Conjugation, Prodrug, and Co-Administration Strategies in Support of Nanotechnologies to Improve the Therapeutic Efficacy of Phytochemicals in the Central Nervous System

Quercetin-functionalized nanomaterials: Innovative therapeutic avenues for Alzheimer's disease management

Alzheimer's Disease (AD) is a major global health challenge, largely due to its complex pathology and the limited effectiveness of existing treatments. Quercetin, a bioactive compound belonging to the flavonoid class, its promising antioxidant, anti-inflammatory, and neuroprotective effects in addressing AD. However, its therapeutic potential is hindered by challenges such as low bioavailability, instability, and restricted permeability across the blood-brain barrier (BBB). Advances in nanotechnology have paved the way for quercetin-functionalized nanomaterials, offering solutions to these challenges. These nanostructures enhance quercetin's solubility, stability, and targeted brain delivery, thereby augmenting its therapeutic potential. In this review, nanocarriers (like liposomes, polymeric nanoparticles, and metal-based nanosystems) are explored for their potential application in optimizing quercetin delivery in AD management. It discusses the mechanisms by which these nanostructures enhance BBB penetration and exert neuroprotective effects. Furthermore, the review examines the outcomes of preclinical and in vitro studies, while addressing the challenges of scaling these approaches for clinical application. By merging the fields of nanotechnology and neurotherapeutics, the importance of quercetin-functionalized nanomaterials in advancing AD management strategies is underscored in this review.

Curcumin-Loaded Gelatin Nanoparticles Cross the Blood-Brain Barrier to Treat Ischemic Stroke by Attenuating Oxidative Stress and Neuroinflammation

Background

Ischemic stroke is a medical emergency for which effective treatment remains inadequate. Curcumin (Cur) is a natural polyphenolic compound that is regarded as a potent neuroprotective agent. Compared to synthetic pharmaceuticals, Cur possesses minimal side effects and exhibits multiple mechanisms of action, offering significant advantages in the treatment of ischemic stroke. However, drawbacks such as poor water solubility and transmembrane permeability limit the efficacy of Cur. In recent years, nano-delivery systems have attracted great interest in the field of stroke therapy as an effective method to improve drug solubility and cross the blood-brain barrier (BBB).

Methods

In this study, a novel nanomedicine (Cur@GAR NPs) for ischemic stroke treatment was developed based on Cur-loaded gelatin nanoparticles (Cur@Gel NPs) that were then functionalized and modified with rabies virus glycoprotein (RVG29) to target brain tissue. The stability, antimicrobial properties, antioxidant properties, neuroprotective effects, neuronal cell uptake, and biocompatibility of Cur@GAR NPs were investigated in vitro. The in vivo therapeutic effect of Cur@GAR NPs on ischemic stroke was investigated in a middle cerebral artery occlusion (MCAO) rat model using the Morris water maze test and the open field test, and the potential mechanism of action was further investigated by histological analysis.

Results

The resulting Cur@GAR NPs improved the solubility of Cur and exhibited good dispersion. In vitro studies have shown that Cur@GAR NPs exhibit great antimicrobial properties, antioxidant properties and intracellular reactive oxygen species (ROS) protection. Notably, RVG29 significantly enhanced the uptake of Cur@GAR NPs by SH-SY5Y cells. Furthermore, in vivo studies verified the role of Cur@GAR NPs in reducing nerve damage and supporting neurological recovery. In the MCAO rat model, Cur@GAR NPs significantly attenuated neuroinflammation, reduced neuronal apoptosis and restored behavioral functions to a great extent.

Conclusion

Together these findings implied that Cur@GAR NPs could provide a novel and promising approach for effective ischemic stroke treatment.

Exploring Piperine: Unleashing the multifaceted potential of a phytochemical in cancer therapy

Radiotherapy is a cornerstone in the treatment of solid tumors, with extensive Phase III trials confirming its effectiveness. As advancements in treatment technologies and our understanding of tumor resistance mechanisms continue, the role of radiation oncology is set to become even more pivotal. Addressing the global challenge of lethal cancers demands innovative strategies, particularly in minimizing the side effects associated with traditional chemotherapy and ionizing radiation (IR). Recently, there has been growing interest in natural compounds for radioprotection, aiming to prevent tumor development and metastasis. Piperine, a compound found in black and long pepper, has emerged as a promising chemopreventive agent that works effectively without harming normal cells. Mechanistically, piperine modulates key signaling pathways, inhibits cancer cell migration and invasion, and enhances sensitivity to IR. Combining piperine with radiotherapy offers a compelling approach, boosting treatment efficacy while protecting healthy tissues from radiation damage. Piperine's versatile role goes beyond radiosensitization to include radioprotection by inhibiting NF-κB activation, reducing autophagy, and promoting apoptosis in cancer cells. This dual action makes it a promising candidate for personalized cancer care. As research advances, the therapeutic potential of piperine may drive new frontiers in cancer treatment strategies.

Polyethylene Glycol-Based Polymer-Drug Conjugates: Novel Design and Synthesis Strategies for Enhanced Therapeutic Efficacy and Targeted Drug Delivery

Due to their potential to enhance therapeutic results and enable targeted drug administration, polymer-drug conjugates that use polyethylene glycol (PEG) as both the polymer and the linker for drug conjugation have attracted much research. This study seeks to investigate recent developments in the design and synthesis of PEG-based polymer-drug conjugates, emphasizing fresh ideas that fill in existing knowledge gaps and satisfy the increasing need for more potent drug delivery methods. Through an extensive review of the existing literature, this study identifies key challenges and proposes innovative strategies for future investigations. The paper presents a comprehensive framework for designing and synthesizing PEG-based polymer-drug conjugates, including rational molecular design, linker selection, conjugation methods, and characterization techniques. To further emphasize the importance and adaptability of PEG-based polymer-drug conjugates, prospective applications are highlighted, including cancer treatment, infectious disorders, and chronic ailments.

Polyphenols in Inner Ear Neurobiology, Health and Disease: From Bench to Clinics

There is substantial experimental and clinical interest in providing effective ways to both prevent and slow the onset of hearing loss. Auditory hair cells, which occur along the basilar membrane of the cochlea, often lose functionality due to age-related biological alterations, as well as from exposure to high decibel sounds affecting a diminished/damaged auditory sensitivity. Hearing loss is also seen to take place due to neuronal degeneration before or following hair cell destruction/loss. A strategy is necessary to protect hair cells and XIII cranial/auditory nerve cells prior to injury and throughout aging. Within this context, it was proposed that cochlea neural stem cells may be protected from such aging and environmental/noise insults via the ingestion of protective dietary supplements. Of particular importance is that these studies typically display a hormetic-like biphasic dose-response pattern that prevents the occurrence of auditory cell damage induced by various model chemical toxins, such as cisplatin. Likewise, the hormetic dose-response also enhances the occurrence of cochlear neural cell viability, proliferation, and differentiation. These findings are particularly important since they confirmed a strong dose dependency of the significant beneficial effects (which is biphasic), whilst having a low-dose beneficial response, whereas extensive exposures may become ineffective and/or potentially harmful. According to hormesis, phytochemicals including polyphenols exhibit biphasic dose-response effects activating low-dose antioxidant signaling pathways, resulting in the upregulation of vitagenes, a group of genes involved in preserving cellular homeostasis during stressful conditions. Modulation of the vitagene network through polyphenols increases cellular resilience mechanisms, thus impacting neurological disorder pathophysiology. Here, we aimed to explore polyphenols targeting the NF-E2-related factor 2 (Nrf2) pathway to neuroprotective and therapeutic strategies that can potentially reduce oxidative stress and inflammation, thus preventing auditory hair cell and XIII cranial/auditory nerve cell degeneration. Furthermore, we explored techniques to enhance their bioavailability and efficacy.