Neuroprotective Effect of Quercetin Encapsulated Liposomes: A Novel Therapeutic Strategy against Alzheimer's Disease

Abstract

Problem statement:The prevalence of Alzheimer's disease is increasing but the efficacy of treatment is still very limited due to various factors including the blood brain barrier. Recent findings demonstrated the crucial role of oxidative stress on the pathophysiology of disease. In addition the burden of blood brain barrier can be overcome by nasal administration and vesicle-carrier mediated delivery system. Based on the potent antioxidant effect of quercetin and the burden of blood brain barrier, we hypothesized that the nasal administration of quercetin liposomes could protect against neurodegeneration in Alzheimer's disease. Approach: This study was designed to evaluate the effect and possible action of nasal administration of quercetin liposomes on neurodegeneration in animal model of Alzheimer's disease. Male Wistar rats were pretreated with quercetin liposomes, containing 0.5 mg of quercetin in 20 μL via intranasal route once daily continually for 2 weeks before and 1 week after AF64A administration. After the quercetin liposomes treatment, the density of neurons and cholinergic neurons in hippocampus were assessed using histochemical and immunohistochemical techniques whereas the activities of Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPx) and Malondialdehide (MDA), a lipid peroxidation product, were determined using biochemical assays. Results: Quercetin liposomes attenuated the degeneration of neurons and cholinergic neurons in hippocampus. The elevation of SOD, CAT and GPx activities and the reduction of MDA in hippocampus were also observed. Therefore, the neuroprotective of quercetin liposomes occurred partly via the reduction of oxidative stress. Conclusion: Our studies suggested that nasal administration of quercetin liposomes may be the potential novel therapeutic strategy against Alzheimer's disease. However, further researches are still essential.

<i>COSCINIUM FENESTRATUM</i> PROTECTS AGAINST ETHANOL-INDUCED NEURODEGENERATION IN ADULT RAT BRAIN

“…Ethanol itself is pro-oxidant because it directly generates reactive oxygen species during its metabolism (Koop, 2006). For the same reason, dietary antioxidant supplementation is now regarded as a neuroprotecting measure to counteract alcohol deleterious effects (Phachonpai et al, 2010;.…”

Getting into the brain: liposome-based strategies for effective drug delivery across the blood&ndash;brain barrier

“…As oxidative stress plays a very important role in the neuropathogenesis of AD, the use of quercetin liposomes has been shown to decrease neuronal oxidative stress. [93][94][95] Moreover, there have been several studies exploring different strategies to block the effects of Aβ and tau proteins that constitute major hallmarks of AD. [84][85][86][87]91 Once encapsulated into liposomes, the H102 peptide, a β-sheet breaker, was able to block the early steps of aggregation and misfolding of the soluble Aβ, improving the spatial memory impairment of AD in rats.…”

“…For AD, 26 full-text article reviews were performed, and 12 studies were included for their fulfillment of inclusion criteria ( Figure 3, Table 3). 80,[83][84][85][86][87][88][89][90][91][92][93][94][95] For PD, 19 full-text articles were reviewed, and eight articles had all the requisites to be considered here ( Figure 3, Table 3). [96][97][98][99][100][101][102][103] Unfortunately, for Huntington's disease, just one full article was analyzed and this article did not show any outcome of interest for this disease, and for this reason was not included here ( Figure 3).…”

Effect of Temperature and Time to the Antioxidant Activity in Plecranthus amboinicus Lour.

“…Plant sourced food antioxidants like vitamin C, vitamin E, carotenes, phenolic acids, phytate and phytoestrogens have been recognized as having the potential to reduce disease risk (Seyydnejad et al, 2010). Many naturally occurring antioxidants-form plant sources-have been identified as free radical scavengers or active oxygen-scavengers Phachonpai et al, 2010).…”