Application of UPLC-Triple TOF-MS/MS metabolomics strategy to reveal the dynamic changes of triterpenoid saponins during the decocting process of Asian ginseng and American ginseng.

Triterpenoid saponins are the main bioactive components contributed to the nutritional value of ginseng, and different process conditions will affect their content and quality. To study the holistic characterization and dynamic changes of triterpenoid saponins in Asian ginseng (ASG) and American ginseng (AMG) during soaking and decoction, a UPLC-Triple TOF-MS/MS-based metabolomics strategy was used to characterize and discover differential saponin markers. In total, 739 triterpenoid saponins (including 225 potential new saponins) were identified from ASG and AMG in untargeted metabolomics. Based on PCA and OPLS-DA, 51 and 48 saponin markers were screened from soaked and decocted ASG and AMG, respectively. Additionally, targeted metabolomics analysis and HCA of 22 ginsenoside markers suggested that decoction of ASG and AMG for 2 h to 4 h could significantly increase the contents of rare ginsenosides (G), such as G-Rg3, G-Rg5, G-F4. This study provides a scientific insight that high boiling combined with simmering enriches ASG and AMG extracts with rich rare ginsenosides that are more beneficial to human health.

Synaptic aging disrupts synaptic morphology and function in cerebellar Purkinje cells.

Synapses are key structures in neural networks, and are involved in learning and memory in the central nervous system. Investigating synaptogenesis and synaptic aging is important in understanding neural development and neural degeneration in diseases such as Alzheimer disease and Parkinson's disease. Our previous study found that synaptogenesis and synaptic maturation were harmonized with brain development and maturation. However, synaptic damage and loss in the aging cerebellum are not well understood. This study was designed to investigate the occurrence of synaptic aging in the cerebellum by observing the ultrastructural changes of dendritic spines and synapses in cerebellar Purkinje cells of aging mice. Immunocytochemistry, DiI diolistic assays, and transmission electron microscopy were used to visualize the morphological characteristics of synaptic buttons, dendritic spines and synapses of Purkinje cells in mice at various ages. With synaptic aging in the cerebellum, dendritic spines and synaptic buttons were lost, and the synaptic ultrastructure was altered, including a reduction in the number of synaptic vesicles and mitochondria in presynaptic termini and smaller thin specialized zones in pre- and post-synaptic membranes. These findings confirm that synaptic morphology and function is disrupted in aging synapses, which may be an important pathological cause of neurodegenerative diseases.