dl-3-n-Butylphthalide prevents oxidative damage and reduces mitochondrial dysfunction in an MPP+-induced cellular model of Parkinson's disease

Targeting mitochondria with small molecules: A promising strategy for combating Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disorder, is one of the most significant challenges confronting modern societies, affecting millions of patients globally each year. The pathophysiology of PD is significantly influenced by mitochondrial dysfunction, as evident by the contribution of altered mitochondrial dynamics, bioenergetics, and increased oxidative stress to neuronal death. This review examines the potential use of small molecules that target mitochondria as a therapeutic approach for treating PD. Progress in mitochondrial biology has revealed various mitochondrial targets that can be modulated to restore function and mitigate neurodegeneration. Small molecules that promote mitochondrial biogenesis, enhance mitochondrial dynamics, decrease oxidative stress, and prevent the opening of the mitochondrial permeability transition pore (mPTP) have shown promise in preclinical models. Additionally, targeting mitochondrial quality control mechanisms, such as mitophagy, provides another therapeutic approach. This review explores recent research on small molecules targeting mitochondria, examines their mechanisms of action, and assesses their potential efficacy and safety profiles. By highlighting the most promising candidates and addressing the challenges and future directions in this field, this review aims to offer a comprehensive overview of current and future prospects for mitochondrial-targeted therapies in PD. Ultimately, treating mitochondrial dysfunction holds significant promise for developing disease-modifying PD medications, giving patients hope for better outcomes and improved quality of life.

3-N-butylphthalide attenuates neuroinflammation in rotenone-induced Parkinson's disease models via the cGAS-STING pathway

Neuroinflammation is crucial in the onset and progression of dopaminergic neuron loss in Parkinson's disease (PD). We aimed to determine whether 3-N-Butylphthalide (NBP) can protect against PD by inhibiting the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway and the inflammatory response of microglia. MitoSOX/MitoTracker/Hoechst staining was used to detect the levels of mitochondrial reactive oxygen species (ROS) in BV2 cells. Quantitative Real-Time Polymerase Chain Reaction was used to measure the levels of free cytoplasmic mitochondrial DNA (mtDNA) in BV2 cells and mouse brain tissues. Behavioral impairments were assessed using rotarod, T-maze, and balance beam tests. Dopaminergic neurons and microglia were observed using immunohistochemical staining. Expression levels of cGAS, STING, nuclear factor kappa-B (NfκB), phospho- NfκB (p-NfκB), inhibitor of NfκBα (IκBα), and phospho-IκBα (p-IκBα) proteins in the substantia nigra and striatum were detected using Western Blot. NBP decreased mitochondrial ROS levels in rotenone-treated BV2 cells. NBP alleviated behavioral impairments and protected against rotenone-induced microgliosis and damage to dopaminergic neurons in the substantia nigra and striatum of rotenone-induced PD mice. NBP decreased rotenone-induced mtDNA leakage and mitigated neuroinflammation by inhibiting cGAS-STING pathway activation. NBP exhibited a protective effect in rotenone-induced PD models by significantly inhibiting the cGAS-STING pathway. Moreover, NBP can alleviate neuroinflammation, and is a potential therapeutic drug for alleviating clinical symptoms and delaying the progression of PD. This study provided insights for the potential role of NBP in PD therapy, potentially mitigating neurodegeneration, and consequently improving the quality of life and lifespan of patients with PD. The limitations are that we have not confirmed the exact mechanism by which NBP decreases mtDNA leakage, and this study was unable to observe the actual clinical therapeutic effect, so further cohort studies are required for validation.

Effects of Dl-3-n-butylphthalide on cognitive functions and blood-brain barrier in chronic cerebral hypoperfusion rats

Vascular cognitive impairment (VCI) has been one of the major types of cognitive impairment. Blood-brain barrier damage plays an essential part in the pathogenesis of VCI. At present, the treatment of VCI is mainly focused on prevention, with no drug clinically approved for the treatment of VCI. This study aimed to investigate the effects of DL-3-n-butylphthalide (NBP) on VCI rats. A modified bilateral common carotid artery occlusion (mBCCAO) model was applied to mimic VCI. The feasibility of the mBCCAO model was verified by laser Doppler, 13N-Ammonia-Positron Emission Computed Tomography (PET), and Morris Water Maze. Subsequently, the Morris water maze experiment, Evans blue staining, and western blot of tight junction protein were performed to evaluate the effect of different doses of NBP (40 mg/kg, 80 mg/kg) on the improvement of cognitive impairment and BBB disruption induced by mBCCAO. Immunofluorescence was employed to examine the changes in pericyte coverage in the mBCCAO model and the effect of NBP on pericyte coverage was preliminarily explored. mBCCAO surgery led to obvious cognitive impairment and the decrease of whole cerebral blood flow, among which the blood flow in the cortex, hippocampus and thalamus brain regions decreased more significantly. High-dose NBP (80 mg/kg) improved long-term cognitive function in mBCCAO rats, alleviated Evans blue leakage and reduced the loss of tight junction proteins (ZO-1, Claudin-5) in the early course of the disease, thereby exerting a protective effect on the blood-brain barrier. No significant changes in pericyte coverage were observed after mBCCAO. High-dose NBP improved cognitive function in mBCCAO rats. High-dose NBP protected the integrity of BBB by upregulating TJ protein expression, rather than regulating pericyte coverage ratio. NBP could be a potential drug for the treatment of VCI.

Neurological Applications of Celery (Apium graveolens): A Scoping Review

Apium graveolens is an indigenous plant in the family Apiaceae, or Umbelliferae, that contains many active compounds. It has been used traditionally to treat arthritic conditions, gout, and urinary infections. The authors conducted a scoping review to assess the quality of available evidence on the overall effects of celery when treating neurological disorders. A systematic search was performed using predetermined keywords in selected electronic databases. The 26 articles included upon screening consisted of 19 in vivo studies, 1 published clinical trial, 4 in vitro studies and 2 studies comprising both in vivo and in vitro methods. A. graveolens and its bioactive phytoconstituent, 3-n-butylphthalide (NBP), have demonstrated their effect on neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke-related neurological complications, depression, diabetes-related neurological complications, and epilepsy. The safety findings were minimal, showing that NBP is safe for up to 18 weeks at 15 mg/kg in animal studies, while there were adverse effects (7%) reported when consuming NBP for 24 weeks at 600 mg daily in human trials. In conclusion, the safety of A. graveolens extract and NBP can be further investigated clinically on different neurological disorders based on their potential role in different targeted pathways.

Dl-3-n-Butylphthalide Protects against Memory Deficits in Vascular Dementia Rats by Attenuating Pyroptosis via TLR-4/NF-κB Signaling Pathway

INTRODUCTION

Inflammation is closely associated with the pathogenesis of vascular dementia (VD). Dl-3-n-butylphthalide (NBP) is a small molecule compound extracted from the seeds of Chinese celery, which have anti-inflammatory properties in animal models of acute ischemia and patients with stroke. In this experiment, we studied the protective effects of NBP in a rat model of VD induced by permanent bilateral occlusion of the common carotid arteries and investigated the role of the TLR-4/NF-κB inflammatory signaling pathway in the pathology of VD.

METHODS

The Morris water maze test was used to evaluate cognitive deficits in the VD rats. Western blot, immunohistochemistry, and PCR analyses were used to analyze the molecular basis of the inflammatory response.

RESULTS

NBP significantly improved the learning and memory ability of VD rats. With regard to the protective mechanism, the results showed that NBP significantly downregulated the relative expression of Cleaved Cas-1/Cas-1 and Cleaved GSDMD/GSDMD. Moreover, NBP decreased the levels of the TLR-4 and NF-κB (P65) protein and phosphorylation of P65 in the hippocampus of VD rats via the TLR-4/NF-κB signaling pathway.

CONCLUSION

These findings demonstrate that NBP protects against memory deficits in permanent bilateral common carotid artery occlusion-induced VD rats by attenuating pyroptosis via the TLR-4/NF-κB signaling pathway.

Dl-3-n-Butylphthalide (NBP) Mitigates Muscular Injury Induced by Limb Ischemia/Reperfusion in Mice through the HMGB1/TLR4/NF-κB Pathway

Objective

Limb ischemia/reperfusion (I/R) injury is a clinical syndrome associated with severe damages to skeletal muscles and other fatal outcomes. Oxidative stress and inflammatory response play vital roles in the development of limb I/R injury. Existing evidence further indicates that Dl-3-n-butylphthalide (NBP) has anti-inflammatory and antioxidative properties. However, whether NBP can protect skeletal muscles from limb I/R injury and the mechanism in mediating the action of NBP treatment still remain to be investigated, which are the focuses of the current study.

Methods

The model of limb I/R injury was established and H&E staining was adopted to assess the pathological changes in skeletal muscles following limb I/R injury. Additionally, the W/D ratio of muscle tissue was also measured. ELISA and biochemical tests were carried out to measure the levels of inflammatory cytokines and oxidative stress in mouse models of limb I/R injury. Moreover, the levels of the HMGB1/TLR4/NF-κB pathway-related proteins were also determined using immunohistochemistry and immunoblotting.

Results

It was established that NBP treatment alleviated I/R-induced pathological changes in muscular tissue of mice, accompanied by lower W/D ratio of skeletal muscular tissue. Meanwhile, the limb I/R-induced inflammation and oxidative stress in skeletal muscles of mice were also inhibited by NBP. Mechanistic study indicated that the alleviatory effect of NBP was ascribed to inactivation of the HMGB1/TLR4/NF-κB pathway.

Conclusions

Our findings highlighted the potential of NBP as a novel strategy for limb I/R-driven muscle tissue damages by suppressing inflammatory response and oxidative stress via the HMGB1/TLR4/NF-κB pathway.

Dl-3-n-butylphthalide attenuates brain injury caused by cortical infarction accompanied by cranial venous drainage disturbance

Background

Cerebral venous disorder may have a harmful effect on ischaemic stroke; however, the underlying mechanism remains to be elucidated. Although Dl-3-n-butylphthalide is a multitarget agent for antiischaemic stroke, its neuroprotective role in brain ischaemia accompanied by brain venous disturbance remains unclear. In this study, we induced cerebral venous disturbance by the occlusion of bilateral external jugular veins (EJVs) to explore the potential mechanism of the adverse effects of cerebrovenous disorders in cerebral infarction and explore the protective effect of Dl-3-n-butylphthalide on cerebral infarction accompanied through cerebral venous disturbance.

Methods

Cerebral venous disturbance was induced in Sprague-Dawley rats through the permanent occlusion of bilateral EJVs, and cerebral ischaemic stroke was induced through the permanent occlusion of the right cortical branches of the middle cerebral artery. 2,3,5-triphenyltetrazolium chloride staining, MRI, Evans blue extravasation and behavioural test were performed to evaluate infarction volume, cerebral blood flow (CBF), blood–brain barrier (BBB) integrity and neurological function. Immunofluorescence staining and western blot analysis were performed to detect loss of neuron, endothelial cells, pericytes and tight junctions.

Results

Bilateral EJVs occlusion did not cause cerebral infarction; however, it increased the infarction volume compared with the simple middle cerebral artery occlusion (MCAO) group, accompanied by severe neuron loss, worse neurological function, lower CBF, increased EJVs pressure, exacerbated Evans blue extravasation and brain oedema, as well as attenuated angiogenesis. Dl-3-n-butylphthalide displayed a neuroprotective effect in rats with MCAO accompanied by EJVs occlusion by reducing neuron loss, accelerating CBF restoration, promoting angiogenesis and relieving BBB damage.

Conclusion

Bilateral EJVs occlusion did not significantly affect normal rats but aggravated brain damage in the case of ischaemic stroke. Dl-3-n-butylphthalide treatment plays a neuroprotective role in rats with MCAO accompanied by EJVs occlusion, mainly due to the promotion of CBF restoration and BBB protection.

Autophagy-Lysosomal Pathway as Potential Therapeutic Target in Parkinson's Disease

Cellular quality control systems have gained much attention in recent decades. Among these, autophagy is a natural self-preservation mechanism that continuously eliminates toxic cellular components and acts as an anti-ageing process. It is vital for cell survival and to preserve homeostasis. Several cell-type-dependent canonical or non-canonical autophagy pathways have been reported showing varying degrees of selectivity with regard to the substrates targeted. Here, we provide an updated review of the autophagy machinery and discuss the role of various forms of autophagy in neurodegenerative diseases, with a particular focus on Parkinson's disease. We describe recent findings that have led to the proposal of therapeutic strategies targeting autophagy to alter the course of Parkinson's disease progression.

Dl-3-n-butylphthalide Attenuates Spinal Cord Injury via Regulation of MMPs and Junction Proteins in Mice

As a serious trauma of the neurological system, spinal cord injury (SCI) results in permanent disability, gives rise to immediate vascular damage and a wide range of matters that induce the breakage of blood spinal cord barrier (BSCB). SCI activates the expression of MMP-2/9, which are considered to accelerate the disruption of BSCB. Recent research shows that Dl-3-n-butylphthalide (NBP) exerted protective effects on blood spinal cord barrier in animals after SCI, but the underlying molecular mechanism of NBP on the BSCB undergoing SCI is unknown. Here, our research show that NBP inhibited the expression of MMP-2/9, then improved the permeability of BSCB following SCI. After the T9 level of spinal cord performed with a moderate injury, NBP was managed by intragastric administration and further performed once a day. NBP remarkably improved the permeability of BSCB and junction proteins degration, then promoted locomotion recovery. The protective effect of NBP on BSCB destruction is related to the regulation of MMP-2/9 induced by SCI. Moreover, NBP obviously inhibited the MMP-2/9 expression and junction proteins degradation in microvascular endothelial cells. In conclusion, our results indicate that MMP-2/9 are relevant to the breakdown of BSCB, NBP impairs BSCB destruction through inhibiting MMP-2/9 and promotes functional recovery subjected to SCI. NBP is likely to become a new nominee as a therapeutic to treat SCI via a transigent BSCB.

Dl-3-n-Butylphthalide Alleviates Behavioral and Cognitive Symptoms Via Modulating Mitochondrial Dynamics in the A53T-α-Synuclein Mouse Model of Parkinson's Disease

Background

Aggregation and neurotoxicity of the presynaptic protein α-synuclein and the progressive loss of nigral dopaminergic neurons are believed to be the key hallmarks of Parkinson’s disease (PD). A53T mutant α-synuclein causes early onset PD and more severe manifestations. A growing body of evidence shows that misfolding or deposition of α-synuclein is linked to the maintenance of mitochondrial dynamics, which has been proven to play an important role in the pathogenesis of PD. It has been observed that Dl-3-n-butylphthalide (NBP) may be safe and effective in improving the non-tremor-dominant PD. However, the potential mechanism remains unclear. This study aimed to investigate whether NBP could decrease the loss of dopaminergic neurons and α-synuclein deposition and explore its possible neuroprotective mechanisms.

Methods

A total of 20 twelve-month-old human A53T α-synuclein transgenic mice and 10 matched adult C57BL/6 mice were included in the study; 10 adult C57BL/6 mice were selected as the control group and administered with saline (0.2 ml daily for 14 days); 20 human A53T α-synuclein transgenic mice were randomly divided into A53T group (treated in the same manner as in the control group) and A53T + NBP group (treated with NBP 0.2 ml daily for 14 days). Several markers of mitochondrial fission and fusion and mitophagy were determined, and the behavioral, olfactory, and cognitive symptoms were assessed as well.

Results

In the present study, it was observed that the A53T-α-synuclein PD mice exhibited anxiety-like behavioral disturbance, impairment of coordination ability, memory deficits, and olfactory dysfunction, loss of dopaminergic neurons, and α-synuclein accumulation. Meanwhile, the mitofusin 1 expression was significantly decreased, and the mitochondrial number and dynamin-related protein 1, Parkin, and LC3 levels were increased. The detected levels of all markers were reversed by NBP treatment, and the mitochondrial morphology was partially recovered.

Conclusion

In the present study, a valuable neuropharmacological role of NBP has been established in the A53T-α-synuclein PD mouse model. Possible neuroprotective mechanisms might be that NBP is involved in the maintenance of mitochondrial dynamics including mitochondrial fission and fusion and clearance of damaged mitochondria. It is essential to perform further experiments to shed light on the precise mechanisms of NBP on mitochondrial homeostasis.

Co-administration of TiO2-nanowired dl-3-n-butylphthalide (dl-NBP) and mesenchymal stem cells enhanced neuroprotection in Parkinson's disease exacerbated by concussive head injury

dl-3-n-butylphthalide (dl-NBP) is a powerful antioxidant compound with profound neuroprotective effects in stroke and brain injury. However, its role in Parkinson's disease (PD) is not well known. Traumatic brain injury (TBI) is one of the key factors in precipitating PD like symptoms in civilians and particularly in military personnel. Thus, it would be interesting to explore the possible neuroprotective effects of NBP in PD following concussive head injury (CHI). In this chapter effect of nanowired delivery of NBP together with mesenchymal stem cells (MSCs) in PD with CHI is discussed based on our own investigations. It appears that CHI exacerbates PD pathophysiology in terms of p-tau, α-synuclein (ASNC) levels in the cerebrospinal fluid (CSF) and the loss of TH immunoreactivity in substantia niagra pars compacta (SNpc) and striatum (STr) along with dopamine (DA), dopamine decarboxylase (DOPAC). And homovanillic acid (HVA). Our observations are the first to show that a combination of NBP with MSCs when delivered using nanowired technology induces superior neuroprotective effects in PD brain pathology exacerbated by CHI, not reported earlier.

Vascular protection and regenerative effects of intranasal DL-3-N-butylphthalide treatment after ischaemic stroke in mice

Objective

To investigate the effects of DL-3-N-butylphthalide (NBP) via intranasal delivery after ischaemic stroke in mice.

Methods

C57BL/6 mice were divided into three groups: sham, stroke with vehicle and stroke with NBP treatment. Ischaemic stroke was induced by permanent ligation of right middle cerebral artery with 7 min common carotid artery occlusion. NBP (100 mg/kg) or vehicle was intranasally administered at 1 hour after stroke and repeated once a day until sacrifice. Bromodeoxyuridine (BrdU) (50 mg/kg/day) was given from the third day until sacrifice. Sensorimotor function was tested during 1–21 days after stroke. Local cerebral blood flow in the ischaemic and peri-infarct regions was measured using laser Doppler flowmetry before, during and 3 days after ischaemia. Expressions of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase as well as regenerative marker BrdU in the peri-infarct region were analysed by western blotting and immunohistochemical methods.

Results

Compared with the vehicle group, NBP treatment significantly increased the VEGF expression in the poststroke brain. Stroke mice that received NBP showed significantly less vascular damage after stroke and more new neurons and blood vessels in the peri-infarct region at 21 days after stroke. In the adhesive removal test, the sensorimotor function of stroke mice treated with NBP performed significantly better at 1, 3 and 7 days after stroke compared with vehicle controls.

Conclusion

Daily intranasal NBP treatment provides protective and neurogenic/angiogenic effects in the poststroke brain, accompanied with functional improvements after a focal ischaemic stroke in mice.

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 protective effect of decoction of Rehmanniae via PI3K/Akt/mTOR pathway in MPP+-induced Parkinson's disease model cells

This research aims to explore the function of DOR in 1-methyl-4-phenylpyridinium (MPP⁺)-induced Parkinson's disease model cell SH-SY5Y. SH-SY5Y cells were exposed with various doses of MPP + or DOR. Cell counting Kit-8 (CCK-8) assay and flow cytometry (FCM) were used to detect the cell viability, apoptosis and reactive oxygen species (ROS) levels in MPP⁺ Parkinson's disease model cells SH-SY5Y. The oxidative stress markers were measured by Enzyme-linked immunosorbent assay (ELISA), Western blot and quantitative real-time reverse transcription PCR (qRT-PCR) assays. To further determine the protective effect of DOR on acute injury via PI3K/Akt/mTOR pathway, cells were treated with LY294002 (LY), a PI3K/Akt/mTOR pathway inhibitor, with MMP + or DOR or not. MPP⁺ at various doses caused cell injury with decrease of viability, increase of apoptosis and ROS level, while DOR partly prevented the cell against injury induced by MPP⁺. Bax, Cyt-c and cleaved-Caspase-12, 9 and 3 were increased, and meanwhile Bcl-2 was decreased in MPP⁺ stimulated cells, while those changes could be partly inhibited by DOR incubation. Furthermore, the phosphorylation level of PI3K, AKT and mTOR was suppressed by MPP⁺, while DOR treatment could enhanced the level of phosphorylated-PI3K (p-PI3K), AKT (P-AKT) and mTOR. LY aggravated the injury of SH-SY5Y cells treated with MPP⁺, and DOR could partly alleviate those effects. DOR had a protective effect against MPP⁺ induced injury of Parkinson's disease model cell through activating the PI3K/Akt/mTOR pathway. It suggests that DOR should be further explored in Parkinson's disease.

Amelioration of Mitochondrial Quality Control and Proteostasis by Natural Compounds in Parkinson's Disease Models

Parkinson’s disease (PD) is a well-known age-related neurodegenerative disorder associated with longer lifespans and rapidly aging populations. The pathophysiological mechanism is a complex progress involving cellular damage such as mitochondrial dysfunction and protein homeostasis. Age-mediated degenerative neurological disorders can reduce the quality of life and also impose economic burdens. Currently, the common treatment is replacement with levodopa to address low dopamine levels; however, this does not halt the progression of PD and is associated with adverse effects, including dyskinesis. In addition, elderly patients can react negatively to treatment with synthetic neuroprotection agents. Recently, natural compounds such as phytochemicals with fewer side effects have been reported as candidate treatments of age-related neurodegenerative diseases. This review focuses on mitochondrial dysfunction, oxidative stress, hormesis, proteostasis, the ubiquitin‒proteasome system, and autophagy (mitophagy) to explain the neuroprotective effects of using natural products as a therapeutic strategy. We also summarize the efforts to use natural extracts to develop novel pharmacological candidates for treatment of age-related PD.

Neuroprotective mechanisms of 3-n-butylphthalide in neurodegenerative diseases

Since 3-n-butylphthalide (NBP) was approved by the China Food and Drug Administration for the treatment of acute ischemia stroke in 2002, a number of studies have investigated NBP worldwide. In recent years, NBP has also demonstrated potential as treatment of several neurodegenerative diseases, which has increased the interest in its mechanisms of protection and action. Clinical studies and studies that used cell or animal models, have directly demonstrated neuroprotective effects of NBP via the following mechanisms: i) Inhibiting the inflammatory reaction; ii) reducing mitochondrial oxidative stress; iii) regulating apoptosis and autophagy; iv) inducing resistance to endoplasmic reticulum stress; and v) decreasing abnormal protein deposition. Therefore, NBP may be a potential drug for neurodegenerative diseases, and it is particularly important to identify the mechanism of NBP as it may assist with the development of new drugs for neurodegeneration. The present review summarizes the neuroprotective mechanisms of NBP and discusses new perspectives and prospects. The aim of the current review is to provide a new summary regarding NBP and its associated mechanisms.

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.

L-3-n-butylphthalide soft capsules in the treatment of Parkinson disease dementia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In recent years, L-3-n-butylphthalide (L-NBP) has been used for Parkinson disease dementia (PDD) to attenuate cognitive impairments in China. Therefore, we selected published and qualified clinical trials to conduct a systematic review and meta-analysis with the aim of assessing the effectiveness and safety of L-NBP in the treatment of PDD.

OBJECTIVE

This systematic review and meta-analysis aimed to assess the effectiveness and safety of L-NBP in the treatment of PDD.

METHODS

We searched PubMed, EMBASE, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP database), and Wan-Fang Database to collect eligible articles. We calculated pooled estimates of odds ratios or the standard mean deviation with 95% confidence intervals.

RESULTS

Eight randomized controlled trials were included in our meta-analysis. Our meta-analysis showed that L-NBP combined with Western medicine (WM) had a better effect on improving cognitive dysfunction, the total effective rate, symptoms of Parkinson disease (PD), and activities of daily living function than WM alone. Regarding safety, no serious adverse events were observed in the experimental group.

CONCLUSION

We found that L-NBP as a complementary therapy may have a positive therapeutic effect for improving cognitive dysfunction, the total effective rate, symptoms of PD, quality of life, and the related serum factors in the treatment of PDD. Furthermore, L-NBP was a safe treatment for PDD. However, the findings of our meta-analysis may be influenced by the low quality of the included studies. We highlight the need to conduct trials with higher methodological quality.

A Systematic Review of Neuroprotective Efficacy and Safety of DL-3-N-Butylphthalide in Ischemic Stroke

DL-3-n-butylphthalide (NBP) is widely used as a neuroprotective drug for ischemic stroke in China. There is, however, no established evidence on its efficacy and safety for patients with ischemic stroke. We, therefore, conducted a systematic review and meta-analysis. Major databases were searched to identify randomized controlled trials that assessed the efficacy and safety of NBP on ischemic stroke, reporting outcomes among patients treated with NBP alone or combined with standard anti-ischemic stroke drugs vs. standard anti-ischemic stroke drugs. Continuous data were validated, extracted and synthesized of standardized mean differences (SMDs) by random effects models, while dichotomous data were validated, extracted and synthesized of relative risk (RR) by random effects models. Twelve randomized controlled trials involving 1160 patients were identified. Results suggested that NBP monotherapy is not superior to standard anti-ischemic stroke drugs based on the Barthel Index (SMD, 0.25; 95% CI [Formula: see text]0.14 to 0.63; [Formula: see text]) and the National Institutes of Health Stroke Scale (SMD, 0.73; 95% CI [Formula: see text]0.14 to 1.59; [Formula: see text]). In contrast, the combination of NBP and standard anti-ischemic stroke drugs appears to be superior to standard drugs alone, again based on both the Barthel index (SMD, 1.65; 95% CI 1.25 to 2.04; [Formula: see text]) and National Institutes of Health Stroke Scale (SMD, 1.40; 95% CI 0.72 to 2.09; [Formula: see text]). However, the use of NBP may cause adverse event on the function of the liver (RR, 3.55; 95% CI 1.19 to 10.56; [Formula: see text]). The combination use of NBP and standard anti-ischemic stroke drugs is more effective than standard drugs. However, more attention should be payed to the adverse effects on liver function. Our findings provided an established evidence of NBP as a neuroprotective drug, which may improve the current guideline for treatment of ischemic stroke.

Plant Extracts and Phytochemicals Targeting α-Synuclein Aggregation in Parkinson's Disease Models

α-Synuclein (α-syn) is a presynaptic protein that regulates the release of neurotransmitters from synaptic vesicles in the brain. α-Syn aggregates, including Lewy bodies, are features of both sporadic and familial forms of Parkinson's disease (PD). These aggregates undergo several key stages of fibrillation, oligomerization, and aggregation. Therapeutic benefits of drugs decline with disease progression and offer only symptomatic treatment. Novel therapeutic strategies are required which can either prevent or delay the progression of the disease. The link between α-syn and the etiopathogenesis and progression of PD are well-established in the literature. Studies indicate that α-syn is an important therapeutic target and inhibition of α-syn aggregation, oligomerization, and fibrillation are an important disease modification strategy. However, recent studies have shown that plant extracts and phytochemicals have neuroprotective effects on α-syn oligomerization and fibrillation by targeting different key stages of its formation. Although many reviews on the antioxidant-mediated, neuroprotective effect of plant extracts and phytochemicals on PD symptoms have been well-highlighted, the antioxidant mechanisms show limited success for translation to clinical studies. The identification of specific plant extracts and phytochemicals that target α-syn aggregation will provide selective molecules to develop new drugs for PD. The present review provides an overview of plant extracts and phytochemicals that target α-syn in PD and summarizes the observed effects and the underlying mechanisms. Furthermore, we provide a synopsis of current experimental models and techniques used to evaluate plant extracts and phytochemicals. Plant extracts and phytochemicals were found to inhibit the aggregation or fibril formation of oligomers. These also appear to direct α-syn oligomer formation into its unstructured form or promote non-toxic pathways and suggested to be valuable drug candidates for PD and related synucleinopathy. Current evidences from in vitro studies require confirmation in the in vivo studies. Further studies are needed to ascertain their potential effects and safety in preclinical studies for pharmaceutical/nutritional development of these phytochemicals or dietary inclusion of the plant extracts in PD treatment.

DL-3-n-butylphthalide therapy for Parkinson's disease: A randomized controlled trial

Currently available treatments for Parkinson's disease (PD) do not delay or prevent disease development and progression. DL-3-n-butylphthalide (NBP), isolated from Apium graveolens seeds, alleviates oxidative damage and mitochondrial dysfunction. It has been revealed to reduce the loss of dopamine neurons in pre-clinical PD models, and has been approved for the treatment of ischemic stroke patients. The purpose of the present study was to examine whether NBP has the capacity provide a benefit for PD patients and to slow disease progression. A randomized, controlled trial was performed between September 2014 and December 2016. Pairs of patients matched by age, gender and off-medication Unified PD Rating Scale motor subscale (UPDRS-III) scores, were randomly assigned to an NBP treatment group and a control group. All patients continued their originally prescribed medication regimen and those in the NBP group were administered NBP at 200 mg three times daily for 24 weeks. Primary outcome measures were changes in UPDRS-III, including tremor score and non-tremor score, the Pittsburgh sleep quality index (PSQI) and the PD 39-items questionnaire (PDQ) scores. Assessments were completed by blinded evaluators at baseline and 12, 24 and 48 weeks after randomization. All patients were monitored for adverse events (AEs). A total of 103 patients were enrolled in the present study. The NBP group exhibited significantly greater improvements in the non-tremor, PSQI and PDQ-39 scores than the control group, which generally exhibited no improvement. NBP-associated AEs were uncommon and primarily consisted of mild gastrointestinal symptoms. In conclusion, over the 6-month treatment period, NBP was safe and effective for improving the symptoms and impairing the progression of patients with PD (Trial registry number, ChiCTR1800018892).

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.

Natural Molecules From Chinese Herbs Protecting Against Parkinson's Disease via Anti-oxidative Stress

Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease, affecting about 7–10 million patients worldwide. The major pathological features of PD include loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the midbrain and the presence of α-synuclein-enriched Lewy bodies. Although the mechanism underlying PD pathogenesis remains to be elucidated, oxidative stress induced by the overproduction of reactive oxygen species (ROS) is widely accepted to be a key pathogenic factors. ROS cause oxidative damage to proteins, lipids, and DNA, which subsequently lead to neurodegeneration. Great efforts have been made to slow or stop the progress of PD. Unfortunately there is no effective cure for PD till now. Compounds with good antioxidant activity represent the promising candidates for therapeutics of PD. Some natural molecules from Chinese herbs are found to have good antioxidant activity. Both in vitro and in vivo studies demonstrate that these natural molecules could mitigate the oxidative stress and rescue the neuronal cell death in PD models. In present review, we summarized the reported natural molecules that displayed protective effects in PD. We also addressed the possible signal pathway through which natural molecules achieved their antioxidative effects and mitigate PD phenotypes. Hopefully it will pave the way to better recognize and utilize Chinese herbs for the treatment of PD.

DL-3-n-butylphthalide induced neuroprotection, regenerative repair, functional recovery and psychological benefits following traumatic brain injury in mice

Previous investigations suggest that DL-3-n-butylphthalide (NBP) is a promising multifaceted drug for the treatment of stroke. It is not clear whether NBP can treat traumatic brain injury (TBI) and what could be the mechanisms of therapeutic benefits. To address these issues, TBI was induced by a controlled cortical impact in adult male mice. NBP (100 mg/kg) or saline was intraperitoneally administered within 5 min after TBI. One day after TBI, apoptotic events including caspase-3/9 activation, cytochrome c release from the mitochondria, and apoptosis-inducing factor (AIF) translocation into the nucleus in the pericontusion region were attenuated in NBP-treated mice compared to TBI-saline controls. In the assessment of the nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) pathway, NBP ameliorated the p65 expression and the p-IκB-α/IκB-α ratio, indicating reduced NF-κB activation. Consistently, NBP reduced the upregulation of proinflammatory cytokines such as tumor necrotizing factor-alpha (TNF-α) and interleukin-1beta (IL-1β) after TBI. In sub-acute treatment experiments, NBP was intranasally delivered once daily for 3 days. At 3 days after TBI, this repeated NBP treatment significantly reduced the contusion volume and cell death in the pericontusion region. In chronic experiments up to 21 days after TBI, continues daily intranasal NBP treatment increased neurogenesis, angiogenesis, and arteriogenesis in the post-TBI brain, accompanied with upregulations of regenerative genes including brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), endothelial-derived nitric oxide synthase (eNOS), and matrix metallopeptidase 9 (MMP-9). The NBP treatment significantly improved sensorimotor functional recovery and reduced post-TBP depressive behavior. These new findings demonstrate that NBP shows multiple therapeutic benefits after TBI.

Dl-3-n-butylphthalide prevents the disruption of blood-spinal cord barrier via inhibiting endoplasmic reticulum stress following spinal cord injury

After spinal cord injury (SCI), the destruction of blood-spinal cord barrier (BSCB) is shown to accelerate gathering of noxious blood-derived components in the nervous system, leading to secondary neurodegenerative damages. SCI activates endoplasmic reticulum stress (ER stress), which is considered to evoke secondary damages of neurons and glia. Recent evidence indicates that Dl-3-n-butylphthalide (NBP) has the neuroprotective effect in ischaemic brain injury, but whether it has protective effects on SCI or not is largely unclear. Here, we show that NBP prevented BSCB disruption after SCI via inhibition of ER stress. Following a moderate contusion injury of the T9 level of spinal cord, NBP was administered by oral gavage and further treated once a day. NBP significantly attenuated BSCB permeability and breakdown of adherens junction (AJ) and tight junction (TJ) proteins, then improved locomotion recovery following SCI. The protective role of NBP on BSCB disruption is associated with the restrain of ER stress caused by SCI. Furthermore, NBP considerably constrained the expression of ER stress-associated proteins and degradation of TJ and AJ in human brain microvascular endothelial cells (HBMECs) treated with TG. In conclusion, our results indicate that ER stress is associated with the disruption of BSCB integrity after injury, NBP attenuates BSCB disruption via inhibiting ER stress and improve functional recovery following SCI.

Dl-3-n-butylphthalide attenuates acute inflammatory activation in rats with spinal cord injury by inhibiting microglial TLR4/NF-κB signalling

In this study, we examined the neuroprotective effects and anti-inflammatory properties of Dl-3-n-butylphthalide (NBP) in Sprague-Dawley (SD) rats following traumatic spinal cord injury (SCI) as well as microglia activation and inflammatory response both in vivo and in vitro. Our results showed that NBP improved the locomotor recovery of SD rats after SCI an significantly diminished the lesion cavity area of the spinal cord, apoptotic activity in neurons, and the number of TUNEL-positive cells at 7 days post-injury. NBP inhibited activation of microglia, diminished the release of inflammatory mediators, and reduced the upregulation of microglial TLR4/NF-κB expression at 1 day post-injury. In a co-culture system with BV-2 cells and PC12 cells, NBP significantly reduced the cytotoxicity of BV-2 cells following lipopolysaccharide (LPS) stimulation. In addition, NBP reduced the activation of BV-2 cells, diminished the release of inflammatory mediators, and inhibited microglial TLR4/NF-κB expression in BV-2 cells. Our findings demonstrate that NBP may have neuroprotective and anti-inflammatory properties in the treatment of SCI by inhibiting the activation of microglia via TLR4/NF-κB signalling.

L-3-n-Butylphthalide Protects HSPB8 K141N Mutation-Induced Oxidative Stress by Modulating the Mitochondrial Apoptotic and Nrf2 Pathways

Charcot-Marie-Tooth disease (CMT), also known as hereditary motor and sensory neuropathy, is the most common inherited peripheral nerve disorder. Missense mutations, such as K141N, in the small heat shock protein HSPB8 are known to cause distal hereditary motor neuropathy 2A (dHMN2A) or Charcot-Marie-Tooth neuropathy type 2L (CMT2L). However, of critical clinical significance, very few specific therapies for this disease exist. In the present study, we investigated the impact of mutant K141N HSPB8 on mitochondrial distribution and function in a cellular model of CMT2L. Our results indicate that K141N HSPB8 induced mitochondrial aggregation and caused increased oxidative stress injury. As an extraction from Chinese celery Apium graveolens Linn seeds, L-3-n-Butylphthalide (NBP), has been reported to exert many neuroprotective effects, we interrogated whether NBP could elicit a protective effect on the cell injury typically caused by HSPB8 K141N mutations. We found NBP could reverse the pathological processes induced by HSPB8 K141N mutation via an antioxidant effect, modulation of the Bax/Bcl-2 mitochondrial apoptotic and Nrf2 pathways. We propose a novel function of HSPB8, highlighting the consequence of the K141N pathogenic mutation. Furthermore, we suggest NBP may have promising therapeutic potential in the treatment of CMT2L.

DL-3-n-butylphthalide protects endothelial cells against advanced glycation end product-induced injury by attenuating oxidative stress and inflammation responses

Endothelial dysfunction, regarded as a key step in the pathophysiological course of diabetic vascular complications, is initiated and deteriorated by advanced glycation end products (AGEs). DL-3-n-butylphthalide (DL-NBP) has been proven to have protective effects on neurons and vascular endothelial cells against ischemic and anoxic damage. The aim of the present study was to investigate whether NBP is able to attenuate AGE-induced endothelial dysfunction in vitro, and also elucidate the possible underlying mechanism. An injury model of human umbilical vein endothelial cells (HUVECs) induced by AGEs (200 µg/ml) was established. The results demonstrated that pretreatment with NBP (1-100 µM) significantly increased HUVEC viability and inhibited the apoptosis induced by AGEs. In addition, AGEs stimulated the expression levels of the receptor for AGEs protein and the downstream protein nuclear factor-κB in HUVECs, which were inhibited by pretreatment with NBP. Furthermore, it significantly reduced reactive oxygen species generation and the level of the inflammatory cytokines, intercellular cell adhesion molecule-1 and monocyte chemotactic protein-1, in HUVECs mediated by AGEs. The current findings indicated that NBP attenuated AGE-induced endothelial dysfunction by ameliorating inflammation and oxidative stress responses.

3-n-Butylphthalide reduces the oxidative damage of muscles in an experimental autoimmune myositis animal model

3-n-Butylphthalide (NBP) protects the mitochondria and reduces apoptosis in multiple disease models. However, it remains to be determined whether NBP can protect muscle cells from oxidative stress, lipid peroxidation and apoptosis in myositis. In the present study, a myosin immunization protocol was applied to induce experimental autoimmune myositis (EAM) in guinea pigs. After 4 weeks, a low- or high-dose NBP solution was injected intraperitoneally into the guinea pigs, with saline solution serving as the negative control. After 10 days, the guinea pigs were sacrificed and muscle cells were isolated for analysis. The results revealed that NBP increased the superoxide dismutase and catalase activity, and reduced malondialdehyde activity in the EAM model. Furthermore, NBP enhanced ATPase activity in muscle mitochondrial membranes and muscle fiber membranes, reduced the number of apoptotic cells, and differentially regulated the Bcl-2, Bax and BAD mRNA and protein expression levels in muscle tissues and sera. NBP directly protects muscle mitochondria and muscle cells from oxidative damage. Notably, NBP reduced muscle cell apoptosis. Thus, it is speculated that, as an antioxidant treatment, NBP may benefit individuals with myopathy.

The efficacy and safety of Dl-3n-butylphthalide on progressive cerebral infarction: A randomized controlled STROBE study

Progressive cerebral infarction (PCI) is associated with high rates of mortality and disability. Many studies have shown that Dl-3n-butylphthalide (NBP) is effective against acute ischemic stroke. The administration of NBP can result in an increased number of capillaries in the ischemic region, promote the establishment of collateral circulation, protect the mitochondria, and narrow the infarction area, among other effects. In the present study, we evaluated the efficacy and safety of NBP for the treatment of PCI.Between March 2008 and May 2012, we performed a randomized, double-blind placebo-controlled study including 304 inpatients with PCI. These patients were randomly assigned to the test (152 cases) and control groups (152 cases). The test group received 200 mg of NBP soft capsules orally, 15 minutes before each meal, 3 times daily. The control group received 200 mg of placebo soft capsules orally, 15 minutes before each meal, 3 times daily. Treatment was administered during 21 days. The National Institute of Health Stroke Scale (NIHSS) score was assessed before the treatment and on days 7, 14, 21, and 30 after treatment. The Barthel index (BI) was assessed on the same days and on day 90.In the test group, the NIHSS scores on days 7, 14, 21, and 30 were 14.75 ± 4.85, 11.62 ± 3.49, 8.87 ± 5.17, and 6.38 ± 4.93, respectively. In the control group, they were 16.08 ± 3.76, 13.28 ± 5.02, 11.05 ± 4.25, and 8.43 ± 5.41 (P < .05), respectively. The BI on days 7, 14, 21, 30, and 90 were 51.57 ± 15.11, 61.21 ± 16.39, 70.48 ± 18.21, 76.41 ± 19.02, and 81.10 ± 15.52 for the test group and 46.79 ± 18.42, 55.93 ± 19.12, 64.84 ± 17.67, 70.65 ± 18.54, and 76.54 ± 17.05 for the control group (P < .05), respectively. Adverse events were elevation of alanine aminotransferase and aspartate aminotransferase (P > .05).NBP was useful to improve the outcome of patients with PCI and decreased their disability for activities of daily living. NBP was an efficacious and safe treatment for PCI.

Dl-3-n-butylphthalide protects the heart against ischemic injury and H9c2 cardiomyoblasts against oxidative stress: involvement of mitochondrial function and biogenesis

Background

Myocardial infarction (MI) is an acute and fatal condition that threatens human health. Dl-3-n-butylphthalide (NBP) has been used for the treatment of acute ischemic stroke. Mitochondria may play a protective role in MI injury. However, there are few reports on the cardioprotective effect of NBP or the potential mitochondrial mechanism for the NBP-induced protection against cardiac ischemia injury. We investigated the therapeutic effects of NBP in an in vivo MI model and an in vitro oxidative stress model, as well as the potential mitochondrial mechanism.

Methods

This study comprised two different experiments. The aim of experiment 1 was to determine the protective effects of NBP on MI and the underlying mechanisms in vivo. In part 1, myocardial infarct size was measured by staining with 2,3,5-triphenyltetrazoliumchloride (TTC). Myocardial enzymes and mitochondrial enzymes were assayed. The aim of experiment 2 was to investigate the role of NBP in H₂O₂-induced myocardial ischemic injury in H9c2 cells and to determine the potential mechanism. In part 2, H9c2 cell viability was evaluated. ROS levels, mitochondrial morphology, and mitochondrial membrane potential of H9c2 cells were measured. ATP levels were evaluated using an assay kit; mitochondrial DNA (mtDNA), the expressions of NRF-1 and TFAM, and mitochondrial biogenesis factors were determined.

Results

NBP treatment significantly reduced the infarct ratio, as observed by TTC staining, decreased serum myocardial enzymes in MI, and restored heart mitochondrial enzymes (isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and a-ketoglutarate dehydrogenase (a-KGDH) activities after MI. Moreover, in in vitro studies, NBP significantly increased the viability of H9c2 cells in a dose-dependent manner, reduced cell apoptosis, protected mitochondrial functions, elevated the cellular ATP levels, and promoted H₂O₂-induced mitochondrial biogenesis in H9c2 cardiomyoblasts.

Conclusion

Collectively, the results from both the in vivo and in vitro experiments suggested that NBP exerted a cardioprotective effect on cardiac ischemic injury via the regulation of mitochondrial function and biogenesis.

Neuroprotective mechanisms of plant extracts against MPTP induced neurotoxicity: Future applications in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease, affecting about seven to 10 million patients worldwide. The major pathological features of PD are loss of dopaminergic neurons in the nigrostriatal pathway and accumulation of alpha-synuclein molecules, forming Lewy bodies. Until now, there is no effective cure for PD, and investigators are searching for neuroprotective strategies to stop or slow the disease progression. The MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) induced neurotoxicity of the nigrostriatal pathway has been used to initiate PD in animal models. Multiple experimental studies showed the ability of several plant extracts to protect against MPTP induced neurotoxicity through activation of catalase, superoxide dismutase, and glutathione reductase enzymes, which reduce the cellular concentration of free radicals, preventing intracellular Ca⁺⁺ release and subsequent apoptosis signaling. Other neuroprotective mechanisms of plant extracts include promoting autophagy of alpha-synuclein molecules and exerting an antiapoptotic activity via inhibition of proteolytic poly (ADP-ribose) polymerase and preventing caspase cleavage. The variety of neuroprotective mechanisms of natural plant extracts may allow researchers to target PD progression in different pathological stages and may be through multiple pathways. Further investigations are required to translate these neuroprotective mechanisms into safe and effective treatments for PD.