Evaluation of antioxidant and anti-inflammatory efficacy of caffeine in rat model of neurotoxicity

Moringa oleifera leaves ethanolic extract counteracts cortical neurodegeneration induced by aluminum chloride in rats

Background

Aluminum, a well-recognized neurotoxin, is implicated in various neurodegenerative disorders. Moringa oleifera (M. oleifera), known as a miracle tree, is utilized as a functional food and nutritional supplement. This study investigates the potential preventive effects of M. oleifera extract on aluminum chloride (AlCl3)-induced cortical neurodegeneration in rats.

Materials and methods

Therefore, 24 adult male Wistar rats were randomly divided into four distinct groups: negative control, M. oleifera extract (MOE), AlCl3, and AlCl3 + MOE. Treatments were administered orally for 28 consecutive days. Cognitive performance, brain oxidative/nitrosative stress, neuroinflammation, apoptotic-cell death, and associated histopathological alterations were assessed.

Results

Our results showed that MOE improved spatial learning and memory, enhanced antioxidant superoxide dismutase enzyme activity, antagonized nitrosative stress, reduced inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), decreased caspase-3, increased Bcl-2, and facilitated repair of cortical and hippocampal structures.

Conclusions

We concluded that MOE exhibits protective effects against cortical neurodegeneration, making it a promising supplement to counteract aluminum-induced neurotoxic effects.

Overview of Caffeine Effects on Human Health and Emerging Delivery Strategies

Caffeine is a naturally occurring alkaloid found in various plants. It acts as a stimulant, antioxidant, anti-inflammatory, and even an aid in pain management, and is found in several over-the-counter medications. This naturally derived bioactive compound is the best-known ingredient in coffee and other beverages, such as tea, soft drinks, and energy drinks, and is widely consumed worldwide. Therefore, it is extremely important to research the effects of this substance on the human body. With this in mind, caffeine and its derivatives have been extensively studied to evaluate its ability to prevent diseases and exert anti-aging and neuroprotective effects. This review is intended to provide an overview of caffeine's effects on cancer and cardiovascular, immunological, inflammatory, and neurological diseases, among others. The heavily researched area of caffeine in sports will also be discussed. Finally, recent advances in the development of novel nanocarrier-based formulations, to enhance the bioavailability of caffeine and its beneficial effects will be discussed.

Neuro-amelioration of Ficus lyrata (fiddle-leaf fig) extract conjugated with selenium nanoparticles against aluminium toxicity in rat brain: relevance to neurotransmitters, oxidative, inflammatory, and apoptotic events

Aluminium is a non-essential metal, and its accumulation in the brain is linked with potent neurotoxic action and the development of many neurological diseases. This investigation, therefore, intended to examine the antagonistic efficacy of Ficus lyrata (fiddle-leaf fig) extract (FLE) conjugated with selenium nanoparticles (FLE-SeNPs) against aluminium chloride (AlCl₃)-induced hippocampal injury in rats. Rats were allocated to five groups: control, FLE, AlCl₃ (100 mg/kg), AlCl₃ + FLE (100 mg/kg), and AlCl₃ + FLE-SeNPs (0.5 mg/kg). All agents were administered orally every day for 42 days. The result revealed that pre-treated rats with FLE-SeNPs showed markedly lower acetylcholinesterase and Na⁺/K⁺-ATPase activities in the hippocampus than those in AlCl₃ group. Additionally, FLE-SeNPs counteracted the oxidant stress-mediated by AlCl₃ by increasing superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione contents in rat hippocampus. Besides, the formulated nanoparticles decreased the hippocampal malondialdehyde, carbonyl protein, and nitric oxide levels of AlCl₃-exposed animals. Furthermore, FLE-SeNPs attenuated neural tissue inflammation, as demonstrated by decreased interleukin-1 beta, interleukin-6, nuclear factor kappa B, and glial fibrillary acidic protein. Remarkable anti-apoptotic action was exerted by FLE-SeNPs by increasing B cell lymphoma 2 and decreasing caspase-3 and Bcl-2-associated-X protein in AlCl₃-exposed rats. The abovementioned results correlated well with the hippocampal histopathological findings. Given these results, SeNPs synthesized with FLE imparted a remarkable neuroprotective action against AlCl₃-induced neurotoxicity by reversing oxidative damage, neuronal inflammation, and apoptosis in exposed rats.

Probing Caffeine Administration as a Medical Management for Hydrocephalus: An Experimental Study

BACKGROUND

Hydrocephalus is currently managed by cerebrospinal fluid diversion from the cerebral ventricles to other body sites, but this is complicated by obstruction and infection in young infants, thus adding to morbidity and mortality. Studies have reported caffeine to be a pleiotropic neuroprotective drug in the developing brain due to its antioxidant, anti-inflammatory, and antiapoptotic properties, with improved white matter microstructural development. In this study, we investigate the use of caffeine administration as a possible means of pharmacological management for hydrocephalus.

METHODS

A total of 76 three-day-old mice pups from 10 dams were divided into four groups: hydrocephalus was induced in the pups in two groups by intracisternal injection of kaolin suspension, and their dams were given either caffeine (50 mg/kg by gavage) or water daily for 21 days; the dams in the other 2 (non-hydrocephalic) groups similarly had either caffeine or water; the pups received caffeine administered via lactation. Developmental neurobehavioral tests were performed until day 21, when the pups were sacrificed. Their brains were removed and processed for Cresyl and Golgi staining; both quantitative and qualitative analyses were then carried out.

RESULTS

Improved developmental motor activities and reflexes were observed in the hydrocephalus + caffeine-treated pups. Caffeine administration was associated with reduced cell death and increased dendritic arborization of the neurons in the sensorimotor cortex and striatum of hydrocephalic mice pups.

CONCLUSION

Caffeine administration appears to have promise as an adjunct in hydrocephalus management, and its use needs to be further explored.

A novel TcS allele conferring the high-theacrine and low-caffeine traits and having potential use in tea plant breeding

Theacrine (1,3,7,9-tetramethyluric acid) is a natural product with remarkable pharmacological activities such as antidepressant, sedative and hypnotic activities, while caffeine (1,3,7-trimethylxanthine) has certain side effects to special populations. Hence, breeding tea plants with high theacrine and low caffeine will increase tea health benefits and promote consumption. In this study, we construct an F₁ population by crossing 'Zhongcha 302' (theacrine-free) and a tea germplasm 'Ruyuan Kucha' (RY, theacrine-rich) to identify the causal gene for accumulating theacrine. The results showed that the content of theacrine was highly negatively correlated with caffeine (R² > 0.9). Bulked segregant RNA sequencing analysis, molecular markers and gene expression analysis indicated that the theacrine synthase (TcS) gene was the candidate gene. The TcS was located in the nucleus and cytoplasm, and the theacrine can be detected in stably genetic transformed tobacco by feeding the substrate 1,3,7-trimethyluric acid. Moreover, an in vitro enzyme activity experiment revealed that the 241st amino acid residue was the key residue. Besides, we amplified the promoter region in several tea accessions with varied theacrine levels, and found a 234-bp deletion and a 271-bp insertion in RY. Both GUS histochemical analysis and dual-luciferase assay showed that TcS promoter activity in RY was relatively high. Lastly, we developed a molecular marker that is co-segregate with high-theacrine individuals in RY's offspring. These results demonstrate that the novel TcS allele in RY results in the high-theacrine and low-caffeine traits and the developed functional marker will facilitate the breeding of characteristic tea plants.

Hibiscus, Rooibos, and Yerba Mate for Healthy Aging: A Review on the Attenuation of In Vitro and In Vivo Markers Related to Oxidative Stress, Glycoxidation, and Neurodegeneration

The world is currently undergoing a demographic change towards an increasing number of elderly citizens. Aging is characterized by a temporal decline in physiological capacity, and oxidative stress is a hallmark of aging and age-related disorders. Such an oxidative state is linked to a decrease in the effective mechanisms of cellular repair, the incidence of post-translational protein glycation, mitochondrial dysfunction, and neurodegeneration, just to name some of the markers contributing to the establishment of age-related reduction-oxidation, or redox, imbalance. Currently, there are no prescribed therapies to control oxidative stress; however, there are strategies to elevate antioxidant defenses and overcome related health challenges based on the adoption of nutritional therapies. It is well known that herbal teas such, as hibiscus, rooibos, and yerba mate, are important sources of antioxidants, able to prevent some oxidation-related stresses. These plants produce several bioactive metabolites, have a pleasant taste, and a long-lasting history as safe foods. This paper reviews the literature on hibiscus, rooibos, and yerba mate teas in the context of nutritional strategies for the attenuation of oxidative stress-related glycoxidation and neurodegeneration, and, here, Alzheimer’s Disease is approached as an example. The focus is given to mechanisms of glycation inhibition, as well as neuroprotective in vitro effects, and, in animal studies, to frame interest in these plants as nutraceutical agents related to current health concerns.

Dietary sources, health benefits, and risks of caffeine

Dietary intake of caffeine has significantly increased in recent years, and beneficial and harmful effects of caffeine have been extensively studied. This paper reviews antioxidant and anti-inflammatory activities of caffeine as well as its protective effects on cardiovascular diseases, obesity, diabetes mellitus, cancers, and neurodegenerative and liver diseases. In addition, we summarize the side effects of long-term or excessive caffeine consumption on sleep, migraine, intraocular pressure, pregnant women, children, and adolescents. The health benefits of caffeine depend on the amount of caffeine intake and the physical condition of consumers. Moderate intake of caffeine helps to prevent and modulate several diseases. However, the long-term or over-consumption of caffeine can lead to addiction, insomnia, migraine, and other side effects. In addition, children, adolescents, pregnant women, and people who are sensitive to caffeine should be recommended to restrict/reduce their intake to avoid potential adverse effects.

Impact of Caffeine on Alzheimer’s Disease Pathogenesis—Protective or Risk Factor?

Alzheimer’s disease (AD), the most common dementia worldwide, remains without an effective treatment to this day despite intensive research conducted during the last decades. In this context, researchers have turned their attention towards the prevention of this pathology, focusing on early detection and better control of the most important risk factors, concomitantly with trying to find potentially protective factors that may delay the onset of AD. From the multitude of factors studied, coffee (especially its main component, caffeine) is a current interesting research topic, taking into consideration the contradictory results of recent years’ studies. On the one hand, much of the evidence from fundamental research suggests the potentially protective trait of caffeine in AD, while other data mainly from human studies lean toward no correlation or even suggesting that caffeine is a veritable risk factor for dementia. Given the methodological heterogeneity of the studies, this review aims to bring new evidence regarding this topic and to try to clearly establish a correlation between the two entities. Thus, in the first part, the authors make a clear distinction between the effects of coffee and the effects of caffeine in AD, presenting a rich basis of clinical trials on both animal models and the human subject. Subsequently, the main pathophysiological mechanisms that would explain the action of caffeine in the etiopathogenesis of AD are reviewed. Finally, the role of computational models is presented, having beneficial impact on both better understanding of the disease mechanism and the development of new therapeutic approaches for AD prevention.

Tea combats circadian rhythm disorder syndrome via the gut-liver-brain axis: potential mechanisms speculated

Circadian rhythm is an intrinsic mechanism developed by organisms to adapt to external environmental signals. Nowadays, owing to the job and after-work entertainment, staying up late - Circadian rhythm disorders (CRD) are common. CRD is linked to the development of fatty liver, type 2 diabetes, and chronic gastroenteritis, which affecting the body's metabolic and inflammatory responses via multi-organ crosstalk (gut-liver-brain axis, etc.). However, studies on the mechanisms of multi-organ interactions by CRD are still weak. Current studies on therapeutic agents for CRD remain inadequate, and phytochemicals have been shown to alleviate CRD-induced syndromes that may be used for CRD-therapy in the future. Tea, a popular phytochemical-rich beverage, reduces glucolipid metabolism and inflammation. But it is immature and unclear in the mechanisms of alleviation of CRD-mediated syndrome. Here, we have analyzed the threat of CRD to hosts and their offspring' health from the perspective of the "gut-liver-brain" axis. The potential mechanisms of tea in alleviating CRD were further explored. It might be by interfering with bile acid metabolism, tryptophan metabolism, and G protein-coupled receptors, with FXR, AHR, and GPCR as potential targets. We hope to provide new perspectives on the role of tea in the prevention and mitigation of CRD.HighlightsThe review highlights the health challenges of CRD via the gut-liver-brain axis.CRD research should focus on the health effects on healthy models and its offspring.Tea may prevent CRD by regulating bile acid, tryptophan, and GPCR.Potential targets for tea prevention and mitigation of CRD include FXR, AHR and GPCR.A comprehensive assessment mechanism for tea in improving CRD should be established.

Natural Plant Compounds: Does Caffeine, Dipotassium Glycyrrhizinate, Curcumin, and Euphol Play Roles as Antitumoral Compounds in Glioblastoma Cell Lines?

Many plant-derived compounds are shown to be promising antitumor therapeutic agents by enhancing apoptosis-related pathways and cell cycle impairment in tumor cells, including glioblastoma (GBM) cell lines. We aimed to review four natural plant compounds effective in GBM cell lines as caffeine, dipotassium glycyrrhizinate (DPG), curcumin, and euphol. Furthermore, antitumoral effect of these plant compounds on GBM cell lines through microRNAs (miRs) modulation was investigated. However, only DPG and curcumin were found as effective on miR modulation. Caffeine arrests GBM cell cycle in G0/G1 phase by cyclin-dependent kinases (CDK) complex inhibition and by decreasing BCL-2 and increasing FOXO1 expression levels causing greater apoptotic activity. Caffeine can also directly inhibit IP3R3, p38 phosphorylation, and rho-associated protein kinase (ROCK), decreasing cell invasion and migration capacity or indirectly by inhibiting the tissue inhibitor metalloproteinase-1 (TIMP-1) and integrins β1 and β3, leading to lower matrix metalloproteinases, MMP-2 and MMP-9. DPG presents antitumoral effect in GBM cells related to nuclear factor kappa B (NF-κB) pathway suppression by IRAK2 and TRAF6-mediating miR-16 and miR-146a, respectively. More recently, it was observed that DPG upregulated miR-4443 and miR-3620, responsible for post-transcriptional inhibition of the NF-κB pathway by CD209 and TNC modulation, respectively leading to lower MMP-9 and migration capacity. Curcumin is able to increase miR-223-3p, miR-133a-3p, miR-181a-5p, miR-34a-5p, miR-30c-5p, and miR-1290 expression leading to serine or threonine kinase (AKT) pathway impairment and also it decreases miR-27a-5p, miR-221-3p, miR-21-5p, miR-125b-5p, and miR-151-3p expression causing p53-BCL2 pathway inhibition and consequently, cellular apoptosis. Interestingly, lower expression of miR-27a by curcumin action enhanced the C/EBP homologous protein(CHOP) expression, leading to paraptosis. Curcumin can inhibit miR-21 expression and consequently activate apoptosis through caspase 3 and death receptor (DR) 4 and 5 activation. Autophagy is controlled by the LC-3 protein that interacts with Atg family for the LC3-II formation and autophagy activation. Euphol can enhance LC3-II levels directly in GBM cells or inhibits tumor invasion and migration through PDK1 modulation.

Caffeine Protects Against Retinal Inflammation

Caffeine, one of the most consumed central nervous system (CNS) stimulants, is an antagonist of A₁ and A_2A adenosine receptors. In this study, we investigated the potential protective effects of this methylxanthine in the retinal tissue. We tested caffeine by using in vitro and in vivo paradigms of retinal inflammation. Human retinal pigment epithelial cells (ARPE-19) were exposed to lipopolysaccharide (LPS) with or without caffeine. This latter was able to reduce the inflammatory response in ARPE-19 cells exposed to LPS, attenuating the release of IL-1β, IL-6, and TNF-α and the nuclear translocation of p-NFκB. Additionally, caffeine treatment restored the integrity of the ARPE-19 monolayer assessed by transepithelial electrical resistance (TEER) and the sodium fluorescein permeability test. Finally, the ischemia reperfusion (I/R) injury model was used in C57BL/6J mice to induce retinal inflammation and investigate the effects of caffeine treatment. Mouse eyes were treated topically with caffeine, and a pattern electroretinogram (PERG) was used to assess the retinal ganglion cell (RGC) function; furthermore, we evaluated the levels of IL-6 and BDNF in the retina. Retinal BDNF dropped significantly (p < 0.05) in the I/R group compared to the control group (normal mice); on the contrary, caffeine treatment maintained physiological levels of BDNF in the retina of I/R eyes. Caffeine was also able to reduce IL-6 mRNA levels in the retina of I/R eyes. In conclusion, these findings suggest that caffeine is a good candidate to counteract inflammation in retinal diseases.

Amazon-derived nutraceuticals: Promises to mitigate chronic inflammatory states and neuroinflammation

Nutraceuticals have been the focus of numerous research in recent years and accumulating data support their use for promoting some health benefits. Several nutraceuticals have been widely studied as supplements due to their functional properties ameliorating symptoms associated with neurological disorders, such as oxidative stress and chronic inflammatory states. This seems to be the case of some fruits and seeds from the Amazon Biome consumed since the pre-Columbian period that could have potential beneficial impact on the human nervous system. The beneficial activities of these food sources are possibly related to a large number of bioactive molecules including polyphenols, carotenoids, unsaturated fatty acids, vitamins, and trace elements. In this context, this review compiled the research on six Amazonian fruits and seeds species and some of the major nutraceuticals found in their composition, presenting brief mechanisms related to their protagonist action in improving inflammatory responses and neuroinflammation.

Potential of Caffeine in Alzheimer's Disease-A Review of Experimental Studies

Alzheimer's disease (AD) is the most common type of dementia leading to progressive memory loss and cognitive impairment. Considering that pharmacological treatment options for AD are few and not satisfactory, increasing attention is being paid to dietary components that may affect the development of the disease. Such a dietary component may be caffeine contained in coffee, tea or energy drinks. Although epidemiological data suggest that caffeine intake may counteract the development of cognitive impairment, results of those studies are not conclusive. The aim of the present study is to review the existing experimental studies on the efficacy of caffeine against AD and AD-related cognitive impairment, focusing on the proposed protective mechanisms of action. In conclusion, the reports of studies on experimental AD models generally supported the notion that caffeine may exert some beneficial effects in AD. However, further studies are necessary to elucidate the role of caffeine in the effects of its sources on cognition and possibly AD risk.

The Protective Effects of Melatonin on Aluminum-Induced Hepatotoxicity and Nephrotoxicity in Rats

Aluminum (Al) is a ubiquitous element with known toxicity for both humans and animals. Herein, we aimed to investigate the potential role of melatonin (MEL) in hepatotoxicity and nephrotoxicity following aluminum chloride (AlCl₃) treatment in rats. Adult male rats were treated with AlCl₃ (34 mg/kg bwt) for eight weeks. Exposure to AlCl₃ enhanced the serum activities of the liver transaminases (alanine aminotransferase and aspartate aminotransferase) and increased the level of bilirubin, in addition to the serum kidney function markers urea and creatinine. AlCl₃ intoxication boosted oxidative stress, as evidenced by increases in the levels of lipid peroxidation (LPO) and nitric oxide (NO) along with simultaneous decreases in the levels of glutathione (GSH), various antioxidant enzymes, and Nrf2 mRNA expression. MEL (5 mg/kg bwt) treatment repressed LPO and NO levels, whereas it augmented GSH content. The activities of the antioxidant enzymes GPx, SOD, CAT, and GR were also restored concomitantly when MEL was administered before AlCl₃. MEL also suppressed the apoptotic effect of AlCl₃ by enhancing Bcl-2 protein expression in the liver and kidney and decreasing the expression levels of proinflammatory cytokines. Histopathological findings in the liver and kidney tissues confirmed the beneficial effect of MEL against AlCl₃ toxicity. These findings indicate that MEL prevents AlCl₃ toxicity by enhancing the antioxidant defense system.

Identification and Characterization of the Tyrosinase Inhibitory Activity of Caffeine from Camellia Pollen

Tyrosinase inhibitors are important in cosmetic, medical, and food industries due to their regulation of melanin production. A tyrosinase inhibitor was purified from Camellia pollen using high-speed countercurrent chromatography and preparative high-performance liquid chromatography and was identified as caffeine by NMR and mass spectrometry. It showed strong mushroom tyrosinase inhibitory activity with an IC₅₀ of 18.5 ± 2.31 μg/mL in a noncompetitive model. The caffeine did not interact with copper ions in the active center of the enzyme but could quench fluorescence intensity and change the secondary conformation of this tyrosinase. A molecular dynamics simulation showed that caffeine bound this tyrosinase via Lys379, Lys 376, Asp357, Glu356, Thr308, Gln307, Asp312, and Trp358, thus changing the binding sites of l-tyrosine and the loop conformation adjacent to the active center. In vitro cell model analysis revealed that caffeine exhibited significant inhibitory effects on both intracellular tyrosinase activity and melanin production of B16-F10 melanoma cells in a concentration-dependent manner. These comprehensive results suggest that caffeine is a strong tyrosinase inhibitor that has the potential to be developed as skin-whitening agents in the cosmetics and pharmaceutical industries or as antibrowning agents in the food industry.

Caffeine attenuates brain injury but increases mortality induced by high-intensity blast wave exposure

Caffeine is a substance that is consumed worldwide, and it may exert neuroprotective effects against various cerebral insults, including neurotrauma, which is the most prevalent injury among military personnel. To investigate the effects of caffeine on high-intensity blast wave-induced severe blast injury in mice, three different paradigms of caffeine were applied to male C57BL/6 mice with severe whole body blast injury (WBBI). The results demonstrated that chronic caffeine treatment alleviated blast-induced traumatic brain injury (bTBI); however, both chronic and acute caffeine treatments exacerbated blast-induced lung injuries and, more importantly, increased both the cumulative and time-segmented mortalities postinjury. Interestingly, withdrawing caffeine intake preinjury resulted in favorable outcomes in mortality and lung injury, similar to the findings in water-treated mice, and had the trend to attenuate brain injury. These findings demonstrated that although drinking coffee or caffeine preparations attenuated blast-induced brain trauma, these beverages may place personnel in the battlefield at high risk of casualties, which will help us re-evaluate the therapeutic strategy of caffeine application, particularly in multiple-organ-trauma settings. Furthermore, these findings provided possible strategies for reducing the risk of casualties with caffeine consumption, which may help to change the coffee-drinking habits of military personnel.