be observed through its modulatory effect on the signaling molecules of neurotrophic signaling pathways such as glycogen synthase kinase 3 (GSK3β), extracellular signal-regulated protein kinase (Erk1/2), which was further verified by immunocytochemistry. Overall, these findings provide information on the molecular mechanism of processed and unprocessed garlic for neuronal growth, survival, and memory function which may have the potential for the prevention of several neurological disorders.
大蒜（L.）是一种芳香草本植物，其烹饪和药用价值已有数百年的历史。未经加工的（白）大蒜和经过加工的（黑）大蒜都被认为可以预防神经退行性疾病（如阿尔茨海默病（AD）和帕金森病（PD））的病理生物学，这归因于它们的抗炎和抗氧化特性。关于未经加工和加工的大蒜对神经元突起生长、成熟和突触发育的影响的信息有限。本研究旨在调查和比较未经加工（白蒜提取物，WGE）和加工（黑蒜提取物，BGE）大蒜的乙醇提取物对原代海马神经元成熟的影响。WGE 和 BGE 以剂量依赖的方式刺激神经突生长，最有效的剂量分别为 15 μg/mL 和 60 μg/mL，没有显示细胞毒性。在这个最佳浓度下，两种提取物都促进了轴突和树突的生长和成熟。此外，两种提取物都大大增加了功能性突触的形成。然而，WGE 的作用在神经元的每个发育阶段都更为显著。此外，气相色谱和质谱（GC-MS）分析显示了 BGE 和 WGE 中各种生物活性物质的化学特征。两种提取物中都发现的化合物芳樟醇具有促进神经元培养物中神经突生长的活性，这表明大蒜提取物的神经营养活性至少部分归因于该化合物。通过网络药理学，还可以通过观察芳樟醇对神经营养信号通路（如糖原合酶激酶 3（GSK3β）、细胞外信号调节蛋白激酶（Erk1/2）的信号分子的调节作用，观察到其在神经元发育中的作用，这一作用进一步通过免疫细胞化学得到验证。总的来说，这些发现提供了关于加工和未加工大蒜对神经元生长、存活和记忆功能的分子机制的信息，这可能有潜力预防几种神经退行性疾病。
