Physicochemical investigation of a novel curcumin diethyl γ-aminobutyrate, a carbamate ester prodrug of curcumin with enhanced anti-neuroinflammatory activity

Relationship of Curcumin with Aging and Alzheimer and Parkinson Disease, the Most Prevalent Age-Related Neurodegenerative Diseases: A Narrative Review

The elderly population is increasing worldwide every day. Age is a significant factor in the progression of neurological diseases, which can also cause cognitive decline and memory disorders. Inflammation and oxidative stress are primary drivers of senescence and disorders, particularly those associated with aging and neurodegenerative diseases. Bioactive phytochemicals are considered a promising therapeutic strategy in combating aging and age-related pathological conditions. One of the phytochemicals with diverse biological properties encompassing antioxidant, anti-inflammatory, antibacterial, antiviral, anticancer, antifungal, antidepressant, anti-allergic, and anti-aging properties is curcumin. Curcumin, a polyphenolic structure with a distinct orange hue and unique chemical properties, is derived from the roots of Curcuma longa, a member of the Zingiberaceae family, commonly known as turmeric. It has been noted that the incidence of neurodegenerative diseases is low in societies that consume curcumin widely. Therefore, this review investigates the effect of curcumin on aging and Alzheimer and Parkinson disease, which are the most prevalent age-related neurodegenerative diseases.

Research progress of prodrugs for the treatment of cerebral ischemia

It is well-known that pharmacotherapy plays a pivotal role in the treatment and prevention of cerebral ischemia. Nevertheless, existing drugs, including numerous natural products, encounter various challenges when applied in cerebral ischemia treatment. These challenges comprise poor brain absorption due to low blood-brain barrier (BBB) permeability, limited water solubility, inadequate bioavailability, poor stability, and rapid metabolism. To address these issues, researchers have turned to prodrug strategies, aiming to mitigate or eliminate the adverse properties of parent drug molecules. In vivo metabolism or enzymatic reactions convert prodrugs into active parent drugs, thereby augmenting BBB permeability, improving bioavailability and stability, and reducing toxicity to normal tissues, ultimately aiming to enhance treatment efficacy and safety. This comprehensive review delves into multiple effective prodrug strategies, providing a detailed description of representative prodrugs developed over the past two decades. It underscores the potential of prodrug approaches to improve the therapeutic outcomes of currently available drugs for cerebral ischemia. The publication of this review serves to enrich current research progress on prodrug strategies for the treatment and prevention of cerebral ischemia. Furthermore, it seeks to offer valuable insights for pharmaceutical chemists in this field, offer guidance for the development of drugs for cerebral ischemia, and provide patients with safer and more effective drug treatment options.

Fast and novel multiwalled carbon nanotubes decorated with metal oxide nanoparticles for potentiometric detection of a prohibited medication in sports acebutolol hydrochloride

A straightforward approach for creating fast and novel potentiometric sensors that are modified with multi-walled nanotubes (MWCNTs) was described. The impact of the selective sensor's material was studied. The suggested sensors were successfully fabricated for instant and fast detection of the prohibited β-adrenoreceptor blocking agent acebutolol hydrochloride (AC) in commercial products. Acebutolol-phosphomolybdate (AC-PM) carbon paste sensor was formed by mixing AC and phosphomolybdic acid and graphite powder in the presence of o-nitrophenyl octyl ether (o-NPOE) as a plasticizing agent. The functionalized AC-PM-MWCNTs and AC-PM-MWCNTs-Al2O3 nanocomposite sensors were prepared and all parameters affecting the sensors' potential responses have been investigated as well as the green synthesis of Al2O3NPs has been characterized using various microscopic and spectroscopic techniques. AC-PM-MWCNTs and AC-PM-MWCNTs-Al2O3 nanocomposite sensors demonstrated linearity of 1.0 × 10-7-1.0 × 10-2 and 1.0 × 10-8-1.0 × 10-2 mol L-1, respectively with regression equations -53.571x + 423.24 (r = 0.999) and -57.107x + 518.54 (r = 0.999). It also revealed excellent selectivity and sensitivity for the determination and quantification of AC. The developed potentiometric system was suitable for the determination of AC in bulk powder and commercial products.

Curcumin, inflammation, and neurological disorders: How are they linked?

Background

Despite the extensive research in recent years, the current treatment modalities for neurological disorders are suboptimal. Curcumin, a polyphenol found in Curcuma genus, has been shown to mitigate the pathophysiology and clinical sequalae involved in neuroinflammation and neurodegenerative diseases.

Methods

We searched PubMed database for relevant publications on curcumin and its uses in treating neurological diseases. We also reviewed relevant clinical trials which appeared on searching PubMed database using 'Curcumin and clinical trials'.

Results

This review details the pleiotropic immunomodulatory functions and neuroprotective properties of curcumin, its derivatives and formulations in various preclinical and clinical investigations. The effects of curcumin on neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), brain tumors, epilepsy, Huntington's disorder (HD), ischemia, Parkinson's disease (PD), multiple sclerosis (MS), and traumatic brain injury (TBI) with a major focus on associated signalling pathways have been thoroughly discussed.

Conclusion

This review demonstrates curcumin can suppress spinal neuroinflammation by modulating diverse astroglia mediated cascades, ensuring the treatment of neurological disorders.

Cationic Ester Prodrugs of Curcumin with N,N-dimethyl Amino Acid Promoieties Improved Poor Water Solubility and Intestinal Absorption

PURPOSE

Although curcumin (Cur) has powerful pharmacological effects, its use in medicine has not been established yet. The oral bioavailability (BA) of Cur is limited because of its poor water solubility. The purpose of this study was to confirm whether cationic N,N-dimethyl amino acid esters of Cur could act as prodrugs and improve its water solubility and oral bioavailability.

METHODS

Two N,N-dimethyl amino acid esters of Cur were synthesized. The hydrolysis profile of the esters was evaluated using rat and human microsomes. A pharmacokinetic study after oral administration of the Cur ester derivatives was performed in rats and compared to the administration of suspended or dissolved Cur formulation. The anti-inflammatory effects of the Cur derivatives were evaluated using macrophage RAW 264.7 stimulated with lipopolysaccharide.

RESULTS

Cur ester derivatives showed  > 200 mM water solubility. The derivatives were reconverted to the parent compound (Cur) after cleavage of the ester bonds by microsomal esterase, indicating that the compounds could act as Cur prodrugs. The Cur prodrugs enhanced the absolute oral bioavailability of Cur by a 9- and threefold increase of suspended and dissolved Cur administration, respectively, thereby improving intestinal absorption. Cur prodrugs strongly attenuated COX2, iNOS, and ERK phosphorylation.

CONCLUSIONS

The cationic N,N-dimethyl amino acid ester prodrugs of Cur improved the water solubility of Cur and enhanced oral bioavailability in rats. These Cur prodrugs may be good candidates for developing medicinal options previously unavailable due to the poor water solubility and oral BA of Cur.

Fabrication of Curcumin Diethyl γ-Aminobutyrate-Loaded Chitosan-Coated Magnetic Nanocarriers for Improvement of Cytotoxicity against Breast Cancer Cells

This study shows the effectiveness of magnetic-guide targeting in the delivery of curcumin diethyl γ-aminobutyrate (CUR-2GE), a prodrug of curcumin (CUR) previously synthesized to overcome unfavorable physicochemical properties of CUR. In this study, chitosan (Ch)-coated iron oxide nanoparticles (Ch-IONPs) were fabricated and optimized using Box-Behnken design-based response surface methodology for delivery of CUR-2GE. Ch was used as a coating material on the nanoparticle surface to avoid aggregation. The optimized condition for preparing Ch-IONPs consisted of using 4 mg Ch fabricated at pH 11 under a reaction temperature of 85 °C. The optimized Ch-IONPs were successfully loaded with CUR-2GE with sufficient loading capacity (1.72 ± 0.01%) and encapsulation efficiency (94.9 ± 0.8%). The obtained CUR-2GE-loaded Ch-IONPs (CUR-2GE-Ch-IONPs) exhibited desirable characteristics including a particle size of less than 50 nm based on TEM images, superparamagnetic property, highly crystalline IONP core, sufficient stability, and sustained-release profile. In the presence of permanent magnets, CUR-2GE-Ch-IONPs significantly increased cellular uptake and cytotoxicity toward MDA-MB-231 with a 12-fold increase in potency compared to free CUR-2GE, indicating the potential of magnetic-field assisted delivery of CUR-2GE-Ch-IONPs for the treatment of triple-negative breast cancer.

Ivermectin and curcumin cause plasma membrane rigidity in Leishmania amazonensis due to oxidative stress

Spin label electron paramagnetic resonance (EPR) spectroscopy was used to study the mechanisms of action of ivermectin and curcumin against Leishmania (L.) amazonensis promastigotes. EPR spectra showed that treatment of the parasites with both compounds results in plasma membrane rigidity due to oxidative processes. With the IC₅₀ and EPR measurements for assays using different parasite concentrations, estimations could be made for the membrane-water partition coefficient (K_M/W), and the concentration of the compound in the membrane (c_m50) and in the aqueous phase (c_w50), which inhibits cell growth by 50%. The K_M/W values indicated that ivermectin has a greater affinity than curcumin for the parasite membrane. Therefore, the activity of ivermectin was higher for experiments with low cell concentrations, but for concentrations greater than 1.5 × 10⁸ parasites/mL the compounds did not show significantly different results. The c_m50 values indicated that the concentration of compound in the membrane leading to growth inhibition or membrane alteration is approximately 1 M for both ivermectin and curcumin. This high membrane concentration suggests that many ivermectin molecules per chlorine channel are needed to cause an increase in chlorine ion influx.

Curcumin Diethyl γ-Aminobutyrate, a Prodrug of Curcumin, for Enhanced Treatment of Inflammatory Pain

Curcumin is a naturally occurring polyphenol compound with potential analgesic effects. It has been shown to improve pain-like behaviors in numerous models of pain. Despite its potential, curcumin exhibits poor physicochemical and pharmacokinetic properties, which hinder its oral therapeutic efficacy. Curcumin diethyl γ-aminobutyrate (CUR-2GE), a carbamate prodrug of curcumin, was designed to overcome these limitations and demonstrated greater anti-neuroinflammatory effects compared to curcumin in vitro. Thus, this study evaluated the effect of CUR-2GE and its parent compound on pain-like behaviors in carrageenan- and LPS-induced mouse models. The possible side effects of CUR-2GE were also assessed by exploring its effects on motor coordination and spontaneous locomotor activity after acute and chronic treatments. The results showed that CUR-2GE improved mechanical and thermal hyperalgesia and locomotor activity to a greater extent than curcumin in carrageenan-induced mice. These results are in line with the ability of CUR-2GE to suppress peripheral inflammation in the paw tissue of carrageenan-induced mice, indicated by a significant decrease in TNF-α and IL-6 expression levels. Similarly, in LPS-induced mice, CUR-2GE improved sickness and pain-like behaviors (exploratory behaviors and long-term locomotor activity) to a greater extent than curcumin. Furthermore, CUR-2GE significantly reduced the level of proinflammatory cytokines in both the plasma and spinal cord tissue of LPS-induced mice, exhibiting significantly higher inhibition than curcumin. Moreover, the motor coordination, and locomotive behaviors of mice were not affected by both acute and chronic administration of CUR-2GE, indicating no potential CNS side effects. Thus, CUR-2GE demonstrated enhanced therapeutic efficacy in mouse models of inflammatory pain without any possible CNS side effects, suggesting its potential to be developed as an analgesic agent against inflammatory pain.

Accessing Lipophilicity and Biomimetic Chromatography Profile of Biologically Active Ingredients of Botanicals Used in the Treatment of Inflammatory Bowel Disease

In the present study, various procedures have been compared for the determination of lipophilicity, hydrophobicity, and plasma protein binding of curcuminoids, boswellic acids, andrographolides, and piperine as biologically active ingredients of botanicals used in IBD treatment. Our results have shown that IAM-HPLC assay is the most suitable one for lipophilicity determination of all analytes regardless of their class and botanical source. HSA-HPAC and AGP-HPAC assays revealed that all investigated compounds have a higher affinity for HSA which is the most abundant protein in human plasma. The high affinity of biologically active compounds to all biological structures (phospholipids and proteins) admonishes that their small portion is available for therapeutic effects in IBD patients. Our experimental research is complemented by various theoretical approaches based on different algorithms for pharmacokinetic properties prediction. The similarities between experimental and calculated values were evaluated using PCA and CA as a statistical tool. The statistical analysis implies that plasma protein binding is a complex process, and theoretical approaches still cannot fully replace experimental ones.