Chemical fingerprint of Bacopa monnieri L. and Rosmarinus officinalis L. and their neuroprotective activity against Alzheimers disease in rat models putative modulation via cholinergic and monoaminergic pathways

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.