Rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone prevent amnesia induced in scopolamine zebrafish (Danio rerio) model by increasing the mRNA expression of bdnf, npy, egr-1, nfr2α, and creb1 genes

Solanum macrocarpon L. Ethanolic Leaf Extract Exhibits Neuroprotective and Anxiolytic Effects in Scopolamine-Induced Amnesic Zebrafish Model

Background/Objectives: Solanum macrocarpon L. has been studied for its neuroprotective potential and memory-enhancing properties. Research suggests that bioactive compounds, including flavonoids, alkaloids, and phenolics, contribute to its cognitive benefits. These compounds may help protect against oxidative stress, neuroinflammation, and cholinergic dysfunction factors in memory impairment. This study was undertaken to investigate the effects of S. macrocarpon ethanolic leaf extract (SMEE) on the memory, anxiety-like behavior, and brain antioxidant status of scopolamine (SCOP, 100 μM)-induced amnesic zebrafish (Danio rerio) and thus to understand its possible mechanism of action. Methods: Adult zebrafish (n = 100) were divided into two cohorts (±SCOP) of five experimental groups: (I) control; (II) galantamine (GAL, 1 mg/L), serving as a positive control for both behavioral and biochemical assessments; (III-V) three groups treated with SMEE (1, 3, and 6 mg/L); (VI) scopolamine (SCOP, 100 μM); (VII) SCOP (100 μM) combined with GAL (1 mg/L); and (VIII-X) three groups treated with SCOP (100 μM) plus SMEE (1, 3, and 6 mg/L). The treatment lasted 23 days and amnesia was induced by a single dose of SCOP (100 μM) before testing. Results: The phenolic characterization from the samples was performed by using HPLC-PDA chromatography. Following HPLC analysis, an in silico pharmacokinetic evaluation was conducted using the ADMET model to investigate the pharmacological and toxicological profiles of the identified compounds. Spatial memory was evaluated through the Y-maze and novel object recognition (NOR) tests, while anxiety-like behavior was assessed using the novel tank diving test (NTT), novel approach test (NAT), and light-dark test (LDT). The zebrafish were euthanized, and homogenates of isolated brain samples were assayed for acetylcholinesterase (AChE) activity and brain antioxidant markers. The HPLC analysis revealed that the main major compounds in the extract were chlorogenic acid and rutin, both recognized for their significant antioxidant properties. Conclusions: SMEE enhanced memory by inhibiting AChE, alleviated SCOP-induced anxiety-like behavior, and significantly decreased oxidative stress markers. These findings support the potential role of SMEE in counteracting SCOP-induced cognitive and behavioral dysfunctions, related to dementia conditions.

Apigenin mitigates oxidative stress, neuroinflammation, and cognitive impairment but enhances learning and memory in aluminum chloride-induced neurotoxicity in rats

INTRODUCTION

Aluminum chloride (AlCl3) exposure has been linked to neurotoxicity in various animal models, presenting significant concern to human health due to its potential implications in neurodegenerative diseases. Aluminum chloride is a widely recognized neurotoxin and has been used as an animal model of Alzheimer's disease via mechanisms linked with oxidative stress and inflammation. The study investigated the potential ameliorative effect of apigenin on AlCl3-induced neurotoxicity in rats.

METHODS

Forty adult male Wistar rats were randomly divided into four different groups - control, AlCl3 (100 mg/kg), apigenin (50 mg/kg) plus AlCl3, and apigenin (50 mg/kg) alone administered orally for 14 days.

RESULTS

Our findings revealed AlCl3 exposure induced significant neurobehavioral deficits, oxidative stress, neuroinflammation, and loss of the Purkinje cell layer of the cerebellum. Treatment with apigenin attenuated neuroinflammation and enhanced learning and memory with significant improvement in recognition index.

DISCUSSION

Apigenin demonstrates promising ameliorative effects against AlCl3-induced neurotoxicity in rats.

HIGHLIGHTS

Aluminum chloride toxicity caused significant reduction in learning, exploration, and memory. Aluminum chloride toxicity induced neurotoxicity, increased biomarkers of oxidative stress, neuroinflammation, and precipitated cognitive impairment. Apigenin improved brain antioxidant, enhanced learning, exploration, and memory.

Enhancement of Cognitive Benefits and Anti-Anxiety Effects of Phytolacca americana Fruits in a Zebrafish (Danio rerio) Model of Scopolamine-Induced Memory Impairment

Phytolacca americana fruits exhibit a wide range of biological activities, including antimicrobial, anti-inflammatory, and anticancer properties. This study aims to investigate the phenolic profile of hydroethanolic extracts from both fresh (PEC) and dried (PEU) fruits of P. americana using high-performance liquid chromatography (HPLC) and to evaluate their impact on anxiety-like behavior, memory, oxidative stress, and cholinergic status in zebrafish (Danio rerio, Tübingen strain) treated with scopolamine (SCO, 100 μM). Acute administration of PEC and PEU (0.1, 0.5, and 1 mg/L) was conducted for one hour per day. In silico analyses were performed to evaluate the pharmacokinetic characteristics of the phenolic compounds discerned in the two extracts, using platforms such as SwissAdme, Molinspiration, ProToX-III, AdmetLab 3.0, PKCSM, and PASS. Anxiety-like behavior and memory performance were assessed through specific behavioral assays, including the novel tank test (NTT), light/dark test (LD), novel approach test (NAT), Y-maze, and novel object recognition (NOR). Subsequently, the activity of acetylcholinesterase (AChE) and the extent of oxidative stress in the zebrafish brain were investigated. Our findings suggest that both PEC and PEU possess anxiolytic effects, alleviating SCO-induced anxiety and enhancing cognitive performance in amnesic zebrafish. Furthermore, these extracts demonstrated the ability to mitigate cholinergic deficits by inhibiting AChE activity and supporting antioxidant defense mechanisms through increased activity of antioxidant enzymes and reduced lipid and protein peroxidation. These results highlight the potential use of P. americana fruit extracts in managing anxiety and cognitive impairments related to dementia conditions.