The Additive Effects of Low Dose Intake of Ferulic Acid, Phosphatidylserine and Curcumin, Not Alone, Improve Cognitive Function in APPswe/PS1dE9 Transgenic Mice

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

Therapeutic potential of natural products against Alzheimer's disease via autophagic removal of Aβ

The pathological features of Alzheimer's disease (AD), a progressive neurodegenerative disorder, include the deposition of extracellular amyloid beta (Aβ) plaques and intracellular tau neurofibrillary tangles. A decline in cognitive ability is related to the accumulation of Aβ in patients with AD. Autophagy, which is a primary intracellular mechanism for degrading aggregated proteins and damaged organelles, plays a crucial role in AD. In this review, we summarize the most recent research progress regarding the process of autophagy and the effect of autophagy on Aβ. We further discuss some typical monomers of natural products that contribute to the clearance of Aβ by autophagy, which can alleviate AD. This provides a new perspective for the application of autophagy modulation in natural product therapy for AD.

Phosphatidylserine, inflammation, and central nervous system diseases

Phosphatidylserine (PS) is an anionic phospholipid in the eukaryotic membrane and is abundant in the brain. Accumulated studies have revealed that PS is involved in the multiple functions of the brain, such as activation of membrane signaling pathways, neuroinflammation, neurotransmission, and synaptic refinement. Those functions of PS are related to central nervous system (CNS) diseases. In this review, we discuss the metabolism of PS, the anti-inflammation function of PS in the brain; the alterations of PS in different CNS diseases, and the possibility of PS to serve as a therapeutic agent for diseases. Clinical studies have showed that PS has no side effects and is well tolerated. Therefore, PS and PS liposome could be a promising supplementation for these neurodegenerative and neurodevelopmental diseases.

Inorganic Nanomaterials Versus Polymer-Based Nanoparticles for Overcoming Neurodegeneration

Neurodegenerative disorders (NDs) affect a great number of people worldwide and also have a significant socio-economic impact on the aging population. In this context, nanomedicine applied to neurological disorders provides several biotechnological strategies and nanoformulations that improve life expectancy and the quality of life of patients affected by brain disorders. However, available treatments are limited by the presence of the blood–brain barrier (BBB) and the blood–cerebrospinal fluid barrier (B–CSFB). In this regard, nanotechnological approaches could overcome these obstacles by updating various aspects (e.g., enhanced drug-delivery efficiency and bioavailability, BBB permeation and targeting the brain parenchyma, minimizing side effects). The aim of this review is to carefully explore the key elements of different neurological disorders and summarize the available nanomaterials applied for neurodegeneration therapy looking at several types of nanocarriers. Moreover, nutraceutical-loaded nanoparticles (NPs) and synthesized NPs using green approaches are also discussed underling the need to adopt eco-friendly procedures with a low environmental impact. The proven antioxidant properties related to several natural products provide an interesting starting point for developing efficient and green nanotools useful for neuroprotection.

Efficacy and safety of adjuvant curcumin therapy in ulcerative colitis: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumin, an active polyphenol extracted from Traditional Chinese medicine Curcuma longa (turmeric), has shown many health-related benefits and pharmacological effects. Adjuvant curcumin therapy for ulcerative colitis has become increasingly popular, but its efficacy and safety of which is still controversial. The purpose of this study is to evaluate the efficacy and safety of adjuvant curcumin therapy in ulcerative colitis.

MATERIALS AND METHODS

The Medline, EMBASE, the Cochrane Library, CNKI, VIP, WanFang, and SinoMed databases were searched from inception to June 2021, to identify all randomized controlled clinical trials with adjuvant curcumin therapy in ulcerative colitis. The primary outcomes were clinical and endoscopic remission, and subgroup analyses were also performed.

RESULTS

Six randomized trials with a total of 385 participants were included in this study. Qualified trials recommended that adjuvant curcumin therapy for ulcerative colitis was effective in inducing clinical remission (RR = 2.10, 95% CI 1.13 to 3.89), but not in clinical improvement (RR = 1.62, 95% CI 1.00 to 2.61), endoscopic remission (RR = 4.17, 95% CI 0.63 to 27.71) or endoscopic improvement (RR = 4.13, 95% CI 0.20 to 87.07). Included studies showed that appropriate dosage, formation, longer duration, and topical medication may have a greater potential advantage. No severe adverse effects had been reported.

CONCLUSIONS

Available evidence suggested that adjuvant curcumin therapy may be effective for clinical remission in ulcerative colitis patients without causing severe adverse effects. The appropriate methods of administration can achieve better curative effect, which requires further study to verify.

Therapeutic Potential of Ferulic Acid in Alzheimer's Disease

Alzheimer's Disease (AD) is one of the most important neurodegenerative diseases and it covers 60% of whole dementia cases. AD is a constantly progressing neurodegenerative disease as a result of the production of β-amyloid (Aβ) protein and the accumulation of hyper-phosphorylated Tau protein; it causes breakages in the synaptic bonds and neuronal deaths to a large extent. Millions of people worldwide suffer from AD because there is no definitive drug for disease prevention, treatment or slowdown. Over the last decade, multiple target applications have been developed for AD treatments. These targets include Aβ accumulations, hyper-phosphorylated Tau proteins, mitochondrial dysfunction, and oxidative stress resulting in toxicity. Various natural or semisynthetic antioxidant formulations have been shown to protect brain cells from Aβ induced toxicity and provide promising potentials for AD treatment. Ferulic acid (FA), a high-capacity antioxidant molecule, is naturally synthesized from certain plants. FA has been shown to have different substantial biological properties, such as anticancer, antidiabetic, antimicrobial, anti-inflammatory, hepatoprotective, and cardioprotective actions, etc. Furthermore, FA exerted neuroprotection via preventing Aβ-fibril formation, acting as an anti-inflammatory agent, and inhibiting free radical generation and acetylcholinesterase (AChE) enzyme activity. In this review, we present key biological roles of FA and several FA derivatives in Aβ-induced neurotoxicity, protection against free radical attacks, and enzyme inhibitions and describe them as possible therapeutic agents for the treatment of AD.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.

Innovative Therapies and Nanomedicine Applications for the Treatment of Alzheimer's Disease: A State-of-the-Art (2017-2020)

The field of nanomedicine is constantly expanding. Since the first work dated in 1999, almost 28 thousand articles have been published, and more and more are published every year: just think that only in the last five years 20,855 have come out (source PUBMED) including original research and reviews. The goal of this review is to present the current knowledge about nanomedicine in Alzheimer’s disease, a widespread neurodegenerative disorder in the over 60 population that deeply affects memory and cognition. Thus, after a brief introduction on the pathology and on the state-of-the-art research for NPs passing the BBB, special attention is placed to new targets that can enter the interest of nanoparticle designers and to new promising therapies. The authors performed a literature review limited to the last three years (2017–2020) of available studies with the intention to present only novel formulations or approaches where at least in vitro studies have been performed. This choice was made because, while limiting the sector to nanotechnology applied to Alzheimer, an organic census of all the relevant news is difficult to obtain.

Interplay of curcumin and its liver metabolism on the level of Aβ in the brain of APPswe/PS1dE9 mice before AD onset

BACKGROUND

An increasing number of studies have shown that Alzheimer's disease (AD) is a systemic disease characterized by brain dysfunction. In this study, we aimed to investigate the effects of curcumin on the liver, an important metabolic organ, and on the brain in APP_swe/PS1_dE9 (APP/PS1) mice, and the interaction between these effects.

METHODS

Curcumin was administered to 5-month-old APP/PS1 transgenic mice for 7 consecutive days using the intragastric (ig) and intracerebroventricular (icv) administration routes, respectively. The object recognition test (ORT) and open field test (OFT) were conducted to evaluate long-term recognition memory and anxiety after curcumin administration. Levels of β-amyloid (Aβ), Aβ_42, and interleukin-1β (IL-1β) in the brain and liver were measured.

RESULTS

In the ig group, curcumin ameliorated anxiety-like behavior and suppressed the level of Aβ₄₂ in the liver and the total Aβ in the brain. In the icv group, curcumin treatment affected the distribution of Aβ₄₂ and IL-1β in the brain compared to the liver. There was a significant treatment-region interaction in Aβ₄₂ level for the icv group (F(1, 24) = 17.7, p < 0.001), but no interaction effect for the ig group.

CONCLUSION

Our findings show that curcumin administration before Aβ deposition shows promise for preventing AD, and further that curcumin may play an important role in the clearance of Aβ₄₂ from the brain to the peripheral circulation.