Novel mechanisms of Anshen Dingzhi prescription against PTSD: Inhibiting DCC to modulate synaptic function and inflammatory responses.

ETHNOPHARMACOLOGICAL RELEVANCE: Anshen Dingzhi prescription (ADP), documented in "Yi Xue Xin Wu", is a famous prescription for treating panic-related mental disorders such as post-traumatic stress disorder (PTSD). However, the underlying mechanism remains unclear. AIM OF THE STUDY: This study aimed to investigate the mechanisms by which ADP intervened in PTSD-like behaviors. METHODS: A mouse model of single prolonged stress (SPS) was established to evaluate the ameliorative effects and mechanisms of ADP on PTSD. Behavioral tests were used to assess PTSD-like behaviors in mice; transmission electron microscopy was used to observe changes in the ultrastructure of hippocampal synapses, and western blot, immunofluorescence, and ELISA were used to detect the expression of hippocampal deleted in colorectal cancer (DCC) and downstream Ras-related C3 botulinum toxin substrate 1 (Rac1) - P21-activated kinase 1 (PAK1) signal, as well as levels of synaptic proteins and inflammatory factors. Molecular docking technology simulated the binding of potential brain-penetrating components of ADP to DCC. RESULTS: SPS induced PTSD-like behaviors in mice and increased expression of hippocampal netrin-1 (NT-1) and DCC on the 14th day post-modeling, with concurrent elevation in serum NT-1 levels. Simultaneously, SPS also decreased p-Rac1 level and increased p-PAK1 level, the down-stream molecules of DCC. Lentiviral overexpression of DCC induced or exacerbated PTSD-like behaviors in control and SPS mice, respectively, whereas neutralization antibody against NT-1 reduced DCC activation and ameliorated PTSD-like behaviors in SPS mice. Interestingly, downstream Rac1-PAK1 signal was altered according to DCC expression. Moreover, DCC overexpression down-regulated N-methyl-d-aspartate (NMDA) receptor 2A (GluN2A) and postsynaptic density 95 (PSD95), up-regulated NMDA receptor 2B (GluN2B) and increased neuroinflammatory responses. Administration of ADP (36.8 mg/kg) improved PTSD-like behaviors in the SPS mice, suppressed hippocampal DCC, and downstream Rac1-PAK1 signal, upregulated GluN2A and PSD95, downregulated GluN2B, and reduced levels of inflammatory factors NOD-like receptor protein 3 (NLRP3), nuclear factor kappa-B (NF-κB) and interleukin-6 (IL-6). Importantly, DCC overexpression could also reduce the ameliorative effect of ADP on PTSD. Additionally, DCC demonstrated a favorable molecular docking pattern with the potential brain-penetrating components of ADP, further suggesting DCC as a potential target of ADP. CONCLUSION: Our data indicate that DCC is a key target for the regulation of synaptic function and inflammatory response in the onset of PTSD, and ADP likely reduces DCC to prevent PTSD via modulating downstream Rac1-PAK1 pathway. This study provides a novel mechanism for the onset of PTSD and warrants the clinical application of ADP.

Anshen Dingzhi prescription in the treatment of PTSD in mice: Investigation of the underlying mechanism from the perspective of hippocampal synaptic function.

BACKGROUND: Anshen Dingzhi prescription (ADP) is an important prescription for the treatment of mental diseases in traditional Chinese medicine and is widely used to treat neuropsychiatric disorders. PURPOSE: To explore the ameliorative effect of ADP on post-traumatic stress disorder (PTSD)-like behaviors in mice and determine the underlying mechanism. METHODS: The constituents of ADP were analyzed by UPLC-Q-TOF/MS. The PTSD-like behaviors of mice subjected to single prolonged stress (SPS) were evaluated using behavioral tests. Potential pathological changes in the hippocampus were assessed by hematoxylin and eosin (H&E) staining. Western blotting and immunohistochemistry (IHC) were employed to detect the expression of proteins involved in relevant signaling pathways. RESULTS: Five quality control markers (ginsenoside Rg1, ginsenoside Rb1, tenuifolin, poricoic acid B, and α-asarone) were detected in the ADP solution. The ginsenoside Rg1 content in ADP was found to be 0.114 mg/g. Mice subjected to SPS showed obvious fear generalization and anxiety-like behaviors. ADP treatment prevented the behavioral changes caused by exposure to SPS. Compared with control animals, the number of normal pyramidal cells in the hippocampal CA1 region of mice exposed to SPS was decreased and the number of degenerating pyramidal cells was increased; however, ADP administration could counteract these effects. Furthermore, the protein expression of BDNF, p-TrkB, µ-calpain, PSD95, GluN2A, GluA1, p-AKT, p-mTOR, and ARC was decreased, while that of PTEN and GluN2B was increased in the hippocampus of mice subjected to SPS compared with that in control animals; however, these changes in protein expression were reversed following ADP treatment. Importantly, the ameliorative effect of ADP on PTSD-like behaviors and synaptic protein expression were inhibited by rapamycin administration. CONCLUSIONS: ADP administration improves PTSD-like behaviors in mice and this effect may be mediated through an mTOR-dependent improvement in synaptic function in the hippocampus.

Polysaccharides from Polygonatum cyrtonema Hua Reduce Depression-Like Behavior in Mice by Inhibiting Oxidative Stress-Calpain-1-NLRP3 Signaling Axis.

Polysaccharides from Polygonatum cyrtonema Hua (PSP) exert antioxidant, anti-inflammatory, and antidepressant effects. Production of reactive oxygen species (ROS) and activation of the calpain system and the NOD-like receptor protein 3 (NLRP3) inflammasome are closely related to the pathogenesis of depression. However, the relationships among those pathways and the protective effects of PSP have not been characterized. In this study, lipopolysaccharide (LPS) and chronic unpredictable mild stress- (CUMS-) induced depression models were used to evaluate the protective mechanisms of PSP against depression. ROS levels were measured in HT-22 cells using flow cytometry. Brain tissues were collected to determine the levels of oxidation-related indicators and inflammatory cytokines. The protein levels of calpain-1, calpain-2, calpastatin, phosphatase and Tensin Homolog deleted on Chromosome 10 (PTEN), suprachiasmatic nucleus circadian oscillatory protein (SCOP), nuclear factor-erythroid factor 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NLRP3, apoptosis-associated speck-like protein (ASC), caspase-1, cleaved-caspase-1, ionized calcium binding adapter molecule 1 (Iba1), phosphorylation of extracellular signal-regulated kinase (p-ERK), nuclear factor-kappa B (NF-κB), interleukin-1ß (IL-1ß), and glial fibrillary acidic protein (GFAP) were measured using western blotting or immunofluorescence. In cellular experiments, we showed that PSP attenuated LPS-induced production of ROS in HT-22 cells. In animal experiments, we found that LPS increased the expression of calpain-1, NLRP3, ASC, caspase-1, cleaved-caspase-1, Iba1, p-ERK, NF-κB, and GFAP and reduced the expression of calpastatin, PTEN, SCOP, and Nrf2. Administration of PSP reversed these changes. N-Acetyl-L-cysteine (NAC) administration also inhibited oxidative stress and activation of the calpain system and the NLRP3 inflammasome. Furthermore, PSP, calpeptin, MCC950 (a selective NLRP3 inflammasome inhibitor), and NAC reduced LPS-induced proinflammatory cytokine release. We also showed that PSP prevented CUMS-induced changes in the calpain system and the Nrf2 and NLRP3 signaling pathways and reduced depression-like behavior. These results indicate that PSP exerts antidepressant effects through regulation of the oxidative stress-calpain-1-NLRP3 signaling axis.

p53-mediated ferroptosis is required for 1-methyl-4-phenylpyridinium-induced senescence of PC12 cells.

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra and striatum. Aging is the most important risk factor of PD. Ferroptosis is an iron-dependent form of cell death associated with PD. However, it is not clear whether ferroptosis accelerates PD by promoting cellular senescence. This study investigated the mechanism of 1-methyl-4-phenylpyridinium (MPP+) -induced PC12 cells injury. We found that MPP+ induced cell senescence with increased ß-galactosidase activity and the expression of p53, p21 and p16 activation in cells. In addition, MPP+ treatment showed smaller mitochondria and increased membrane density, downregulation of ferritin heavy chain 1 expression and upregulation of acyl-CoA synthetase long chain family member 4 expression, and enhanced levels of oxidative stress, which were important characteristics of ferroptosis. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, was tested to eliminate MPP+-induced cell senescence. Fer-1 downregulated the expression of p53 and upregulated the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase-4 (GPX4) in MPP+-induced ferroptosis. Inhibition of p53 eliminated cell senescence by upregulation the expression of of SLC7A11 and GPX4. Thus, these results suggest that MPP+ induces senescence in PC12 cells via the p53/ SLC7A11/ GPX4 signaling pathway in the ferroptosis regulation mechanism.

Brusatol reverses lipopolysaccharide-induced epithelial-mesenchymal transformation and induces apoptosis through PI3K/Akt/NF-кB pathway in human gastric cancer SGC-7901 cells.

Brusatol is a butyrolactone compound isolated from traditional Chinese medicine Brucea javanica. It has been reported to possess strong cytotoxicity against various cancer cells, thus showing its potential as an anticancer drug. Besides, lipopolysaccharide (LPS) plays a central role in the tumor microenvironment, while epithelial-mesenchymal transformation (EMT), a biological process by which epithelial cells are transformed into mesenchymal phenotypic cells through specific procedures, participates in chronic inflammation and tumor metastasis. This study aimed to investigate the inhibition of LPS-induced tumor cell invasion and metastasis and the molecular mechanism of apoptosis induced by brusatol in human gastric cancer SGC-7901 cells. Cell viability, cell migration and invasion ability, inflammatory factor release, and protein expression were detected using methyl thiazolyl tetrazolium assays, transwell assays, ELISA kit, and Western blot analysis, respectively. The change of EMT marker protein vimentin was assessed using immunofluorescence, while the apoptosis rate was measured using flow cytometry. In summary, brusatol inhibited LPS-induced EMT via the deactivation of the PI3K/Akt/NF-кB signaling pathway. This provides a useful new theoretical basis for the treatment of gastric cancer in the future.

Gastrodin Inhibits H2O2-Induced Ferroptosis through Its Antioxidative Effect in Rat Glioma Cell Line C6.

Ferroptosis is a form of necrosis caused by iron-induced accumulation of lipid hydroperoxide, involving several molecular events, and has been implicated in Parkinson's disease. Gastrodin is a component of Gastrodia elata Blume with strong antioxidant activity. We examined whether gastrodin can prevent H2O2-induced cytotoxicity in rat glioma cell line C6. For this purpose, C6 cells were pretreated with gastrodin (1, 5, 25 µM) and then exposed to 100 µM H2O2. Results showed that pretreatment of C6 cells with gastrodin decreased H2O2-induced lactate dehydrogenase (LDH) release and cell death. Moreover, gastrodin decreased intracellular malondialdehyde (MDA) level, whereas increased glutathione peroxidase (GPX) activity and glutathione (GSH) level after H2O2 treatment. In addition, treatment of deferoxamine (DFO), ferrostatin-1, and liproxstatin-1 abolished ferroptosis induced by H2O2 or erastin pretreatment. Treatment with gastrodin attenuated H2O2-induced ferroptosis and decreased lipid reactive oxygen species (ROS) (C11-BODIPY) production in C6 cells. Moreover, gastrodin increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), GPX4, ferroportin-1 (FPN1), and heme oxygenase-1 (HO-1) in C6 cells treated with H2O2. RSL3, a GPX4 inhibitor, inhibited GPX4 protein level in cells co-treated with gastrodin and 100 µM H2O2. These findings indicate that gastrodin can inhibit H2O2-induced ferroptosis through its antioxidative effect in C6 cells.

Synthesis and evaluation of paeonol derivatives as potential multifunctional agents for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder characterized by memory loss, language impairment, personality changes and intellectual decline. Taking into account the key pathological features of AD, such as low levels of acetylcholine, beta-amyloid (Aß) aggregation, oxidative stress and dyshomeostasis of biometals, a new series of paeonol derivatives 5a-5d merging three different functions, i.e., antioxidant, anti-acetylcholinesterase (AChE) activity, metal chelating agents for AD treatment have been synthesized and characterized. Biological assays revealed that compared with paeonol (309.7 µM), 5a-5d had a lower DPPH IC50 value (142.8-191.6 µM). 5a-5d could significantly inhibit hydrogen peroxide-induced neuronal PC12 cell death assessed by MTT assay in the concentration range of 5-40 µM. AChE activity was effectively inhibited by 5a-5d, with IC50 values in the range of 0.61-7.04 µM. 5a-5d also exhibited good metal-chelating ability. All the above results suggested that paeonol derivatives may be promising multifunctional agents for AD treatment.

[Gambogenic acid induces mitochondria-dependent apoptosis in human gastric carcinoma cell line].

OBJECTIVE: To study the effects of Gambogenic acid (GNA) on the growth of human gastric carcinoma cell line MGC-803 and its underlying mechanisms. METHODS: MTT assay was used to measure the cell viability. Apoptosis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) were detected using flow cytometry method. Among them, Annexin V-FITC/PI double staining was employed in the analysis of apoptosis, Rh123 in analyzing MMP and H2DCFDA in analyzing ROS formation. P53 expression was confirmed by Western blot. RESULTS: 4.0 micromol/L GNA inhibited MGC-803 cells growth in a time dependent manner from 24 to 48 h. At the concentration range from 1.0 to 12.0 micromol/L, the inhibitory effect was in a concentration dependent manner. After treatment with 4.0 micromol/L GNA for 48 h, apoptosis was obviously observed as assayed by Annexin V-FITC/PI staining. Importantly, MMP was decreased and ROS formation was increased following GNA treatment. Additionally, P53 expression was up-regulated following 4.0 micromol/ L GNA treatment in a time dependent manner. CONCLUSION: GNA induces mitochondria-dependent apoptosis and increases P53 expression in human gastric carcinoma cell line.

[Effect of chaperone-mediated autophagy in MPP(+) -induced SH-SY5Y cells and interventional effect of puerarin].

OBJECTIVE: To study the protective effect of puerarin on MPP(+) -induced SH-SY5Y cells by chaperone-mediated autophagy (CMA). METHOD: The Parkinson's disease cell model was established by injuring SH-SY5Y cells with 1 mmol x L(-1) MPP+. The CCK-8 staining was adopted to detect the effect the puerarin of different concentrations on the survival rate of MPP(+)-induced SH-SYSY cells. The autophagosome formation was observed under transmission electron microscope. The AO staining showed the changes in the lysosome activity. RT-PCR was used to detect the changes in Lamp2a and Hsc70 mRNA expressions. The western blotting was adopted to test the expressions of Lamp2a, Hsc70 and alpha-synuclein protein in cells. RESULT: Within the concentration range of 12. 5-50.0 micromol x L(-1), the pretreatment with puerain for 30 minutes could protect the injury of MPP+ in SH-SY5Y cells, and showed a certain dose-effect relationship. The AO staining and electron microscope showed the effect of puerain within the concentration range of 12.5-50.0 micromol x L(-1) on 1 mmol x L(-1) MPP(+)-induced SH-SY5Y cells; autophagosomes emerged in cells, and increased along with the rise in the puerarin dose. The results of the flow cytometry revealed that 50.0 micromol x L(-1) of puerarin could protect against the increase of the ROS level in 1 mmol x L(-1) MPP(+) -induced SH-SY5Y cells and prevent the oxidative injury. The results of RT-PCR and western blotting indicated that puerain within the concentration range of 12.5-50.0 micromol x L(-1) alleviated the MPP(+)-induced SH-SY5Y cell injury, and inhibited the accumulation of alpha-synuclein proteins in MPP(+) -induced SH-SY5Y cells by up-regulating Hsc70, Lamp2a mRNA and protein level. CONCLUSION: Puerarin could protect against the MPP(+) -induced cell injury, whose protective mechanism may be related to the chaperone-mediated autophagy pathway of interventional molecules.

Neuroprotective effects of puerarin on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced Parkinson's disease model in mice.

Puerarin, an active component of Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep is well-known for its anti-oxidative and neuroprotective activities. Although anti-Parkinson's disease activity of puerarin was reported in both of in vivo and in vitro model, detailed mechanisms are not clarified. In this study, we addressed that puerarin attenuated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced behavioral deficits, dopaminergic neuronal degeneration and dopamine depletion. Puerarin administration enhanced glutathione (GSH) activity, glial cell line-derived neurotrophic factor (GDNF) expression and PI3K/Akt pathway activation, which might ameliorate MPTP injection-induced progressive elevation of reactive oxygen species (ROS) formation in mice. In addition to the effect on ROS, puerarin ameliorated MPTP-reduced lysosome-associated membrane protein type 2A (Lamp 2A) expression. Taken together, our data demonstrate that puerarin attenuates MPTP-induced dopaminergic neuronal degeneration via modulating GDNF expression, PI3K/Akt pathway and GSH activation, which subsequently ameliorate MPTP-induced ROS formation and decrease of Lamp 2A expression.

[Study on protective effect of salvianolic acid B on glutamate-induced excitotoxicity in pheochromocytoma PC12 cells].

OBJECTIVE: To study the protective effect and mechanism of salvianolic acid B (Sal B) on glutamate-induced excito-toxicity. METHOD: Glutamate-induced PC12 cell injury model was established to detect the cell survival rate by MTT, the leakage rate of lactic dehydrogenases using LDH, and the cell apoptosis by using AO/EB double staining for fluorescence microscope and PI single staining flow cytometry which was also used to detect the content of intracellular reactive oxygen species. The expression of Caspase-3 protein was also detected by the Western blotting method. RESULT: Sal B is proved to inhibit glutamate-induced PC12 cells from injury and prevent them from releasing LDH within the range from 50 micromol x L(-1) to 200 micromol x L(-1). Meanwhile, Sal B has an effect on significantly reducing the expression of inhibit glutamate-induced active Caspase-3 protein, inhibiting accumulated glutamate-induced ROS and decreasing PC12 cell apoptosis rate within the range from 50 micromol x L(-1) to 200 micromol x L(-1). CONCLUSION: The study proves that Sal B prevented against glutamate-induced cell injury via inhibiting ROS formation and Caspase-3 pathway-dependent apoptosis in PC12 cells.

Two new compounds from the fruits of Buddleja lindleyana with neuroprotective effect.

Two new triterpenoid glycosides, mimengosides H (1) and I (2), were isolated from the fruits of Buddleja lindleyana Fort. Their structures were determined by extensive spectroscopic methods. Neuroprotective effects of these isolates against 1-methyl-4-phenylpyridinium ion-induced neurotoxicity in PC12 cells were evaluated. Pretreatment with compound 1 had potential protective effect in a concentration range from 0.1 to 1 µmol l⁻¹.

Involvement of activation of PI3K/Akt pathway in the protective effects of puerarin against MPP+-induced human neuroblastoma SH-SY5Y cell death.

In an attempt to clarify the protective effect of puerarin on toxin-insulted dopaminergic neuronal death, this present study was carried out by using a typical Parkinson's disease (PD) model - 1-methyl-4-phenylpyridinium iodide (MPP(+))-induced dopaminergic SH-SY5Y cellular model. Data are presented, which showed that puerarin up-regulated Akt phosphorylation in both of MPP(+)-treated and non-MPP(+)-treated cells. The presence of PI3K inhibitor LY294002 completely blocked puerarin-induced activation of Akt phosphorylation. Moreover, puerarin decreased MPP(+)-induced cell death, which was blocked by phosphoinositide 3-kinase (PI3K) inhibitor LY294002. We further demonstrated that puerarin protected against MPP(+)-induced p53 nuclear accumulation, Puma (p53-upregulated mediator of apoptosis) and Bax expression and caspase-3-dependent programmed cell death (PCD). This protection was blocked by applying a PI3K/Akt inhibitor. Additionally, it was Pifithrin-α, but not Pifithrin-µ, which blocked MPP(+)-induced Puma and Bax expression, caspase-3 activation and cell death. Collectively, these data suggest that the activation of PI3K/Akt pathway is involved in the protective effect of puerarin against MPP(+)-induced neuroblastoma SH-SY5Y cell death through inhibiting nuclear p53 accumulation and subsequently caspase-3-dependent PCD. Puerarin might be a potential therapeutic agent for PD.

Gambogenic acid inhibits proliferation of A549 cells through apoptosis inducing through up-regulation of the p38 MAPK cascade.

Gamboge is a dry resin secreted from Garcinia hanburryi, and gambogenic acid (GNA) is one of the main active compounds of gamboge. We have previously demonstrated the anticancer activity of GNA in A549 cells and pointed out its potential effects in anticancer therapies. Previous studies reported that GNA induced apoptosis in many cancer cell lines and inhibited A549 tumor growth in xenograft of nude mice in vivo. However, the anticancer mechanism of GNA has still not been well studied. In this paper, we have investigated whether GNA-induced apoptosis is critically mediated by the p38 mitogen-activated protein kinase (MAPK) pathway. Our findings revealed that GNA could induce apoptosis, inhibit proliferation, down-regulate the expression of p38 and MAPK, increase the activations of caspase-9, caspase-3, and cytochrome c release. Furthermore, using SB203580, an adenosine triphosphate-competitive inhibitor of p38 MAPK, inhibit the expression of p-p38 and the experimental results show that it may promote the occurrence of apoptosis induced by GNA. Taken together, these results suggested that up-regulation of the p38 MAPK cascade may account for the activation of GNA-induced apoptosis.

Paeonol prevents excitotoxicity in rat pheochromocytoma PC12 cells via downregulation of ERK activation and inhibition of apoptosis.

Paeonol, an active component of Moutan Cortex, has been recognized as a potential neuroprotective drug. In the present study, an injury model based on glutamate-induced cell death of rat pheochromocytoma cells was used to investigate the neuroprotective potential of paeonol and its mechanism of action. Our findings showed that paeonol dose-dependently prevented glutamate-induced cell death as evidenced by cell viability, lactate dehydrogenase release, and trypan blue exclusion. In addition, flow cytometry of propidium iodide-stained cells revealed that paeonol pretreatment reduced the level of glutamate-induced apoptosis in pheochromocytoma cells. Paeonol was also able to decrease the glutamate-induced injury of mitochondria by normalization of mitochondrial membrane potential and cytochrome c release. The glutamate-induced activity of caspase-3 and p-ERK were dose-dependently reduced by paeonol pretreatments. Taken together, our data suggest that paeonol develops its neuroprotective effect against glutamate neurotoxicity through inhibition of the apoptotic signaling pathway and upregulation of the p-ERK pathway.

[Study on the chemical composition of triterpenoid from the fruit of Buddleja lindleyana and their neuroprotective activitiy].

OBJECTIVE: To study the chemical composition of triterpenoid from the fruit of Buddleja lindleyana. METHODS: The chemical components were isolated by chromatography. The structures were identified by spectral data. The neuroprotective activity of these compounds were evaluated by using MPP+ induced injury in PC12 cells. RESULTS: 3 compounds were separated and identified as oleanane, alpha-L-msnnopyranoside derive (1), 13, 28-epoxy-3beta,23-dihydroxy-11-oleanene (2), 3, 23, 28-trihydroxyolean-11,13 (18)-diene (3). Compounds 1-3 showed obviously neuroprotective activity. CONCLUSION: The data of compound (1) is reported for the first time. The neuroprotective activities of compounds 1, 2, 3 are reported for the first time.

Involvement of ubiquitin proteasome system in protective mechanisms of Puerarin to MPP(+)-elicited apoptosis.

It has been well documented that dysfunction of ubiquitin proteasome system (UPS) in the neuron exacerbated the Parkinson's disease (PD). However, whether or not UPS is involved in the protective effect of Puerarin on 1-Methyl-4-Phenyl-1, 2, 3, 6-Tetrahydropyridine (MPP(+))-elicited cell death is yet to be elucidated. In this study, treatment of SH-SY5Y cells with 1mM MPP(+)-elicited a characteristic apoptotic cell death and pretreatment with Puerarin protected cells against MPP(+)-induced apoptosis as evidenced by promoting cell viability, improving morphological changes and reducing apoptotic rate. To further explore the potential protective mechanism of Puerarin in MPP(+)-induced SH-SY5Y cell death, UPS activity, mitochondria-dependent apoptosis and caspase-3 activity were measured. Puerarin pretreatment attenuated MPP(+)-induced dysfunction of protease activity, thereby reducing accumulation of ubiquitin-conjugated proteins. Meanwhile, caspase-3 activity was remarkably attenuated by Puerarin. In addition, the ratio of bcl-2/bax was increased by Puerarin in comparison with MPP(+)-treated group. Taken together, these results suggest that Puerarin could protect MPP(+)-induced SH-SY5Y cells from apoptosis by regulating the function of UPS.