Polyprenols mitigate cognitive dysfunction and neuropathology in the APP/PS1 mouse

Polyprenols in Ginkgo biloba; a review of their chemistry (synthesis of polyprenols and their derivatives), extraction, purification, and bioactivities

The Ginkgo biloba L. (GB) contains high bioactive compounds. To date, flavonoids and terpene trilactone have received the majority of attention in GB studies, and the GB has been utilized globally in functional food and pharmacological firms, with sales > $10 billion since 2017, while the other active components, for instance, polyprenols (a natural lipid) with various bioactivities have received less attention. Hence, this review focused on polyprenols' chemistry (synthesis of polyprenols and their derivatives) extraction, purification, and bioactivities from GB for the first time. The various extractions and purification methods (nano silica-based adsorbent, bulk ionic liquid membrane, etc.) were delved into, and their advantages and limitations were discussed. Besides, numerous bioactivities of the extracted Ginkgo biloba polyprenols (GBP) were reviewed. The review showed that GB contains some polyprenols in acetic esters' form. Prenylacetic esters are free of adverse effects. Besides, the polyprenols from GB have numerous bioactivities such as anti-bacterial, anti-cancer, anti-viral activity, etc. The application of GBPs in the food, cosmetics, and drugs industries such as micelles, liposomes, and nano-emulsions was delved into. Finally, the toxicity of polyprenol was reviewed, and it was concluded that GBP was not carcinogenic, teratogenic, or mutagenic, giving a theoretical justification for using GBP as a raw material for functional foods. This article will aid researchers to better understand the need to explore GBP usage.

Dl-3-n-butylphthalide alleviates cognitive impairment in amyloid precursor protein/presenilin 1 transgenic mice by regulating the striatal-enriched protein tyrosine phosphatase/ERK/cAMP-response element-binding protein signaling pathway

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive impairment and the deposition of amyloid plaques in the brain. In a transgenic mouse model of AD, cognitive impairment and synaptic dysfunction were revealed to be associated with soluble amyloid oligomers and to occur prior to plaque formation. The results of our previous studies revealed that striatal-enriched protein tyrosine phosphatase (STEP)₆₁ negatively regulated the β-amyloid protein-mediated ERK/cAMP-response element-binding protein (CREB) signaling pathway. Dl-3-n-butylphthalide (NBP) is a synthetic compound approved by the Food and Drug Administration of China for the treatment of ischemic stroke in 2002. Studies have shown that the neuroprotective effects of NBP involve multiple mechanisms. The present study further explored the mechanism of NBP therapy in amyloid precursor protein (APP)/presenilin 1 (PS1) transgenic mice, and the involvement of the STEP/ERK/CREB signaling pathway. The results suggested that NBP treatment effectively ameliorated the spatial learning and memory impairment of the APP/PS1 transgenic mice, which was assessed using a Morris water maze. In addition, NBP reduced amyloid-induced activation of STEP₆₁ levels, while increasing phosphorylated (p)-ERK1/2 and p-CREB levels in the cerebral cortex and hippocampus of APP/PS1 transgenic mice by western blotting and immunostaining. In conclusion, the present study provided evidence to suggest that the new drug NBP improved amyloid-induced learning and memory deficits, likely through the regulation of the STEP/ERK/CREB pathway. The results revealed that NBP, as a multi-target drug, may exert a neuroprotective effect. Therefore, NBP may serve as an effective treatment for AD.

High-throughput lipidomics analysis to discover lipid biomarkers and profiles as potential targets for evaluating efficacy of Kai-Xin-San against APP/PS1 transgenic mice based on UPLC-Q/TOF-MS

Lipid metabolism has a significant function in the central nervous system and Alzheimer's disease (AD) is an age-related senile disease characterized by central nerve degeneration. The pathological development of AD is closely related to lipid metabolism disorders. To reveal the influence of Kai-Xin-San (KXS) on lipid metabolism in APP/PSI transgenic mice and potential therapeutic targets for treating AD, brain tissue samples were collected and analyzed by high-throughput lipidomics based on UPLC-Q/TOF-MS. The collected raw data were processed by multivariate data analysis to discover the potential biomarkers and lipid metabolic profiles. Compared with the control wild-type mouse group, nine potential lipid biomarkers were found in the AD model group, of which seven were up-regulated and two were down-regulated. Orally administrated KXS can reverse the changes in these potential biomarkers. Compared with the model group, a total of six differential metabolites showed a recovery trend and may be potential targets for KXS to treat AD. This study showed that high-throughput lipidomics can be used to discover the perturbed pathways and lipid biomarkers as potential targets to reveal the therapeutic effects of KXS.

Herbal Formula Fo Shou San Attenuates Alzheimer's Disease-Related Pathologies via the Gut-Liver-Brain Axis in APP/PS1 Mouse Model of Alzheimer's Disease

Fo Shou San (FSS) is an ancient paired-herb decoction, used in China to treat blood deficiency, blood stasis, stroke, and ischemic cerebral vascular disease for about one thousand years. The mechanisms associated with these properties, however, are not completely understood. Gut bacteria, gut bacterial lipopolysaccharides (LPS), alkaline phosphatase (AP), and lipid peroxidation are common biochemical signaling that takes place on gut-liver-brain axis. Growing evidences have revealed that gut bacterial lipopolysaccharides (LPS) enter the systemic circulation via the portal vein, and finally entering the brain tissue is an important cause of inflammatory degeneration of Alzheimer's disease (AD). Alkaline phosphatase (AP) dephosphorylates LPS forming a nontoxic LPS and reduces systemic inflammation via gut-liver-brain axis. In this study, to identify the differentially gut-liver-brain axis among APP/PS1 mice, FSS-treated APP/PS1 mice, and control mice, behavioral tests were performed to assess the cognitive ability and hematoxylin-eosin staining was used to assess neuronal damage in the hippocampus; immunohistochemistry, western blotting, a quantitative chromogenic end-point Tachypleus amebocyte lysate (TAL) assay kit, Malondialdehyde (MDA) assay kit, AP Assay Kit, and real-time quantitative PCR (qPCR) were used to assess the level of LPS, MDA, AP, and gut bacteria. We found that FSS regulates gut-liver-brain axis to regulate AP and gut bacteria and attenuate the LPS-related systemic inflammation, oxidative stress (MDA), and thereby AD-related pathology in APP/PS1 mice. This is the first study to provide a reference for FSS-treated AD mice to aid in understanding the underlying mechanisms of FSS. FSS may also improve gastrointestinal tract barrier and blood-brain barrier and thus ameliorates the symptoms of AD; this is subject to our further study.