Valproic Acid Derivatives Research Articles

A validated high-performance liquid chromatography-ultraviolet method for the determination of valproic acid derivatives in pharmaceutical formulations with a microbiological suitability evaluation

Valproic acid and its derivatives are common drugs used in the treatment of epilepsy, a result of CNS disorders. Because the molecular structure of valproic acid, as a fatty acid, does not contain any chromophore groups, its peak response demanded special conditions to be detected in HPLC, ensuring the best precision results. Still, the current approach illustrates simple, validated procedures for conduction. The conducted chromatographic system consists of the BDS Hypersil C8, 150 × 4.6 mm, 5 µm column using a mobile phase of acetonitrile: phosphate buffer (4:6) at a detection wavelength of 215 nm at room temperature. A full method validation study was conducted and approved to ensure precise, repeatable, and accurate results by implementing system suitability parameters. In microbiological terms, a suitability test is used to validate microbiological testing methods, ensuring their efficacy despite potential interference from antimicrobial properties in the tested materials. The HPLC-UV developed and validated analytical method was evaluated, and it was found to be sensitive for use in the detection of low concentrations of methylparaben, propylparaben, and valproate with an optimum run time of six minutes. limit of detection (LODs) were statistically estimated and found to be 2.27 µg/mL, 39.77 ng/mL, and 1.84 µg/mL for methylparaben, propylparaben, and valproate, respectively. Additionally, the method demonstrated a high recovery of methylparaben, propylparaben, and valproate with an excellent closed-accuracy range (98.84% - 101.34%). An excellent regression coefficient (r) of 0.99924, 0.99998, and 0.99997 for methylparaben, valproate, and propylparaben, respectively, was achieved. Assay determination of various pharmaceutical dosage forms in the local market was implemented, yielding admirable results.

Pharmacological screening of a new valproic acid derivative using the pharmacoencephalography method in rats

Introduction. The naïve Bayes classifier combined with principal component analysis allows to distinguish the effects of antipsychotic agents effectively as well as evaluate their dose-dependency based on their impact on electroencephalogram parameters in rats. Further development of this method requires its validation as an instrument for the screening of new understudied molecules. Valproic acid derivatives appear to be a promising neuropharmacological group as they exhibit not only antiepileptic activity but also mood-stabilizing, antimigraine, neuroprotective and analgesic effects.Aim. This work was carried out to perform the pharmacological screening of a valproic acid aminoester (AVA) that exhibits antidote properties in case of poisoning with anticholinesterase agents.Materials and methods. The experiments were conducted in white outbred rats with chronically implanted electrocorticographic electrodes. AVA was administered at doses of 0,5, 5 and 30 mg/kg. The training set, used as a reference to determine the pharmacological effects of each dose of the investigated substance, included matrixes of effects of 7 drugs: the antiepileptic agent sodium valproate, the D2-dopamine receptor blocker haloperidol, the M-cholinergic receptor blocker tropicamide, the H1-histamine receptor blocker chloropyramine, the acetylcholinesterase inhibitor galantamine, the sedative dexmedetomidine, and the anxiolytic phenazepam.Results and discussion. AVA at the dose of 0,5 mg/kg showed effects similar to those of sodium valproate, while a tenfold dose increase led to the predominance of an atropine-like effect. When administered at the dose of 30 mg/kg, the compound exhibited dexmedetomidine-like action. The central M-anticholinergic effect of AVA was confirmed by an arecoline test in mice, in which the substance at a dose of 88 mg/kg completely abolished the onset of tremor. Dexmedetomidine-like action was cancelled by the administration of atipamezole in equimolar quantities, which may indicate the potential сapability of AVA to activate α2-adrenergic receptors at a high dose. The results of molecular docking suggest that this effect is related specifically to the original aminoester molecule and not to its presumable active metabolites.Сonclusion. The obtained results confirm the effectiveness of the naïve Bayes classifier as an instrument for the prediction of the pharmacological activity of compounds based on their impact on electroencephalogram parameters in rats. Identification of new pharmacological effects of understudied compounds may widen the potential range of their clinical application as well as reveal probable adverse effects.

Transcriptome analysis of Burkitt lymphoma cells treated with anti-convulsant drugs that are inhibitors of Epstein-Barr virus lytic reactivation.

Herpesviruses have two distinct life cycle stages, latency and lytic replication. Epstein-Barr virus (EBV), a gamma-herpesvirus, establishes latency in vivo and in cultured cells. Cell lines harboring latent EBV can be induced into the lytic cycle by treatment with chemical inducing agents. In the Burkitt lymphoma cell line HH514-16 the viral lytic cycle is triggered by butyrate, a histone deacetylase (HDAC) inhibitor. Butyrate also alters expression of thousands of cellular genes. However, valproic acid (VPA), another HDAC inhibitor with global effects on cellular gene expression blocks EBV lytic gene expression in Burkitt lymphoma cell lines. Valpromide (VPM), an amide derivative of VPA, is not an HDAC inhibitor, but like VPA blocks induction of the EBV lytic cycle. VPA and VPM are the first examples of inhibitors of initial stages of lytic reactivation. We compared the effects of VPA and VPM, alone and in combination with butyrate, on host cellular gene expression using whole transcriptome analysis (RNA-seq). Gene expression was analyzed 6 h after addition of the compounds, a time before the first EBV lytic transcripts are detected. The results address two alternative, yet possibly complementary, mechanisms for regulation of EBV lytic reactivation. First, cellular genes that were up- or down-regulated by butyrate, but no longer altered in the presence of VPA or VPM, represent genes that correlated with EBV lytic reactivation. Second, genes regulated similarly by VPA and VPM in the absence and presence of butyrate are candidates for suppressors of EBV reactivation. Two genes upregulated by the lytic cycle inhibitors, CHAC1 and SLC7A11, are related to redox status and the iron-dependent cell death pathway ferroptosis. This study generates new hypotheses for control of the latency to lytic cycle switch of EBV and provides the first description of effects of the anti-convulsant drug VPM on global human cellular gene expression.

Study of the anticonvulsant activity of the original valproic acid amino ester in various models of convulsive syndrome

Introduction. Despite a significant number of antidotes (atropine, pyridoxine) and anti-seizure drugs in clinical practice (benzodiazepines, barbiturates, valproates, anesthetics), the development of new antidotes for the relief of refractory seizures and recurrence of convulsive syndrome is actual problem. 
 The aim of the work was to study the specific pharmacological activity of a new original derivative of valproic acid in an experiment on models of convulsive syndrome with different mechanisms of action.
 Material and methods. A comparative study of the effectiveness of the original substance ((1-methylpiperidin-4-yl)-2-propylpentanoate hydrochloride, VAA) was carried out on electroshock, GABA-lytic, catecholamine-dependent seizure models in rats and mice.
 Results. A significant decrease in seizure activity was revealed in the group with prophylactic administration 
 of VAA in the dose range of 11, 27 and 65 mg/kg in comparison with the control group received only phenylcarbamate. In an intergroup comparison, a low dose (11 mg/kg) more than others had an effect on the latent period of the onset of phenylcarbamate seizures, an average dose (27 mg/kg) reduced the duration of the seizure period, a high dose (65 mg/kg) affected the severity of convulsions, while the integral indicator (convulsive activity) did not differ between the medium and high dose subgroups. There was no significant decrease in seizure activity in models with the use of corazol, camphor, and the model of maximum electric shock.
 Limitations. Testing of new pharmaceutical substances (study of efficacy and safety) should be carried out on laboratory animals before confirmation of efficacy in humans. The quantity of animals was limited by the need to comply with bioethical principles and sufficient number for statistically significant results and amounted 
 6 individuals in each group.
 Conclusion. The release of valproic acid during the metabolism of VAA is slow and its concentration is insufficient to realize the universal anticonvulsant activity of VAA. It is necessary to further study the effect on cognitive functions and neuroprotective properties. Since antidote efficacy superior to atropine has been previously demonstrated, VAA is recommended for development as an antidote for organophosphorus poisoning.

Hexyl-pentynoic acid serves as a novel radiosensitizer for breast cancer by inhibiting UCHL3-dependent Rad51 deubiquitination

ObjectiveTo investigate the effects and underlying mechanism of 2-hexyl-4-pentynoic acid (HPTA), a derivative of valproic acid (VPA), on radiotherapy in breast cancer. MethodsMCF7 cells and 7,12-dimethylbenz-[α]-anthracene (DMBA)-induced transformed human normal breast cells (MCF10A–DMBA cells) were irradiated with 8 ​Gy X-rays. For both cells there were four groups: control, valproic acid (VPA)/HPTA, IR, and VPA/HPTA+IR groups. MTT and clonogenic survival assays were performed to assess cell proliferation, and comet assay was performed to evaluate DNA damage. Protein expression of γH2AX, 53BP1, Rad51, and BRCA1 was examined via immunofluorescence and immunoblotting. Cycloheximide chase and ubiquitination experiments were conducted to determine Rad51 ubiquitination. In vivo experiments involved a rat model of DMBA-induced breast cancer, with four fractionated doses of 2 ​Gy. Tumor tissue pathological changes and γH2AX, Rad51, and UCHL3 expression levels were measured by hematoxylin-eosin staining, immunohistochemistry, and immunoblotting. ResultsCompared with the IR group, 15 ​μmol/L HPTA reduced the cell proliferation ability of irradiated MCF7 cells (t=2.16, P<0.05). The VPA/HPTA+IR group exhibited significantly increased DNA double-strand breaks relative to those in the IR group (VPA+IR vs. IR, t=13.37, P<0.05; HPTA+IR vs. IR, t=8.48, P<0.05). Immunofluorescence and immunoblotting experiments demonstrated that the VPA/HPTA+IR group displayed significantly increased cell foci formation, γH2AX and 53BP1 protein expression levels compared to the IR group [(γH2AX: VPA+IR vs. IR, t=8.88, P< 0.05; HPTA+IR vs. IR, t=8.90, P< 0.05), (53BP1, VPA+IR vs. IR, t=5.73, P< 0.05; HPTA+IR vs. IR, t=6.40, P< 0.05)]. Further, Rad51 expression was downregulated (VPA+IR vs. IR, t=3.12, P< 0.05; HPTA+IR vs. IR, t ​= ​2.70, P<0.05), and Rad51 inhibition effectively counteracted HPTA-induced radiosensitization. Ubiquitination detection further verified that HPTA inhibits Rad51 expression via UCHL3-dependent Rad51 deubiquitination. In vivo study results showed that 20 ​mg/kg HPTA significantly enhanced the radiosensitivity of breast tumors in rats by inhibiting Rad51 expression. ConclusionsHPTA is a highly effective radiosensitizer that enhances the radiotherapeutic efficacy of breast cancer treatment through UCHL3-dependent deubiquitination of Rad51.

Untargeted LC-MS/MS Metabolomics Study of HO-AAVPA and VPA on Breast Cancer Cell Lines.

Breast cancer (BC) is one of the biggest health problems worldwide, characterized by intricate metabolic and biochemical complexities stemming from pronounced variations across dysregulated molecular pathways. If BC is not diagnosed early, complications may lead to death. Thus, the pursuit of novel therapeutic avenues persists, notably focusing on epigenetic pathways such as histone deacetylases (HDACs). The compound N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA), a derivative of valproic acid (VPA), has emerged as a promising candidate warranting pre-clinical investigation. HO-AAVPA is an HDAC inhibitor with antiproliferative effects on BC, but its molecular mechanism has yet to be deciphered. Furthermore, in the present study, we determined the metabolomic effects of HO-AAVPA and VPA on cells of luminal breast cancer (MCF-7) and triple-negative breast cancer (MDA-MB-231) subtypes. The LC-MS untargeted metabolomic study allowed for the simultaneous measurement of multiple metabolites and pathways, identifying that both compounds affect glycerophospholipid and sphingolipid metabolism in the MCF-7 and MDA-MB-231 cell lines, suggesting that other biological targets were different from HDACs. In addition, there are different dysregulate metabolites, possibly due to the physicochemical differences between HO-AAVPA and VPA.

Estimation of mutagenic potential of the valproic acid derivative containing a tertiary amino group

Estimation of mutagenic potential of the valproic acid derivative containing a tertiary amino group

Hepatotoxic Evaluation of N-(2-Hydroxyphenyl)-2-Propylpentanamide: A Novel Derivative of Valproic Acid for the Treatment of Cancer.

Valproic acid (VPA) is a drug that has various therapeutic applications; however, it has been associated with liver damage. Furthermore, it is interesting to propose new compounds derived from VPA as N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA). The HO-AAVPA has better antiproliferative activity than the VPA in different cancer cell lines. The purpose of this study was to evaluate the liver injury of HO-AAVPA by acute treatment (once administration) and repeated doses for 7 days under intraperitoneal administration. The median lethal dose value (LD50) was determined in rats and mice (females and males) using OECD Guideline 425. In the study, male rats were randomly divided into 4 groups (n = 7), G1: control (without treatment), G2: vehicle, G3: VPA (500 mg/kg), and G4: HO-AAVPA (708 mg/kg, in equimolar ratio to VPA). Some biomarkers related to hepatotoxicity were evaluated. In addition, macroscopic and histological studies were performed. The LD50 value of HO-AAVPA was greater than 2000 mg/kg. Regarding macroscopy and biochemistry, the HO-AAVPA does not induce liver injury according to the measures of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, glutathione peroxidase, glutathione reductase, and catalase activities. Comparing the treatment with HO-AAVPA and VPA did not show a significant difference with the control group, while malondialdehyde and glutathione-reduced levels in the group treated with HO-AAVPA were close to those of the control (p ≤ 0.05). The histological study shows that liver lesions caused by HO-AAVPA were less severe compared with VPA. Therefore, it is suggested that HO-AAVPA does not induce hepatotoxicity at therapeutic doses, considering that in the future it could be proposed as an antineoplastic drug.

Phosphonate Derivatives of Paracetamol and Valproic Acid.

Paracetamol and valproic acid are standalone drugs with leading position in the world drug market. The phosphonate analogues of these drugs were synthesized and were tested in vivo. N-(4-hydroxyphenylcarbamoyl)phosphonic acid was four times more potent than paracetamol in preventing acetic acid-induced writhing. Phosphonate derivative of valproic acid, (2-propylpentanoyl)phosphonic acid, had similar in vivo activity to valproic acid in the pentylenetetrazole-induced kindling mouse model.

Evaluation of the inhibitory potential of Valproic acid against histone deacetylase of Leishmania donovani and computational studies of Valproic acid derivatives

Valproic acid (VA) is a proven inhibitor of human histone deacetylases (HDACs). The homogenous HDAC has been associated with all major human parasitic pathogens and hence, it has been considered an attractive drug target for anti-leishmanial therapy. To assist in drug design endeavors for HDACs, an in-vitro study has been presented to investigate the VA inhibition on Leishmania donovani HDAC (LdHDAC). The regression analysis of VA by 24 hrs viability assay confirmed its activity against LdHDAC. Moreover, the toxicity of VA is also well documented. Thus, the in-silico experiments were also conducted to screen the non-toxic VA derivatives as anti-leishmanial drug candidates having potential as inhibitors of LdHDAC. For in-silico study, the 3D structure of target LdHDAC was developed by homology modeling. Based on their in-silico activity, we shortlisted 13 VA derivatives having maximum affinity for LdHDAC and identified four potential derivatives that can specifically bind to this protein. After that, these ligands were subjected to molecular dynamics simulation. These derivatives may be effective against L. donovani promastigotes since they followed Lipinski's RO5 and were non-toxic. Thus, screened derivatives can be considered as lead ligands for targeting LdHDAC and may be used as possible drug candidates to treat leishmaniasis and overcome the limitation of anti-leishmanial drugs. This is the first report of antileishmanial potential of VA and its derivatives targeting LdHDAC. Hence, the current investigation presents a search for novel target specific drugs to aid the anti-leishmanial drug development. Communicated by Ramaswamy H. Sarma

Prospects for the development of new prolonged forms of valproic acid derivatives for the relief of convulsive syndrome

Poisoning with pesticides containing convulsive substances is the cause of death of thousand people in the world. Convulsive syndrome can also develop with infection of the central nervous system, intracranial hemorrhages and strokes, alcohol withdrawal syndrome, eclampsia. Up to 10% of all of the people on the Earth had experienced seizures. The most common cause of seizures is epilepsy. Existing drugs are not always effective and have side effects. Alternative therapies are being developed. Valproates (derivatives of valproic acid) are one of the most studied drugs of choice for epilepsy and other variants of convulsive syndrome, have many years of experience in use, are included in international and Russian clinical guidelines for the treatment of epilepsy. The antiepileptic, mood stabilizing and neuroprotective properties of valproate due to pre- and postsynaptic modulation of GABA-ergic transmission, regulation of glutamate activity, serotonin and dopamine levels in the hippocampus, modulation of sodium, calcium and potassium channels, epigenetic effects on the body are described. However, valproates have a number of undesirable side effects, usually associated with high doses of drugs used for a long time. Attempts to reduce the risk through the development of drugs with controlled release of the active substance are not always effective - the high individual sensitivity of about 15% of patients with epilepsy makes standard doses toxic, the pharmacokinetics and effectiveness of the developed generics are significantly inferior to the original imported drug. An alternative could be the development of Russian preparations containing a proactive component from which valproic acid is gradually released during the metabolism.

ERK1/2 kinases and dopamine D2 receptors participate in the anticonvulsant effects of a new derivative of benzoylpyridine oxime and valproic acid

Inhibition of the activity of extracellular signal-regulated kinases (ERK1/2) induced by the activation of the dopamine D2 receptor signalling cascade may be a promising pharmacological target. The aim of this work was to study the involvement of ERK1/2 and dopamine D2 receptor in the mechanism of the anticonvulsant action of valproic acid (VA) and a new benzoylpyridine oxime derivative (GIZH-298), which showed antiepileptic activity in different models of epilepsy. We showed that subchronic exposure to maximal electroshock seizures (MES) for 5 days reduced the density of dopamine D2 receptors in the striatum of mice. GIZH-298 counteracted the decrease in the number of dopamine D2 receptors associated with MES and increased the number of ligand binding sites of dopamine D2 receptors in mice without MES. The affinity of dopamine D2 receptors to the ligand was not changed by GIZH-298. MES caused an increase in ERK1/2 and synapsin I phosphorylation in the striatum while GIZH-298, similar to VA, reduced the levels of both phospho-ERK1/2 and phosphosynapsin I after MES, which correlated with the decrease in the intensity of seizure in mice. In addition, GIZH-298 suppressed ERK1/2 phosphorylation in SH-SY5Y human neuroblastoma cells at therapeutic concentrations, while VA inhibited ERK1/2 phosphorylation in vivo but not in vitro. The data obtained expand the understanding of the mechanisms of action of VA and GIZH-298, which involve regulating the activity of ERK1/2 kinases, probably by modulating dopamine D2 receptors in limbic structures, as well as (in the case of GIZH-298) directly inhibiting of the ERK1/2 cascade.

Is there evidence for using anticonvulsants in the prevention and/or treatment of delirium among older adults?

<h3>Introduction</h3> Delirium is an acute neuropsychiatric syndrome characterized by impaired attention, awareness and cognition. It develops over a short period of time (hours to days), represents a change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day. The highest prevalence of delirium is found in the older adults, being particularly high in the hospitalized older adults. The highest incidence rates for delirium among the older adults are observed in the intensive care units, and in postoperative and palliative care settings. Delirium is associated with poorer clinical outcomes including a worsening of nutritional status, cognition and medical co-morbidities. It is associated with greater lengths and costs of hospitalization, and greater burden of care on the nursing staff. Delirium also increases the risk for developing cognitive impairment, institutionalization and death. The average medical care cost for individuals with delirium is more than two-and-a half times the cost for individuals without. Both non-pharmacologic and pharmacologic treatments are used in the management of delirium. Non-pharmacologic treatments that benefit older adults with delirium include frequent reorientation, making eye contact, frequent touching and using clear verbal instructions when talking to patients. Additionally, minimizing of sensory impairments including vision and hearing loss by use of assistive devices, reducing the use of physical restraints, providing treatment in a non-stimulating environment and minimizing staff and room changes, have proven beneficial as well. Pharmacotherapy is often used to treat the underlying causes of delirium in older adults, especially in the management of behaviors that are not managed by non-pharmacological strategies. Agents that have shown benefit among older adults with delirium include antipsychotics, cholinesterase inhibitors and benzodiazepines. Valproic acid derivatives have been used in the treatment of delirium among younger adults with some success. Many different mechanisms have been proposed for this, including the actions of valproic acid derivatives on the glutamatergic system, dopaminergic system, GABAergic system, Kynurenine Pathway. Oral or intravenous valproic acid preparations appear to be efficacious in delirium when antipsychotics and/or benzodiazepines are ineffective, the management requires large and/or frequent dosing of medications, or the medications cause significant adverse effects. Valproic acid derivatives have been beneficial in over 70% of the cases, with benefits noted in the first week of treatment, and the medication was well tolerated. Given the emerging evidence for the efficacy of valproic acid preparations among individuals with delirium, we decided to conduct a systematic review that examined the current evidence for using anticonvulsants in the prevention and/or treatment of delirium among older adults from published randomized control trials (RCTs). If there is good evidence for their use in the older adult population, then it would broaden the pharmaceutic options available to manage this serious condition among a vulnerable group of individuals. <h3>Methods</h3> A comprehensive search of databases: MEDLINE ALL (Ovid), Embase (Ovid), PsycINFO (Ovid), Web of Science Core Collection and Cochrane Central Register of Controlled was conducted. <h3>Results</h3> The search identified four RCTs that evaluated the use of anticonvulsants among older adults with delirium. One RCT evaluated the perioperative use of gabapentin among patients undergoing spinal surgery and the development of postoperative delirium. One RCT evaluated the relationship between the use of perioperative gabapentin and the development of postoperative delirium among patients undergoing spinal surgery and hip and knee arthroplasty. Two post-hoc analyses of RCTs that evaluated the use of gabapentin and pregabalin among patients undergoing total knee replacement (TKA) and total hip replacement (THA). The perioperative use of gabapentin reduced the incidence of postoperative delirium among older adults undergoing spinal surgery. The perioperative use of gabapentin did not reduce the rates, severity or duration of postoperative delirium among older adults who were undergoing spine and hip and knee arthroplasty. The perioperative use of gabapentin did not reduce the incidence or duration of postoperative delirium among older adults undergoing elective TKA. The perioperative use of pregabalin did not reduce the incidence of postoperative delirium among older adults undergoing elective THA. Gabapentin and pregabalin were well tolerated among the patients enrolled in these trials. There were no RCTs identified that evaluated the use of other anticonvulsants for the prevention and/or treatment of delirium among older adults. <h3>Conclusions</h3> Based on current evidence, the routine use of anticonvulsants for the prevention and/or treatment of delirium among older adults cannot be recommended.

Late-stage sequela of an isolated optic neuropathy after acute magnesium valproate overdose: A case report.

Magnesium valproate is a valproic acid (VPA) derivative that is widely used for the treatment of epilepsy and bipolar disorders. Acute overdose of VPA may cause complicated systemic syndromes; however, the reports of ocular sequelae caused by toxic optic neuropathy (TON) are rare. We present a case of a 19-year-old female with bilateral damage to visual function after acute VPA overdose. She was comatose and received systemic treatments for 1 month, during which she suffered a substantial loss of visual function without any evident neurological sequelae. The first recorded visual acuity was no light perception in the right eye (OD) and hand motion in the left eye (OS). Her best-corrected visual acuity improved to 20/100 OS after 4 months of hyperbaric oxygen therapy and neurotrophic treatments. Her visual field was limited to an inferior nasal area OS. Therefore, a diagnosis of TON was made. Her visual function remained stable in the left eye, but did not recover in the right eye during the 5-month follow-up. We found damage to the optic nerve pathway during ophthalmic examinations. We report a rare case of TON caused by acute VPA overdose. Hyperbaric oxygen therapy, and neuroprotective and neurotrophic treatments might be effective at the early stage but cannot fully reverse the damage to the optic nerve. The present case indicates the potential neurotoxicity of VPA. It is crucial to determine the severity of an isolated optic nerve sequela caused by VPA overdose, though it might be rare as observed in previous reports. Further confirmation of the likelihood of its causation and its pathophysiology is needed in the future.

Apoptotic Effects of N-(2-Hydroxyphenyl)-2-Propylpentanamide on U87-MG and U-2 OS Cells and Antiangiogenic Properties.

Histone Deacetylases (HDACs) are important therapeutic targets for many types of human cancers. A derivative of valproic acid, N-(2-hydroxyphenyl)-2-propylpentanamide (HOAAVPA), has antiproliferative properties on some cancer cell lines and inhibits the HDAC1 isoform. In this work, HO-AAVPA was tested as an antiproliferative agent in U87-MG (human glioblastoma) and U-2 OS cells (human osteosarcoma), which are types of cancer that are difficult to treat, and its antiangiogenic properties were explored. HO-AAVPA had antiproliferative effects at 48h with an IC50=0.655mM in U87-MG cells and an IC50=0.453mM in U-2 OS cells. Additionally, in the colony formation assay, HO-AAVPA decreased the number of colonies by approximately 99% in both cell lines and induced apoptosis by 31.3% in the U-2 OS cell line and by 78.2% in the U87-MG cell line. Additionally, HO-AAVPA reduced the number of vessels in Chorioallantoic Membranes (CAMs) by approximately 67.74% and IL-6 levels in both cell lines suggesting that the biochemical mechanism on cancer cell of HO-AAVPA is different compared to VPA. HO-AAVPA has antiproliferative effects on glioblastoma and osteosarcoma and antiangiogenic properties.

2-hexyl-4-pentynoic acid, a potential therapeutic for breast carcinoma by influencing RPA2 hyperphosphorylation-mediated DNA repair

Breast carcinoma is one of the most common malignancies in women. Previous studies have reported that 500 μM valproic acid can sensitize breast tumor cells to the anti-neoplastic agent hydroxyurea. However, the dose requirements for valproic acid is highly variable due to the wide inter-individuals clinical characteristics. High therapeutic dose of valproic acid required to induce anti-tumor activity in solid tumor was associated with increased adverse effects. There are attempts to locate suitably high-efficient low-toxicity valproic acid derivatives. We demonstrated that lower dose of 2-hexyl-4-pentynoic acid (HPTA; 15 μM) has similar effects as 500 μM VPA in inhibiting breast cancer cell growth and sensitizing the tumor cells to hydroxyurea on MCF7 cells, EUFA423 cells, MCF7 cells with defective RPA2-p gene and primary culture cells derived from tissue-transformed breast tumor cells. We discovered HPTA resulted in more DNA double-strand breaks, the homologous recombination was inhibited through the interference of the hyperphosphorylation of replication protein A2 and recombinase Rad51. Our data postulate that HPTA may be a potential novel sensitizer to hydroxyurea in the treatment of breast carcinoma.

Microinjection of valproic acid into the ventrolateral orbital cortex exerts an antinociceptive effect in a rat of neuropathic pain.

Ventrolateral orbital cortex (VLO) has been found to play an important role in the regulation of neuropathic pain (NPP). As a traditional mood stabilizer, valproic acid (VPA) is currently employed in the treatment of NPP. However, whether VPA plays an analgesic role in VLO is still unknown. To elucidate the underlying analgesic mechanism of microinjection of VPA into the VLO on spared nerve injury (SNI), an animal model of NPP. We firstly examined the role of VPA by intraperitoneal and intral-VLO injection. Then, we accessed its role as a histone deacetylase inhibitor by intral-VLO microinjection of sodium butyrate. Finally, the GABAergic mechanism was measured through the intra-VLO microinjection of several agonists and antagonists of various GABAergic receptor subtypes. Both intraperitoneal and intral-VLO injection of VPA attenuated SNI-induced mechanical allodynia. Microinjection of sodium butyrate, one of the histone deacetylase inhibitors, into the VLO attenuated the mechanical allodynia. Besides, microinjection of valpromide, a derivative of VPA which is a GABAergic agonist, into the VLO also attenuated allodynia. Furthermore, microinjection of picrotoxin, a GABAA receptor antagonist, into the VLO attenuated mechanical allodynia; microinjection of picrotoxin before VPA into the VLO increased VPA-induced anti-allodynia. Besides, microinjection of CGP 35348, a GABAB receptor antagonist, into the VLO attenuated allodynia; microinjection of CGP 35348 before VPA into the VLO also increased VPA-induced anti-allodynia. What is more, microinjection of imidazole-4-acetic acid (I4AA), a GABAC receptor antagonist, into the VLO enhanced allodynia; microinjection of I4AA before VPA into the VLO decreased VPA-induced anti-allodynia. These results suggest that both the histone acetylation mechanism and GABAergic system are involved in mediating VLO-induced anti-hypersensitivity.

Anti-epileptic activity, toxicity and teratogenicity in CD1 mice of a novel valproic acid arylamide derivative, N-(2-hydroxyphenyl)-2-propylpentanamide

N-(2-hydroxyphenyl)-2-propylpentamide (HO-AAVPA) is a novel arylamide derivative of valproic acid (VPA) designed in silico, with better antioxidant and antiproliferative effect on cancer cell lines than VPA. This study was aimed to evaluate the anticonvulsant activity, the toxicity and teratogenicity produced in HO-AAVPA-treated CD1 mice using VPA as positive control. With the maximal electroshock (MES)- and pentylenetetrazole (PTZ)-induced seizure models, HO-AAVPA reduced the time of hind limb extension, stupor and recovery, the number of clonic and tonic seizures and the mortality rate in a dose-dependent manner, obtaining an ED50 of 370 and 348 mg/kg for MES and PTZ, respectively. On the rotarod test, mice administered with 600 mg/kg HO-AAVPA manifested reduced locomotor activity (2.78%); while HO-AAVPA at 300 mg/kg and VPA at 500 mg/kg gave a similar outcome (∼60%). The LD50 of 936.80 mg/kg herein found for HO-AAVPA reflects moderate toxicity. Concerning teratogenicity, the administration of HO-AAVPA to pregnant females at 300 and 600 mg/kg on gestation day (GD) 8.5 generated less visceral and skeletal alterations in the fetuses, as well as, minor rate of modifications in the expression pattern of the neuronal marker Tuj1 and endothelial marker PECAM1 in embryos, that those induced by VPA administration. Altered embryonic development occurred with less frequency and severity with HO-AAVPA at 600 mg/kg than VPA at 500 mg/kg. In conclusion, the protective effect against convulsions provided by HO-AAVPA was comparable to that of VPA in the MES and PZT seizure models, showed lower toxicity and less damage to embryonic and fetal development.

Synthesis and Antiepileptic Activity Evaluation of Valproic Acid Derivatives by Niche Chemistry

In order to prepare new antiepileptic drugs with a broader clinical application and lower toxic side effects, we have employed esterification and condensation reactions (we call it Niche Chemistry) to reduce the use of valproic acid as the target molecule. In combination with the study of a broad‐spectrum of novel anticonvulsants, we have synthesized two valeric acid derivative compounds [(4‐acetamidophenyl 2‐propylvalerate (1), and (E)‐5‐(4‐((2‐propylpentanoyl)oxy)styryl)‐1,3‐phenylene bis(2‐propylvalerate) (2) by an esterification reaction. The maximum shock seizure test for products 1 and 2 has been successfully carried out, and their cytotoxic activity and survival effects have also been carefully investigated.

Targeting Breast Cancer Cells with G4 PAMAM Dendrimers and Valproic Acid Derivative Complexes.

Our research group has developed some Valproic Acid (VPA) derivatives employed as anti-proliferative compounds targeting the HDAC8 enzyme. However, some of these compounds are poorly soluble in water. Employed the four generations of Polyamidoamine (G4 PAMAM) dendrimers as drug carriers of these compounds to increase their water solubility for further in vitro evaluation. VPA derivatives were subjected to Docking and Molecular Dynamics (MD) simulations to evaluate their affinity on G4 PAMAM. Then, HPLC-UV/VIS, 1H NMR, MALDI-TOF and atomic force microscopy were employed to establish the formation of the drug-G4 PAMAM complexes. The docking results showed that the amide groups of VPA derivatives make polar interactions with G4 PAMAM, whereas MD simulations corroborated the stability of the complexes. HPLC UV/VIS experiments showed an increase in the drug water solubility which was found to be directly proportional to the amount of G4 PAMAM. 1H NMR showed a disappearance of the proton amine group signals, correlating with docking results. MALDI-TOF and atomic force microscopy suggested the drug-G4 PAMAM dendrimer complexes formation. In vitro studies showed that G4 PAMAM has toxicity in the micromolar concentration in MDAMB- 231, MCF7, and 3T3-L1 cell lines. VPA CF-G4 PAMAM dendrimer complex showed anti-proliferative properties in the micromolar concentration in MCF-7 and 3T3-L1, and in the milimolar concentration in MDAMB- 231, whereas VPA MF-G4 PAMAM dendrimer complex didn't show effects on the three cell lines employed. These results demonstrate that G4 PAMAM dendrimers are capableof transporting poorly watersoluble aryl-VPA derivate compounds to increase its cytotoxic activity against neoplastic cell lines.