ABSTRACT
Alzheimer's disease [AD] is a progressive neurodegenerative disorder. Increased oxidative stress has been shown to be a prominent and early feature in AD. Medicinal plants with antioxidant activities have been used traditionally in the treatment of several human diseases. The present study aimed to investigate the possible prophylactic and therapeutic effects of aqueous infusions of Boswellia serrata on AD induced in rats. Ninety adult male Sprague Dawley rats were enrolled in this study and were divided into 9 groups [ten each]. Groups 1-5 for the protective study, 6-9 for the therapeutic study as follows: 1st group: negative control group in which rats were given daily oral dose of 1ml tab water, 2nd group: induction of animal model mimicking AD by daily oral administration of aluminum chloride [AlCl[3]] to rats in a dose of 17 mg/kg for 4 successive weeks; 3rd, 4th, and 5th groups: rats were orally given rivastigmine [0.3 mg/kg/day], Boswellia serrata [45 and 90 mg/kg /day respectively], for two weeks followed by combination of each treatment with AlCl[3] for another four successive weeks. Groups 6-9 for the therapeutic study: 6th group: AD induced group which acted as a model mimicking AD in humans received orally 1ml of tab water only for 12 successive weeks and served as therapeutic untreated group. 7th, 8th and 9th groups: AD rats treated orally with rivastigmine [0.3 mg/kg/day], Boswellia serrata [45 and 90 mg/kg /day respectively] daily for 12 successive weeks. At baseline [before induction of AD], before treatment, then after each treatment, behavioral stress tests as activity cages, rotarod, and T-maze tests were done. At the end of all experiments rats' brains were dissected and divided sagitally into two portions, the first portion was homogenized for determination of acetylcholine [Ach] and acetycholinesterase [AchE] levels. The second portion was used for histopathologic examination. The present study indicated that Boswellia serrata when was used for treatment of AlCl[3] induced AD, its high dose only produced increased activity of rats in the activity cage, duration of rats revolving on the rotarod and reduction in the duration taken by rats to reach food in the T-maze test. Both doses produced elevation of Ach level and reduction of AchE activity in brain homogenates. These results were consistent with the histopathological findings in brain tissues where, the neurons appear more or less like normal ones. This study revealed that the treatment of AD-induced rats with aqueous infusions of B. serrata significantly ameliorates the neurodegenerative characteristics of ADs in rats