African mistletoe (loranthaceae) enhances spatial and non-spatial working memory in hypercholesterolemia model of Alzheimer's disease

Abstract

Background: Cholesterol is invaluable in the development and maintenance of the structural integrity of the brain. However, a disturbed cholesterol homeostasis and heightened level of cholesterol lead to memory deficit, a major cognitive hallmark of Alzheimer's dementia. African Mistletoe (Loranthaceae) has long been categorized as a traditional herbal medicine in Africa. In addition to its application in cancer therapy, mistletoe has also been used in the treatment of hypertensions, diabetes mellitus, and epilepsies in Africa. In the present study, we investigated the memory enhancing property in mouse hypercholesterolemia model of AD

Materials and Methods: An experimental model of AD was established by feeding the mice with a high cholesterol diet and CuSO ₄-poisoned drinking water for 60 days. The  mice were subsequently treated with mistletoe methanolic extract preparation via oral administration (200 mg/kg daily for 15 days) or with normal saline (0.5 ml) as a Control. Behavioural changes were recorded with the Y-Maze and Novel Object Recognition tests. Histopathological changes were observed by haematoxylin and eosin staining. Plasma cholesterol levels were determined using colorimetric assay. With the aid of GraphPad Prism V.5.0 software, data were analysed using One-way ANOVA and Two-way ANOVA followed by Tukey's multiple range and Benferroni post-tests, respectively. The level of statistical significance was put at p<0.05.

Results: Memory deficits were recorded in animals following a high cholesterol diet and CuSO ₄- poisoned  drinking water compared with the Control; post treatment with African mistletoe significantly ameliorated memory deficits. Furthermore, histoarchitectural changes were observed in the AD model and marked restorations were seen after treatment with African mistletoe methanolic extract.

Conclusion: The present investigation has demonstrated that methanolic extract of African mistletoe enhances memory following impairment induced by a high cholesterol diet feeding in mice.