Apigenin-rivastigmine hybrids as multi-target-directed liagnds for the treatment of Alzheimer’s disease

A comprehensive review on phytochemistry, bioactivities, toxicity studies, and clinical studies on Ficus carica Linn. leaves

The leaves of Ficus carica Linn. (FC) have been widely used for medicine purposes since ancient times, and its decoction is consumed as tea. Many scientific papers have been published in the literature and the researchers across the world are still exploring the health benefits of FC leaves. In this review, we have collected the literature published since 2010 in the databases: Pubmed, Scopus, Web of Science, SciFinder, Google Scholar, Baidu Scholar and local classic herbal literature. The summary of the chemical constituents in FC leaves, biological activities, toxicity studies, and clinical studies carried out on FC leaves is provided in this review. In addition, the molecular mechanisms of the active constituents in FC leaves are also comprehended. FC leaves are reported to 126 constituents out of which the polyphenolic compounds are predominant. Many scientific studies have proven the antidiabetic, antioxidant, anti-inflammatory, anticancer, anticholinesterase, antimicrobial, hepatoprotective, and renoprotective activities. Many studies have carried out to provide the insights on molecular pathways involved in the biological activities of FC leaves. The toxicity studies have suggested that FC leaves exhibit toxicity only at very high doses. We believe this review serve as a comprehensive resource for those who are interested to understand the scientific evidence that support the medicinal values of FC leaves and also the research gaps to further improve the commercial value and health benefits of FC leaves.

In vitro anti-inflammatory properties of honey flavonoids: A review

Honey is a natural ready-to-eat product rich in flavonoids, which is known by the wound healing properties due to both antibacterial and antioxidant activity. Flavonoids mitigate inflammatory processes, and thus it could currently support studies of anti-inflammatory potential of honeys. In this review, in vitro anti-inflammatory properties of flavonoids found in honey were prioritized. Mechanistic information of specific isolated flavonoids as modulators of inflammatory processes are summarized aiming to stimulate studies regarding the action of honey in inflammatory events. Lastly, a structure-activity relationship (SAR) of flavonoids was also included. Flavonoids found in honey have demonstrated antioxidant properties and ability to inhibit pro-inflammatory enzymes such as COX, LOX, iNOS, and pro-inflammatory mediators, including nitric oxide, cytokines and chemokines. Transcriptional factors such as NF-κB are also modulated by flavonoids, controlling the expression of several inflammatory mediators. SAR studies demonstrate the effect of flavonoids in the prevention of inflammatory cascades. Despite the promising reports of in vitro anti-inflammatory activity, well-designed clinical trials need yet to be performed to confirm the benefits of honeys from different botanical sources in diseases that include episodes of inflammation.

Role of natural products for the treatment of Alzheimer's disease

Negative psychological and physiological consequences of neurodegenerative disorders represent a high social and health cost. Among the neurodegenerative disorders Alzheimer's disease (AD) is recognized as a leading neurodegenerative condition and a primary cause of dementia in the elderlys. AD is considered as neurodegenerative disorder that progressively impairs cognitive function and memory. According to current epidemiological data, about 50 milLion people worldwide are suffering from AD. The primary symptoms of AD are almost inappreciable and usually comprise forgetfulness of recent events. Numerous processes are involved in the development of AD, for example oxidative stress (OS) mainly due to mitochondrial dysfunction, intracellular the accumulation of hyperphosphorylated tau (τ) proteins in the form of neurofibrillary tangles, excessive the accumulation of extracellular plaques of beta-amyloid (Aβ), genetic and environmental factors. Running treatments only attenuate symptoms and temporarily reduce the rate of cognitive progression associated with AD. This means that most treatments focus only on controlLing symptoms, particularly in the initial stages of the disease. In the past, the first choice of treatment was based on natural ingredients. In this sense, diverse natural products (NPs) are capable to decrease the symptoms and alleviate the development of several diseases including AD attracting the attention of the scientific community and the pharmaceutical industry. Specifically, numerous NPs including flavonoids, gingerols, tannins, anthocyanins, triterpenes and alkaloids have been shown anti-inflammatory, antioxidant, anti-amyloidogenic, and anti-choLinesterase properties. This review provide a summary of the pathogenesis and the therapeutic goals of AD. It also discusses the available data on various plants and isolated natural compounds used to prevent and diminish the symptoms of AD.

Design, synthesis and evaluation of novel dimethylamino chalcone-O-alkylamines derivatives as potential multifunctional agents against Alzheimer's disease

A novel series of dimethylamino chalcone-O-alkylamines derivatives was designed and synthesized as multifunctional agents for the treatment of AD. All the target compounds exhibited significant abilities to inhibit and disaggregate Aβ aggregation, and acted as potential selective AChE inhibitors, biometal chelators and selective MAO-B inhibitors. Among these compounds, compound TM-6 showed the greatest inhibitory activity against self-induced Aβ aggregation (IC50 = 0.88 μM) and well disaggregation ability toward self-induced Aβ aggregation (95.1%, 25 μM), the TEM images, molecular docking study and molecular dynamics simulations provided reasonable explanation for its high efficiency, and it was also found to be a remarkable antioxidant (ORAC-FL values of 2.1eq.), the best AChE inhibitor (IC50 = 0.13 μM) and MAO-B inhibitor (IC50 = 1.0 μM), as well as a good neuroprotectant. UV-visual spectrometry and ThT fluorescence assay revealed that compound TM-6 was not only a good biometal chelator by inhibiting Cu2+-induced Aβ aggregation (95.3%, 25 μM) but also could disassemble the well-structured Aβ fibrils (88.1%, 25 μM). Further, TM-6 could cross the blood-brain barrier (BBB) in vitro. More importantly, compound TM-6 did not show any acute toxicity in mice at doses of up to 1000 mg/kg and improved scopolamine-induced memory impairment. Taken together, these data indicated that TM-6, an excellent balanced multifunctional inhibitor, was a potential lead compound for the treatment of AD.

Development of genistein-O-alkylamines derivatives as multifunctional agents for the treatment of Alzheimer's disease

The multi-target-directed ligands have been regarded as the promising multifunctional agents for the treatment of Alzheimer's disease (AD). Based on our previous work, a series of genistein-O-alkylamines derivatives was developed to further explore the structure-activity-relationship. The results showed that compound 7d indicated reversible and highly selective hAChE inhibitory activity with IC₅₀ value of 0.53 μM. Compound 7d also displayed good antioxidant activity (ORAC = 1.1 eq.), promising neuroprotective effect and selective metal chelation property. Moreover, compound 7d significantly inhibited self-induced, hAChE-induced and Cu²⁺-induced Aβ aggregation with 39.8%, 42.1% and 74.1%, respectively, and disaggregated Cu²⁺-induced Aβ_1-42 aggregation (67.3%). In addition, compound 7d was a potential autophagy inducer and improved the levels of GPX4 protein. Furthermore, compound 7d presented good blood-brain-barrier permeability in vitro. More importantly, compound 7d did not show any acute toxicity at doses of up to 1000 mg/kg and presented good precognitive effect on scopolamine-induced memory impairment. Therefore, compound 7d was a promising multifunctional agent for the development of anti-AD drugs.

Therapeutic Potential of Multifunctional Derivatives of Cholinesterase Inhibitors

The aim of this work is to review tacrine analogues from the last three years, which were not included in the latest review work, donepezil and galantamine hybrids from 2015 and rivastigmine derivatives from 2014. In this account, we summarize the efforts toward the development and characterization of non-toxic inhibitors of cholinesterases based on mentioned drugs with various interesting additional properties such as antioxidant, decreasing β-amyloid plaque aggregation, nitric oxide production, pro-inflammatory cytokines release, monoamine oxidase-B activity, cytotoxicity and oxidative stress in vitro and in animal model that classify these hybrids as potential multifunctional therapeutic agents for Alzheimer's disease. Moreover, herein, we have described the cholinergic hypothesis, mechanisms of neurodegeneration and current pharmacotherapy of Alzheimer's disease based on the restoration of cholinergic function through blocking enzymes that break down acetylcholine.