Qiao Zhang

Anti-proliferative and pro-apoptotic activities of Alpinia oxyphylla on HepG2 cells through ROS-mediated signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE Fructus Alpiniae oxyphyllae (A. oxyphylla) is a traditional herb which is widely used in East Asian for the treatment of dyspepsia, diarrhea, abdominal pain, poor memory, inflammatory conditions and cancer. MATERIALS AND METHODS The cytotoxic activities of ethanol extract (EE) and five extract layers including petroleum ether (PE), dichloromethane (DCLM), acetoacetate (EtOAc), n-Butanol (n-Bu) and water fractions (WF) of A. oxyphylla were tested on HepG2, SW480, MCF-7, K562 and HUVEC cell lines using MTT assay and LDH release assay. The component analysis was performed on HPLC with gradient elution. Hoechst 33342 staining, DCFH-DA fluorescence microscopy, flow cytometry analysis, western blot and migration assays were carried out to determine the anti-cancer mechanisms of PE. RESULTS MTT analysis showed that EE, PE and DCLM could inhibit cell proliferation on HepG2, SW480, MCF-7, K562 and HUVEC cell lines, especially PE fraction. HPLC analysis pointed out five main components which may contribute to the anti-proliferative activity of PE. Further study showed that PE increased LDH release, induced apoptosis, disrupted mitochondrial membrane potential and elevated intracellular reactive oxygen species (ROS) in HepG2 cells, whereas the antioxidant N-acetyl-l-cysteine (NAC) prevented PE-induced ROS generation. The results of western blot revealed that PE induced apoptosis in HepG2 cells by enhancing Bax/Bcl-2 ratio, increasing cytochrome c in cytosol and activating caspase-3/9. Meanwhile, high levels of ROS could induce DNA damage-mediated protein expression, AKT, ERK inactivation and SAPKs activation. Furthermore, PE conspicuously blocked the migration of HUVEC cells. CONCLUSION The present results demonstrated that PE induced apoptosis in HepG2 cells may be via a ROS-mediated signaling pathway.

Neuroprotective effects of Kukoamine B against hydrogen peroxide-induced apoptosis and potential mechanisms in SH-SY5Y cells

Oxidative stress mediates the cell damage in several neurodegenerative diseases, including multiple sclerosis, Alzheimers disease (AD) and Parkinsons disease (PD). This study aimed at investigating the protective effects of Kukoamine B (KuB) against hydrogen peroxide (H2O2) induced cell injury and potential mechanisms in SH-SY5Y cells. Our results revealed that treatment with KuB prior to H2O2 exposure effectively increased the cell viability, and restored the mitochondria membrane potential (MMP). Furthermore, KuB enhanced the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreased the malondialdehyde (MDA) content. Moreover, KuB minimized the ROS formation and inhibited mitochondria-apoptotic pathway, MAPKs (p-p38, p-JNK, p-ERK) pathways, but activated PI3K-AKT pathway. In conclusion, we believed that KuB may potentially serve as an agent for prevention of several human neurodegenerative and other disorders caused by oxidative stress.

Neuroprotection by Kukoamine A against oxidative stress may involve N-methyl-D-aspartate receptors.

BACKGROUND Accumulative evidences have indicated that oxidative-stress and over-activation of N-methyl-d-aspartate receptors (NMDARs) are important mechanisms of brain injury. This study investigated the neuroprotection of Kukoamine A (KuA) and its potential mechanisms. METHODS Molecular docking was used to discover KuA that might have the ability of blocking NMDARs. Furthermore, the MTT assay, the measurement of LDH, SOD and MDA, the flow cytometry for ROS, MMP and Annexin V-PI double staining, the laser confocal microscopy for intracellular Ca2+ and western-blot analysis were employed to evaluate the neuroprotection of KuA. RESULTS KuA attenuated H2O2-induced cell apoptosis, LDH release, ROS production, MDA level, MMP loss, and intracellular Ca2+ overload (both induced by H2O2 and NMDA), as well as increased the SOD activity. In addition, it could modulate the apoptosis-related proteins (Bax, Bcl-2, p53, procaspase-3 and procaspase-9), the SAPKs (ERK, p38), AKT, CREB, NR2A and NR2B expression. CONCLUSIONS All the results indicated that KuA has the ability of anti-oxidative stress and this effect may partly via blocking NMDARs in SH-SY5Y cells. GENERAL SIGNIFICANCE KuA might have the potential therapeutic interventions for brain injury.

Neuroprotective effects of Kukoamine A on neurotoxin-induced Parkinson's model through apoptosis inhibition and autophagy enhancement

&NA; Parkinsons disease (PD) is characterized by the loss of dopaminergic neurons in substantia nigra (SN). Our previous study demonstrated Kukoamine A to exhibit strong neuroprotective effects through anti‐oxidative stress, anti‐inflammation, anti‐excitoxicity. In the present study, MPP+ and MPTP‐induced PD models of cell and animal were used to investigate the effects of KuA on PD. Our results demonstrated that KuA ameliorated cell loss and mitochondrial membrane potential (MMP) loss, and inhibited Bax/Bcl‐2 ratio and MAPKs family that were induced by MPP+. In addition, animal experiments showed that KuA improved the motor function and neuronal activity, and increased the positive cells of tyrosine hydroxylase (TH) both in substantia nigra (SN) and striatum (Str). Moreover, KuA could decrease the expression of &agr;‐synuclein in brain. Finally, KuA exerted apparent autophagy enhancement both in vitro and in vivo. In conclusion, KuA protected against neurotoxin‐induced PD due to the apoptosis inhibition and autophagy enhancement, suggesting that KuA treatment might represent a neuroprotective treatment for PD. Graphical abstract Figure. No caption available. HighlightsIt was the first time to report that KuA have effects on PD both in vitro and in vivo.It was the first time to report that KuA could induce autophagy both in vitro and in vivo.The action mechanisms of KuA on PD were involved in multiple signalling pathways.KuA might be a promising neuroprotective agent for the prevention of PD.

Kukoamine B, an amide alkaloid, protects against NMDA-induced neurotoxicity and potential mechanisms in vitro

A major cause of cerebral ischemia is overactivation of the N-methyl-D-aspartate receptors (NMDARs). Therefore, NMDAR antagonists are needed for the treatment of cerebral ischemia. In our research, KuB protected the SH-SY5Y cells against NMDA-induced injury, apoptosis, LDH release and MMP loss. In addition, KuB could decrease MDA levels while increasing SOD activity. Meanwhile, KuB decreased NADPH oxidase-mediated ROS production, inhibited Ca(2+) influx, and increased the Bcl-2/Bax ratio. Furthermore, KuB not only down-regulated expression of the NR2B subunit of NMDAR but also actively modulated expression of the signaling molecules downstream of NR2B, including p-ERK, p-CREB, p-AKT and SAPKs. Finally, docking results showed that KuB had a high affinity for NR2B-containing NMDARs. Therefore, we conclude that KuB protected the SH-SY5Y cells from NMDA-induced injury likely by antagonizing NMDARs and reducing oxidative stress.

Neuroprotective effects of Kukoamine A against cerebral ischemia via antioxidant and inactivation of apoptosis pathway

ABSTRACT Kukoamine A (KuA) is a bioactive compound, which is known for a hypotensive effect. Recent studies have shown that KuA has anti‐oxidative effect and anti‐apoptosis stress in vitro. However, its neuroprotective effect in rats with cerebral ischemia is still unclear. In the study, we investigated whether KuA could attenuate cerebral ischemia induced by permanent middle cerebral artery occlusion (pMCAO) in rats. Results revealed that KuA could significantly reduce infarct volume both pre‐treatment and post‐treatment, and increase corresponding Garcia neurological scores. Acute KuA postconditioning not only significantly reduced cerebral infarct volume, brain water content and improved neurological deficit scores, but also decreased the number of TUNEL‐positive cells. Moreover, it markedly increased the activities of Cu/Zn‐SOD and Mn‐SOD, reduced levels of MDA and H2O2. Increased expressions of caspase‐3, cytochrome c and the ratio of Bax/Bcl‐2 were significantly alleviated with KuA treatment. These findings demonstrated that KuA was able to protect the brain against injury induced by pMCAO via mitochondria mediated apoptosis signaling pathway. HIGHLIGHTSKuA could reduce the infarct volume both in pre‐occlusion and post‐occlusion.KuA could attenuate brain swelling and the number of apoptotic cells in the ischemic brain.The potential mechanisms may be involved in modulating oxidative status and inactivation mitochondrial apoptosis pathway.

Erratum to: Caffeoylquinic Acid Derivatives Protect SH-SY5Y Neuroblastoma Cells from Hydrogen Peroxide-Induced Injury Through Modulating Oxidative Status

Oxidative stress has been confirmed as a contribution to the pathogenesis and pathophysiology of many neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Caffeoylquinic acids (CQAs) are considered to have anti-oxidative stress ability in a previous study, but the structure–activity relationships (SARs) of CQAs in neuroprotective effects are still unclear. In the present study, we primarily expound the SARs of CQAs in counteracting H2O2-induced injury in SH-SY5Y cells. We found that CQAs (1–10) represented the protection of SH-SY5Y cells against H2O2-induced injury in varying degrees and malonyl groups could obviously increase the anti-oxidative stress ability of CQAs. Intensive studies of 4,5-O-dicaffeoyl-1-O-(malic acid methyl ester)-quinic acid (MDCQA) indicated that the mechanisms could potentially involve activation of endogenous antioxidant enzymes and the regulation of the phosphorylation of MAPKs and AKT. In conclusion, MDCQA could serve as a neuroprotective agent with a potential to attenuate oxidative stress.

Ethanol extract and its dichloromethane fraction of Alpinia oxyphylla Miquel exhibited hepatoprotective effects against CCl4-induced oxidative damage in vitro and in vivo with the involvement of Nrf2

Alpinia oxyphylla Miq. (A. oxyphylla), as a kind of medicine which also be used as food, is widely used in East Asian for the treatment of dyspepsia, diarrhea, abdominal pain and deficiency cold of spleen and stomach. This study aimed to investigate the protective effects of ethanol extract (EE) and its dichloromethane fraction (DM) of A. oxyphylla, which are rich in phenolic compounds, against CCl4-induced hepatic injury in vitro and in vivo. EE, DM and silymarin ameliorated CCl4-induced decrease of cell viability and increase of reactive oxygen species (ROS) in HepG2 cells. The CCl4-induced changes of glutathione (GSH) and methane dicarboxylic aldehyde (MDA) levels, and the decrease of superoxide dismutase (SOD) and catalase (CAT) activities were all restored with the pretreatment of EE, DM and silymarin. The results in liver injury model in rats showed that EE, DM and silymarin could significant decrease the levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and total bilirubin than the model group. Liver histopathology revealed that EE and DM attenuated the incidence of liver lesions triggered by CCl4 intoxication. They also effectively relieved CCl4-induced oxidative damage. Western blot analysis indicated NF-E2-related factor (Nrf2) pathway played an critical role in the protection of EE and DM against CCl4-induced oxidative stress. In conclusion, the extracts from A. oxyphylla might be used as hepatoprotective agents.

Non-alkaloids extract from Stemona sessilifolia enhances the activity of chemotherapeutic agents through P-glycoprotein-mediated multidrug-resistant cancer cells

One of the major impediments to the successful treatment of cancer is the development of resistant cancer cells, which could cause multidrug resistance (MDR), and overexpression of ABCB1/P-glycoprotein (P-gp) is one of the most common causes of MDR in cancer cells. Recently, natural products or plant-derived chemicals have been investigated more and more widely as potential multidrug-resistant (MDR) reversing agents. The current study demonstrated for the first time that non-alkaloids extract from Stemona sessilifolia significantly reversed the resistance of chemotherapeutic agents, adriamycin, paclitaxel and vincristine to MCF-7/ADR cells compared with MCF-7/S cells in a dose-dependent manner. The results obtained from these studies indicated that the non-alkaloids extract from S. sessilifolia plays an important role in reversing MDR of cancer as a P-gp modulator in vitro and may be effective in the treatment of multidrug-resistant cancers.