Does caffeine influence the anticholinesterase and antioxidant properties of donepezil? Evidence from in vitro and in vivo studies

Chronic Caffeine Consumption, Alone or Combined with Agomelatine or Quetiapine, Reduces the Maximum EEG Peak, As Linked to Cortical Neurodegeneration, Ovarian Estrogen Receptor Alpha, and Melatonin Receptor 2

RATIONALE

Evidence of the effects of chronic caffeine (CAFF)-containing beverages, alone or in combination with agomelatine (AGO) or quetiapine (QUET), on electroencephalography (EEG), which is relevant to cognition, epileptogenesis, and ovarian function, remains lacking. Estrogenic, adenosinergic, and melatonergic signaling is possibly linked to the dynamics of these substances.

OBJECTIVES

The brain and ovarian effects of CAFF were compared with those of AGO + CAFF and QUET + CAFF. The implications of estrogenic, adenosinergic, and melatonergic signaling and the brain-ovarian crosstalk were investigated.

METHODS

Adult female rats were administered AGO (10 mg/kg), QUET (10 mg/kg), CAFF, AGO + CAFF, or QUET + CAFF, once daily for 8 weeks. EEG, estrous cycle progression, and microstructure of the brain and ovaries were examined. Brain and ovarian 17β-estradiol (E2), antimullerian hormone (AMH), estrogen receptor alpha (E2Rα), adenosine receptor 2A (A2AR), and melatonin receptor 2 (MT2R) were assessed.

RESULTS

CAFF, alone or combined with AGO or QUET, reduced the maximum EEG peak, which was positively linked to ovarian E2Rα, negatively correlated to cortical neurodegeneration and ovarian MT2R, and associated with cystic ovaries. A large corpus luteum emerged with AGO + CAFF and QUET + CAFF, antagonizing the CAFF-mediated increased ovarian A2AR and reduced cortical E2Rα. AGO + CAFF provoked TTP delay and increased ovarian AMH, while QUET + CAFF slowed source EEG frequency to δ range and increased brain E2.

CONCLUSIONS

CAFF treatment triggered brain and ovarian derangements partially antagonized with concurrent AGO or QUET administration but with no overt affection of estrus cycle progression. Estrogenic, adenosinergic, and melatonergic signaling and brain-ovarian crosstalk may explain these effects.

Bitter yet beneficial: The dual role of dietary alkaloids in managing diabetes and enhancing cognitive function

With the rising prevalence of diabetes and its association with cognitive impairment, interest in the use of dietary alkaloids and other natural products has grown significantly. Understanding how these compounds manage diabetic cognitive dysfunction (DCD) is crucial. This comprehensive review explores the etiology of DCD and the effects of alkaloids in foods and dietary supplements that have been investigated as DCD therapies. Data on how dietary alkaloids like berberine, trigonelline, caffeine, capsaicin, 1-deoxynojirimycin, nuciferine, neferine, aegeline, tetramethylpyrazine, piperine, and others regulate cognition in diabetic disorders were collected from PubMed, Research Gate, Web of Science, Science Direct, and other relevant databases. Dietary alkaloids could improve memory in behavioral models and modulate the mechanisms underlying the cognitive benefits of these compounds, including their effects on glucose metabolism, gut microbiota, vasculopathy, neuroinflammation, and oxidative stress. Evidence suggests that dietary alkaloids hold promise for improving cognition in diabetic patients and could open exciting avenues for future research in diabetes management.

Thiazolidin-4-one prevents against memory deficits, increase in phosphorylated tau protein, oxidative damage and cholinergic dysfunction in Alzheimer disease model: Comparison with donepezil drug

Alzheimer's disease (AD) is characterized mostly by memory decline. The current therapeutic arsenal for treating AD is limited, and the available drugs only produce symptomatic benefits, but do not stop disease progression. The search for effective therapeutic alternatives with multitarget actions is therefore imperative. One such a potential alternative is thiazolidin-4-one, a compound that exhibits anti-amnesic, anticholinesterase, and antioxidant activities. The aim of this study was evaluated the effects of 2-(4-(methylthio)phenyl)- 3-(3-(piperidin-1-yl)propyl) thiazolidin-4-one (DS12) on memory and neurochemical parameters in a model of AD induced by an intracerebroventricular injection of streptozotocin (STZ). Adult male rats were divided into five groups: I, control (saline); II, DS12 (10 mg/kg); III, STZ; IV, STZ + DS12 (10 mg/kg); V, STZ + donepezil (5 mg/kg). The rats were orally treated with DS12 and donepezil for a period of 20 days. Memory, acetylcholinesterase (AChE) activity, phosphorylated tau protein levels and oxidative stress were analyzed in the cerebral cortex, hippocampus, and cerebellum. Biochemical and hematological parameters were evaluated in the blood and serum. Memory impairment and the increase in AChE activity and phosphorylated tau protein level induced by STZ were prevented by DS12 and donepezil treatment. Streptozotocin induces an increase in reactive oxygen species levels and a decrease in catalase activity in the hippocampus, cerebral cortex, and cerebellum. DS12 treatment conferred protection from oxidative alterations in all brain structures. No changes were observed in serum biochemical parameters (glucose, triglycerides, cholesterol, uric acid, and urea) or hematological parameters, such as platelets, lymphocytes, hemoglobin, hematocrit, and total plasma protein. DS12 improved memory and neurochemical changes in an AD model and did not show toxic effects, suggesting the promising therapeutic potential of this compound.

Effect of chlorogenic acid plus donepezil on critical neurocortical enzyme activities, inflammatory markers, and synaptophysin immunoreactivity in scopolamine-assaulted rats, supported by multiple ligand simultaneous docking

The effect of chlorogenic acid (a natural phenolic acid ubiquitous in plant foods) on selected therapeutic properties of donepezil (DON) in a scopolamine (SCOP)-induced rat model of amnesia was the focus of this study. Adult albino (Wister strain) rats were allocated into five groups (n = 11) consisting of control, SCOP, SCOP + chlorogenic acid (CGA), SCOP + DON, and SCOP + CGA + DON for 7 days. Post-treatment, the rat brain cerebral cortex homogenate was assayed for cholinesterase and monoamine oxidase activities. Also, the reactive oxygen species, total thiol and nitric oxide contents, alongside catalase, and superoxide dismutase activities were determined. Routine histology for neuronal and glial cells as well as synaptophysin immunoreactivity was also carried out on the cerebral cortex. Thereafter, multiple ligand simultaneous docking was carried out for DON and CGA at the active sites of AChE and BChE. The results revealed that the biochemical parameters, glial cells, and synaptophysin immunoreactivity were significantly impaired in the cerebral cortex of scopolamine-treated rats. However, impaired butyrylcholinesterase and monoamine oxidase activity, together with antioxidant, glial cells, and synaptophysin levels were significantly ameliorated in scopolamine-treated rats administered DON + CGA compared to donepezil alone. The docking of both DON and CGA at the active sites of AChE or BChE showed higher binding energy to both enzymes compared to individual interactions of either DON or CGA. Hence, this study has been able to show that CGA could improve some of the therapeutic effects of DON, which could broaden the therapeutic spectrum of this drug. PRACTICAL APPLICATIONS: This study showed that chlorogenic acid (a major phenolic acid found in plant foods such as coffee) modulated some of the therapeutic properties of donepezil (an anticholinesterase drug used in the treatment of mild-to-moderate Alzheimer's disease). The combinations elicited better anti-butyrylcholinesterase, antimonoamine oxidase, and antioxidant properties, thus presenting this food-drug interaction as potentially able to offer better therapeutic properties.

A multi-biomarker approach for the early assessment of the toxicity of hospital wastewater using the freshwater organism Daphnia magna

Hospital wastewater (HWW) contains different hazardous substances resulting from a combination of medical and non-medical activities of hospitals, including pharmaceutical residues. These substances may represent a threat to the aquatic environment if they do not follow specific treatment processes. Therefore, we aimed to investigate the effects of the untreated effluent collected from a general hospital in Mahdia City (Tunisia) on neonatal stages of the freshwater crustacean Daphnia magna. Test organisms were exposed to three proportions (3.12%, 6.25%, and 12.5% v/v) of HWW. After 48 h of exposure, a battery of biomarkers was measured, including the quantification of antioxidant enzymes [catalase (CAT) and total and selenium-dependent glutathione peroxidase (total GPx; Se-GPx)], phase II biotransformation isoenzymes glutathione-S-transferases (GSTs), cyclooxygenases (COX) involved in the regulation of the inflammatory process, and total cholinesterases (ChEs) activities. Lipid peroxidation (LPO) was measured to estimate oxidative damage. The here-obtained results showed significant decreases of CAT and GSTs activities and also on LPO content in daphnids, whereas Se-GPx activity was significantly increased in a dose-dependent manner. Impairment of cholinesterasic and COX activities were also observed, with a significant decrease of ChEs and an increase of COX enzymatic activities. Considering these findings, HWW was capable of inducing an imbalance of the antioxidant defense system, but without resulting in oxidative damage in test organisms, suggesting that peroxidases and alternative detoxifying pathways were able to prevent the oxidant potential of several drugs, which were found in the tested effluents. In general, this study demonstrated the toxicity of hospital effluents, measured in terms of the potential impairment of key pathways, namely neurotransmission, antioxidant defense, and inflammatory homeostasis of crustaceans.

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.

Binding Characteristics and Superimposed Antioxidant Properties of Caffeine Combined with Superoxide Dismutase

The binding characteristics and superimposed antioxidant properties of caffeine combined with copper/zinc superoxide dismutase (SOD) were studied. The superimposed antioxidant activity of caffeine with SOD was investigated by detecting the concentration of malondialdehyde (MDA) present in cells, which was induced by hyperthermia and heavy metal exposure. The interactions between the SOD enzyme and caffeine were researched by ultraviolet spectrum, fluorescence spectrum, and molecular computation. The relative amounts of MDA contents of caffeine (0.1 mmol/L), SOD (0.1 mg/L), and caffeine (0.1 mmol/L) and SOD (0.1 mg/L) to water in cells were 0.70, 0.72, and 0.54, respectively, indicating that the antioxidant properties of caffeine combined with SOD may be superimposed. The fluorescence spectroscopy and molecular computation results show that the mixture of caffeine and SOD can result in the formation of a 1:1 complex through hydrogen bond and van der Waals forces spontaneously. The binding constant (K _a) of caffeine with SOD at five different temperatures are 4.41 × 10⁴, 3.30 × 10⁴, 2.29 × 10⁴, 1.71 × 10⁴, and 1.17 × 10⁴ L/mol. The changes of Gibbs-free energy (ΔG) are -26.50, -26.21, -25.71, -25.12, and -24.29 KJ/mol and the ΔG of molecular docking calculation is -26.95 KJ/mol. The experimental results are in accordance with the results of theoretical calculations. The combination of caffeine with SOD can change the conformation and microenvironment of SOD but does not change the activity of SOD. In addition, the combination can superimpose the antioxidant activity of caffeine and SOD.

Caffeine improves sperm quality, modulates steroidogenic enzyme activities, restore testosterone levels and prevent oxidative damage in testicular and epididymal tissues of scopolamine-induced rat model of amnesia

Objectives

This study was designed to assess the role of caffeine on fertility parameters in testicular and epididymal tissues of scopolamine-induced model of amnesia in rats.

Methods

Adult male rats were treated with scopolamine with or without caffeine. The modulatory effects of caffeine or scopolamine on fertility parameters were assessed in rats' testicular and epididymal homogenates.

Key findings

Scopolamine-induced sperm abnormalities, reduced steroidogenic enzyme 3β-Hydroxysteroid dehydrogenase (3β-HSD) and 17β-Hydroxysteroid dehydrogenase (17β-HSD) activities and serum testosterone levels in rats' testicular tissues. Treatment with caffeine increased 3β-HSD and 17β-HSD as well as testosterone levels. Caffeine also reversed sperm viability, sperm motility and sperm count in testicular tissues of scopolamine-treated rats. Furthermore, scopolamine-induced oxidative damage in rats' epididymal and testicular tissues via reduction of thiol and non-protein thiol content as well as increase in reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Caffeine attenuated oxidative stress in testicular and epididymal tissues of rats treated with scopolamine via increase in non-protein and protein thiol levels with concomitant reduction in ROS and MDA levels.

Conclusion

This study revealed that caffeine (5 and 25 mg/kg) improved sperm quality, increased steroidogenic enzyme activities and attenuated oxidative damage in testis and epididymis of rats treated with scopolamine.

Comparative biophysical characterization: A screening tool for acetylcholinesterase inhibitors

Among neurodegenerative diseases, Alzheimer’s disease (AD) is one of the most grievous disease. The oldest cholinergic hypothesis is used to elevate the level of cognitive impairment and acetylcholinesterase (AChE) comprises the major targeted enzyme in AD. Thus, acetylcholinesterase inhibitors (AChEI) constitutes the essential remedy for the treatment of AD. The study aims to evaluate the interactions between natural molecules and AChE by Surface Plasmon Resonance (SPR). The molecules like alkaloids, polyphenols and substrates of AChE have been considered for the study with a major emphasis on affinity and kinetics. To better understand the activity of small molecules, the investigation is supported by both experimental and theoretical approach such as fluorescence, Circular Dichroism (CD) and molecular docking studies. Amongst the screened ones tannic acid showed promising results compared with others. The methodology followed here have highlighted many molecules with a higher affinity towards AChE and these findings may take lead molecules generated in preclinical studies to treat neurodegenerative diseases. Additionally, we suggest a unique signature for the heterogeneous analyte model using competitive experiments for analyzing simultanous interactions of both the analytes.

Effect of Alkaloid Extract from African Jointfir (Gnetum africanum) Leaves on Manganese-Induced Toxicity in Drosophila melanogaster

Metal-induced toxicity in fruit fly (Drosophila melanogaster) is one of the established models for studying neurotoxicity and neurodegenerative diseases. Phytochemicals, especially alkaloids, have been reported to exhibit neuroprotection. Here, we assessed the protective effect of alkaloid extract from African Jointfir (Gnetum africanum) leaf on manganese- (Mn-) induced toxicity in wild type fruit fly. Flies were exposed to 10 mM Mn, the alkaloid extract and cotreatment of Mn plus extract, respectively. The survival rate and locomotor performance of the flies were assessed 5 days posttreatment, at which point the flies were homogenized and assayed for acetylcholinesterase (AChE) activity, nitric oxide (NO), and reactive oxygen species (ROS) levels. Results showed that the extract significantly reverted Mn-induced reduction in the survival rate and locomotor performance of the flies. Furthermore, the extract counteracted the Mn-induced elevation in AChE activity, NO, and ROS levels. The alkaloid extract of the African Jointfir leaf may hence be a source of useful phytochemicals for the development of novel therapies for the management of neurodegeneration.

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.

Green leafy vegetables from two Solanum spp. (Solanum nigrum L and Solanum macrocarpon L) ameliorate scopolamine-induced cognitive and neurochemical impairments in rats

This study examined the modulatory effect of Black nightshade (Solanum nigrum L) and African eggplant (Solanum macrocarpon L) leaves on cognitive function, antioxidant status, and activities of critical enzymes of monoaminergic and cholinergic systems of neurotransmission in scopolamine-administered rats. Cognitive impairment was induced in albino rats pretreated with dietary inclusions of Black nightshade (BN) and African eggplant (AE) leaves by single administration (i.p.) of scopolamine (2 mg/kg body weight). Prior to termination of the experiment, the rats were subjected to spontaneous alternation (Y-maze) test to assess their spatial working memory. Thereafter, activities of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO), arginase, and antioxidant enzymes (catalase, SOD, and GST) of rat brain homogenate were determined. Also, the malondialdehyde (MDA), nitrite, and GSH contents of the homogenate were determined. The results showed that pretreatment with dietary inclusions of AE and BN significantly reversed the impairment in the rats' spatial working memory induced by scopolamine. Similarly, elevations in activities of AChE, BChE, and MAO induced by scopolamine were significantly reversed in rats pretreated with dietary inclusions of AE and BN. In addition, impaired antioxidant status induced by scopolamine was reversed by pretreatment with dietary inclusions of AE and BN. This study has shown that dietary inclusions of AE and BN could protect against cognitive and neurochemical impairments induced by scopolamine, and hence, these vegetables could be used as a source of functional foods and nutraceuticals for the prevention and management of cognitive impairments associated diseases such as Alzheimer's disease.

Diverse Effects of an Acetylcholinesterase Inhibitor, Donepezil, on Hippocampal Neuronal Death after Pilocarpine-Induced Seizure

Epileptic seizures are short episodes of abnormal brain electrical activity. Many survivors of severe epilepsy display delayed neuronal death and permanent cognitive impairment. Donepezil is an acetylcholinesterase inhibitor and is an effective treatment agent for Alzheimer’s disease. However, the role of donepezil in seizure-induced hippocampal injury remains untested. Temporal lobe epilepsy (TLE) was induced by intraperitoneal injection of pilocarpine (25 mg/kg). Donepezil (2.5 mg/kg/day) was administered by gavage in three different settings: (1) pretreatment for three days before the seizure; (2) for one week immediately after the seizure; and (3) for three weeks from three weeks after the seizure. We found that donepezil showed mixed effects on seizure-induced brain injury, which were dependent on the treatment schedule. Pretreatment with donepezil aggravated neuronal death, oxidative injury, and microglia activation. Early treatment with donepezil for one week showed neither adverse nor beneficial effects; however, a treatment duration of three weeks starting three weeks after the seizure showed a significant reduction in neuronal death, oxidative injury, and microglia activation. In conclusion, donepezil has therapeutic effects when injected for three weeks after seizure activity subsides. Therefore, the present study suggests that the therapeutic use of donepezil for epilepsy patients requires a well-conceived strategy for administration.