Santosh Prajapati - Academia.edu (original) (raw)

Papers by Santosh Prajapati

Research paper thumbnail of Centella asiatica prevents D-galactose-Induced cognitive deficits, oxidative stress and neurodegeneration in the adult rat brain

Drug and Chemical Toxicology, 2020

Chronic D-galactose (D-gal) administration causes cognitive impairment and is used widely in anim... more Chronic D-galactose (D-gal) administration causes cognitive impairment and is used widely in animal models for anti-aging studies. Centella asiatica (CA), a traditional herbal medicine, has been used as a brain tonic to enhance memory. This study evaluates the neuroprotective role of an ethanolic extract of Centella asiatica (CAE) against D-gal-induced aging in rats. Healthy male rats were divided into three groups: Control, D-gal, and D-gal þ CAE. The Control group received normal saline (i.p.), whereas the Dgal group received D-gal (120 mg/kg b.w., i.p.), and the D-gal þ CAE group received D-gal (120 mg/kg b.w., i.p.) and CAE (300 mg/kg b.w., orally) daily for 42 days. Behavioral and brain biochemical and histopathological changes were assessed after treatment. The results of the behavioral study depicted that D-gal significantly reduces the spontaneous alternation and locomotor activity indicating behavioral and cognitive impairment. Biochemical studies showed that D-gal significantly increases the oxidative stress and acetylcholinesterase activity (AChE) in rat brain. Histopathological study showed that D-gal disturbs the normal architecture of hippocampal and cortical cells, indicating degeneration in these brain areas. D-gal and CAE co-treatment for 42 days attenuated the behavioral, biochemical, and neuroanatomical impairments caused by the D-gal; it markedly suppresses the D-gal-induced oxidative stress and AChE activity in the brain, and maintains the normal cellular architecture in hippocampal and cortical areas. Thus, this study shows that CAE can protect the brain from the adverse effects of D-gal (e.g., memory loss and cognitive impairment) by modulating AChE activity and oxidative stress.

Research paper thumbnail of Pharmacological Investigations of Selected Multitarget‐Direct Ligands for the Treatment of Alzheimer's Disease

Research paper thumbnail of Development and treatment of cognitive inflexibility in sub-chronic stress–re-stress (SRS) model of PTSD

Pharmacological Reports, 2021

BACKGROUND Cognitive inflexibility is one of the major clinical symptoms of post-traumatic stress... more BACKGROUND Cognitive inflexibility is one of the major clinical symptoms of post-traumatic stress disorder (PTSD). Studies have examined the impact of traumatic events on anxiety. However, there were limited reports on the effect of traumatic episodes on cognitive flexibility. Therefore, animal models developing cognitive inflexibility would provide new insight of pathophysiology and pharmacotherapy of PTSD. METHODS Male Wistar rats were subjected to stress-re-stress (SRS) procedure by restraining them for 2 h followed by foot shock (FS) and halothane exposure on day 2 (D-2). Then, the rats were exposed every week to FS as re-stress cue up to D-32. Donepezil (3 mg/kg; po) and sertraline (10 mg/kg; po) dosing was started from D-8 and continued up to D-32. RESULTS SRS exposure caused cognitive inflexibility by producing deficits in intra-dimension (ID) and extra-dimension (ED) set-shifting which was significantly attenuated by donepezil. However, sertraline mitigated only ID shift in SRS-subjected rats. SRS-induced PTSD-like symptoms such as fear response, anxiety-like behaviour and cognitive deficits were attenuated by both donepezil and sertraline. Donepezil did not modulate the SRS-induced hypothalamic-pituitary-adrenal (HPA) axis dysfunction and activation of serotonergic and nor-adrenergic system. Interestingly, exposure of SRS caused a decrease in acetylcholine level and increase in acetylcholine esterase activity in prefrontal cortex (PFC) and hippocampus (HIP) which was only mitigated by donepezil. Donepezil significantly attenuated SRS-induced down-regulation of choline-acetyl transferase and α-7 nicotinic acetylcholine receptor expressions in PFC and HIP. CONCLUSION Cognitive inflexibility is developed in the SRS model along with other PTSD-like symptoms which were attenuated by donepezil.

Research paper thumbnail of Supplementation of taurine improves ionic homeostasis and mitochondrial function in the rats exhibiting post-traumatic stress disorder-like symptoms

European Journal of Pharmacology

RATIONALE Current pharmacotherapy for post-traumatic stress disorder (PTSD) is limited to few ant... more RATIONALE Current pharmacotherapy for post-traumatic stress disorder (PTSD) is limited to few antidepressants. Mitochondrial dysfunction is observed in PTSD, along with altered potassium homeostasis. Nutritional supplementation of taurine can improve ionic homeostasis and thereby treat PTSD-like symptoms in rats. AIM The purpose is to study the pharmacological effect of taurine in stress re-stress-induced PTSD in rats. METHODS As per protocol, animals were restrained for 2 h then exposed to footshock (FS) (2 mA/10 s) followed by halothane-induced anesthesia. Behavioral assessments such as elevated plus maze (EPM) and Y-maze tests were performed on days 2, 8, and 32 of experimental protocol after re-stress. In addition, daily oral administration of taurine (100, 200, and 300 mg/kg) and paroxetine (PAX) (10 mg/kg) was done from D-8 to D-32 followed by re-stress. The plasma concentration of taurine, corticosterone, and potassium was measured on Day-32 along with mitochondrial function in discrete brain regions. RESULTS Sub-chronic administration of taurine in high and medium doses significantly ameliorated PTSD-like symptoms such as hyperarousal, anxiety, and improved spatial recognition memory. Taurine in all doses restored the plasma concentration of corticosterone and potassium. SRS-induced alterations in mitochondrial bioenergetics, complex enzyme activities, and reduced mitochondrial membrane potential in different brain regions were ameliorated by taurine. CONCLUSION Nutritional supplementation of taurine improves potassium ionic homeostasis, mitochondrial function, and attenuated PTSD-like symptoms in SRS subjected rats.

Research paper thumbnail of Discovery of new phenyl sulfonyl-pyrimidine carboxylate derivatives as the potential multi-target drugs with effective anti-Alzheimer’s action: Design, synthesis, crystal structure and in-vitro biological evaluation

European Journal of Medicinal Chemistry, 2021

Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behav... more Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behavioural and cognitive functions. The multitarget-directed ligand (MTDL) strategies are promising paradigm in drug development, potentially leading to new possible therapy options for complex AD. Herein, a series of novel MTDLs phenylsulfonyl-pyrimidine carboxylate (BS-1 to BS-24) derivatives were designed and synthesized for AD treatment. All the synthesized compounds were validated by 1HNMR, 13CNMR, HRMS, and BS-19 were structurally validated by X-Ray single diffraction analysis. To evaluate the plausible binding affinity of designed compounds, molecular docking study was performed, and the result revealed their significant interaction with active sites of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The synthesized compounds displayed moderate to excellent in vitro enzyme inhibitory activity against AChE and BuChE at nanomolar (nM) concentration. Among 24 compounds (BS-1 to BS-24), the optimal compounds (BS-10 and BS-22) displayed potential inhibition against AChE; IC50 = 47.33 ± 0.02 nM and 51.36 ± 0.04 nM and moderate inhibition against BuChE; IC50 = 159.43 ± 0.72 nM and 153.3 ± 0.74 nM respectively. In the enzyme kinetics study, the compound BS-10 displayed non-competitive inhibition of AChE with Ki = 8 nM. Respective compounds BS-10 and BS-22 inhibited AChE-induced Aβ1-42 aggregation in thioflavin T-assay at 10 μM and 20 μM, but BS-10 at 10 μM and 20 μM concentrations are found more potent than BS-22. In addition, the aggregation properties were determined by the dynamic light scattering (DLS) and was found that BS-10 and BS-22 could significantly inhibit self-induced as well as AChE-induced Aβ1-42 aggregation. The effect of compounds (BS-10 and BS-22) on the viability of MC65 neuroblastoma cells and their capability to cross the blood-brain barrier (BBB) in PAMPA-BBB were further studied. Further, in silico approach was applied to analyze physicochemical and pharmacokinetics properties of the designed compounds via the SwissADME and PreADMET server. Hence, the novel phenylsulfonyl-pyrimidine carboxylate derivatives can act as promising leads in the development of AChE inhibitors and Aβ disaggregator for the treatment of AD.

Research paper thumbnail of Neuro-nutraceutical potential of Asparagus racemosus: A review

Neurochemistry International, 2021

Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multif... more Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multifactorial pathophysiology. Their treatment strategies often only provide symptomatic relief, delaying disease progression without giving a complete cure. Potent and safer treatment alternatives beyond symptomatic relief are sought. Herbal supplements have surely been explored due to their multiple component nature to enhance the effect of western medications. One such well-documented nutraceutical in the ancient Greek, Chinese, and Ayurvedic medicine system is known for its various medicinal benefits is Asparagus racemosus. Widely used for its lactogenic properties, A. racemosus is also cited in Ayurveda as a nervine tonic. A. racemosus based nutraceuticals have shown to possess adaptogenic, neuroprotective, antioxidant, anti-inflammatory, and nootropic activity under preclinical and clinical settings without posing significant adverse effects. A. racemosus extracts restore the perturbed neurotransmitters and prevent oxidative neuronal damage. From the available neuropharmacological researches, the physiological actions of A. racemosus can ultimately be directed for either augmentation of cognitive ability or in the management of neurological conditions such as stress, anxiety, depression, epilepsy, Parkinson's, and Alzheimer's disease. The studies focus on the multi-component extract, and the lack of standardization has been a major hurdle in preventing the allotment of reported neuropharmacological activity to one of the phytoconstituent. Herbal standardization of the plant extract based on a specific biomarker can help elucidate the intricate biomolecular pathway and neurocircuitries being involved. This, followed by rigorous standardized clinical trials, fixing dosages, and determining contraindications would facilitate the translation of A. racemosus to a FDA-approved neuromedicine for neurological disorders.

Research paper thumbnail of Neurochemical Evidence of Preclinical and Clinical Reports on Target-Based Therapy in Alcohol Used Disorder

Neurochemical Research, 2020

Alcohol use disorder (AUD) is a chronic relapsing disorder, which enforces a person to compulsive... more Alcohol use disorder (AUD) is a chronic relapsing disorder, which enforces a person to compulsively seek alcohol, restricting control over alcohol intake leads to emergence of an undesired emotional state during abstinence. There are recent advances for better understanding of neurocircuitry involved in the pathophysiology of AUD. Alcohol interaction with neuronal membrane proteins results in changes in neuronal circuits. It is also linked with the potential medication and their clinical validation concerning their pharmacological targets for alcoholic abstinence. This review covers research work from the past few decades on the therapeutic advances on treatment of alcohol dependence; further detailing the fundamental neurochemical mechanisms after alcohol administration. It also covers interaction of alcohol with GABAergic, glutaminergic, dopaminergic, serotonergic and opioid systems. This review further elaborated the neurobiology of noradrenergic, cholinergic and cannabinoid systems and their interaction with AUD. Elaborative information of potential drug targets under current exploration for AUD treatment with their mechanisms are reported here along with clinical outcomes and the associated side effects.

Research paper thumbnail of A novel stress re-stress model: modification of re-stressor cue induces long-lasting post-traumatic stress disorder-like symptoms in rats

International Journal of Neuroscience, 2020

Background: Post-traumatic stress disorder (PTSD) develops after exposure to a severe traumatic e... more Background: Post-traumatic stress disorder (PTSD) develops after exposure to a severe traumatic event. Stress re-stress (SRS) model of PTSD using the forced swim as a re-stress shows hypocortisolism, an index of hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Despite this, the SRS model lacks development of hyperarousal and intrusive memory which are prominent symptoms of PTSD. Aim: Developing a model which shows more clinical similarities to PTSD. We used intense foot-shock (FS) (2 mA for 10 sec) instead of the forced-swim test (FST) as a re-stress cue. Methods: The stress session was performed on D-2 except control group. The FST group rats were forced to swim for 20 min, and FS group rats were exposed to foot shock of 2 mA for 10 sec. The re-stress sessions of FST and FS were performed on D-8, 14, 20, 26 and 32. The freezing behavior was evaluated after the FS restress cue, and remaining behavioral assessments such as anxiety and depressive-like behavior, and cognitive dysfunction were performed on last day of the experiment. Results: The FS-induced PTSD-like (anxiety and depressive-like behavior, and cognitive dysfunction) symptoms and a decrease in plasma corticosterone (CORT) were more significant compared to FST. The hyperarousal and intrusive memory induced by FS were additional symptoms in the SRS model. Treatment with paroxetine significantly attenuated FST and FS-induced behavioral deficits in PTSD rats. Conclusion: FS as a re-stress model shows prominent PTSD-like symptoms with HPA axis dysfunction compared to FST.

Research paper thumbnail of Design and development of molecular hybrids of 2-pyridylpiperazine and 5-phenyl-1,3,4-oxadiazoles as potential multifunctional agents to treat Alzheimer's disease

European Journal of Medicinal Chemistry, 2019

The diverse nature of Alzheimer's disease (AD) has prompted researchers to develop multi-function... more The diverse nature of Alzheimer's disease (AD) has prompted researchers to develop multi-functional agents. Herein, we have designed and synthesized molecular hybrids of 2-pyridylpiperazine and 5phenyl-1,3,4-oxadiazoles. Biological activities of synthesized compounds suggested significant and balanced inhibitory potential against target enzymes. In particular, compound 49 containing 2,4-difluoro substitution at terminal phenyl ring considered as most potential lead with inhibition of acetylcholinesterase (hAChE, IC 50 ¼ 0.054 mM), butyrylcholinesterase (hBChE, IC 50 ¼ 0.787 mM) and beta-secretase-1 (hBACE-1, IC 50 ¼ 0.098 mM). The enzyme kinetics study of 49 against hAChE suggested a mixed type of inhibition (Ki ¼ 0.030 mM). Also, 48 and 49 showed significant displacement of propidium iodide from the peripheral anionic site (PAS) of hAChE, excellent blood-brain barrier (BBB) permeability in parallel artificial membrane permeation assay (PAMPA), and neuroprotective ability against SH-SY5Y neuroblastoma cell lines. Further, 49 also exhibited anti-Ab aggregation activity in self-and AChE-induced thioflavin T assay, which was ascertained by morphological characterization by atomic force microscopy (AFM). Moreover, in vivo behavioral studies signified learning and memory improvement by compound 49 in scopolamine-and Ab-induced cognitive dysfunctions performed on Y-maze and Morris water maze. The ex vivo studies suggested decreased AChE activity and antioxidant potential of compound 49, with good oral absorption characteristics ascertained by pharmacokinetic studies.

Research paper thumbnail of Repeated caffeine administration aggravates post-traumatic stress disorder-like symptoms in rats

Physiology & Behavior, 2019

Research paper thumbnail of Design and development of multitarget-directed N-Benzylpiperidine analogs as potential candidates for the treatment of Alzheimer's disease

European Journal of Medicinal Chemistry, 2019

The multitarget-directed strategy offers an effective and promising paradigm to treat the complex... more The multitarget-directed strategy offers an effective and promising paradigm to treat the complex neurodegenerative disorder, such as Alzheimer's disease (AD). Herein, a series of N-benzylpiperidine analogs (17-31 and 32-46) were designed and synthesized as multifunctional inhibitors of acetylcholinesterase (AChE) and β-secretase-1 (BACE-1) with moderate to excellent inhibitory activities. Amongst tested inhibitors, 25, 26, 40, and 41 presented the most significant and balanced inhibition against both the targets. Compounds 40 and 41 exhibited high brain permeability in PAMPA-BBB assay, significant displacement of propidium iodide from peripheral anionic site (PAS) of AChE, and were devoid of neurotoxicity towards SH-SY5Y neuroblastoma cell lines up to the maximum tested concentration of 80 µM. Meanwhile, both these compounds inhibited self-and AChEinduced Aβ aggregation in thioflavin T assay, which was also reaffirmed by morphological characterization of Aβ aggregates using atomic force microscopy (AFM). Moreover, 40 and 41 ameliorated the scopolamine-induced cognitive impairment in elevated plus and Y-maze experiments. Ex vivo and biochemical analysis established the brain AChE inhibitory potential and antioxidant properties of these compounds. Further, improvement in Aβ 1-42induced cognitive impairment was also observed by compound 41 in the Morris water maze experiment with significant oral absorption characteristics ascertained by the pharmacokinetic studies.

Research paper thumbnail of Coenzyme Q10 Prevents Mitochondrial Dysfunction and Facilitates Pharmacological Activity of Atorvastatin in 6-OHDA Induced Dopaminergic Toxicity in Rats

Neurotoxicity Research, 2017

Through document analysis, classroom observation and analysis of children's performance in readin... more Through document analysis, classroom observation and analysis of children's performance in reading, we investigated tests from Provinha Brasil, as well as the relationships between children's outcomes and practices of their teachers. It was shown that there was a relationship between the results of Provinha Brasil and teaching practices, but the teachers didn't dedicate enough time to teaching reading texts. It was concluded that the impacts upon Provinha Brasil stemmed from teaching the alphabet basis and that the reading level required by Provinha's questions did not demand more elaborated text comprehension skills.

Research paper thumbnail of Long-term caffeine intake exaggerates PTSD-like symptoms independent of HPA axis activity

IBRO Reports, 2019

interfere with the neurogenic potential of astrocytes after stroke. Based on our results, we can ... more interfere with the neurogenic potential of astrocytes after stroke. Based on our results, we can speculate that NCX1, by regulating microglia/astrocytes activation and polarization, might interfere with the neurogenic potential of astrocytes under ischemic conditions.

Research paper thumbnail of Centella asiatica prevents D-galactose-Induced cognitive deficits, oxidative stress and neurodegeneration in the adult rat brain

Drug and Chemical Toxicology, 2020

Chronic D-galactose (D-gal) administration causes cognitive impairment and is used widely in anim... more Chronic D-galactose (D-gal) administration causes cognitive impairment and is used widely in animal models for anti-aging studies. Centella asiatica (CA), a traditional herbal medicine, has been used as a brain tonic to enhance memory. This study evaluates the neuroprotective role of an ethanolic extract of Centella asiatica (CAE) against D-gal-induced aging in rats. Healthy male rats were divided into three groups: Control, D-gal, and D-gal þ CAE. The Control group received normal saline (i.p.), whereas the Dgal group received D-gal (120 mg/kg b.w., i.p.), and the D-gal þ CAE group received D-gal (120 mg/kg b.w., i.p.) and CAE (300 mg/kg b.w., orally) daily for 42 days. Behavioral and brain biochemical and histopathological changes were assessed after treatment. The results of the behavioral study depicted that D-gal significantly reduces the spontaneous alternation and locomotor activity indicating behavioral and cognitive impairment. Biochemical studies showed that D-gal significantly increases the oxidative stress and acetylcholinesterase activity (AChE) in rat brain. Histopathological study showed that D-gal disturbs the normal architecture of hippocampal and cortical cells, indicating degeneration in these brain areas. D-gal and CAE co-treatment for 42 days attenuated the behavioral, biochemical, and neuroanatomical impairments caused by the D-gal; it markedly suppresses the D-gal-induced oxidative stress and AChE activity in the brain, and maintains the normal cellular architecture in hippocampal and cortical areas. Thus, this study shows that CAE can protect the brain from the adverse effects of D-gal (e.g., memory loss and cognitive impairment) by modulating AChE activity and oxidative stress.

Research paper thumbnail of Pharmacological Investigations of Selected Multitarget‐Direct Ligands for the Treatment of Alzheimer's Disease

Research paper thumbnail of Development and treatment of cognitive inflexibility in sub-chronic stress–re-stress (SRS) model of PTSD

Pharmacological Reports, 2021

BACKGROUND Cognitive inflexibility is one of the major clinical symptoms of post-traumatic stress... more BACKGROUND Cognitive inflexibility is one of the major clinical symptoms of post-traumatic stress disorder (PTSD). Studies have examined the impact of traumatic events on anxiety. However, there were limited reports on the effect of traumatic episodes on cognitive flexibility. Therefore, animal models developing cognitive inflexibility would provide new insight of pathophysiology and pharmacotherapy of PTSD. METHODS Male Wistar rats were subjected to stress-re-stress (SRS) procedure by restraining them for 2 h followed by foot shock (FS) and halothane exposure on day 2 (D-2). Then, the rats were exposed every week to FS as re-stress cue up to D-32. Donepezil (3 mg/kg; po) and sertraline (10 mg/kg; po) dosing was started from D-8 and continued up to D-32. RESULTS SRS exposure caused cognitive inflexibility by producing deficits in intra-dimension (ID) and extra-dimension (ED) set-shifting which was significantly attenuated by donepezil. However, sertraline mitigated only ID shift in SRS-subjected rats. SRS-induced PTSD-like symptoms such as fear response, anxiety-like behaviour and cognitive deficits were attenuated by both donepezil and sertraline. Donepezil did not modulate the SRS-induced hypothalamic-pituitary-adrenal (HPA) axis dysfunction and activation of serotonergic and nor-adrenergic system. Interestingly, exposure of SRS caused a decrease in acetylcholine level and increase in acetylcholine esterase activity in prefrontal cortex (PFC) and hippocampus (HIP) which was only mitigated by donepezil. Donepezil significantly attenuated SRS-induced down-regulation of choline-acetyl transferase and α-7 nicotinic acetylcholine receptor expressions in PFC and HIP. CONCLUSION Cognitive inflexibility is developed in the SRS model along with other PTSD-like symptoms which were attenuated by donepezil.

Research paper thumbnail of Supplementation of taurine improves ionic homeostasis and mitochondrial function in the rats exhibiting post-traumatic stress disorder-like symptoms

European Journal of Pharmacology

RATIONALE Current pharmacotherapy for post-traumatic stress disorder (PTSD) is limited to few ant... more RATIONALE Current pharmacotherapy for post-traumatic stress disorder (PTSD) is limited to few antidepressants. Mitochondrial dysfunction is observed in PTSD, along with altered potassium homeostasis. Nutritional supplementation of taurine can improve ionic homeostasis and thereby treat PTSD-like symptoms in rats. AIM The purpose is to study the pharmacological effect of taurine in stress re-stress-induced PTSD in rats. METHODS As per protocol, animals were restrained for 2 h then exposed to footshock (FS) (2 mA/10 s) followed by halothane-induced anesthesia. Behavioral assessments such as elevated plus maze (EPM) and Y-maze tests were performed on days 2, 8, and 32 of experimental protocol after re-stress. In addition, daily oral administration of taurine (100, 200, and 300 mg/kg) and paroxetine (PAX) (10 mg/kg) was done from D-8 to D-32 followed by re-stress. The plasma concentration of taurine, corticosterone, and potassium was measured on Day-32 along with mitochondrial function in discrete brain regions. RESULTS Sub-chronic administration of taurine in high and medium doses significantly ameliorated PTSD-like symptoms such as hyperarousal, anxiety, and improved spatial recognition memory. Taurine in all doses restored the plasma concentration of corticosterone and potassium. SRS-induced alterations in mitochondrial bioenergetics, complex enzyme activities, and reduced mitochondrial membrane potential in different brain regions were ameliorated by taurine. CONCLUSION Nutritional supplementation of taurine improves potassium ionic homeostasis, mitochondrial function, and attenuated PTSD-like symptoms in SRS subjected rats.

Research paper thumbnail of Discovery of new phenyl sulfonyl-pyrimidine carboxylate derivatives as the potential multi-target drugs with effective anti-Alzheimer’s action: Design, synthesis, crystal structure and in-vitro biological evaluation

European Journal of Medicinal Chemistry, 2021

Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behav... more Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behavioural and cognitive functions. The multitarget-directed ligand (MTDL) strategies are promising paradigm in drug development, potentially leading to new possible therapy options for complex AD. Herein, a series of novel MTDLs phenylsulfonyl-pyrimidine carboxylate (BS-1 to BS-24) derivatives were designed and synthesized for AD treatment. All the synthesized compounds were validated by 1HNMR, 13CNMR, HRMS, and BS-19 were structurally validated by X-Ray single diffraction analysis. To evaluate the plausible binding affinity of designed compounds, molecular docking study was performed, and the result revealed their significant interaction with active sites of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The synthesized compounds displayed moderate to excellent in vitro enzyme inhibitory activity against AChE and BuChE at nanomolar (nM) concentration. Among 24 compounds (BS-1 to BS-24), the optimal compounds (BS-10 and BS-22) displayed potential inhibition against AChE; IC50 = 47.33 ± 0.02 nM and 51.36 ± 0.04 nM and moderate inhibition against BuChE; IC50 = 159.43 ± 0.72 nM and 153.3 ± 0.74 nM respectively. In the enzyme kinetics study, the compound BS-10 displayed non-competitive inhibition of AChE with Ki = 8 nM. Respective compounds BS-10 and BS-22 inhibited AChE-induced Aβ1-42 aggregation in thioflavin T-assay at 10 μM and 20 μM, but BS-10 at 10 μM and 20 μM concentrations are found more potent than BS-22. In addition, the aggregation properties were determined by the dynamic light scattering (DLS) and was found that BS-10 and BS-22 could significantly inhibit self-induced as well as AChE-induced Aβ1-42 aggregation. The effect of compounds (BS-10 and BS-22) on the viability of MC65 neuroblastoma cells and their capability to cross the blood-brain barrier (BBB) in PAMPA-BBB were further studied. Further, in silico approach was applied to analyze physicochemical and pharmacokinetics properties of the designed compounds via the SwissADME and PreADMET server. Hence, the novel phenylsulfonyl-pyrimidine carboxylate derivatives can act as promising leads in the development of AChE inhibitors and Aβ disaggregator for the treatment of AD.

Research paper thumbnail of Neuro-nutraceutical potential of Asparagus racemosus: A review

Neurochemistry International, 2021

Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multif... more Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multifactorial pathophysiology. Their treatment strategies often only provide symptomatic relief, delaying disease progression without giving a complete cure. Potent and safer treatment alternatives beyond symptomatic relief are sought. Herbal supplements have surely been explored due to their multiple component nature to enhance the effect of western medications. One such well-documented nutraceutical in the ancient Greek, Chinese, and Ayurvedic medicine system is known for its various medicinal benefits is Asparagus racemosus. Widely used for its lactogenic properties, A. racemosus is also cited in Ayurveda as a nervine tonic. A. racemosus based nutraceuticals have shown to possess adaptogenic, neuroprotective, antioxidant, anti-inflammatory, and nootropic activity under preclinical and clinical settings without posing significant adverse effects. A. racemosus extracts restore the perturbed neurotransmitters and prevent oxidative neuronal damage. From the available neuropharmacological researches, the physiological actions of A. racemosus can ultimately be directed for either augmentation of cognitive ability or in the management of neurological conditions such as stress, anxiety, depression, epilepsy, Parkinson's, and Alzheimer's disease. The studies focus on the multi-component extract, and the lack of standardization has been a major hurdle in preventing the allotment of reported neuropharmacological activity to one of the phytoconstituent. Herbal standardization of the plant extract based on a specific biomarker can help elucidate the intricate biomolecular pathway and neurocircuitries being involved. This, followed by rigorous standardized clinical trials, fixing dosages, and determining contraindications would facilitate the translation of A. racemosus to a FDA-approved neuromedicine for neurological disorders.

Research paper thumbnail of Neurochemical Evidence of Preclinical and Clinical Reports on Target-Based Therapy in Alcohol Used Disorder

Neurochemical Research, 2020

Alcohol use disorder (AUD) is a chronic relapsing disorder, which enforces a person to compulsive... more Alcohol use disorder (AUD) is a chronic relapsing disorder, which enforces a person to compulsively seek alcohol, restricting control over alcohol intake leads to emergence of an undesired emotional state during abstinence. There are recent advances for better understanding of neurocircuitry involved in the pathophysiology of AUD. Alcohol interaction with neuronal membrane proteins results in changes in neuronal circuits. It is also linked with the potential medication and their clinical validation concerning their pharmacological targets for alcoholic abstinence. This review covers research work from the past few decades on the therapeutic advances on treatment of alcohol dependence; further detailing the fundamental neurochemical mechanisms after alcohol administration. It also covers interaction of alcohol with GABAergic, glutaminergic, dopaminergic, serotonergic and opioid systems. This review further elaborated the neurobiology of noradrenergic, cholinergic and cannabinoid systems and their interaction with AUD. Elaborative information of potential drug targets under current exploration for AUD treatment with their mechanisms are reported here along with clinical outcomes and the associated side effects.

Research paper thumbnail of A novel stress re-stress model: modification of re-stressor cue induces long-lasting post-traumatic stress disorder-like symptoms in rats

International Journal of Neuroscience, 2020

Background: Post-traumatic stress disorder (PTSD) develops after exposure to a severe traumatic e... more Background: Post-traumatic stress disorder (PTSD) develops after exposure to a severe traumatic event. Stress re-stress (SRS) model of PTSD using the forced swim as a re-stress shows hypocortisolism, an index of hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Despite this, the SRS model lacks development of hyperarousal and intrusive memory which are prominent symptoms of PTSD. Aim: Developing a model which shows more clinical similarities to PTSD. We used intense foot-shock (FS) (2 mA for 10 sec) instead of the forced-swim test (FST) as a re-stress cue. Methods: The stress session was performed on D-2 except control group. The FST group rats were forced to swim for 20 min, and FS group rats were exposed to foot shock of 2 mA for 10 sec. The re-stress sessions of FST and FS were performed on D-8, 14, 20, 26 and 32. The freezing behavior was evaluated after the FS restress cue, and remaining behavioral assessments such as anxiety and depressive-like behavior, and cognitive dysfunction were performed on last day of the experiment. Results: The FS-induced PTSD-like (anxiety and depressive-like behavior, and cognitive dysfunction) symptoms and a decrease in plasma corticosterone (CORT) were more significant compared to FST. The hyperarousal and intrusive memory induced by FS were additional symptoms in the SRS model. Treatment with paroxetine significantly attenuated FST and FS-induced behavioral deficits in PTSD rats. Conclusion: FS as a re-stress model shows prominent PTSD-like symptoms with HPA axis dysfunction compared to FST.

Research paper thumbnail of Design and development of molecular hybrids of 2-pyridylpiperazine and 5-phenyl-1,3,4-oxadiazoles as potential multifunctional agents to treat Alzheimer's disease

European Journal of Medicinal Chemistry, 2019

The diverse nature of Alzheimer's disease (AD) has prompted researchers to develop multi-function... more The diverse nature of Alzheimer's disease (AD) has prompted researchers to develop multi-functional agents. Herein, we have designed and synthesized molecular hybrids of 2-pyridylpiperazine and 5phenyl-1,3,4-oxadiazoles. Biological activities of synthesized compounds suggested significant and balanced inhibitory potential against target enzymes. In particular, compound 49 containing 2,4-difluoro substitution at terminal phenyl ring considered as most potential lead with inhibition of acetylcholinesterase (hAChE, IC 50 ¼ 0.054 mM), butyrylcholinesterase (hBChE, IC 50 ¼ 0.787 mM) and beta-secretase-1 (hBACE-1, IC 50 ¼ 0.098 mM). The enzyme kinetics study of 49 against hAChE suggested a mixed type of inhibition (Ki ¼ 0.030 mM). Also, 48 and 49 showed significant displacement of propidium iodide from the peripheral anionic site (PAS) of hAChE, excellent blood-brain barrier (BBB) permeability in parallel artificial membrane permeation assay (PAMPA), and neuroprotective ability against SH-SY5Y neuroblastoma cell lines. Further, 49 also exhibited anti-Ab aggregation activity in self-and AChE-induced thioflavin T assay, which was ascertained by morphological characterization by atomic force microscopy (AFM). Moreover, in vivo behavioral studies signified learning and memory improvement by compound 49 in scopolamine-and Ab-induced cognitive dysfunctions performed on Y-maze and Morris water maze. The ex vivo studies suggested decreased AChE activity and antioxidant potential of compound 49, with good oral absorption characteristics ascertained by pharmacokinetic studies.

Research paper thumbnail of Repeated caffeine administration aggravates post-traumatic stress disorder-like symptoms in rats

Physiology & Behavior, 2019

Research paper thumbnail of Design and development of multitarget-directed N-Benzylpiperidine analogs as potential candidates for the treatment of Alzheimer's disease

European Journal of Medicinal Chemistry, 2019

The multitarget-directed strategy offers an effective and promising paradigm to treat the complex... more The multitarget-directed strategy offers an effective and promising paradigm to treat the complex neurodegenerative disorder, such as Alzheimer's disease (AD). Herein, a series of N-benzylpiperidine analogs (17-31 and 32-46) were designed and synthesized as multifunctional inhibitors of acetylcholinesterase (AChE) and β-secretase-1 (BACE-1) with moderate to excellent inhibitory activities. Amongst tested inhibitors, 25, 26, 40, and 41 presented the most significant and balanced inhibition against both the targets. Compounds 40 and 41 exhibited high brain permeability in PAMPA-BBB assay, significant displacement of propidium iodide from peripheral anionic site (PAS) of AChE, and were devoid of neurotoxicity towards SH-SY5Y neuroblastoma cell lines up to the maximum tested concentration of 80 µM. Meanwhile, both these compounds inhibited self-and AChEinduced Aβ aggregation in thioflavin T assay, which was also reaffirmed by morphological characterization of Aβ aggregates using atomic force microscopy (AFM). Moreover, 40 and 41 ameliorated the scopolamine-induced cognitive impairment in elevated plus and Y-maze experiments. Ex vivo and biochemical analysis established the brain AChE inhibitory potential and antioxidant properties of these compounds. Further, improvement in Aβ 1-42induced cognitive impairment was also observed by compound 41 in the Morris water maze experiment with significant oral absorption characteristics ascertained by the pharmacokinetic studies.

Research paper thumbnail of Coenzyme Q10 Prevents Mitochondrial Dysfunction and Facilitates Pharmacological Activity of Atorvastatin in 6-OHDA Induced Dopaminergic Toxicity in Rats

Neurotoxicity Research, 2017

Through document analysis, classroom observation and analysis of children's performance in readin... more Through document analysis, classroom observation and analysis of children's performance in reading, we investigated tests from Provinha Brasil, as well as the relationships between children's outcomes and practices of their teachers. It was shown that there was a relationship between the results of Provinha Brasil and teaching practices, but the teachers didn't dedicate enough time to teaching reading texts. It was concluded that the impacts upon Provinha Brasil stemmed from teaching the alphabet basis and that the reading level required by Provinha's questions did not demand more elaborated text comprehension skills.

Research paper thumbnail of Long-term caffeine intake exaggerates PTSD-like symptoms independent of HPA axis activity

IBRO Reports, 2019

interfere with the neurogenic potential of astrocytes after stroke. Based on our results, we can ... more interfere with the neurogenic potential of astrocytes after stroke. Based on our results, we can speculate that NCX1, by regulating microglia/astrocytes activation and polarization, might interfere with the neurogenic potential of astrocytes under ischemic conditions.