與年齡相關的認知衰退，或正常（非病理性的）的認知老化是人體衰老的一個過程。隨著時間的推移，人類老化會伴隨一定程度的認知能力下降，與認知能力相關的一些生物基礎也逐漸老化和減退，包括腦容量的下降，神經纖維纏結，髓鞘完整性喪失，皮質變薄，受損的五羥色胺，乙酰膽鹼和多巴胺與受體結合和信號轉導。

在日益老齡化的社會中，預防和治療中老年人認知功能障礙具有非常大的重要意義。這項研究的結果（人參皂苷Rg1能夠預防認知障礙和海馬衰老）可能為藥物開指示了一條方向。

Related Articles:
Ginsenoside rg1 prevents cognitive impairment and hippocampus senescence in a rat model of d-galactose-induced aging.
PLoS One. 2014;9(6):e101291
Authors: Zhu J, Mu X, Zeng J, Xu C, Liu J, Zhang M, Li C, Chen J, Li T, Wang Y

Abstract
Neurogenesis continues throughout the lifetime in the hippocampus, while the rate declines with brain aging. It has been hypothesized that reduced neurogenesis may contribute to age-related cognitive impairment.
Ginsenoside Rg1 is an active ingredient of Panax ginseng in traditional Chinese medicine, which exerts anti-oxidative and anti-aging effects.
This study explores the neuroprotective effect of ginsenoside Rg1 on the hippocampus of the D-gal (D-galactose) induced aging rat model. Sub-acute aging was induced in male SD rats by subcutaneous injection of D-gal (120 mg/kg·d) for 42 days, and the rats were treated with ginsenoside Rg1 (20 mg/kg·d, intraperitoneally) or normal saline for 28 days after 14 days of D-gal injection.
In another group, normal male SD rats were treated with ginsenoside Rg1 alone (20 mg/kg·d, intraperitoneally) for 28 days.
It showed that administration of ginsenoside Rg1 significantly attenuated all the D-gal-induced changes in the hippocampus, including cognitive capacity, senescence-related markers and hippocampal neurogenesis, compared with the D-gal-treated rats.
Further investigation showed that ginsenoside Rg1 protected NSCs/NPCs (neural stem cells/progenitor cells) shown by increased level of SOX-2 expression; reduced astrocytes activation shown by decrease level of Aeg-1 expression; increased the hippocampal cell proliferation; enhanced the activity of the antioxidant enzymes GSH-Px (glutathione peroxidase) and SOD (Superoxide Dismutase); decreased the levels of IL-1β, IL-6 and TNF-α, which are the proinflammatory cytokines; increased the telomere lengths and telomerase activity; and down-regulated the mRNA expression of cellular senescence associated genes p53, p21Cip1/Waf1 and p19Arf in the hippocampus of aged rats.
Our data provides evidence that ginsenoside Rg1 can improve cognitive ability, protect NSCs/NPCs and promote neurogenesis by enhancing the antioxidant and anti-inflammatory capacity in the hippocampus.
PMID: 24979747 [PubMed - in process]

Source: Dammarane Saponins