Phytochemicals from Achillea fragrantissima are Modulators of AβPP Metabolism

Alzheimer's disease and neuroinflammation: will new drugs in clinical trials pave the way to a multi-target therapy?

Despite extensive research, no disease-modifying therapeutic option, able to prevent, cure or halt the progression of Alzheimer's disease [AD], is currently available. AD, a devastating neurodegenerative pathology leading to dementia and death, is characterized by two pathological hallmarks, the extracellular deposits of amyloid beta (Aβ) and the intraneuronal deposits of neurofibrillary tangles (NFTs) consisting of altered hyperphosphorylated tau protein. Both have been widely studied and pharmacologically targeted for many years, without significant therapeutic results. In 2022, positive data on two monoclonal antibodies targeting Aβ, donanemab and lecanemab, followed by the 2023 FDA accelerated approval of lecanemab and the publication of the final results of the phase III Clarity AD study, have strengthened the hypothesis of a causal role of Aβ in the pathogenesis of AD. However, the magnitude of the clinical effect elicited by the two drugs is limited, suggesting that additional pathological mechanisms may contribute to the disease. Cumulative studies have shown inflammation as one of the main contributors to the pathogenesis of AD, leading to the recognition of a specific role of neuroinflammation synergic with the Aβ and NFTs cascades. The present review provides an overview of the investigational drugs targeting neuroinflammation that are currently in clinical trials. Moreover, their mechanisms of action, their positioning in the pathological cascade of events that occur in the brain throughout AD disease and their potential benefit/limitation in the therapeutic strategy in AD are discussed and highlighted as well. In addition, the latest patent requests for inflammation-targeting therapeutics to be developed in AD will also be discussed.

Antitumor activity of methoxylated flavonoids separated from Achillea fragrantissima extract in Ehrlich’s ascites carcinoma model in mice

Introduction: Achillea fragrantissima extract has been used in folk medicine as an anticancer. The present study describes the antitumor activities of the extract and the flavonoid compounds and attempts to explain the mechanisms underlying these activities. Methods: The whole plant of A. fragrantissima was collected and ground to produce a fine powder which subjected to the maceration process. Step gradient elution was used using silica gel vacuum liquid chromatography (VLC). The fractions were compared by thin layer chromatography (TLC) and concentrated. Final purification was performed using Sephadex LH-20 to give three compounds cirsiliol, chrysosplenol D and cirsimaritin from F4 and one compound, eupatilin-7-methyl ether from F6. In this study, Ehrlich’s ascites carcinoma (EAC) model was used as the model of cancer. Results: Achillea fragrantissima extract and its isolated methoxylated flavonoids significantly reduced the weight of tumor discs compared to EAC-control group. In addition, cirsimaritin and eupatilin 7-methyl ether treatments produced a dose-dependent reduction in tumor weight. Serum tumor necrosis factor-alpha (TNF-ɑ) level showed that A. fragrantissima extract and its isolated methoxylated flavonoid compounds significantly reduced its serum level compared to the EAC-control group. Furthermore, A. fragrantissima extract and the flavonoids significantly increased the Total antioxidant capacity (TAC) compared to EAC-control. A. fragrantissima extract and its isolated methoxylated flavonoids produced a better differentiation of tumor cells, with reduced nuclear pleomorphism and better formed tubular structures especially with high dose indicating the induction of apoptotic mechanism. Conclusion: Achillea fragrantissima extract and its isolated methoxylated flavonoids exhibit antitumor activities that may be attributed to the antioxidant properties and the induction of the apoptotic process.