Mehtap Kara

The γ-aminobutyric acid type A (GABA-A) receptor is a key regulator of inhibitory neurotransmission in the central nervous system, and a promising target for cognitive and neurological disorders. Histamine interacts with a distinct allosteric pocket located at the β3–β3 subunit interface, providing an opportunity for the discovery of novel ligands. In the present study, an integrated in silico workflow combining ligand-based similarity analysis, ADMET filtering, molecular docking, and molecular dynamics simulations was applied to identify candidate ligands for this histamine-associated site. Docking analysis showed that ligand efficiency-related metrics discriminated active from inactive ligands more effectively than docking score alone, supporting their use during virtual screening. Three compounds were evaluated by 100 ns molecular dynamics simulations, which showed preserved receptor structural integrity and stable protein–ligand complexes. CHEMBL3236582 exhibited the most favorable dynamic profile, combining low backbone and ligand RMSD (root mean square deviation) values with the most favorable Molecular Mechanics/Poisson–Boltzmann Surface Area (MM/PBSA) binding energy estimate, whereas CHEMBL521996 maintained stable binding despite adopting an alternative binding orientation. Overall, the integrated computational workflow identified CHEMBL3236582 as the most promising candidate for experimental validation and supports further investigation of the histamine-associated allosteric pocket for the discovery of novel GABA-A receptor ligands.

Cognitive impairment and mood disturbances are increasingly linked to underlying mechanisms such as oxidative stress, neurotransmitter dysregulation, and reduced neurotrophic support. As conventional pharmacological treatments often provide limited efficacy or are associated with tolerability concerns, there is growing scientific interest in botanical supporting strategies that may modulate the above pathways and provide complementary support for cognitive function and emotional well-being. This study aimed to investigate the mechanistic basis of a botanical association consisting of a standardized Ginkgo biloba extract (GBE) from leaves and phosphatidylserine (PS) (combined referred as GBP) (Virtiva™ Plus), focusing on its potential effects on neurotransmitter-related enzymes and receptors, neuroprotection under oxidative stress, neurotrophic signaling, and antioxidant capacity. GBP was characterized analytically and evaluated in a series of validated in vitro assays using human SH-SY5Y neuroblastoma cells and multiple cell-free antioxidant systems. Neurotransmitter effect assays demonstrated that GBP inhibited acetylcholinesterase (AChE) and monoamine oxidase-A (MAO-A) in a concentration-dependent manner, suggesting selective modulation of cholinergic and monoaminergic pathways relevant to cognition and mood regulation. Enzyme modulation observed at micromolar concentrations supports mechanistic plausibility of G. biloba constituents in neurochemical pathways rather than direct modeling of physiological exposure. In SH-SY5Y cells exposed to hydrogen peroxide (H ₂ O ₂ ), GBP improved cell viability, confirming no intrinsic cytotoxicity, and reduced lactate dehydrogenase (LDH) release, indicating protection against oxidative stress-induced cytotoxicity. GBP also partially restored brain-derived neurotrophic factor (BDNF) levels in SH-SY5Y cells suppressed by H ₂ O ₂ , supporting preservation of neurotrophic signaling linked to neuronal survival and synaptic plasticity. In cell-free antioxidant assays, GBP demonstrated broad-spectrum activity across 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), Ferric reducing antioxidant power (FRAP), Oxygen radical absorbance capacity (ORAC), Hydroxyl radical antioxidant capacity (HORAC), total phenolic content (TPC), and total antioxidant status (TAS) assays, validating its capacity to neutralize free radicals and support redox balance. Collectively, these findings provide mechanistic evidence supporting the biological plausibility of multi-target actions of GBP, including neurotransmitter modulation, antioxidant effects, neuroprotection, and preservation of neurotrophic signaling, which may help explain previously reported cognitive- and mood-related outcomes.

Currently, the development of new in vitro models and the enhancement of existing ones are increasingly prioritized to significantly reduce laboratory animal use, in line with the 3R principles (replacement, reduction, and refinement) of animal welfare legislation. This study aims to evaluate the cytotoxic effects of individual and binary mixtures of selected phthalates on differentiated pancreatic cell models-islet-like cell aggregates (ICA), developed from human pancreatic carcinoma (PANC-1) cells. In this study, PANC-1 cells are differentiated into ICA which was confirmed by microscopy imaging and the determining the levels of insulin, glucagon, somatostatin and stem cell factor (cKIT) by ELISA assay. Expression levels of NGN3, ISL-1, INS, GCG, PDX and SST marker genes were evaluated by RT-qPCR. Differentiated cells are exposed to diethyl phthalate (DEP), dimethyl phthalate (DMP), dibutyl phthalate (DBP) and diisobutyl phthalate (DiBP). IC50 values were calculated as 870.215, 571.390, 589.219 and 388.471 µM, respectively, for DEP, DMP, DBP and DiBP. All binary mixtures displayed antagonism starting from IC10 values, except, DMP + DBP mixture displayed synergism at the IC90 level.

In recent years, genetically engineered probiotics have gained increasing scientific interest owing to their potential applications in human health and nutrition. Streptococcus salivarius K12 is a well-established oral probiotic with an excellent safety record, and a genetically modified derivative, S. salivarius eK12, has been recently developed to enhance its functional properties. The present study evaluated the safety and tolerability of S. salivarius eK12 administered as a dietary supplement in healthy adults. In a randomized, double-blind, placebo-controlled, parallel-group study conducted at the Jam Ghulam Qadir Civil Hospital, Hub, Pakistan (March–August 2025), 29 healthy adults (18–60 years) were assigned to receive S. salivarius eK12 ( n = 13) or placebo ( n = 16). Participants consumed one orally dissolving tablet twice daily (10 billion CFU/day) for 1 month, followed by 3 months of observation. This dose corresponded to approximately 10 times the level typically used in commercial probiotic formulations. Safety assessments included systemic, oral, and gastrointestinal examinations; self-reported questionnaires; vital signs; body weight; and laboratory investigations encompassing hematology, liver and renal function, electrolytes, HbA1c, thyroid profile, urinalysis, stool occult blood, bacterial culture, and inflammatory markers C-reactive protein (CRP), ferritin, and procalcitonin. All participants completed the study. Streptococcus salivarius eK12 was well-tolerated, with no serious adverse events (AEs) or discontinuations. Clinical, oral, and gastrointestinal examinations were unremarkable, and self-reported symptoms were minimal and comparable to placebo. Laboratory parameters and inflammatory markers remained within normal limits without clinically meaningful deviations. Stool and urine analyses were normal, and bacterial cultures were consistently negative. Extended follow-up revealed no delayed or cumulative adverse effects. These results provide the first clinical evidence that S. salivarius eK12, administered at 10 billion CFU/day for 1 month, is safe and well-tolerated in healthy adults. No adverse clinical or laboratory findings, and no evidence of infections or related complications, were observed during 4 months of monitoring, supporting its safe nutritional use and further clinical development. Clinical trial registration: https://clinicaltrials.gov/ , identifier NCT06380270.

Background: Low mood and cognitive impairments are multifactorial conditions often linked to oxidative stress, neurotransmitter imbalances, and neuroinflammation. Bilberry (Vaccinium myrtillus L.) extract, particularly rich in anthocyanins, has shown promising neuropharmacological properties in recent studies.Aims of the study: This study aimed to comprehensively evaluate the biochemical, antioxidant, and neuroprotective properties of a standardized bilberry extract (Mirtoselect™), alongside assessing its potential health benefits on mood and cognitive enhancement in a clinical setting.Methods: In vitro assays were conducted to explore the neuromodulatory, antioxidant, and cytoprotective properties of Bilberry extract. Enzyme inhibition assays targeted γ-Aminobutyric acid transaminase (GABA-T), monoamine oxidase A (MAO-A), and acetylcholinesterase (AChE), while GABA_A receptor binding was also evaluated. Antioxidant capacity was assessed using DPPH, ABTS, FRAP, ORAC, HORAC, and TAS assays. Neuroprotection was investigated using SH-SY5Y cells exposed to H₂O₂, assessing cell viability (MTT), membrane integrity (LDH release), and BDNF expression. Cytotoxicity was determined through the MTT assay in SH-SY5Y cells. A randomized, double-blind, placebo-controlled pilot clinical study was conducted on healthy adult subjects (n = 33) (aged 25–55 years) to evaluate the effects of Bilberry extract on mood (POMS) and cognitive function.Results: Bilberry extract demonstrated significant inhibition of GABA-T, MAO-A, and AChE, alongside moderate GABA_A receptor binding. It exhibited robust antioxidant activity in DPPH (EC₅₀: 9.24 ± 0.22 μg/mL), ABTS (EC₅₀: 12.70 ± 0.11 μg/mL), FRAP, ORAC, HORAC, and TAS assays. Neuroprotective effects included enhanced cell viability, reduced LDH release, and upregulation of BDNF in SH-SY5Y cells under oxidative stress. Cytotoxicity tests confirmed a favorable safety profile. In the pilot study, Bilberry extract supplementation significantly improved mood parameters, including reduced tension, depression, and confusion scores (p < 0.05) compared to placebo, with minimal adverse effects.Conclusion: Bilberry extract exhibits potent antioxidant, neuromodulatory, and neuroprotective properties, supporting its potential as a natural intervention for managing low mood and cognitive health. The favorable safety profile and preliminary clinical benefits warrant further research.

Endocrine disruptors, particularly phthalates like Dimethyl phthalate (DMP) and Diisobutyl phthalate (DiBP), are prevalent environmental contaminants posing significant health risks. This study investigates the combined neurotoxic effects of DMP and DiBP on SH-SY5Y neuroblastoma cells by analyzing cytotoxicity, oxidative stress, and apoptosis. Using MTT and Neutral Red Uptake assays, we determined the IC50 values for DMP and DiBP as 11.35 mM and 1.307 mM, respectively. Flow cytometry revealed increased Reactive Oxygen Species (ROS) levels, indicating oxidative stress, while apoptosis assays showed enhanced cell death with combined phthalate exposure. The results demonstrate a synergistic effect, exacerbating cytotoxic and oxidative damage beyond individual exposures. This study highlights the compounded risk of phthalate mixtures, urging comprehensive risk assessments and regulatory policies to mitigate human health risks from combined chemical exposures.

Background: Grape seed extract (GSE) from Vitis vinifera L. is rich in polyphenols and oligomeric proanthocyanidin complexes (OPCs), and it has shown potential benefits in managing low mood and cognitive function. In this study, we investigated the potential bioactivities of Enovita^®, a standardized GSE extract (GSEe herein) rich in OPCs, in key mechanistic pathways related to low mood conditions and cognitive function. Methods: In vitro assays were conducted to assess GSEe’s inhibitory effects on γ-aminobutyric acid transaminase (GABA-T) and monoamine oxidase A (MAO-A), its binding affinity to the GABA site of GABA-A receptors, and its effects on acetylcholinesterase (AChE). Its neuroprotective effects on human SH-SY5Y neuroblastoma cells under oxidative stress (induced by H₂O₂) were assessed using MTT and LDH release assays. Its antioxidant activities were evaluated using DPPH, ABTS, FRAP, ORAC, HORAC, total phenolic content, and TAS assays. Its cytotoxicity was also evaluated. Results: GSEe showed significant GABA-T inhibitory activity. It also exhibited MAO-A and AChE inhibition, along with moderate binding affinity to the GABA-A receptor. In neuroprotective assays, GSEe provided significant protection to SH-SY5Y cells against oxidative stress. GSEe demonstrated robust antioxidant activity in all assays, including scavenging of DPPH and ABTS radicals, high ferric-reducing power, high polyphenolic contents, and a substantial total antioxidant capacity. Conclusions: GSEe exhibits promising bioactivities, highlighting its potential as a supplement for modulating mood and enhancing cognitive function. Overall, the promising results from these in vitro studies provide a strong foundation for the continued exploration and development of GSEe as a viable natural supplement for enhancing mental health and cognitive function.

Background:Melissa officinalis L. (MO), commonly known as lemon balm, a member of the mint family, is considered a calming herb. In various traditional medicines, it has been utilized to reduce stress and anxiety and promote sleep. A growing body of clinical evidence suggests that MO leaf extract supplementation possesses considerable neuropharmacological properties. However, its possible mechanism of action largely remains unknown.Objective: In the present in vitro studies, we comparatively investigated the central nervous system (CNS)-calming and antioxidative stress properties of an innovative standardized phospholipid carrier-based (Phytosome™) MO extract (Relissa™) vs. an unformulated dry MO extract.Methods: The neuropharmacological effect of the extract was studied in the anti-depressant enzymes γ-aminobutyrate transaminase (GABA-T) and monoamine oxidase A (MAO-A) assays and SH-SY5Y cells brain-derived neurotrophic factor (BDNF) expression assay. The neuroprotective effect of the extract against oxidative stress was assessed in SH-SY5Y cell-based (H₂O₂-exposed) Total Antioxidant Status (TAS) and Total Reactive Oxygen Species (ROS) assays. The cytotoxic effect of the extract was evaluated using MTT and LDH assays. The extract antioxidant effect was also evaluated in cell-free chemical tests, including TEAC-ABTS, DPPH, Ferric Reducing Antioxidant Power (FRAP), Oxygen Radical Antioxidant Capacity (ORAC), and Hydroxyl Radical Antioxidant Capacity (HORAC) assays.Results: Relissa™ exhibited high GABA-T inhibitory activity, IC₅₀ (mg/mL) = 0.064 vs. unformulated dry MO extract, IC₅₀ (mg/mL) = 0.27. Similar inhibitory effects were also observed for MAO-A. Relissa™ demonstrated an improved neuroprotective antioxidant effect on SH-SY5Y cells against H₂O₂-induced oxidative stress. Compared to unformulated dry MO extract, Relissa™ exerted high protective effect on H₂O₂-exposed SH-SY5Y cells, leading to higher cells BDNF expression levels. Moreover, cell-free chemical tests, including TEAC-ABTS, DPPH radical scavenging, FRAP, ORAC, and HORAC assays, validated the improved antioxidant effect of Relissa™ vs. unformulated dry MO extract.Conclusion: The results of the present study support the neuromodulating and neuroprotective properties of Relissa™, and its supplementation may help in the amelioration of emotional distress and related conditions.

Cases of poisoning caused by seafood are common around the world, especially in developing sea and ocean coastal countries. Domoic acid, which became popular with the mass poisoning case in the 1980s, was actually used in alternative treatment practices. Poisoning caused by domoic acid is called amnesic shellfish poisoning. Although poisoning caused by humans attracts more attention, mass poisoning cases caused by other creatures such as sea lions are also important for the ecosystem. Domoic acid poisoning cases are mostly observed after algal blooms. The effects of acute poisoning are fatal and can also lead to chronic poisoning, leading to serious neurological disorders in the longer term. Several different species of Pseudo-nitzschia produced the domoic acid. There is no complete treatment for domoic acid poisoning yet, and studies on treatment strategies are continuing.