Abstract

Alzheimer’s disease is characterized by progressive degeneration of cortical and hippocampal neurons. This study aims to characterize the metabolic profiles of the hydro-ethanolic extracts of Bacopa monnieri L. (BM) and Rosmarinus officinalis L. (RO) cultivated in Egypt via UPLC–ESI/MS analyses and reveal their possible mechanism of the prophylactic effect(s) on neuro-degeneration in rat model of Alzheimer’s disease (AD). Here, UPLC–ESI/MS analyses were employed for the characterization of hydro-ethanolic extracts. Forty-two male albino rats were intra-peritoneally injected with Aluminum chloride at a dose of 4.2 mg/kg to induce AD. The extracts of BM and RO were separately orally administered at doses of 300 and 450 mg/kg, and Donazil® was orally administered at dose 2.5 mg/kg. Serum levels of malondialdehyde (MDA), and total antioxidant capacity (TAC) were measured using ELISA. Further, Amyloid β-protein, acetylcholinesterase (AChE), τ-protein and serotonin levels were measured in brain tissue using ELISA. The UPLC–ESI/MS analyses revealed the presence of fifteen and seventeen active metabolites in BM and RO extracts respectively which may account for their effects on neuro-degeneration. Serum level of MDA, amyloid β-protein, AChE and τ-protein were significantly decreased in herbal treated groups when compared to AD group (P value < 0.0001). On the other hand, TAC and serotonin levels were significantly elevated in groups treated with BM and RO compared to AD group (P value < 0.0001). Consequently, BM and RO extracts were found to have a potential neuroprotective effect in AD rat model due to their variety of active metabolites.

Key words: Alzheimer's, serotonin, anti-AChE, antioxidant, Bacopa monnieri, Rosmarinus officinalis.