Objective Analysis and adscription of volatiles from Guizhi Tang and study on its improvement of the learning and memory in dementia mice induced by scopolamine.Methods The volatile oil from Guizhi Tang(GZT),Guizhi and Shengjiang was extracted using steam distillation method and was analyzed by GC-MS. Morris water maze and step-down test were carried out for obtain the difference of the learning and memory improvement in 40 ICR mice from randomized groups, such as the control group, the model group, the donepezil group (2 mg/kg), the low dose of volatile oil of GZT (5 mg/kg), and the high dose of volatile oil of GZT (20 mg/kg), and ACh, AchE, BchE and chE in serum were detected by ELISA. Results Among 38 identyfied volatile ingredients from GZT, 18(44% in weight) was from Guizhi, and 9 was from Shengjiang. Compared with the model group, the low and high dose of GZT volatile oil significantly increased swimming distance ratio in destination quadrant (26.74% ± 16.42%vs.9.42% ± 8.50%, P<0.05); goal quadrant time scale (43.51% ± 25.12%vs. 14.50% ± 12.23%,P<0.05)) increased significantly than the model group ; the number of errors in the experiment platform (1.63 ± 1.19vs. 0.25 ± 0.46, P<0.05) obviously increased than model group ; platform test in the made errors times (0.57 ± 0.98vs. 4.43 ± 2.4, P<0.05) significantly reduced. The GZT total volatile oil groups significantly reduced cognitive obstacles small rat serum in the cholinester enzyme (chE) (140.90 ± 3.27, 144.79 ± 6.71vs. 134.49 ± 3.36,P<0.05); acetylcholinesterase (AchE) (3.30 ± 1.31, 3.94 ± 0.78 vs.8.52 ± 3.39,P<0.05); butyrylcholinesterase (BchE) (3.22 ± 0.45, 3.66 ± 0.53vs. 7.99 ± 0.79,P<0.05); and acetylcholine (Ach) (4.10 ± 0.38, 3.03 ± 0.25vs.1.72 ± 0.50, P<0.05) significantly increased.Conclusions The GZT volatile oil mainly from Guizhi and Shengjiang can improve the learning and memory ability in dementia mice induced by scopolamine via a cholinergic mechnism.

Demyelination of the central nervous system often occurs in neurodegenerative diseases， such as multiple sclerosis （MS）. The myelin sheath， a layer of myelin membrane wrapping the axon， plays a role in the rapid conduction and metabolic coupling of impulses for neurons. The exposure of the axon will lead to axonal degeneratio， and further neuronal degeneration， which is the main cause of dysfunction and even disability in patients with demyelinating neurodegenerative diseases. In addition to the demyelination of mature myelin sheath， remyelination disorder is also one of the major reasons leading to the development of the diseases. The myelin sheath is composed of oligodendrocytes （OLs） derived from oligodendrocyte progenitor cells （OPCs） which are differentiated from neural stem cells （NSCs）. The process of myelin regeneration， i.e.， remyelination， is the differentiation of NSCs into OLs. Recent studies have shown that this process is regulated by a variety of genes. MicroRNAs， as important regulators of neurodegenerative diseases， form a complex regulatory network in the process of myelin regeneration. This review summarizes the main molecular pathways of myelin regeneration and microRNAs involved in this process and classifies the mechanisms and targets. This review is expected to provide a theoretical reference for the future research on the treatment of demyelinating diseases by targeting the regulation of microRNAs.