Pseudoginsenoside-F11 attenuates cognitive dysfunction and tau phosphorylation in sporadic Alzheimer's disease rat model.

We previously reported that pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, significantly ameliorated Alzheimer's disease (AD)-associated cognitive defects in APP/PS1 and SAMP8 mice by inhibiting Aß aggregation and tau hyperphosphorylation, suggesting a potential therapeutic effect of PF11 in the treatment of AD. In the present study we further evaluated the therapeutic effects of PF11 on relieving cognitive impairment in a rat model of sporadic AD (SAD). SAD was induced in rats by bilateral icv infusion of streptozotocin (STZ, 3 mg/kg). The rats were treated with PF11 (2, 4, 8 mg·kg-1·d-1, ig) or a positive control drug donepezil (5 mg·kg-1·d-1, ig) for 4 weeks. Their cognitive function was assessed in the nest building, Y-maze, and Morris water maze tests. We showed that STZ icv infusion significantly affected the cognitive function, tau phosphorylation, and insulin signaling pathway in the hippocampus. Furthermore, STZ icv infusion resulted in significant upregulation of the calpain I/cyclin-dependent protein kinase 5 (CDK5) signaling pathway in the hippocampus. Oral administration of PF11 dose-dependently ameliorated STZ-induced learning and memory defects. In addition, PF11 treatment markedly reduced the neuronal loss, protected the synapse structure, and modulated STZ-induced expression of tau phosphorylation by regulating the insulin signaling pathway and calpain I/CDK5 signaling pathway in the hippocampus. Donepezil treatment exerted similar beneficial effects in STZ-infused rats as the high dose of PF11 did. This study highlights the excellent therapeutic potential of PF11 in managing AD.

Identification of a novel triterpene saponin from Panax ginseng seeds, pseudoginsenoside RT8, and its antiinflammatory activity.

BACKGROUND: Panax ginseng Meyer (Araliaceae) is a highly valued medicinal plant in Asian regions, especially in Korea, China, and Japan. Chemical and biological studies on P. ginseng have focused primarily on its roots, whereas the seeds remain poorly understood. This study explores the phytochemical and biological properties of compounds from P. ginseng seeds. METHODS: P. ginseng seeds were extracted with methanol, and 16 compounds were isolated using various chromatographic methods. The chemical structures of the isolates were determined by spectroscopic data. Antiinflammatory activities were evaluated for triterpene and steroidal saponins using lipopolysaccharide-stimulated RAW264.7 macrophages and THP-1 monocyte leukemia cells. RESULTS: Phytochemical investigation of P. ginseng seeds led to the isolation of a novel triterpene saponin, pseudoginsenoside RT8, along with 15 known compounds. Pseudoginsenoside RT8 exhibited more potent antiinflammatory activity than the other saponins, attenuating lipopolysaccharide-mediated induction of proinflammatory genes such as interleukin-1ß, interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2, and matrix metalloproteinase-9, and suppressed reactive oxygen species and nitric oxide generation in a dose-dependent manner. CONCLUSION: These findings indicate that pseudoginsenoside RT8 has a pharmaceutical potential as an antiinflammatory agent and that P. ginseng seeds are a good natural source for discovering novel bioactive molecules.

A new ocotillol-type ginsenoside from stems and leaves of Panax quinquefolium L. and its anti-oxidative effect on hydrogen peroxide exposed A549 cells.

A new ocotillol-type ginsenoside, namely 12-one-pseudoginsenoside F11 (12-one-PF11), was isolated from stems and leaves of Panax quinquefolium, whose structure was elucidated 6-O-[α-L-rhamnopyranosyl-(1-2)-ß-D-glucopyranosyl]-dammar-12-one-20S,24R-epoxy-3ß,6α,25-triol. 12-one-PF11 significantly suppressed hydrogen peroxide induced oxidative stress in human lung carcinoma A549 cells. As compared with model group, 12-one-PF11 improved cell viability of A549 cells in a dose-dependent manner, and significantly decreased the generation of malondialdehyde (MDA) and increased production of superoxide dismutase (SOD) and glutathione (GSH) and protein expression levels of nuclear related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in A549 cells.

A Novel Strategy for Quantitative Analysis of Major Ginsenosides in Panacis Japonici Rhizoma with a Standardized Reference Fraction.

Panacis Japonici Rhizoma (Zhu-Jie-Shen in Chinese), the root of P. japonicus C.A. Mey., is commonly used in traditional Chinese Medicine. Saponins are the major bioactive compounds in this herb. The similarity of polarity and structure of the natural products in herb caused the difficulty of purification and resulted in the shortage and high cost of the reference compounds, which has greatly hindered efforts toward quantification in quality control. A novel strategy using a standardized reference fraction for qualification of the major saponins in Panacis Japonici Rhizoma was proposed to easily and effectively control the quality of PJR. The strategy is feasible and reliable, and the methodology of the developed approach is also validated. The standardized reference fraction was used for quantification, which might solve the shortage of the pure reference compounds in the quality control of herbal medicines.