3-N-butylphthalide improves neuronal morphology after chronic cerebral ischemia

Research progress of prodrugs for the treatment of cerebral ischemia

It is well-known that pharmacotherapy plays a pivotal role in the treatment and prevention of cerebral ischemia. Nevertheless, existing drugs, including numerous natural products, encounter various challenges when applied in cerebral ischemia treatment. These challenges comprise poor brain absorption due to low blood-brain barrier (BBB) permeability, limited water solubility, inadequate bioavailability, poor stability, and rapid metabolism. To address these issues, researchers have turned to prodrug strategies, aiming to mitigate or eliminate the adverse properties of parent drug molecules. In vivo metabolism or enzymatic reactions convert prodrugs into active parent drugs, thereby augmenting BBB permeability, improving bioavailability and stability, and reducing toxicity to normal tissues, ultimately aiming to enhance treatment efficacy and safety. This comprehensive review delves into multiple effective prodrug strategies, providing a detailed description of representative prodrugs developed over the past two decades. It underscores the potential of prodrug approaches to improve the therapeutic outcomes of currently available drugs for cerebral ischemia. The publication of this review serves to enrich current research progress on prodrug strategies for the treatment and prevention of cerebral ischemia. Furthermore, it seeks to offer valuable insights for pharmaceutical chemists in this field, offer guidance for the development of drugs for cerebral ischemia, and provide patients with safer and more effective drug treatment options.

Untargeted metabolomics uncovering neuroprotective effect of Dl-3-n-butylphthalide on improving cognitive impairment induced by chronic cerebral hypoperfusion in rats

Chronic cerebral hypoperfusion (CCH) can cause cognitive impairments. Dl-3-n-butylphthalide (NBP) is widely used in neurological disorders; but, the role of NBP in CCH remains unclear. This study aimed to investigate the potential mechanism of NBP on CCH through untargeted metabolomics. Animals were divided into CCH, Sham, and NBP groups. A rat model of bilateral carotid artery ligation was used to simulate CCH. Cognitive function of the rats was assessed using the Morris water maze test. Additionally, we used LC-MS/MS to detect ionic intensities of metabolites between the three groups for off-target metabolism analysis and to screen for differential metabolites. The analysis showed an improvement in cognitive function in rats after NBP treatment. Moreover, metabolomic studies showed that the serum metabolic profiles of the Sham and CCH groups were significantly altered, and 33 metabolites were identified as potential biomarkers associated with the effects of NBP. These metabolites were enriched in 24 metabolic pathways.And the pathway of differential metabolite enrichment was further verified by immunofluorescence. Thus, the study provides a theoretical basis for the pathogenesis of CCH and the treatment of CCH by NBP, and supports a wider application of NBP drugs.

Effects of NBP injection on the inflammatory response, oxidative stress response and vascular endothelial function in patients with ACI: A systematic review and meta-analysis

BACKGROUND

Acute cerebral infarction (ACI) is a common medical emergency. This study is the first systematic review of the use of Dl-3-n-butylphthalide (NBP) injection in the treatment of ACI. The purpose of this study was to systematically evaluate the effects of NBP injection on the inflammatory response, oxidative stress response and vascular endothelial function in patients with acute ACI. The objective is to provide reference for clinical application.

METHODS

From the establishment of the database until August 2022, we systematically searched EMbase, PubMed, Cochrane Library, Web of Science, CNKI, VIP, and Wanfang Database. RCTs and retrospective studies were included in this study, and the results that qualified for inclusion were screened by 2 researchers and cross-checked. After the relevant data were extracted, a meta-analysis was performed using RevMan5.3 software.

RESULTS

A total of 3307 patients with ACI from 34 studies were analyzed. The meta-analysis showed that the C-reactive protein levels in the NBP combined group were effectively reduced compared with those in the control group (MD = -3.75, 95% confidence intervals [95% CI] [-4.95, -2.56], P < .00001). Based on comparison with the control group, it is evident that combination treatment with NBP is more effective than control group in reducing the oxidative stress response of ACI (MD[superoxide dismutase levels] = 22.16, 95% CI [14.20,30.11], P < .00001; MD[malondialdehyde levels] = -1.97, 95% CI [-2.62, -1.32], P < .00001). Comparison with the control group shows that combination treatment with NBP is more effective in improving vascular endothelial function in ACI patients (MD[vascular endothelial growth factor levels] = 71.44, 95% CI [41.22, 101.66], P < .00001; MD[endothelin-1 levels] = -11.47, 95% CI [-17.39, -5.55], P = .0001; MD[nitric oxide levels] = 9.54, 95% CI [8.39, 10.68], P < .00001) than control group. The NBP combined group also showed a greater reduction in cerebral infarct volume (CIV) and cerebral infarct size (CIS) of ACI (MD[CIV] = -1.52, 95% CI [-2.23, -0.81], P < .0001; MD[CIS] = -2.79, 95% CI [-3.65, -1.94], P < .00001). The NBP combined group did not show an increase in the incidence of adverse reactions compared with the control group (odds ratio = 1.06, 95% CI [0.73, 1.53], P = .77).

CONCLUSION

In summary, the use of NBP in combination with control group for ACI can reduce the degree of nerve damage, reduce inflammation and oxidative stress, improve vascular endothelial function, and reduce CIS and CIV in ACI patients, without increasing the incidence of clinical adverse events.

Neuroprotective effect of Dl-3-n-butylphthalide against ischemia-reperfusion injury is mediated by ferroptosis regulation via the SLC7A11/GSH/GPX4 pathway and the attenuation of blood-brain barrier disruption

Background

Stroke is one of the most severe diseases worldwide, resulting in physical and mental problems. Dl-3-n-butylphthalide, a compound derived from celery seed, has been approved for treating ischemic stroke in China. No study has evaluated how Dl-3-n-butylphthalide affects the ferroptosis SLC7A11/GSH/GPX4 signal pathway and blood-brain barrier (BBB) PDGFRβ/PI3K/Akt signal pathways in the rat middle cerebral artery occlusion/reperfusion (MCAO/R) model of ischemic stroke.

Methods

Sprague-Dawley rats were used to develop the MCAO/R model. Our study used three incremental doses (10, 20, and 30) of Dl-3-n-butylphthalide injected intraperitoneally 24 h after MCAO/R surgery. The neuroprotective effect and success of the model were evaluated using the neurofunction score, brain water content determination, and triphenyl-tetrazolium chloride-determined infarction area changes. Pathological changes in the brain tissue and the degree of apoptosis were examined by hematoxylin and eosin, Nissl, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. In addition, pathway proteins and RNA expression levels were studied to verify the effects of Dl-3-n-butyphthalide on both pathways. At the same time, commercial kits were used to detect glutathione, reactive oxygen species, and malondialdehyde, to detect oxidative stress in brain tissues.

Results

The middle dose of Dl-3-n-butylphthalide not only improved MCAO-induced brain dysfunction and alleviated pathological damage, brain inflammatory response, oxidative stress, and apoptosis but also protected against ferroptosis and reduced BBB damage. These changes resulted in improved neurological function in the cerebral cortex.

Conclusion

We speculate that Dl-3-n-butylphthalide has a neuroprotective effect on focal cerebral ischemia/reperfusion, which may be mediated through ferroptosis-dependent SLC7A11/GSH/GPX4 signal pathway and PDGFRβ/PI3/Akt signal pathway.

Biopharmaceutical, preclinical pharmacokinetic and pharmaco-dynamic investigations of an orally administered novel 3-nbutylphthalide prodrug for ischemic stroke treatment

Ischemic stroke (IS) has been contributing in leading causes of disability and death worldwide and the cases are still increasing. In China, naturally sourced compound 3-n-butylphthalide (NBP) is widely applied in clinical practice for IS treatment with established evidences of efficacy and safety. However, NBP is an oily liquid at room temperature and has no active brain targeting ability, quite limiting its broader application in clinical practice. Via intravenous injection (i.v.) a prodrug compound (DB1) we previously developed deriving from NBP had dramatically enhanced the pharmacological effects, where however, this i.v. route still discount future patient compliance. As druggability of DB1 in oral administration has yet to be elaborated, the current study intended to systemically investigate its biopharmaceutical properties, so as to further consider clinical applicability of DB1 oral preparations. Additionally, pharmacokinetics and pharmacodynamics of DB1 via oral administered route were also studied, illustrating broad potential of further DB1 medicine development. After the derivation, aqueous solubility of DB1 improved 3∼400 folds compared with NBP in various pH media, and n-octanol/water partition coefficient kept in the range of 0∼2. In situ single-pass intestinal perfusion on rats showed effective permeability coefficient of DB1 over 10^-2 cm/s. In contrast to NBP, oral administration of DB1 could display significant enhanced bioavailability in rats and achieve increased accumulation in brain tissues. As expected, DB1 effectively alleviated oxidative stress damage and reduced infarct volume on ischemia/reperfusion (I/R) modeled rats, resulting in reduced mortality. Additionally, this new prodrug did not add any safety concerns based on NBP. Therefore, biopharmaceutical results and preclinical pharmacodynamic evidences support the conclusion that an oral administration of DB1 may have a good potential for clinical IS treatment.

The effect of butylphthalide on aminoacid content in the brain of epileptic mice

BACKGROUND

The aim of this study is to observe the effect of butylphthalide (NBP) on the amino acid content in the brain of epileptic mice.

METHODS

NBP was injected intraperitoneally into the mice, and acute epileptic mice models were made after 30 minutes. The change of the four amino (aspartic acid, gamma-aminobutyric acid, glutamate, glycine) content in the brain of the epileptic mice was investigated.

RESULTS

The contents of Glu and Glu/GABA (control group: 38.78, NBP high-dose group: 5.52) in the NBP high-dose group were lower compared with the control group. The difference was statistically significant.

CONCLUSIONS

NBP could regulate the balance of excitement and inhibition systems by reducing the contents of Glu and Glu/GABA, which might relieve seizures.

A molecular probe carrying anti-tropomyosin 4 for early diagnosis of cerebral ischemia/reperfusion injury

In vivo imaging of cerebral ischemia/reperfusion injury remains an important challenge. We injected porous Ag/Au@SiO₂ bimetallic hollow nanoshells carrying anti-tropomyosin 4 as a molecular probe into mice with cerebral ischemia/reperfusion injury and observed microvascular changes in the brain using photoacoustic imaging with ultrasonography. At each measured time point, the total photoacoustic signal was significantly higher on the affected side than on the healthy side. Twelve hours after reperfusion, cerebral perfusion on the affected side increased, cerebrovascular injury worsened, and anti-tropomyosin 4 expression increased. Twenty-four hours after reperfusion and later, perfusion on the affected side declined slowly and stabilized after 1 week; brain injury was also alleviated. Histopathological and immunohistochemical examinations confirmed the brain injury tissue changes. The nanoshell molecular probe carrying anti-tropomyosin 4 has potential for use in early diagnosis of cerebral ischemia/reperfusion injury and evaluating its progression.

Potential Protective Effect of Dl-3-n-butylphthalide on Chronic Cerebral Ischemia Brain Injury

Chronic cerebral ischemia is one of the common ischemic cerebrovascular diseases. Chronic cerebral ischemia can lead to brain dysfunction, and its pathophysiological mechanism involves inflammation, blood-brain barrier destruction, oxidative stress, and other factors. As it is difficult to detect, it is easily overlooked, and it is often only observed following the onset of cognitive dysfunction. At present, there are only a few drugs for its treatment. Dl-3-n-butylphthalide (NBP), a compound extracted from celery seed, may play an important role in protecting against brain damage caused by chronic cerebral ischemia. Therefore, here, we have paid attention to the prevention and treatment of chronic cerebral ischemia with NBP.

CaMKIIα Signaling Is Required for the Neuroprotective Effects of Dl-3-n-Butylphthalide in Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of neurodegenerative disease and most anti-AD drugs have failed in clinical trials; hence, it is urgent to find potentially effective drugs against AD. DL-3-n-butylphthalide (NBP) is a compound extracted from celery seed and is a multiple-target drug. Several studies have demonstrated the neuroprotective effects of NBP on cognitive impairment, but the mechanisms of NBP remains relatively unexplored. In this study, we found that NBP could alleviated the increase of intracellular Ca²⁺ and reversed down-regulation of Ca²⁺/calmodulin-dependent protein kinase alpha (CaMKIIα) signaling and rescued neuronal apoptosis in SH-SY5Y cells treated by Aβ oligomers. However, these neuroprotective effects of NBP on neuronal damage and CaMKIIα signaling were abolished when CaMKIIα expression was knocked down or its activity was inhibited. Thus, our findings suggested that CaMKIIα signaling was required for the neuroprotective effects of NBP in AD and provided an improved basis for elucidating the mechanism and treatment of NBP in AD.

Efficacy and Safety of DL-3-n-Butylphthalide in the Treatment of Poststroke Cognitive Impairment: A Systematic Review and Meta-Analysis

Background: Poststroke cognitive impairment (PSCI) is a common complication observed after stroke. Current pharmacologic therapies have no definitive evidence for cognitive recovery or disease progression. Recent studies have verified the positive effect of DL-3-n-butylphthalide (NBP). However, the clinical efficacy and safety are still unclear. The aim of this study was to assess the efficacy of NBP and its harmful effect in the treatment of PSCI.

Method: Eligible randomized controlled trials (RCTs) were retrieved from inception to June 2021 from seven medical databases and two clinical registries. The revised Cochrane risk of bias tool (RoB 2.0) was used for methodological quality. RevMan v5.4.1 from Cochrane Collaboration was used for statistical analysis, and Hartung-Knapp-Sidik-Jonkman (HKSJ) method was used for post hoc testing depend on the number of studies. This study has been submitted to PROSPERO with registration number is CRD42021274123.

Result: We identified 26 studies with a total sample size of 2,571 patients. The results of this study showed that NBP as monotherapy or combination therapy had better performance in increasing the MoCA (monotherapy: SMD_N = 1.05, 95% CI [0.69, 1.42], p < 0.00001; SMD_P = 1.06, 95% CI [0.59, 1.52], p < 0.00001. combination: SMD_O = 0.81, 95% CI [0.62, 1.01], p < 0.00001; SMD_N = 0.90, 95% CI [0.46, 1.33], p < 0.0001; SMD_D = 1.04, 95% CI [0.71, 1.38], p < 0.00001), MMSE (monotherapy: MD_N = 4.89, 95% CI [4.14, 5.63]), p < 0.00001). combination: SMD_O = 1.26, 95% CI [0.97, 1.56], p < 0.00001; SMD_C = 1.63, 95% CI [1.28, 1.98], p < 0.00001; SMD_N = 2.13, 95% CI [1.52, 2.75], p < 0.00001) and BI (monotherapy: MD_N = 13.53, HKSJ 95% CI [9.84, 17.22], p = 0.014. combination: SMD_O = 2.24, HKSJ 95%CI [0.37, 4.11], p = 0.032; SMD_C = 3.36, 95%CI [2.80, 3.93], p < 0.00001; SMD_D = 1.48, 95%CI [1.13, 1.83], p < 0.00001); and decreasing the NIHSS (monotherapy: MD_N = −3.86, 95% CI [−5.22, −2.50], p < 0.00001. combination: SMD_O = −1.15, 95% CI [−1.31, −0.98], p < 0.00001; SMD_C = −1.82, 95% CI [−2.25, −1.40], p < 0.00001) and CSS (combination: MD_O = −7.11, 95% CI [−8.42, −5.80], p < 0.00001), with no serious adverse reactions observed. The funnel plot verified the possibility of publication bias.

Conclusion: NBP maintains a stable pattern in promoting the recovery of cognitive function and abilities of daily living, as well as reducing the symptoms of neurological deficits. However, there is still a need for more high-quality RCTs to verify its efficacy and safety.

Discovery of novel brain-penetrant GluN2B NMDAR antagonists via pharmacophore-merging strategy as anti-stroke therapeutic agents

In this work, a novel structural series of brain-penetrant GluN2B NMDAR antagonists were designed, synthesized and biologically evaluated as anti-stroke therapeutic agents via merging the structures of NBP and known GluN2B ligands. Approximately half of them exhibited superior neuroprotective activity to NBP against NMDA-induced neurotoxicity in hippocampal neurons at 10 μM, and compound 45e and 45f exerted equipotent activity to ifenprodil, an approved GluN2B- selective NMDAR antagonist. In particular, 45e, with the most potent neuroprotective activity throughout this series, displayed dramatically enhanced activity (K_i = 3.26 nM) compared to ifenprodil (K_i = 14.80 nM) in Radioligand Competitive Binding Assay, and remarkable inhibition (IC₅₀ = 79.32 nM) against GluN1/GluN2B receptor-mediated current in Patch Clamp Assay. Meanwhile, 45e and its enantiomers exhibited low inhibition rate against the current mediated by other investigated receptors at the concentration of 10 μM, indicating their favorable selectivity for GluN1/GluN2B. In the rat model of middle cerebral artery ischemia (MCAO), 45e exerted comparable therapeutic efficacy to ifenprodil at the same dosage. In addition to the attractive in vitro and in vivo potency, 45e displayed a favorable bioavailability (F = 63.37%) and an excellent brain exposure. In further repeated dose toxicity experiments, compound 45e demonstrated an acceptable safety profile. With the above merits, 45e is worthy of further functional investigation as a novel anti-stroke therapeutic agent.

Overview of therapeutic potentiality of Angelica sinensis for ischemic stroke

BACKGROUND

Ischemic stroke is a common cerebrovascular disease. Due to sudden interruption of blood flow by arterial thrombus, amounts of neurons in ischemic central and penumbral regions occur necrosis and apoptosis resulting in serious injury of neurological function. Chinese medicines have a great advantage in ischemic stroke treatment and recovery, especially Angelica sinensis.

PURPOSE

There are a large number of studies reported that Angelica injection and A. sinensis active compounds. We systematically reviewed the effects and mechanisms of A. sinensis in recent years according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements, and excavated its therapeutic potentiality for exploring more effective and safe compounds for ischemic stroke precision treatment.

RESULTS

A. sinensis extracts and active compounds, such as Z-ligustilide, 3-n-Butylphthalide, and ferulic acid have significant effects of anti-inflammation, anti-oxidative stress, angiogenesis, neurogenesis, anti-platelet aggregation, anti-atherosclerosis, protection of vessels, which contributes to improvement of neurological function on ischemic stroke.

CONCLUSION

A. sinensis is a key agent for ischemic stroke treatment, and worth deeply excavating its therapeutic potentiality with the aid of pharmacological network, computer-aided drug design, artificial intelligence, big data and multi-scale modelling techniques.

Novel brain-targeting 3-n-butylphthalide prodrugs for ischemic stroke treatment

Currently, ischemic stroke is the leading cause of disability and death worldwide, and the performance of corresponding drugs is often unsatisfactory owing to the complex pathological processes and the impediment of the blood-brain barrier (BBB). Here, we employed various tertiary amino groups, including different linear, cyclic, and bimolecular drug structures, to modify 3-n-butylphthalide (NBP), a natural product used for ischemic stroke treatment, which has poor bioavailability, to generate a series of six prodrugs. These prodrugs showed significantly improved solubility and cellular uptake, which were primarily driven by putative pyrilamine cationic transporters. They also displayed more efficient brain delivery in vivo, reaching as high as 21.5-fold brain accumulation increase compared with NBP, leading to much higher bioavailability and stronger therapeutic effects. The toxicity of these molecules is also lower or similar to that of unmodified NBP. We showed that the tertiary amino group-modified NBP prodrugs are effective and safe for treating ischemic stroke with significantly enhanced druggability; hence, they have potential for further clinical development.

L-3-n-butylphthalide promotes restoration after an experimental animal model of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating type of stroke with high morbidity and mortality, and the effective therapies for ICH remain to be explored. L-3-n-butylphthalide (NBP) is widely used in the treatment of ischemic stroke. However, few studies evaluated the therapeutic effects of NBP on ICH. Therefore, the present study aims to evaluate the effects of NBP on ICH and its potential mechanism. The rats were randomly divided into sham-operated group, saline-treated (ICH + saline) group, and NBP-treated (ICH + NBP) group. The ICH model of SD rats induced by IV collagenase was established. The modified Garcia JH score was used to detect the neurological deficit in rats. Western Blot and immunohistochemistry analysis was applied to test the levels of UBIAD1 and caspase-3 expressions in the perihematomal region. The rates of apoptotic cells were detected by TUNEL staining. The results showed that NBP up-regulated the expression of UBIAD1, reduced the apoptotic cells in the perihematomal region, and improved the neurological deficit. Taken together, our study added some new evidence to the application of NBP in ICH treatment.

From Seeds of Apium graveolens Linn. to a Cerebral Ischemia Medicine: The Long Journey of 3-n-Butylphthalide

3-n-Butylphthalide (NBP) as well as its derivatives and analogues (NBPs), in racemic or enantiomerically pure forms, possess potent and diverse pharmacological properties and have shown a great potential therapeutic interest for many human conditions, especially for cerebral ischemia. This Perspective outlines the synthesis and therapeutic applications of NBPs.

The impact of Dl-3-n-butylphthalide on the lipidomics of the hippocampus in a rat model of lipopolysaccharide-induced depression

Elevated inflammation is commonly observed in depression, but whether this association is causal is not determined. Our previous basic research indicated that Dl-3-n-butylphthalide (NBP) possessed an anti-inflammatory effect. Additional recent evidence consistently suggests that depression is associated with lipid metabolism. Therefore, our study performed an untargeted lipidomics approach of ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) to reveal the potential discriminating lipid profile of the hippocampus for NBP involvement in lipopolysaccharide (LPS)-induced depression. Male Sprague-Dawley(SD) rats were randomly allocated to one of three groups (n = 6): control, LPS-induced model of depression (LPS), or NBP involvement in the LPS-induced model of depression (LPS + NBP). Statistical analysis was used to identify differential hippocampus lipids in the LPS, NBP + LPS, and control groups. Our study demonstrated that most of the differentially expressed lipid metabolites were involved in glycerophospholipid metabolism, sphingolipid metabolism, glycerolipid metabolism, and glycosylphosphatidylinositol(GPI)-anchor biosynthesis, which may partially account for the pathophysiological process of depression. However, more pre-clinical and clinical evidence is warranted to determine the extent and consistency of the role of NBP and further elucidate the pathophysiological mechanisms underlying inflammation-induced depression.

Antifungal Activity and Potential Mechanism of N-Butylphthalide Alone and in Combination With Fluconazole Against Candida albicans

Candida albicans is a common opportunistic fungal pathogen that may cause nosocomial fungal infections. The resistance of Candida albicans to traditional antifungal drugs has been increasing rapidly in recent years, and it brings a great challenge in clinical treatment. N-butylphthalide is originally extracted from the seed of Apium graveolens and is currently used for the treatment of ischemic stroke in the clinic. This study demonstrated that n-butylphthalide exhibited antifungal activity against Candida albicans with minimum inhibitory concentrations of 128 μg/ml; moreover, n-butylphthalide combined with fluconazole showed synergistic antifungal effects against resistant Candida albicans, resulting in a decrease in the minimum inhibitory concentrations of fluconazole from >512 to 0.25–1 μg/ml. Time-killing curves verified the antifungal activity in dynamic. Besides, n-butylphthalide exhibited anti-biofilm activity against Candida albicans, biofilms preformed <12 h with sessile minimum inhibitory concentrations of 128–256 μg/ml and synergism was observed when n-butylphthalide combined with fluconazole against resistant Candida albicans biofilms preformed <12 h, resulting in a decrease in the sessile minimum inhibitory concentrations of fluconazole from >1,024 to 0.5–8 μg/ml. Furthermore, in vitro antifungal effects of n-butylphthalide were confirmed in vivo. N-butylphthalide prolonged survival rate of larvae infected by Candida albicans, reduced the fungal burden in larvae and caused less damage to larval tissues. Notably, n-butylphthalide inhibited hyphal growth and induced intracellular reactive oxygen species accumulation and a loss in mitochondrial membrane potential, which was a potential antifungal mechanism. Besides, the synergistic effects between n-butylphthalide and fluconazole potentially relied on the mechanism that n-butylphthalide significantly promoted drug uptake, and suppressed drug efflux via down-regulating the drug transporter encoding genes CDR1 and CDR2. These findings demonstrated the antifungal effects and mechanisms of n-butylphthalide against Candida albicans for the first time, which might provide broad prospects for the identification of new potential antifungal targets.

Application and prospects of butylphthalide for the treatment of neurologic diseases

OBJECTIVE

The 3-N-butylphthalide (NBP) comprises one of the chemical constituents of celery oil. It has a series of pharmacologic mechanisms including reconstructing microcirculation, protecting mitochondrial function, inhibiting oxidative stress, inhibiting neuronal apoptosis, etc. Based on the complex multi-targets of pharmacologic mechanisms of NBP, the clinical application of NBP is increasing and more clinical researches and animal experiments are also focused on NBP. The aim of this review was to comprehensively and systematically summarize the application of NBP on neurologic diseases and briefly summarize its application to non-neurologic diseases. Moreover, recent progress in experimental models of NBP on animals was summarized.

DATA SOURCES

Literature was collected from PubMed and Wangfang database until November 2018, using the search terms including "3-N-butylphthalide," "microcirculation," "mitochondria," "ischemic stroke," "Alzheimer disease," "vascular dementia," "Parkinson disease," "brain edema," "CO poisoning," "traumatic central nervous system injury," "autoimmune disease," "amyotrophic lateral sclerosis," "seizures," "diabetes," "diabetic cataract," and "atherosclerosis."

STUDY SELECTION

Literature was mainly derived from English articles or articles that could be obtained with English abstracts and partly derived from Chinese articles. Article type was not limited. References were also identified from the bibliographies of identified articles and the authors' files.

RESULTS

NBP has become an important adjunct for ischemic stroke. In vascular dementia, the clinical application of NBP to treat severe cognitive dysfunction syndrome caused by the hypoperfusion of brain tissue during cerebrovascular disease is also increasing. Evidence also suggests that NBP has a therapeutic effect for neurodegenerative diseases. Many animal experiments have found that it can also improve symptoms in other neurologic diseases such as epilepsy, cerebral edema, and decreased cognitive function caused by severe acute carbon monoxide poisoning. Moreover, NBP has therapeutic effects for diabetes, diabetes-induced cataracts, and non-neurologic diseases such as atherosclerosis. Mechanistically, NBP mainly improves microcirculation and protects mitochondria. Its broad pharmacologic effects also include inhibiting oxidative stress, nerve cell apoptosis, inflammatory responses, and anti-platelet and anti-thrombotic effects.

CONCLUSIONS

The varied pharmacologic mechanisms of NBP involve many complex molecular mechanisms; however, there many unknown pharmacologic effects await further study.

TiO2-Nanowired Delivery of DL-3-n-butylphthalide (DL-NBP) Attenuates Blood-Brain Barrier Disruption, Brain Edema Formation, and Neuronal Damages Following Concussive Head Injury

DL-3-n-butylphthalide (DL-NBP) is one of the constituents of Chinese celery extract that is used to treat stroke, dementia, and ischemic diseases. However, its role in traumatic brain injury is less well known. In this investigation, neuroprotective effects of DL-NBP in concussive head injury (CHI) on brain pathology were explored in a rat model. CHI was inflicted in anesthetized rats by dropping a weight of 114.6 g from a height of 20 cm through a guide tube on the exposed right parietal bone inducing an impact of 0.224 N and allowed them to survive 4 to 24 h after the primary insult. DL-NBP was administered (40 or 60 mg/kg, i.p.) 2 and 4 h after injury in 8-h survival group and 8 and 12 h after trauma in 24-h survival group. In addition, TiO₂-nanowired delivery of DL-NBP (20 or 40 mg/kg, i.p.) in 8 and 24 h CHI rats was also examined. Untreated CHI showed a progressive increase in blood-brain barrier (BBB) breakdown to Evans blue albumin (EBA) and radioiodine (^[131]-I), edema formation, and neuronal injuries. The magnitude and intensity of these pathological changes were most marked in the left hemisphere. Treatment with DL-NBP significantly reduced brain pathology in CHI following 8 to 12 h at 40-mg dose. However, 60-mg dose is needed to thwart brain pathology at 24 h following CHI. On the other hand, TiO₂-DL-NBP was effective in reducing brain damage up to 8 or 12 h using a 20-mg dose and only 40-mg dose was needed for neuroprotection in CHI at 24 h. These observations are the first to suggest that (i) DL-NBP is quite effective in reducing brain pathology and (ii) nanodelivery of DL-NBP has far more superior effects in CHI, not reported earlier.

3-N-Butylphthalide mitigates high glucose-induced injury to Schwann cells: association with nitrosation and apoptosis

A high glucose state readily causes peripheral axon atrophy, demyelination, loss of nerve fiber function, and delayed regeneration. However, few studies have examined whether nitration is also critical for diabetic peripheral neuropathy. Therefore, this study investigated the effects of high glucose on proliferation, apoptosis, and 3-nitrotyrosine levels of Schwann cells treated with butylphthalide. In addition, we explored potential protective mechanisms of butylphthalide on peripheral nerves. Schwann cells were cultured in vitro with high glucose then stimulated with the peroxynitrite anion inhibitors uric acid and 3-n-butylphthalide for 48 hours. Cell Counting Kit-8 and flow cytometry were used to investigate the effects of uric acid and 3-n-butylphthalide on proliferation and apoptosis of Schwann cells exposed to a high glucose environment. Effects of uric acid and 3-n-butylphthalide on levels of 3-nitrotyrosine in Schwann cells were detected by enzyme-linked immunosorbent assay. The results indicated that Schwann cells cultured in high glucose showed decreased proliferation, but increased apoptosis and intracellular 3-nitrotyrosine levels. However, intervention with uric acid or 3-n-butylphthalide could increase proliferation of Schwann cells cultured in high glucose, and inhibited apoptosis and intracellular 3-nitrotyrosine levels. According to our data, 3-n-butylphthalide may inhibit cell nitrification and apoptosis, and promote cell proliferation, thereby reducing damage to Schwann cells caused by high glucose.

L-3-n-Butylphthalide reduces ischemic stroke injury and increases M2 microglial polarization

Overwhelming evidence suggests that microglia play an important role in ischemic injury and they polarize into two different phenotypes with distinct functions after ischemic stroke. We performed the present study to investigate whether L-3-n butylphthalide (NBP) has an effect on microglial polarization. Mice were subjected to transient middle cerebral artery occlusion (MCAO) for 45 min, and then immediately after reperfusion were treated with NBP or vehicle via the caudal vein for 7 consecutive days. 2,3,5-Triphenyltetrazolium chloride (TTC) staining showed that NBP treatment resulted in a tendency to decrease cerebral infarct volume at 1 day after MCAO, and significant decreased infarct volume at 3 days after MCAO. Sensorimotor function was evaluated by the adhesive removal test and balance beam test, which were superior in NBP-treated mice compared with vehicle-treated mice at 1 and 3 days after MCAO. Immunofluorescent staining further indicated that NBP treatment significantly increased the number of CD206⁺/Iba1⁺ M2 microglia/macrophages and reduced the number of CD16⁺/Iba1⁺ M1 cells at 3 and 7 days after MCAO reperfusion. Western blot also showed an elevation of M2 marker (arginase-1) in NBP-treated brains at 7 days after MCAO. In conclusion, our results clearly show that NBP treatment significantly mitigates ischemic brain damage and promotes recovery of neurological function in early phase after ischemic stroke, probably by skewing M1 microglia/macrophages polarization towards M2 phenotype. Thus, our study provides new evidence that NBP might be a promising candidate for ameliorating injury caused by ischemic stroke.

Dl-3-n-Butylphthalide improves lipopolysaccharide-induced depressive-like behavior in rats: involvement of Nrf2 and NF-κB pathways

RATIONALE AND OBJECTIVES

Dl-3-n-Butylphthalide (NBP), a small molecule compound extracted from the seeds of Apium graveolens, possesses a large range of biological effects. Here, we attempted to explore the therapeutic effects of NBP on lipopolysaccharide (LPS)-induced major depressive disorder (MDD) and gain further insight into the underlying mechanisms of the antidepressant effects of NBP.

METHODS

We evaluated the effect of NBP against LPS-induced behavioral changes in rats. We also examined the inflammation, oxidative stress, and apoptosis markers and analyzed the Nrf2 and NF-κB pathways in the hippocampus of rats following repeated peripheral immune challenge by LPS for 2 weeks (500 μg/kg every other day).

RESULTS

Our results indicated that repeated LPS administration induced the rats to a depressive-like state and activated inflammatory response, oxidative stress, and apoptosis reactions in the hippocampus. NBP treatment attenuated the LPS-induced abnormal behavior and ameliorated pathogenic processes in rats with MDD. NBP reduced the inflammatory response with inhibited expression of pro-inflammatory cytokines including IL-1β and IL-6 and downregulated the NF-κB signal pathway. Concurrent with the anti-inflammation action, NBP reduced LPS-induced oxidative reactions in the hippocampus and enhanced Nrf2-targeted signals, as evidenced by increased transcription of antioxidant enzymes and decreased malondialdehyde (MDA) production. In addition, NBP inhibited LPS-induced neuronal apoptosis in the rat brain, as evidenced by decreased apoptosis marker Caspase-3 production and TUNEL assay.

CONCLUSIONS

These results provide more insight into pathogenesis of MDD and firstly demonstrated the potential antidepressant actions of NBP.

Effects of Dl-3-n-butylphthalide on Cerebral Ischemia Infarction in Rat Model by Mass Spectrometry Imaging

Dl-3-n-butylphthalide (NBP) is a drug that is used in the treatment of ischaemic stroke. However, to the best of our knowledge, there are no systematic studies investigating the effects of dl-3-n-butylphtalide on the brain metabolism of small molecules. In this study, we first investigated the effects of dl-3-n-butylphthalide on the spatial distribution of small molecules in the brains of rats with permanent middle cerebral artery occlusion (pMCAO) using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI–TOF–MS) imaging. After pMCAO modelling or a sham operation, rats were given four mg/kg of dl-3-n-butylphthalide through the caudal vein or saline once a day for nine days. The degree of neurological deficit in rats was evaluated using the modified neurological severity score (mNSS). MALDI–TOF–MS imaging was used to observe the content and distribution of small molecules related to metabolism during focal cerebral ischaemia. Multiple reaction monitoring (MRM) mode with liquid chromatography tandem mass spectrometry (LC–MS/MS) was used to verify the results obtained from MALDI–TOF–MS imaging. These small molecules were found to be involved in glucose metabolism, ATP metabolism, the glutamate–glutamine cycle, malate aspartate shuttle, oxidative stress, and inorganic ion homeostasis. Of the 13 metabolites identified by MALDI–TOF–MS imaging, seven compounds, ATP, ADP, AMP, GMP, N-acetylaspartic acid, ascorbic acid and glutathione, were further validated by LC–MS/MS. Taken together, these results indicate that dl-3-n-butylphthalide significantly improved ATP metabolism, level of antioxidants, and sodium-potassium ion balance in a rat model of pMCAO.

Dl-3n-butylphthalide reduces epileptiform activity through GluA2-lacking calcium-permeable AMPARs in epilepsy models

Epilepsy is the most prevalent chronic neurological disorder, and its pathological mechanism indicates that an imbalance between excitatory and inhibitory neurotransmission leads to neuronal hyperexcitability. Previous studies have suggested that dl-3n-butylphthalide (NBP) regulates the excitatory neurotransmitter glutamate in the brains of epileptic mice, however, the mechanisms are unknown. We investigated behavioral and electrophysiological factors in rats using NBP. In an in vivo pentylenetetrazole (PTZ)-induced epileptic seizure animal model, NBP decreased the generalized tonic-clonic seizure (GTCS) severity. In an acute hippocampal slice 4-aminopyridine (4-AP) epilepsy model in vitro, NBP decreased the epileptiform activity and miniature excitatory postsynaptic current (mEPSC) amplitude; there was no change in the miniature inhibitory postsynaptic current (mIPSC) amplitude or frequency. This effect suggested changes in excitatory synaptic transmission, which was altered through postsynaptic GluA2-lacking calcium-permeable AMPA receptors (CP-AMPARs). These findings showed that NBP suppressed epileptiform activity in these epilepsy models and provided the first detailed electrophysiological analysis of the impact of NBP in epilepsy models, which may be employed in future experimental or clinical therapies for patients with epilepsy.

A Review of Recent Advances in Neuroprotective Potential of 3-N-Butylphthalide and Its Derivatives

The research of alternative treatment for ischemic stroke and degenerative diseases has always been a priority in neurology. 3-N-Butylphthalide (NBP), a family of compounds initially isolated from the seeds of Apium graveolens Linn., has shown significant neuroprotective effects. Previous extensive studies have demonstrated that NBP promotes a better poststroke outcome and exerts a multitargeted action on several mechanisms, from oxidative stress to mitochondrial dysfunction to apoptosis to inflammation. Additionally, recent findings on several neurological disorders have shown that NBP's beneficial effects extend beyond the management of stroke. However, despite the increasing number of studies toward a better understanding and the rapid advances made in therapeutic options, to date, dl-3-N-butylphthalide, a synthetic variation of l-3-N-butylphthalide, remains the only clinically approved anti-ischemic agent in China, stressing the difficulties for a viable and effective transition from experimental to clinical practice. Events indicate that NBP, due to its multitargeted effect and the adaptability of its basic structure, can be an important game changer and a precursor to a whole new therapeutic approach to several neurological conditions. The present review discusses recent advances pertaining to the neuroprotective mechanisms of NBP-derived compounds and the possibility of their clinical implementation in the management of various neurological conditions.

Baclofen ameliorates spatial working memory impairments induced by chronic cerebral hypoperfusion via up-regulation of HCN2 expression in the PFC in rats

Chronic cerebral hypoperfusion (CCH) causes memory deficits and increases the risk of vascular dementia (VD) through several biologically plausible pathways. However, whether CCH causes prefrontal cortex (PFC)-dependent spatial working memory impairments and Baclofen, a GABAB receptor agonist, could ameliorate the impairments is still not clear especially the mechanisms underlying the process. In this study, rats were subjected to permanent bilateral occlusion of the common carotid arteries (two-vessel occlusion, 2VO) to induce CCH. Two weeks later, rats were treated with 25mg/kg Baclofen (intraperitioneal injection, i.p.) for 3 weeks. Spatial working memory was evaluated in a Morris water maze using a modified delayed matching-to-place (DMP) procedure. Western blotting and immunohistochemistry were used to quantify the protein levels and protein localization. Our results showed that 2VO caused striking spatial working memory impairments, accompanied with a decreased HCN2 expression in PFC, but the protein levels of protein gene product 9.5 (PGP9.5, a neuron specific protein), glial fibrillary acidic protein (GFAP), synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), parvalbumin (PV) and HCN1 were not distinguishably changed as compared with sham-operated rats. Baclofen treatment significantly improved the spatial working memory impairments caused by 2VO, accompanied with a reversion of 2VO-induced down-regulation of HCN2. Furthermore, there was a co-localization of HCN2 subunits and parvalbumin-positive neurons in PFC. Therefore, HCN2 may target inhibitory interneurons that is implicated in working memory processes, which may be a possible mechanism of the up-regulation of HCN2 by Baclofen treatment that reliefs spatial working memory deficits in rats with CCH.

Isomer-selective distribution of 3-n-butylphthalide (NBP) hydroxylated metabolites, 3-hydroxy-NBP and 10-hydroxy-NBP, across the rat blood-brain barrier

AIM

To investigate the mechanisms underlying the isomer-selective distribution of 3-n-butylphthalide (NBP) hydroxylated metabolites, 3-hydroxy-NBP (3-OH-NBP) and 10-hydroxy-NBP (10-OH-NBP), across the blood brain barrier (BBB).

METHODS

After oral administration of NBP (20 mg/kg) to rats, the pharmacokinetics of two major hydroxylated metabolites, 3-OH-NBP and 10-OH-NBP, in plasma and brains were investigated. Plasma and brain protein binding of 3-OH-NBP and 10-OH-NBP was also assessed. To evaluate the influences of major efflux transporters, rats were pretreated with the P-gp inhibitor tariquidar (10 mg/kg, iv) and BCRP inhibitor pantoprazole (40 mg/kg, iv), then received 3-OH-NBP (12 mg/kg, iv) or 10-OH-NBP (3 mg/kg, iv). The metabolic profile of NBP was investigated in rat brain homogenate.

RESULTS

After NBP administration, the plasma exposure of 3-OH-NBP was 4.64 times that of 10-OH-NBP, whereas the brain exposure of 3-OH-NBP was only 11.8% of 10-OH-NBP. In the rat plasma, 60%±5.2% of 10-OH-NBP was unbound to proteins versus only 22%±2.3% of 3-OH-NBP being unbound, whereas in the rat brain, free fractions of 3-OH-NBP and 10-OH-NBP were 100%±9.7% and 49.9%±14.1%, respectively. In the rats pretreated with tariquidar and pantoprazole, the unbound partition coefficient Kp,uu of 3-OH-NBP was significantly increased, while that of 10-OH-NBP showed a slight but not statistically significant increase. Incubation of rat brain homogenate with NBP yielded 3-OH-NBP but not 10-OH-NBP.

CONCLUSION

The isomer-selective distribution of 10-OH-NBP and 3-OH-NBP across the BBB of rats is mainly attributed to the differences in plasma and brain protein binding and the efflux transport of 3-OH-NBP. The abundant 10-OH-NBP is not generated in rat brains.

Discovery of 3-n-butyl-2,3-dihydro-1H-isoindol-1-one as a potential anti-ischemic stroke agent

To develop novel anti-ischemic stroke agents with better therapeutic efficacy and bioavailability, we designed and synthesized a series of 3-alkyl-2,3-dihydro-1H-isoindol-1-ones compounds (3a-i) derivatives, one of which (3d) exhibited the strongest inhibitory activity for the adenosine diphosphate-induced and arachidonic acid-induced platelet aggregation. This activity is superior to that of 3-n-butylphthalide and comparable with aspirin and edaravone. Meanwhile, 3d not only exhibited a potent activity in scavenging free radicals and improving the survival of HT22 cells against the reactive oxygen species-mediated cytotoxicity in vitro but also significantly attenuated the ischemia/reperfusion-induced oxidative stress in ischemic rat brains. Results from transient middle cerebral artery occlusion and permanent middle cerebral artery occlusion model, indicated that 3d could significantly reduce infarct size, improve neurobehavioral deficits, and prominently decrease attenuation of cerebral damage. Most importantly, 3d possessed a very high absolute bioavailability and was rapidly distributed in brain tissue to keep high plasma drug concentration for the treatment of ischemic strokes. In conclusion, our findings suggest that 3-alkyl-2,3-dihydro-1H-isoindol-1-ones, a novel series of compounds, might be candidate drugs for the treatment of acute ischemic strokes, and 3d may be a promising therapeutic agent for the primary and secondary prevention of ischemic stroke.