Korean red ginseng polysaccharide as a potential therapeutic agent targeting tau pathology in Alzheimer's disease.

Tau is a microtubule-associated protein that plays a critical role in the stabilization and modulation of neuronal axons. Tau pathology is stronger associated with cognitive decline in patients with Alzheimer's disease (AD) than amyloid beta (Aß) pathology. Hence, tau targeting is a promising approach for the treatment of AD. Previous studies have demonstrated that the non-saponin fraction with rich polysaccharide (NFP) from Korean red ginseng (KRG) can modulate tau aggregation and exert a therapeutic effect on AD. Therefore, we investigated the efficacy of NFP isolated from KRG on tau pathology in experimental models of AD. Our results showed that NFP from KRG ameliorated deposition and hyperphosphorylation of tau in the brain of 3xTg mice. Moreover, NFP from KRG modulated the aggregation and dissociation of tau K18 in vitro. We demonstrated the alleviatory effects of NFP from KRG on hyperphosphorylated tau and tau kinase in okadaic acid-treated HT22 cells. Furthermore, NFP from KRG mitigated Aß deposition, neurodegeneration, and neuroinflammation in 3xTg mice. We revealed the neuroprotective effects of NFP from KRG on tau-induced neuronal loss in HT22 cells. Our results indicate that NFP extracted from KRG is a novel therapeutic agent for the treatment of AD associated with tau pathology.

Red ginseng polysaccharide promotes ferroptosis in gastric cancer cells by inhibiting PI3K/Akt pathway through down-regulation of AQP3.

OBJECTIVE: This study aims to investigate the effect of red ginseng polysaccharide (RGP) on gastric cancer (GC) development and explore its mechanism. METHODS: GC cell lines AGS were treated with varying concentrations of RGP (50, 100, and 200 µg/mL). AGS cells treated with 200 µg/mL RGP were transfected with aquaporin 3 (AQP3) overexpression vector. Cell proliferation, viability, and apoptosis were evaluated by MTT, colony formation assay, and flow cytometry, respectively. Real-time quantitative reverse transcription PCR (qRT-PCR) was used to detect the expression of AQP3. The levels of Fe2+, malondialdehyde, and lactate dehydrogenase were measured using their respective detection kits, and the reactive oxygen species levels was determined by probe 2',7'-dichlorodihydrofluorescein diacetate. The expression of ferroptosis-related protein and PI3K/Akt pathway-related protein were assessed by western blot. In vivo experiments in nude mice were performed and the mice were divided into four groups (n = 5/group) which gavage administrated with 150 mg/kg normal saline, and 75, 150, 300 mg/kg RGP, respectively. Their tumor weight and volume were recorded. RESULTS: RGP treatment effectively inhibited the proliferation and viability of AGS cells in a dosage-dependent manner and induced apoptosis. It induced ferroptosis in AGS cells, as well as inhibiting the expression of PI3K/Akt-related proteins. AQP3 overexpression could reversed the effect of RGP treatment on ferroptosis. Confirmatory in vivo experiments showed that RGP could reduce the growth of implanted tumor, with increased RGP concentration resulting in greater tumor inhibitory effects. CONCLUSION: RGP might have therapeutic potential against GC, effectively inhibiting the proliferation and viability of AGS cells.