Carnosic acid protects against 6-hydroxydopamine-induced neurotoxicity in in vivo and in vitro model of Parkinson’s disease: Involvement of antioxidative enzymes induction

Combining nanoscale magnetic nimodipine liposomes with magnetic resonance image for Parkinson's disease targeting therapy

AIM

To enhance drug targeting and blood-brain barrier penetration for Parkinson's disease (PD), a novel nanoscale magnetic nimodipine (NMD) delivery system was designed and prepared.

MATERIALS & METHODS

The PD rats were established and treated with free NMD or Fe₃O₄-modified NMD liposomes (Fe₃O₄-NMD-lips). Then, factional anisotropy values were measured by MRI to evaluate therapy efficacy.

RESULTS

Fe₃O₄-NMD-lips showed the best neuroprotective effect, and the NMD concentration of lesions was 2.5-fold higher in Fe₃O₄-NMD-lips group than that of free NMD group.

CONCLUSION

These results demonstrated that the magnetic drug system had a great potential to cross the blood-brain barrier and provided a noninvasive and effective therapeutic strategy for PD.

Carnosic Acid Suppresses the H2O2-Induced Mitochondria-Related Bioenergetics Disturbances and Redox Impairment in SH-SY5Y Cells: Role for Nrf2

The phenolic diterpene carnosic acid (CA, C₂₀H₂₈O₄) exerts antioxidant, anti-inflammatory, anti-apoptotic, and anti-cancer effects in mammalian cells. CA activates the nuclear factor erythroid 2-related factor 2 (Nrf2), among other signaling pathways, and restores cell viability in several in vitro and in vivo experimental models. We have previously reported that CA affords mitochondrial protection against various chemical challenges. However, it was not clear yet whether CA would prevent chemically induced impairment of the tricarboxylic acid cycle (TCA) function in mammalian cells. In the present work, we found that a pretreatment of human neuroblastoma SH-SY5Y cells with CA at 1 μM for 12 h prevented the hydrogen peroxide (H₂O₂)-induced impairment of the TCA enzymes (aconitase, α-ketoglutarate dehydrogenase (α-KGDH), succinate dehydrogenase (SDH)) and abolished the inhibition of the complexes I and V and restored the levels of ATP by a mechanism associated with Nrf2. CA also exhibited antioxidant abilities by enhancing the levels of reduced glutathione (GSH) and decreasing the content oxidative stress markers (cellular 8-oxo-2'-deoxyguanosine (8-oxo-dG), and mitochondrial malondialdehyde (MDA), protein carbonyl, and 3-nitrotyrosine). Silencing of Nrf2 by small interfering RNA (siRNA) abrogated the protective effects elicited by CA in mitochondria of SH-SY5Y cells. Therefore, CA prevented the H₂O₂-triggered mitochondrial impairment by an Nrf2-dependent mechanism. The specific role of Nrf2 in ameliorating the function of TCA enzymes function needs further research.

The Role of Reactive Oxygen Species in the Pathogenesis of Alzheimer's Disease, Parkinson's Disease, and Huntington's Disease: A Mini Review

Neurodegenerative diseases affect not only the life quality of aging populations, but also their life spans. All forms of neurodegenerative diseases have a massive impact on the elderly. The major threat of these brain diseases includes progressive loss of memory, Alzheimer's disease (AD), impairments in the movement, Parkinson's disease (PD), and the inability to walk, talk, and think, Huntington's disease (HD). Oxidative stress and mitochondrial dysfunction are highlighted as a central feature of brain degenerative diseases. Oxidative stress, a condition that occurs due to imbalance in oxidant and antioxidant status, has been known to play a vital role in the pathophysiology of neurodegenerative diseases including AD, PD, and HD. A large number of studies have utilized oxidative stress biomarkers to investigate the severity of these neurodegenerative diseases and medications are available, but these only treat the symptoms. In traditional medicine, a large number of medicinal plants have been used to treat the symptoms of these neurodegenerative diseases. Extensive studies scientifically validated the beneficial effect of natural products against neurodegenerative diseases using suitable animal models. This short review focuses the role of oxidative stress in the pathogenesis of AD, PD, and HD and the protective efficacy of natural products against these diseases.

Anti-neuropathic effects of Rosmarinus officinalis L. terpenoid fraction: relevance of nicotinic receptors

Traditional uses and current results highlight the neuroprotective properties of Rosmarinus officinalis L. The compelling need for novel strategies able to relieve neuropathic pain encouraged us to analyze different rosemary leaf extracts in rats following chronic constriction injury (CCI) of sciatic nerve. Ethanol, acetone, and the innovative ultrasound-hexane extractive methods were used to obtain: EE, AE, and for hexane extracts UREprel and URE. Extracts were characterized in terms of typical constituents and repeatedly administered to CCI-rats (13-days treatment, from the day of surgery). URE showed the best efficacy and potency in reducing hypersensitivity to noxious- and non-noxious stimuli and spontaneous pain. URE contained the higher quantity of the terpenoid carnosic acid (CA) and its efficacy was compared to pure CA. Histological analysis of the sciatic nerve revealed that URE prevented axon and myelin derangement, edema and inflammatory infiltrate. In the dorsal horn of the spinal cord, URE did not reduce astrocyte activation. Both the pain reliever and the neuroconservative effects of URE were significantly prevented by the nicotinic receptor (nAChR) antagonist mecamylamine. In conclusion, the hexane-ultrasound rosemary extract is able to reduce neuropathic hypersensitivity and protect nervous tissues. Effectiveness is mainly related to the terpenoid fraction by mechanisms involving nAChRs.

Relevance of carnosic acid to the treatment of several health disorders: Molecular targets and mechanisms

Carnosic acid is a phenolic diterperne compound found in abundance in sage and rosemary, which are both widely used in traditional medicine. Research over the past decade indicates that carnosic acid has multiple bioactive properties including antioxidant, anti-inflammatory and anticancer activities among others. This review summarizes the current in vitro and in vivo data about the efficacy of carnosic acid in the prevention or treatment of various experimental health disorders. The analysis of the literature allows an insight into the participation of numerous signaling pathways modulated by carnosic acid, into its synergistic potential and, thus, into the divergence in cellular mechanisms of action of this molecule.

Phytochemicals as future drugs for Parkinson’s disease: a comprehensive review

Parkinson’s disease (PD) is the second most common chronic neurodegenerative disease that affects motor skills and cognitive performance. The conventional therapeutic approaches for the management of PD are just able to alleviate symptoms. Exploring for achieving novel substances with therapeutic benefits in PD patients is the focus of a wide range of current investigations. The aim of the present study is to comprehensively review phytochemicals with protective or therapeutic activities in PD and focus on their neuropsychopharmacological mechanisms. Various subgroups of polyphenols (flavonoids, phenolic acids, stilbenes, and lignanes) and terpenes are the most abundant groups of phytochemicals with well-established antiparkinsonian effects. Other phytochemical categories, such as alkaloids, cinnamates, carbohydrates, amino acids, and fatty acid amides, also have some representatives with positive effects in PD. Phytochemicals perform their antiparkinsonian effect through several mechanisms of action, including suppressing apoptosis (via the reduction of Bax/Bcl-2, caspase-3, -8, and -9, and α-synuclein accumulation), decreasing dopaminergic neuronal loss and dopamine depletion, reducing the expression of proinflammatory cytokines (such as prostaglandin E2, interleukin-6, interleukin-1β, and nuclear factor-κB), and modulating nuclear and cellular inflammatory signaling, elevation of neurotrophic factors, and improvement of antioxidant status. Plant-derived natural products can be considered as future pharmaceutical drugs or adjuvant treatment with conventional therapeutic approaches to improve their efficacy and alleviate their psychological adverse effects in the management of PD. Well-designed clinical trials are mandatory to evaluate the protective and healing benefits of phytochemicals as promising future drugs in the management of neurodegenerative diseases.

Cloning and Expression Analysis of One Gamma-Glutamylcysteine Synthetase Gene (Hbγ-ECS1) in Latex Production in Hevea brasiliensis

Rubber tree is a major commercial source of natural rubber. Latex coagulation is delayed by thiols, which belong to the important type of antioxidants in laticifer submembrane, and is composed of glutathione (GSH), cysteine, and methionine. The rate-limiting enzyme, γ-ECS, plays an important role in regulating the biosynthesis of glutathione under any environment conditions. To understand the relation between γ-ECS and thiols and to correlate latex flow with one-time tapping and continuous tapping, we cloned and derived the full length of one γ-ECS from rubber tree latex (Hbγ-ECS1). According to qPCR analysis, the expression levels of Hbγ-ECS1 were induced by tapping and Ethrel stimulation, and the expression was related to thiols content in the latex. Continuous tapping induced injury, and the expression of HbγECS1 increased with routine tapping and Ethrel-stimulation tapping (more intensive tapping). According to expression in long-term flowing latex, the gene was related to the duration of latex flow. HbγECS1 was expressed in E. coli Rosetta using pET-sumo as an expression vector and the recombinant enzyme was purified; then we achieved 0.827 U/mg specific activity and about 66 kDa molecular weight. The present study can help us understand the complex role of Hbγ-ECS in thiols biosynthesis, which is influenced by tapping.

Carnosic acid protects SH-SY5Y cells against 6-hydroxydopamine-induced cell death through upregulation of parkin pathway

Parkin is a Parkinson's disease (PD)-linked gene that plays an important role in the ubiquitin-proteasome system (UPS). This study explored whether carnosic acid (CA) from rosemary protects against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity via upregulation of parkin in vivo and in vitro. We found that the reduction in proteasomal activity by 6-OHDA was attenuated in SH-SY5Y cells pretreated with 1 μM CA. Immunoblots showed that CA reversed the induction of ubiquitinated protein and the reduction of PTEN-induced putative kinase 1 (PINK1) and parkin protein in 6-OHDA-treated SH-SY5Y cells and rats. Moreover, in a transgenic OW13 Caenorhabditis elegans model of PD that expresses human α-synuclein in muscle cells, CA reduced α-synuclein accumulation in a dose-dependent manner. In cells pretreated with the proteasome inhibitor MG132, CA no longer reversed the 6-OHDA-mediated induction of cleavage of caspase 3 and poly(ADP)-ribose polymerase and no longer reversed the suppression of proteasome activity. When parkin expression was silenced by use of small interfering RNA, the ability of CA to inhibit apoptosis and induce proteasomal activity was significantly reduced. The reduction in 6-OHDA-induced neurotoxicity by CA was associated with the induction of parkin, which in turn upregulated the UPS and then decreased cell death.

Carnosic Acid Affords Mitochondrial Protection in Chlorpyrifos-Treated Sh-Sy5y Cells

Carnosic acid (CA; C20H28O4) is a phenolic diterpene found in rosemary (Rosmarinus officinalis L.) and exhibits protective properties, e.g., antioxidant, anti-inflammatory, antitumor, and antimicrobial activities. In this context, CA has been viewed as a neuroprotective agent due to its ability in rescuing neuronal cells from pro-oxidant and pro-apoptotic challenges. In the present work, we found that CA pretreatment at 1 µM for 12 h suppressed the mitochondria-related pro-oxidant and mitochondria-dependent pro-apoptotic effects of chlorpyrifos (CPF) in human neuroblastoma SH-SY5Y cells. CA prevented mitochondrial membrane potential disruption and decreased the levels of oxidative stress markers in mitochondrial membranes obtained from cells exposed to CPF. CA also inhibited cytochrome c release and activation of the caspases-9 and -3, as well as decreased DNA fragmentation, in CPF-treated cells. CA upregulated the content of glutathione (GSH) in mitochondria by a mechanism involving the activation of the phosphoinositide-3-kinase (PI3K)/Akt/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, since inhibition of PI3K/Akt or silencing of Nrf2 using siRNA strategy abolished the protection exerted by CA in SH-SY5Y cells. Therefore, CA protected mitochondria of SH-SY5Y cells through the activation of the PI3K/Akt/Nrf2 axis, causing upregulation of the mitochondrial GSH content and consequent antioxidant and anti-apoptotic effects.

Carnosic Acid Attenuates 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells by Inducing Autophagy Through an Enhanced Interaction of Parkin and Beclin1

Enhanced removal of abnormal protein aggregates or injured organelles through autophagy is related to neuroprotection in Parkinson's disease. In this study, we explored whether the induction of autophagy is associated with the neuroprotection of rosemary carnosic acid (CA) against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in SH-SY5Y cells. The results indicated that cells treated with CA had increased protein levels of parkin and autophagy-related markers, including phosphatidylinositol 3-kinase p100, Beclin1, autophagy-related gene 7, and microtubule-associated protein 1 light chain 3-II, as well as enhanced formation of autophagic vacuoles. Treatment of cells with 6-OHDA decreased the levels of parkin and the autophagy markers, but CA pretreatment reversed these effects. However, wortmannin (an autophagosome formation blocker) pretreatment attenuated the effect of CA. After CA pretreatment, the induction of cleaved caspase 3, cleaved poly-ADP ribose polymerase, and nuclear condensation by 6-OHDA were alleviated. Both wortmannin and bafilomycin A1 (an autophagosome-lysosome fusion blocker) inhibited the anti-apoptosis effects of CA. Additionally, we performed immunoprecipitation with anti-parkin antibody and found that the interaction of parkin and Beclin1 protein was reduced by 6-OHDA but that this effect was reversed in cells pretreated with CA. Moreover, transfection of parkin siRNA in cells inhibited the ability of CA to alleviate 6-OHDA-decreased autophagy-related markers and nuclear condensation. In conclusion, CA protects against 6-OHDA-induced apoptosis by inducing autophagy through the interaction of parkin and Beclin1. These results provide a future strategy for use of CA in the prevention of Parkinson's disease.

The Therapeutic Potential of Rosemary (Rosmarinus officinalis) Diterpenes for Alzheimer's Disease

Rosemary (Rosmarinus officinalis L.) is one of the most economically important species of the family Lamiaceae. Native to the Mediterranean region, the plant is now widely distributed all over the world mainly due to its culinary, medicinal, and commercial uses including in the fragrance and food industries. Among the most important group of compounds isolated from the plant are the abietane-type phenolic diterpenes that account for most of the antioxidant and many pharmacological activities of the plant. Rosemary diterpenes have also been shown in recent years to inhibit neuronal cell death induced by a variety of agents both in vitro and in vivo. The therapeutic potential of these compounds for Alzheimer's disease (AD) is reviewed in this communication by giving special attention to the chemistry of the compounds along with the various pharmacological targets of the disease. The multifunctional nature of the compounds from the general antioxidant-mediated neuronal protection to other specific mechanisms including brain inflammation and amyloid beta (Aβ) formation, polymerisation, and pathologies is discussed.

Plant-Derived Natural Products for Parkinson's Disease Therapy

Plant-derived natural products have made their own niche in the treatment of neurological diseases since time immemorial. Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, has no cure and the treatment available currently is symptomatic. This chapter thoughtfully and objectively assesses the scientific basis that supports the increasing use of these plant-derived natural products for the treatment of this chronic and progressive disorder. Proper considerations are made on the chemical nature, sources, preclinical tests and their validity, and mechanisms of behavioural or biochemical recovery observed following treatment with various plants derived natural products relevant to PD therapy. The scientific basis underlying the neuroprotective effect of 6 Ayurvedic herbs/formulations, 12 Chinese medicinal herbs/formulations, 33 other plants, and 5 plant-derived molecules have been judiciously examined emphasizing behavioral, cellular, or biochemical aspects of neuroprotection observed in the cellular or animal models of the disease. The molecular mechanisms triggered by these natural products to promote cell survivability and to reduce the risk of cellular degeneration have also been brought to light in this study. The study helped to reveal certain limitations in the scenario: lack of preclinical studies in all cases barring two; heavy dependence on in vitro test systems; singular animal or cellular model to establish any therapeutic potential of drugs. This strongly warrants further studies so as to reproduce and confirm these reported effects. However, the current literature offers scientific credence to traditionally used plant-derived natural products for the treatment of PD.

Protective effect of carnosic acid against paraquat-induced redox impairment and mitochondrial dysfunction in SH-SY5Y cells: Role for PI3K/Akt/Nrf2 pathway

Carnosic acid (CA) is a phenolic diterpene isolated from Rosmarinus officinalis and exerts anti-inflammatory, antioxidant, and anticarcinogenic activities in different cell types. It has been reported that CA is able to cause protective effects on experimental models of neurodegeneration. However, the exact mechanism by which CA prevents neuronal degeneration remains to be better studied. We investigated here whether there is a role for CA as a neuroprotective agent in a paraquat (PQ) model of Parkinson's disease (PD) regarding cellular and mitochondrial-related redox parameters. SH-SY5Y cells were treated with CA for 12h and were exposed to 100 μM PQ for 24h. It was found that CA at different concentrations prevented the effects of PQ on cell viability and redox parameters. CA alleviated reactive oxygen and nitrogen species production elicited by PQ, as well as decreased the toxic effect on mitochondrial function. Inhibition of Pi3K/Akt pathway with LY294002 or silencing of Nrf2 expression partially blocked the reversal of redox impairment induced by CA. Therefore, CA activated Nrf2 through modulation of PI3K/Akt pathway resulting in increased levels of antioxidant enzymes and consequent neuroprotection. Thus, CA may be viewed as a potential neuroprotective agent to be used in cases of Parkinson's disease (PD).

The Role of Dopamine and Its Dysfunction as a Consequence of Oxidative Stress

Dopamine is a neurotransmitter that is produced in the substantia nigra, ventral tegmental area, and hypothalamus of the brain. Dysfunction of the dopamine system has been implicated in different nervous system diseases. The level of dopamine transmission increases in response to any type of reward and by a large number of strongly additive drugs. The role of dopamine dysfunction as a consequence of oxidative stress is involved in health and disease. Introduce new potential targets for the development of therapeutic interventions based on antioxidant compounds. The present review focuses on the therapeutic potential of antioxidant compounds as a coadjuvant treatment to conventional neurological disorders is discussed.