Effects of safflower yellow on beta-amyloid deposition and activation of astrocytes in the brain of APP/PS1 transgenic mice.

Safflower yellow (SY), one of traditional Chinese medicine extracted from safflower, has been shown to have neuroprotective effects on animal models of vascular dementia and Alzheimer's diseases (AD), by inhibiting oxidative injury, neuronal apoptosis and tau hyperphosphorylation. In this study, we investigated whether safflower yellow (SY) can improve cognitive function, decrease Amyloid ß (Aß) accumulation and overactivation of astrocytes in AD mouse model. We found that SY treatment significantly ameliorated the learning and memory deficits of APP/PS1 mice. By hematoxylin-eosin staining, we found that the neuronal loss and death in APP/PS1 mice was decreased by SY treatment. Immunohistochemical staining showed that SY treatment dramatically down-regulated Aß1-42 deposition and glial fibrillary acidic protein (GFAP) level in APP/PS1 mice. Biochemical analysis also showed that SY treatment reduced soluble and insoluble Aß1-42 level in the cortex and soluble Aß1-42 level in the hippocampus of APP/PS1 mice. Moreover, we found that SY treatment decreased the expression of proteins related to generation of Aß, and markedly increased expression of enzymes associated with clearance of Aß in the brain of APP/PS1 mice. These results indicate that the SY can serve as a promising therapeutic approach for the treatment of AD.

Safflower yellow ameliorates cognition deficits and reduces tau phosphorylation in APP/PS1 transgenic mice.

Alzheimer's disease (AD), the most common cause of dementia worldwide, is mainly characterized by the aggregated ß-amyloid (Aß) and hyperphosphorylated tau. Safflower yellow (SY) is a novel water extract of natural safflower and has been suggested to ameliorate memory deficits in several animal models of dementia. In this study, we aimed to investigate the effect and mechanism of SY on deficits of learning and memory and hyperphosphorylation of tau in APP/PS1 double transgenic mice. APP/PS1 mice were administered with SY (10, 30, 100 mg/kg) by oral gavage for three months at the age of six months. The ability of learning and memory was investigated using the step-down test and Morris water maze test, and protein level in the brain was evaluated using western blot. Here, we found that SY treatment can improve spatial learning and memory ability, and reduce tau hyperphosphorylation at Ser199, Thr205, Ser396, Ser404 sites in APP/PS1 mice. In addition, the activity the of cyclin-dependent kinase 5 (CDK-5) and glycogen synthase kinase 3ß (GSK-3ß), major kinases involved in tau phosphorylation, was siginificantly decreased in APP/PS1 mice by SY treatment. These results support SY can serve as a promising multitarget neuronal therapeutic agent for the treatment of AD.

Safflower yellow reduces lipid peroxidation, neuropathology, tau phosphorylation and ameliorates amyloid ß-induced impairment of learning and memory in rats.

Insoluble plaques of amyloid ß proteins (Aß) and neurofibrillary tangles of hyperphosphorylated tau are key markers for Alzheimer's disease (AD). Safflower yellow (SY) is one of traditional Chinese medicine extracted from safflower, which is suggested to have therapeutic potential for neurodegenerative disorders. However, whether SY can ameliorate impairment of learning and memory in AD model, and its causal mechanism are still unclear. Here, we applied different doses of SY intragastrically to Wistar rats injected with amyloid ß (1-42) for 1 month. By the Morris water maze test, we found that treatment of SY significantly attenuated amyloid ß (1-42)-induced impairment of memory in rats. Mechanistically, SY treatment increased the level of superoxidedismutase (SOD) and Glutathione peroxidase (GSH-Px), and decreased the level of malondialdehyde (MDA) and acetylcholinesterase (T-CHE) in brain tissues of AD rats. Pathological analysis also showed that SY treatment inhibited the morphological alteration of neurons and tau hyperphosphorylation induced by amyloid ß (1-42)-injection in the cortex and hippocampus. Moreover, SY treatment inhibited CDK-5 and GSK-3 signaling pathways, which are upregulated in AD rats. Our data indicate that safflower yellow can serve as a therapeutic candidate for Alzheimer's disease.