Honokiol protects rat brain from focal cerebral ischemia–reperfusion injury by inhibiting neutrophil infiltration and reactive oxygen species production

Farrerol Alleviates Cerebral Ischemia-Reperfusion Injury by Promoting Neuronal Survival and Reducing Neuroinflammation

Ischemia-reperfusion (I/R) injury is a key influencing factor in the outcome of stroke. Inflammatory response, oxidative stress, and neuronal apoptosis are among the main factors that affect the progression of I/R injury. Farrerol (FAR) is a natural compound that can effectively inhibit the inflammatory response and oxidative stress. However, the role of FAR in cerebral I/R injury remains unknown. In this study, we found that FAR reduced brain injury and neuronal viability after cerebral I/R injury. Meanwhile, administration of FAR also reduced the inflammatory response of microglia after brain injury. Mechanistically, FAR treatment directly reduced neuronal death after oxygen glucose deprivation/re-oxygenation (OGD/R) through enhancing cAMP-response element binding protein (CREB) activation to increase the expression of downstream neurotrophic factors and anti-apoptotic genes. Moreover, FAR decreased the activation of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, inhibited microglia activation, and reduced the production of inflammatory cytokines in microglia after OGD/R treatment or LPS stimulation. The compromised inflammatory response by FAR directly promoted the survival of neurons after OGD/R. In conclusion, FAR exerted a protective effect on cerebral I/R injury by directly decreasing neuronal death through upregulating CREB expression and attenuating neuroinflammation. Therefore, FAR could be a potentially effective drug for the treatment of cerebral I/R injury.

Pathophysiology and management of testicular ischemia/reperfusion injury: Lessons from animal models

Testicular torsion is a urological emergency that involves the twisting of the spermatic cord along its course. Compelling pieces of evidence have implicated oxidative stress-sensitive signaling in pathogenesis of testicular I/R injury. Although, surgical detorsion is the mainstay management; blockade of the pathways involved in the pathogenesis may improve the surgical outcome. Experimental studies using various testicular I/R models have been reported in a bid to explore the mechanisms associated with testicular I/R and evaluate the benefits of potential therapeutic measures; however, most are limited by their shortcomings. Thus, this review was intended to describe the details of the available testicular I/R models as well as their merits and drawbacks, the pathophysiological basis and consequences of testicular I/R, and the pharmacological agents that have being proposed to confer testicular benefits against testicular I/R. This provides an understanding of the pathophysiological events and available models used in studying testicular I/R. In addition, this research provides evidence-based molecules with therapeutic potentials as well as their mechanisms of action in testicular I/R.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

SIRT3 Activator Honokiol Inhibits Th17 Cell Differentiation and Alleviates Colitis

BACKGROUND

Honokiol (HKL), a natural extract of the bark of the magnolia tree and an activator of the mitochondrial protein sirtuin-3 (SIRT3), has been proposed to possess anti-inflammatory effects. This study investigated the inhibitory effects of HKL on T helper (Th) 17 cell differentiation in colitis.

METHODS

Serum and biopsies from 20 participants with ulcerative colitis (UC) and 18 healthy volunteers were collected for the test of serum cytokines, flow cytometry analysis (FACS), and relative messenger RNA (mRNA) levels of T cell subsets, as well as the expression of SIRT3 and phosphorylated signal transducer and activator of transcription/retinoic acid-related orphan nuclear receptor γt (p-STAT3/RORγt) signal pathway in colon tissues. In vitro, naïve clusters of differentiation (CD) 4 + T cells isolated from the mouse spleen differentiated to subsets including Th1, Th2, Th17, and regulatory T (Treg) cells. Peripheral blood monocytes (PBMCs) from healthy volunteers were induced to the polarization of Th17 cells. After HKL treatment, changes in T cell subsets, related cytokines, and transcription factors were measured. The dextran sulfate sodium (DSS)-induced colitis and interleukin (IL)-10-deficient mice were intraperitoneally injected with HKL. These experiments were conducted to study the effect of HKL on the development, cytokines, and expression of signaling pathway proteins in colitis.

RESULTS

Patients with UC had higher serum IL-17 and a higher proportion of Th17 differentiation in blood compared with healthy participants; while IL-10 level and the proportion of Treg cells were lower. Higher relative mRNA levels of RORγt and a lower SIRT3 expression in colon tissues were observed. In vitro, HKL had little effect on the differentiation of naïve CD4+ T cells to Th1, Th2, or Treg cells, but it downregulated IL-17 levels and the Th17 cell ratio in CD4+ T cells from the mouse spleen and human PBMCs under Th17 polarization. Even with a STAT3 activator, HKL still significantly inhibited IL-17 levels. In DSS-induced colitis mice and IL-10 deficient mice treated with HKL, the length of the colon, weight loss, disease activity index, and histopathological scores were improved, IL-17 and IL-21 levels, and the proportion of Th17 cells were decreased. Sirtuin-3 expression was increased, whereas STAT3 phosphorylation and RORγt expression were inhibited in the colon tissue of mice after HKL treatment.

CONCLUSIONS

Our study demonstrated that HKL could partially protect against colitis by regulating Th17 differentiation through activating SIRT3, leading to inhibition of the STAT3/RORγt signaling pathway. These results provide new insights into the protective effects of HKL against colitis and may facilitate the research of new drugs for inflammatory bowel disease.

Neuropharmacological potential of honokiol and its derivatives from Chinese herb Magnolia species: understandings from therapeutic viewpoint

Honokiol is a neolignan biphenol found in aerial parts of the Magnolia plant species. The Magnolia plant species traditionally belong to China and have been used for centuries to treat many pathological conditions. Honokiol mitigates the severity of several pathological conditions and has the potential to work as an anti-inflammatory, anti-angiogenic, anticancer, antioxidant, and neurotherapeutic agent. It has a long history of being employed in the healthcare practices of Southeast Asia, but in recent years, a greater scope of research has been conducted on it. Plenty of experimental evidence suggests it could be beneficial as a neuroprotective bioactive molecule. Honokiol has several pharmacological effects, leading to its exploration as a potential therapy for neurological diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), cerebral ischemia, anxiety, depression, spinal cord injury, and so on. So, based on the previous experimentation reports, our goal is to discuss the neuroprotective properties of honokiol. Besides, honokiol derivatives have been highlighted recently as possible therapeutic options for NDs. So, this review focuses on honokiol's neurotherapeutic actions and toxicological profile to determine their safety and potential use in neurotherapeutics.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

Effect of Honokiol on culture time and survival of Alzheimer's disease iPSC-derived neurons

Introduction

Patient-derived induced pluripotent stem cells (iPSCs) have been widely used as disease models to test new therapeutic strategies. Moreover, the regenerative potential of stem cells can be improved with the use of biologically active compounds. Our study was designed to explore the effect of honokiol, a small polyphenol molecule extracted from Magnolia officinalis, on the survival and culture time of iPSC-derived neurons from a sporadic Alzheimer's disease (AD) patient. This study aimed to generate iPSCs from peripheral blood mononuclear cells (PBMCs) of an AD patient using episomal plasmids with a nucleofector system and differentiate them into neurons. These iPSC-derived neurons were used to investigate the effect of honokiol extracted from M. officinalis on their survival and long-term cultures.

Methods

IPSCs were generated from PBMCs of an AD patient by introducing Oct-3/4, Sox2, Klf4, L-Myc, and Lin28 using NucleofectorTM Technology. Differentiation of neurons derived from iPSCs was carried out using inducers and recognized by biomarkers. The viability of iPSC-derived neurons with the addition of honokiol extracted from the bark of M. officinalis was determined by the MTT analytical kit.

Results

IPSCs were generated by reprogramming AD patient-derived PBMCs and subsequently converted into neurons. The survival and growth of iPSC-derived neurons were significantly enhanced by adding honokiol in the experiment conditions.

Conclusion

AD iPSC-derived neurons had a high viability rate when cultured in the presence of honokiol. These results have shown that AD iPSC-derived neurons can be an excellent model for screening neurotrophic agents and improving the conditions for long-term cultures of human iPSC-derived neurons. Honokiol proves to be a potential candidate for cellular therapeutics against neurodegenerative disorders.

Inhibitory Effects of Honokiol on Substantia Gelatinosa Neurons of the Trigeminal Subnucleus Caudalis in Juvenile Mice

Inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine are known to be abundant in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc). Thus, it has been recognized as an initial synaptic site for regulating orofacial nociceptive stimuli. Honokiol, a principal active ingredient derived from the bark of Magnolia officinalis, has been exploited in traditional remedies with multiple biological effects, including anti-nociception on humans. However, the anti-nociceptive mechanism of honokiol on SG neurons of the Vc remains fully elusive. In this study, effects of honokiol on SG neurons of the Vc in mice were investigated using the whole-cell patch-clamp method. In a concentration-dependent manner, honokiol significantly enhanced frequencies of spontaneous postsynaptic currents (sPSCs) that were independent of action potential generation. Notably, honokiol-induced increase in the frequency of sPSCs was attributed to the release of inhibitory neurotransmitters through both glycinergic and GABAergic pre-synaptic terminals. Furthermore, higher concentration of honokiol induced inward currents that were noticeably attenuated in the presence of picrotoxin (a GABAA receptor antagonist) or strychnine (a glycine receptor antagonist). Honokiol also exhibited potentiation effect on glycine- and GABAA receptor-mediated responses. In inflammatory pain model, the increase in frequency of spontaneous firing on SG neurons induced by formalin was significantly inhibited by the application of honokiol. Altogether, these findings indicate that honokiol might directly affect SG neurons of the Vc to facilitate glycinergic and GABAergic neurotransmissions and modulate nociceptive synaptic transmission against pain. Consequently, the inhibitory effect of honokiol in the central nociceptive system contributes to orofacial pain management.

Honokiol alleviated neurodegeneration by reducing oxidative stress and improving mitochondrial function in mutant SOD1 cellular and mouse models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting both upper and lower motor neurons (MNs) with large unmet medical needs. Multiple pathological mechanisms are considered to contribute to the progression of ALS, including neuronal oxidative stress and mitochondrial dysfunction. Honokiol (HNK) has been reported to exert therapeutic effects in several neurologic disease models including ischemia stroke, Alzheimer's disease and Parkinson's disease. Here we found that honokiol also exhibited protective effects in ALS disease models both in vitro and in vivo. Honokiol improved the viability of NSC-34 motor neuron-like cells that expressed the mutant G93A SOD1 proteins (SOD1-G93A cells for short). Mechanistical studies revealed that honokiol alleviated cellular oxidative stress by enhancing glutathione (GSH) synthesis and activating the nuclear factor erythroid 2-related factor 2 (NRF2)-antioxidant response element (ARE) pathway. Also, honokiol improved both mitochondrial function and morphology via fine-tuning mitochondrial dynamics in SOD1-G93A cells. Importantly, honokiol extended the lifespan of the SOD1-G93A transgenic mice and improved the motor function. The improvement of antioxidant capacity and mitochondrial function was further confirmed in the spinal cord and gastrocnemius muscle in mice. Overall, honokiol showed promising preclinical potential as a multiple target drug for ALS treatment.

Sirt3 mediates the benefits of exercise on bone in aged mice

Exercise in later life is important for bone health and delays the progression of osteoporotic bone loss. Osteocytes are the major bone cells responsible for transforming mechanical stimuli into cellular signals through their highly specialized lacunocanalicular networks (LCN). Osteocyte activity and LCN degenerate with aging, thus might impair the effectiveness of exercise on bone health; however, the underlying mechanism and clinical implications remain elusive. Herein, we showed that deletion of Sirt3 in osteocytes could impair the formation of osteocyte dendritic processes and inhibit bone gain in response to exercise in vivo. Mechanistic studies revealed that Sirt3 regulates E11/gp38 through the protein kinase A (PKA)/cAMP response element-binding protein (CREB) signaling pathway. Additionally, the Sirt3 activator honokiol enhanced the sensitivity of osteocytes to fluid shear stress in vitro, and intraperitoneal injection of honokiol reduced bone loss in aged mice in a dose-dependent manner. Collectively, Sirt3 in osteocytes regulates bone mass and mechanical responses through the regulation of E11/gp38. Therefore, targeting Sirt3 could be a novel therapeutic strategy to prevent age-related bone loss and augment the benefits of exercise on the senescent skeleton.

BACE-1 Inhibitors Targeting Alzheimer's Disease

The accumulation of amyloid-β (Aβ) is the main event related to Alzheimer's disease (AD) progression. Over the years, several disease-modulating approaches have been reported, but without clinical success. The amyloid cascade hypothesis evolved and proposed essential targets such as tau protein aggregation and modulation of β-secretase (β-site amyloid precursor protein cleaving enzyme 1 - BACE-1) and γ-secretase proteases. BACE-1 cuts the amyloid precursor protein (APP) to release the C99 fragment, giving rise to several Aβ peptide species during the subsequent γ-secretase cleavage. In this way, BACE-1 has emerged as a clinically validated and attractive target in medicinal chemistry, as it plays a crucial role in the rate of Aβ generation. In this review, we report the main results of candidates in clinical trials such as E2609, MK8931, and AZD-3293, in addition to highlighting the pharmacokinetic and pharmacodynamic-related effects of the inhibitors already reported. The current status of developing new peptidomimetic, non-peptidomimetic, naturally occurring, and other class inhibitors are demonstrated, considering their main limitations and lessons learned. The goal is to provide a broad and complete approach to the subject, exploring new chemical classes and perspectives.

Sanhua decoction: Current understanding of a traditional herbal recipe for stroke

Both thrombolytic and endovascular therapies are optimal treatment options for patients with acute ischemic stroke, but only less than half of these patients can benefit from these treatments. Traditional Chinese medicine has a long history of successfully managing ischemic stroke using both herbal and physical therapeutics. Among herbal recipes, Sanhua decoction (SHD) is one of the classical prescriptions for ischemic stroke. The present review aimed to summarize evidence from both clinical and basic research to demonstrate its efficacy in managing ischemic stroke and the potential mechanisms underlying its therapeutic effects, which will provide evidence on the therapeutic effect of this herbal recipe and guide future studies on this recipe. SHD is composed of four herbs, Rheum palmatum L. [Polygonaceae], Magnolia officinalis Rehder & E.H.Wilson [Magnoliaceae], Citrus × aurantium L. [Rutaceae], Hansenia weberbaueriana (Fedde ex H.Wolff) Pimenov & Kljuykov [Apiaceae]. We found that the majority of clinical studies on SHD are case reports and they showed positive therapeutic effect of SHD on both acute and chronic ischemic stroke. There are over 40 bioactive compounds identified in SHD, but few experimental studies have examined their individual molecular mechanisms. As an extract of SHD, it improves neurological functions through suppressing inflammation, protecting the blood brain barrier from degradation, restoring the number of neural stem cells, inhibiting apoptosis and brain edema, scavenging oxygen free radicals, and regulating the brain-gut axis. These will lay the theoretical foundation for future studies on this prescription and its clinical application. Future research may need to confirm its clinical efficacy in large-scale clinical trials and to disentangle its bioactive compounds and their potential mechanisms.

The Neuropharmacological Effects of Magnolol and Honokiol: A Review of Signal Pathways and Molecular Mechanisms

Magnolol and honokiol are natural lignans with good physiological effects. As the main active substances derived from Magnolia officinalis, their pharmacological activities have attracted extensive attention. It is reported that both of them can cross the blood-brain barrier (BBB) and exert neuroprotective effects through a variety of mechanisms. This suggests that these two ingredients can be used as effective therapeutic compounds to treat a wide range of neurological diseases. This article provides a review of the mechanisms involved in the therapeutic effects of magnolol and honokiol in combating diseases, such as cerebral ischemia, neuroinflammation, Alzheimer's disease, and brain tumors, as well as psychiatric disorders, such as anxiety and depression. Although magnolol and honokiol have the pharmacological effects described above, their clinical potential remains untapped. More research is needed to improve the bioavailability of magnolol and honokiol and perform experiments to examine the therapeutic potential of magnolol and honokiol.

Network pharmacology and in vitro experimental verification to explore the mechanism of Sanhua decoction in the treatment of ischaemic stroke

CONTEXT

Stroke is an illness with high morbidity, disability and mortality that presents a major clinical challenge. Sanhua decoction (SHD) has been widely used to treat ischaemic stroke in the clinic. However, the potential mechanism of SHD remains unknown.

OBJECTIVE

To elucidate the multitarget mechanism of SHD in ischaemic stroke through network pharmacology and bioinformatics analyses.

MATERIALS AND METHODS

Network pharmacology and experimental validation approach was used to investigate the bioactive ingredients, critical targets and potential mechanisms of SHD against ischaemic stroke. Four herbal names of SHD, 'ischemic stroke' or 'stroke' was used as a keyword to search the relevant databases. SH-SY5Y cells were treated with various concentrations of SHD (12.5, 25, 50 or 100 μg/mL) for 4 h, exposed to oxygen and glucose deprivation (OGD) for 1 h, then reoxygenation for 24 h. The cell viability was detected by MTT, the lactate dehydrogenase (LDH) was evaluated by ELISA, and protein expression was detected by western blots.

RESULTS

SHD treatment increased the survival rate from 65.9 ± 4.3 to 85.56 ± 5.7%. The median effective dose (ED₅₀) was 47.1 μg/mL, the LDH decreased from 288.0 ± 12.0 to 122.8 ± 9.1 U/L and the cell apoptosis rate decreased from 33.6 ± 1.8 to 16.3 ± 1.2%. Western blot analysis revealed that SHD increased the levels of p-PI3k, p-Akt and p-CREB1, and decreased the expression of TNF-α and IL-6.

DISCUSSION AND CONCLUSIONS

This study suggests that SHD protects against cerebral ischaemic injury via regulation of the PI3K/Akt/CREB1 and TNF pathways.

Effects of Polyphenols on Oxidative Stress, Inflammation, and Interconnected Pathways during Spinal Cord Injury

Despite the progression in targeting the complex pathophysiological mechanisms of neurodegenerative diseases (NDDs) and spinal cord injury (SCI), there is a lack of effective treatments. Moreover, conventional therapies suffer from associated side effects and low efficacy, raising the need for finding potential alternative therapies. In this regard, a comprehensive review was done regarding revealing the main neurological dysregulated pathways and providing alternative therapeutic agents following SCI. From the mechanistic point, oxidative stress and inflammatory pathways are major upstream orchestras of cross-linked dysregulated pathways (e.g., apoptosis, autophagy, and extrinsic mechanisms) following SCI. It urges the need for developing multitarget therapies against SCI complications. Polyphenols, as plant-derived secondary metabolites, have the potential of being introduced as alternative therapeutic agents to pave the way for treating SCI. Such secondary metabolites presented modulatory effects on neuronal oxidative stress, neuroinflammatory, and extrinsic axonal dysregulated pathways in the onset and progression of SCI. In the present review, the potential role of phenolic compounds as critical phytochemicals has also been revealed in regulating upstream dysregulated oxidative stress/inflammatory signaling mediators and extrinsic mechanisms of axonal regeneration after SCI in preclinical and clinical studies. Additionally, the coadministration of polyphenols and stem cells has shown a promising strategy for improving post-SCI complications.

Intravitreal Injection of Long-Acting Pegylated Granulocyte Colony-Stimulating Factor Provides Neuroprotective Effects via Antioxidant Response in a Rat Model of Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) may cause severe visual loss following direct or indirect head trauma which may result in optic nerve injuries and therefore contribute to the subsequent loss of retinal ganglion cells by inflammatory mediators and reactive oxygen species (ROS). Granulocyte colony-stimulating factor (G-CSF) provides the anti-inflammatory and anti-oxidative actions but has a short half-life and also induces leukocytosis upon typical systemic administration. The purpose of the present study was to investigate the relationship between the anti-oxidative response and neuroprotective effects of long-acting pegylated human G-CSF (PEG-G-CSF) in a rat model of optic nerve crush (ONC). Adult male Wistar rats (150-180 g) were chosen to have a sham operation in one eye and have ONC in the other. PEG-G-CSF or phosphate-buffered saline (PBS control) was immediately administered after ONC by intravitreal injection (IVI). We found the IVI of PEG-G-CSF does not induce systemic leukocytosis, but increases survival of RGCs and preserves the visual function after ONC. TUNEL assays showed fewer apoptotic cells in the retina in the PEG-G-CSF-treated eyes. The number of sorely ED1-positive cells was attenuated at the lesion site in the PEG-G-CSF-treated eyes. Immunoblotting showed up-regulation of p-Akt1, Nrf2, Sirt3, and HO-1 in the ON of the PEG-G-CSF-treated eyes. Our results demonstrated that one IVI of long-acting PEG-G-CSF is neuroprotective in the rONC. PEG-G-CSF activates the p-Akt1/Nrf2/Sirt3 and the p-Akt1/Nrf2/HO-1 axes to provide the antioxidative action and further attenuated RGC apoptosis and neuroinflammation. This provides crucial preclinical information for the development of alternative therapy with IVI of PEG-G-CSF in TON.

Claisened Hexafluoro Inhibits Metastatic Spreading of Amoeboid Melanoma Cells

Metastatic melanoma is characterized by poor prognosis and a low free-survival rate. Thanks to their high plasticity, melanoma cells are able to migrate exploiting different cell motility strategies, such as the rounded/amoeboid-type motility and the elongated/mesenchymal-type motility. In particular, the amoeboid motility strongly contributes to the dissemination of highly invasive melanoma cells and no treatment targeting this process is currently available for clinical application. Here, we tested Claisened Hexafluoro as a novel inhibitor of the amoeboid motility. Reported data demonstrate that Claisened Hexafluoro specifically inhibits melanoma cells moving through amoeboid motility by deregulating mitochondrial activity and activating the AMPK signaling. Moreover, Claisened Hexafluoro is able to interfere with the adhesion abilities and the stemness features of melanoma cells, thus decreasing the in vivo metastatic process. This evidence may contribute to pave the way for future possible therapeutic applications of Claisened Hexafluoro to counteract metastatic melanoma dissemination.

Honokiol ameliorates radiation-induced brain injury via the activation of SIRT3

Objective

Sirtuin 3 (SIRT3) plays a vital role in regulating oxidative stress in tissue injury. The aim of this study was to evaluate the radioprotective effects of honokiol (HKL) in a zebrafish model of radiation-induced brain injury and in HT22 cells.

Methods

The levels of reactive oxygen species (ROS), tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β) were evaluated in the zebrafish brain and HT22 cells. The expression levels of SIRT3 and cyclooxygenase-2 (COX-2) were measured using western blot assays and real-time polymerase chain reaction (RT-PCR).

Results

HKL treatment attenuated the levels of ROS, TNF-α, and IL-1β in both the in vivo and in vitro models of irradiation injury. Furthermore, HKL treatment increased the expression of SIRT3 and decreased the expression of COX-2. The radioprotective effects of HKL were achieved via SIRT3 activation.

Conclusions

HKL attenuated oxidative stress and pro-inflammatory responses in a SIRT3-dependent manner in radiation-induced brain injury.

Magnolia officinalis Reduces Inflammation and Damage Induced by Recurrent Status Epilepticus in Immature Rats

BACKGROUND

Neuroinflammation induced in response to damage caused by status epilepticus (SE) activates the interleukin (IL)1-β pathway and proinflammatory proteins that increase vulnerability to the development of spontaneous seizure activity and/or epilepsy.

OBJECTIVES

The study aimed to assess the short-term anti-inflammatory and neuroprotective effects of Magnolia officinalis (MO) on recurrent SE in immature rats.

METHODS

Sprague-Dawley rats at PN day 10 were used; n = 60 rats were divided into two control groups, SHAM and KA, and two experimental groups, MO (KA-MO) and Celecoxib (KA-Clbx). The anti-inflammatory effect of a single dose of MO was evaluated at 6 and 24 hr by Western blotting and on day 30 PN via a subchronic administration of MO to assess neuronal preservation and hippocampal gliosis by immunohistochemistry for NeunN and GFAP, respectively.

RESULTS

KA-MO caused a decrease in the expression of IL1-β and Cox-2 at 6 and 24 h post-treatment, a reduction in iNOS synthase at 6 and 24 hr post-treatment and reduced neuronal loss and gliosis at postnatal day 30, similar to Clbx.

CONCLUSION

The results indicating that Magnolia officinalis is an alternative preventive treatment for early stages of epileptogenesis are encouraging.

3D-Printed Extracellular Matrix/Polyethylene Glycol Diacrylate Hydrogel Incorporating the Anti-inflammatory Phytomolecule Honokiol for Regeneration of Osteochondral Defects

BACKGROUND

Osteoarthritis is the leading cause of disability worldwide; cartilage degeneration and defects are the central features. Significant progress in tissue engineering holds promise to regenerate damaged cartilage tissue. However, a formidable challenge is to develop a 3-dimensional (3D) tissue construct that can regulate local immune environment to facilitate the intrinsic osteochondral regeneration.

PURPOSE

To evaluate efficacy of a 3D-printed decellularized cartilage extracellular matrix (ECM) and polyethylene glycol diacrylate (PEGDA) integrated novel scaffold (PEGDA/ECM) together with the natural compound honokiol (Hon) for regenerating osteochondral defect.

STUDY DESIGN

Controlled laboratory study.

METHODS

We used a stereolithography-based 3D printer for PEGDA/ECM bioprinting. A total of 36 Sprague-Dawley rats with cylindrical osteochondral defect in the trochlear groove of the femur were randomly assigned into 3 different treatments: no scaffold implantation (Defect group), 3D printed PEGDA/ECM scaffold alone (PEGDA/ECM group), or Hon suspended in a 3D-printed PEGDA/ECM scaffold (PEGDA/ECM/Hon group). 12 rats that underwent only medial parapatellar incision surgery were used as normal controls. The femur specimens were postoperatively harvested at 4 and 8 weeks for gross, micro-CT, and histological evaluations. The efficacy of PEGDA/ECM/Hon scaffold on the release of proinflammatory cytokines from the macrophages stimulated by lipopolysaccharide (LPS) was evaluated in-vitro.

RESULTS

In vitro results determined that PEGDA/ECM/Hon scaffold could suppress the release of proinflammatory cytokines from macrophages that were stimulated by LPS. Macroscopic images showed that the PEGDA/ECM/Hon group had significantly higher ICRS scoring than that of defect and PEGDA/ECM groups. Micro-CT evaluation demonstrated that much more bony tissue was formed in the defect sites implanted with the PEGDA/ECM scaffold or PEGDA/ECM/Hon scaffold compared with the untreated defects. Histological analysis showed that the PEGDA/ECM/Hon group had a significant enhancement in osteochondral regeneration at 4 and 8 weeks after surgery in comparison with the ECM/PEGDA or defect group.

CONCLUSION

This study demonstrated that 3D printing of PEGDA/ECM hydrogel incorporating the anti-inflammatory phytomolecule honokiol could provide a promising scaffold for osteochondral defect repair.

Honokiol Reduces Fungal Load, Toll-Like Receptor-2, and Inflammatory Cytokines in Aspergillus fumigatus Keratitis

Purpose

We characterized the effects of Honokiol (HNK) on Aspergillus fumigatus-caused keratomycosis and the underlying mechanisms. HNK is known to have anti-inflammatory and antifungal properties, but the influence on fungal keratitis (FK) remains unknown.

Methods

In ex vivo, minimum inhibitory concentration and Cell Count Kit-8 assay were carried out spectrophotometrically to provide preferred concentration applied in vivo. Time kill assay pointed that HNK was fungicidal and fungistatic chronologically. Adherence assay, crystal violet staining, and membrane permeability assay tested HNK effects on different fungal stages. In vivo, clinical scores reflected the improvement degree of keratitis outcome. Myeloperoxidase (MPO) assay, flow cytometry (FCM), and immunohistofluorescence staining (IFS) were done to evaluate neutrophil infiltration. Plate count detected HNK fungicidal potentiality. RT-PCR, Western blot, and enzyme-linked immunosorbent assay (ELISA) verified the anti-inflammatory activity of HNK collaboratively.

Results

In vitro, MIC90 HNK was 8 µg/mL (no cytotoxicity), and Minimal Fungicidal Concentration (MFC) was 12 µg/mL for A. fumigatus. HNK played the fungistatic and fungicidal roles at 6 and 24 hours, respectively, inhibiting adherence at the beginning, diminishing biofilms formation, and increasing membrane permeability all the time. In vivo, HNK improved C57BL/6 mice outcome by reducing disease severity (clinical scores), neutrophil infiltration (MPO, FCM, and IFS), and fungal loading (plate count). RT-PCR, Western blot, and ELISA revealed that HNK downregulated mRNA and protein expression levels of Toll-like receptor-2 (TLR-2), high mobility group box 1 (HMGB1), IL-1β, and TNF-α.

Conclusions

Our study suggested HNK played antifungal and anti-inflammatory roles on keratomycosis by reducing survival of fungi, infiltration of leucocytes, and expression of HMGB1, TLR-2, and proinflammatory cytokines, providing a potential treatment for FK.

Honokiol ameliorates oxidative stress-induced DNA damage and apoptosis of c2c12 myoblasts by ROS generation and mitochondrial pathway

Honokiol is one of the main active components of Magnolia officinalis, and has been demonstrated to have multiple pharmacological activities against a variety of diseases. Recently, this phenolic compound is known to have antioxidant activity, but its mechanism of action remains unclear. The purpose of the current study was to evaluate the preventive effects of honokiol against oxidative stress-induced DNA damage and apoptosis in C2C12 myoblasts. The present study found that honokiol inhibited hydrogen peroxide (H₂O₂)-induced DNA damage and mitochondrial dysfunction, while reducing reactive oxygen species (ROS) formation. The inhibitory effect of honokiol on H₂O₂-induced apoptosis was associated with the up-regulation of Bcl-2 and down-regulation of Bax, thus reducing the Bax/Bcl-2 ratio that in turn protected the activation of caspase-9 and -3, and inhibition of poly (ADP-ribose) polymerase cleavage, which was associated with the blocking of cytochrome c release to the cytoplasm. Collectively, these results demonstrate that honokiol defends C2C12 myoblasts against H₂O₂-induced DNA damage and apoptosis, at least in part, by preventing mitochondrial-dependent pathway through scavenging excessive ROS.

Synthesis, characterization and in vivo evaluation of honokiol bisphosphate prodrugs protects against rats' brain ischemia-reperfusion injury

Honokiol (HK) usage is greatly restricted by its poor aqueous solubility and limited oral bioavailability. We synthesized and characterized a novel phosphate prodrug of honokiol (HKP) for in vitro and in vivo use. HKP greatly enhanced the aqueous solubility of HK (127.54 ± 15.53 mg/ml) and the stability in buffer solution was sufficient for intravenous administration. The enzymatic hydrolysis of HKP to HK was extremely rapid in vitro (T1/ 2  = 8.9 ± 2.11 s). Pharmacokinetics studies demonstrated that after intravenous administration of HKP (32 mg/kg), HKP was converted rapidly to HK with a time to reach the maximum plasma concentration of ∼5 min. The prodrug HKP achieved an improved T1/2 (7.97 ± 1.30 h) and terminal volume of distribution (26.02 ± 6.04 ml/kg) compared with direct injection of the equimolar parent drug (0.66 ± 0.01 h) and (2.90 ± 0.342 ml/kg), respectively. Furthermore, oral administration of HKP showed rapid and improved absorption compared with the parent drug. HKP was confirmed to maintain the bioactivity of the parent drug for ameliorating ischemia-reperfusion injury by decreasing brain infarction and improving neurologic function. Taken together, HKP is a potentially useful aqueous-soluble prodrug with improved pharmacokinetic properties which may merit further development as a potential drug candidate.

The role of NOX inhibitors in neurodegenerative diseases

Oxidative stress is a key player in both chronic and acute brain disease due to the higher metabolic demand of the brain. Among the producers of free radicals, NADPH-oxidase (NOX) is a major contributor to oxidative stress in neurological disorders. In the brain, the superoxide produced by NOX is mainly found in leukocytes. However, recent studies have reported that it can be found in several other cell types. NOX has been reported to regulate neuronal signaling, memory processing, and central cardiovascular homeostasis. However, overproduction of NOX can contribute to neurotoxicity, CNS degeneration, and cardiovascular disorders. Regarding the above functions, NOX has been shown to play a crucial role in chronic CNS diseases like Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS), and in acute CNS disorders such as stroke, spinal cord injury, traumatic brain injury (TBI), and related cerebrovascular diseases. NOX is a multi-subunit complex consisting of two membrane-associated and four cytosolic subunits. Thus, in recent years, inhibition of NOX activity has drawn a great deal of attention from researchers in the field of treating chronic and acute CNS disorders and preventing secondary complications. Mounting evidence has shown that NOX inhibition is neuroprotective and that inhibiting NOX in circulating immune cells can improve neurological disease conditions. This review summarizes recent studies on the therapeutic effects and pharmacological strategies regarding NOX inhibitors in chronic and acute brain diseases and focuses on the hurdles that should be overcome before their clinical implementation.

A review of the phytochemistry and pharmacological activities of Magnoliae officinalis cortex

ETHNOPHARMACOLOGICAL RELEVANCE

Magnoliae Officinalis Cortex (the dried bark of Magnolia officinalis), a widely used traditional Chinese medicine, is also known as 'Houpo' (Chinese: ). Magnoliae Officinalis Cortex has a wide range of pharmacological effects and has been used to treat conditions such as abdominal distention, vomiting, diarrhea, food accumulation, Qi stagnation, constipation, phlegm and fluid retention and cough resulting from asthma.

AIMS OF THE REVIEW

The present paper reviews advances in research relating to the botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of Magnoliae Officinalis Cortex. Prospects for future investigation and application of this herb are also discussed.

MATERIALS AND METHODS

Information on Magnoliae Officinalis Cortex was obtained from published materials, including ancient and modern books; PhD and MSc dissertations; monographs on medicinal plants; the pharmacopoeia of different countries and electronic databases, such as SCI finder, PubMed, Web of Science, ACS, Science Direct, Wiley, Springer, Taylor, AGRIS, Europe PMC, EBSCO host, CNKI, WanFang DATA, J-STAGE and Google Scholar.

RESULTS

More than 200 chemical compounds have been isolated from Magnoliae Officinalis Cortex, including lignans, phenylethanoid glycosides, phenolic glycosides, alkaloids, steroids and essential oils. The plant has been reported to have pharmacological effects on the digestive system, nervous system and cardiovascular and cerebrovascular systems, as well as antibacterial, anti-tumour, analgesic, anti-inflammatory and anti-oxidative effects.

CONCLUSIONS

Magnoliae Officinalis Cortex is an essential traditional Chinese medicine with pharmacological activities that mainly affect the digestive system, nervous system and cardiovascular and cerebrovascular systems. This review summarises its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology. These information suggest that we should focus on the development of new drugs related to Magnoliae Officinalis Cortex, including specific constituents, so that Magnoliae Officinalis Cortex can exert greater therapeutic potential. Meanwhile, it is important to pay attention to the rational use of Magnolia resources, avoiding over-harvesting which could lead to lack of resources. We should also pursue research on Magnolia substitutes and develop resources such as Magnoliae Officinalis Flos and Magnolia Leaf.

Magnolol exhibits anti-inflammatory and neuroprotective effects in a rat model of intracerebral haemorrhage

Intracerebral haemorrhage (ICH) induces inflammation, which can cause severe secondary injury. Recent evidence has suggested that magnolol (MG) has a protective effect against ischaemic stroke through the inhibition of inflammation. However, the anti-inflammatory effect of MG in intracerebral haemorrhage (ICH) remains unclear. Here, we report that the protective effect of MG in a rat model of ICH can be achieved by anti-inflammatory processes. We found that MG administration significantly reduced the brain water content, restored the blood-brain barrier (BBB) and subsequently attenuated neurological deficits via decreasing the activation of glial cells, decreasing the infiltration of neutrophils and reducing the production of pro-inflammation factors (IL-1β, TNF-α and MMP-9) in a rat model of ICH. These results suggest that MG reduced inflammatory injury and improved neurological outcomes in ICH model.

Honokiol Ameliorates Myocardial Ischemia/Reperfusion Injury in Type 1 Diabetic Rats by Reducing Oxidative Stress and Apoptosis through Activating the SIRT1-Nrf2 Signaling Pathway

Reducing oxidative stress is a crucial therapeutic strategy for ameliorating diabetic myocardial ischemia/reperfusion (MI/R) injury. Honokiol (HKL) acts as an effective cardioprotective agent for its strong antioxidative activity. However, its roles and underlying mechanisms against MI/R injury in type 1 diabetes (T1D) remain unknown. Since SIRT1 and Nrf2 are pivotal regulators in diabetes mellitus patients suffering from MI/R injury, we hypothesized that HKL ameliorates diabetic MI/R injury via the SIRT1-Nrf2 signaling pathway. Streptozotocin-induced T1D rats and high-glucose-treated H9c2 cells were exposed to HKL, with or without administration of the SIRT1 inhibitor EX527, SIRT1 siRNA, or Nrf2 siRNA, and then subjected to I/R operation. We found that HKL markedly improved the postischemic cardiac function, decreased the infarct size, reduced the myocardial apoptosis, and diminished the reactive oxygen species generation. Intriguingly, HKL remarkably activated SIRT1 signaling, enhanced Nrf2 nuclear translocation, increased antioxidative signaling, and decreased apoptotic signaling. However, these effects were largely abolished by EX527 or SIRT1 siRNA. Additionally, our cellular experiments showed that Nrf2 siRNA blunted the cytoprotective effects of HKL, without affecting SIRT1 expression and activity. Collectively, these novel findings indicate that HKL abates MI/R injury in T1D by ameliorating myocardial oxidative damage and apoptosis via the SIRT1-Nrf2 signaling pathway.

Honokiol inhibits in vitro and in vivo growth of oral squamous cell carcinoma through induction of apoptosis, cell cycle arrest and autophagy

Honokiol, an active natural product derived from Magnolia officinalis, exerted anticancer effects through a variety of mechanisms on multiple types of cancers. In this study, the molecular mechanisms of honokiol in suppressing the human oral squamous cell carcinoma (OSCC) cells were evaluated. Treatment of two OSCC cell lines with honokiol resulted in reducing the cell proliferation and arresting the cell cycle at G1 stage which was correlated with the down‐regulation of Cdk2 and Cdk4 and the up‐regulation of cell cycle suppressors, p21 and p27. In addition, the caspase‐dependent programmed cell death was substantially detected, and the autophagy was induced as the autophagosome formation and autophagic flux proceeded. Modulation of autophagy by autophagic inducer, rapamycin or inhibitors, 3‐MA or bafilomycin, potentiated the honokiol‐mediated anti‐OSCC effects where honokiol exerted multiple actions in suppression of MAPK pathway and regulation of Akt/mTOR or AMPK pathways. As compared to clinical therapeutic agent, 5‐FU, honokiol exhibited more potent activity against OSCC cells and synergistically enhanced the cytotoxic effect of 5‐FU. Furthermore, orally administrated honokiol exerted effective antitumour activity in vivo in OSCC‐xenografted mice. Thus, this study revealed that honokiol could be a promising candidate in preventing human OSCCs.

Microglia and CNS Interleukin-1: Beyond Immunological Concepts

Activation of microglia and expression of the inflammatory cytokine interleukin-1 (IL-1) in the CNS have become almost synonymous with neuroinflammation. In numerous studies, increased CNS IL-1 expression and altered microglial morphology have been used as hallmarks of CNS inflammation. A central concept of how CNS IL-1 and microglia influence functions of the nervous system was derived from the notion initially generated in the peripheral immune system: IL-1 stimulates monocyte/macrophage (the peripheral counterparts of microglia) to amplify inflammation. It is increasingly clear, however, CNS IL-1 acts on other targets in the CNS and microglia participates in many neural functions that are not related to immunological activities. Further, CNS exhibits immunological privilege (although not as absolute as previously thought), rendering amplification of inflammation within CNS under stringent control. This review will analyze current literature to evaluate the contribution of immunological and non-immunological aspects of microglia/IL-1 interaction in the CNS to gain insights for how these aspects might affect health and disease in the nervous tissue.

Neuroprotective effects of honokiol: from chemistry to medicine

The incidence of neurological disorders is growing in developed countries together with increased lifespan. Nowadays, there are still no effective treatments for neurodegenerative pathologies, which make necessary to search for new therapeutic agents. Natural products, most of them used in traditional medicine, are considered promising alternatives for the treatment of neurodegenerative diseases. Honokiol is a natural bioactive phenylpropanoid compound, belonging to the class of neolignan, found in notable amounts in the bark of Magnolia tree, and has been reported to exert diverse pharmacological properties including neuroprotective activities. Honokiol can permeate the blood brain barrier and the blood-cerebrospinal fluid to increase its bioavailability in neurological tissues. Diverse studies have provided evidence on the neuroprotective effect of honokiol in the central nervous system, due to its potent antioxidant activity, and amelioration of the excitotoxicity mainly related to the blockade of glutamate receptors and reduction in neuroinflammation. In addition, recent studies suggest that honokiol can attenuate neurotoxicity exerted by abnormally aggregated Aβ in Alzheimer's disease. The present work summarizes what is currently known concerning the neuroprotective effects of honokiol and its potential molecular mechanisms of action, which make it considered as a promising agent in the treatment and management of neurodegenerative diseases. © 2017 BioFactors, 43(6):760-769, 2017.

Evaluation of the effects of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model

We reported previously that Stachybotrys microspora triprenyl phenol-7 (SMTP-7) showed potential thrombolytic, anti-inflammatory and anti-oxidant effects that account for its excellent pharmacological activity such as having a wider therapeutic time window than tissue plasminogen activator (t-PA) and a significant protection against hemorrhage. The aim of the present study was to evaluate and compare the effect of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model. Thrombotic occlusion was produced in mice by inducing the transfer of acetic acid-induced thrombi from the right common carotid artery into the brain. SMTPs were evaluated by their effect on reducing infarct area, neurological score and edema. Furthermore, plasmin formation, anti-inflammatory and anti-oxidant activities were assessed by fibrin zymography, measuring pro-inflammatory gene expression, and thiobarbituric acid reactive substances (TBARS) assay, respectively. Treatment with either SMTP-22 or SMTP-43 (10mg/kg), which have similar plasmin formation, anti-inflammatory and anti-oxidant activities to SMTP-7, resulted in reduced infarct area, neurological score and edema. Coexistence of all these three activities appears to be important for the treatment of embolic infarction because SMTP-6, SMTP-25, and SMTP-44D (10mg/kg), which are each missing at least one of the three functions, were not as effective. Therefore, these results indicate that SMTP-22 and SMTP-43 have potential as medicinal compounds for the treatment of embolic cerebral infarction.

Effect of the Biphenyl Neolignan Honokiol on Aβ42-Induced Toxicity in Caenorhabditis elegans, Aβ42 Fibrillation, Cholinesterase Activity, DPPH Radicals, and Iron(II) Chelation

The biphenyl neolignan honokiol is a neuroprotectant which has been proposed as a treatment for central nervous system disorders such as Alzheimer's disease (AD). The death of cholinergic neurons in AD is attributed to multiple factors, including accumulation and fibrillation of amyloid beta peptide (Aβ) within the brain; metal ion toxicity; and oxidative stress. In this study, we used a transgenic Caenorhabditis elegans model expressing full length Aβ₄₂ as a convenient in vivo system for examining the effect of honokiol against Aβ-induced toxicity. Furthermore, honokiol was evaluated for its ability to inhibit Aβ₄₂ oligomerization and fibrillation; inhibit acetylcholinesterase and butyrylcholinesterase; scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals; and chelate iron(II). Honokiol displayed activity similar to that of resveratrol and (-)-epigallocatechin gallate (EGCG) in delaying Aβ₄₂-induced paralysis in C. elegans, and it exhibited moderate-to-weak ability to inhibit Aβ₄₂ on-pathway aggregation, inhibit cholinesterases, scavenge DPPH radicals, and chelate iron(II). Moreover, honokiol was found to be chemically stable relative to EGCG, which was highly unstable. Together with its good drug-likeness and brain availability, these results suggest that honokiol may be amenable to drug development and that the synthesis of honokiol analogues to optimize these properties should be considered.

NOX Inhibitors - A Promising Avenue for Ischemic Stroke

NADPH-oxidase (NOX) mediated superoxide originally found on leukocytes, but now recognized in several types of cells in the brain. It has been shown to play an important role in the progression of stroke and related cerebrovascular disease. NOX is a multisubunit complex consisting of 2 membrane-associated and 4 cytosolic subunits. NOX activation occurs when cytosolic subunits translocate to the membrane, leading to transport electrons to oxygen, thus producing superoxide. Superoxide produced by NOX is thought to function in long-term potentiation and intercellular signaling, but excessive production is damaging and has been implicated to play an important role in the progression of ischemic brain. Thus, inhibition of NOX activity may prove to be a promising treatment for ischemic brain as well as an adjunctive agent to prevent its secondary complications. There is mounting evidence that NOX inhibition in the ischemic brain is neuroprotective, and targeting NOX in circulating immune cells will also improve outcome. This review will focus on therapeutic effects of NOX assembly inhibitors in brain ischemia and stroke. However, the lack of specificity and toxicities of existing inhibitors are clear hurdles that will need to be overcome before this class of compounds could be translated clinically.

Honokiol suppresses formyl peptide-induced human neutrophil activation by blocking formyl peptide receptor 1

Formyl peptide receptor 1 (FPR1) mediates bacterial and mitochondrial N-formyl peptides-induced neutrophil activation. Therefore, FPR1 is an important therapeutic target for drugs to treat septic or sterile inflammatory diseases. Honokiol, a major bioactive compound of Magnoliaceae plants, possesses several anti-inflammatory activities. Here, we show that honokiol exhibits an inhibitory effect on FPR1 binding in human neutrophils. Honokiol inhibited superoxide anion generation, reactive oxygen species formation, and elastase release in bacterial or mitochondrial N-formyl peptides (FPR1 agonists)-activated human neutrophils. Adhesion of FPR1-induced human neutrophils to cerebral endothelial cells was also reduced by honokiol. The receptor-binding results revealed that honokiol repressed FPR1-specific ligand N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein binding to FPR1 in human neutrophils, neutrophil-like THP-1 cells, and hFPR1-transfected HEK293 cells. However, honokiol did not inhibit FPR2-specific ligand binding to FPR2 in human neutrophils. Furthermore, honokiol inhibited FPR1 agonist-induced calcium mobilization as well as phosphorylation of p38 MAPK, ERK, and JNK in human neutrophils. In conclusion, our data demonstrate that honokiol may have therapeutic potential for treating FPR1-mediated inflammatory diseases.

Combined NADPH and the NOX inhibitor apocynin provides greater anti-inflammatory and neuroprotective effects in a mouse model of stroke

Our previous study has reported that the pentose phosphate pathway product nicotinamide adenine dinucleotide phosphate (NADPH) protected neurons against ischemia/reperfusion-induced brain injury. NADPH can either act as a co-enzyme to produce GSH or a substrate of NADPH oxidase (NOX) to generate ROS. This study was designed to elucidate the effects of co-treatment with NADPH and NOX inhibitor apocynin on ischemia/reperfusion-induced brain inflammation and neuronal injury. The results showed that both NADPH and apocynin markedly attenuated ischemia/reperfusion-induced increases in the levels of NOX2, NOX4 and ROS. NADPH and apocynin significantly inhibited the phosphorylation and degradation of IκBα, NF-κBp65 nuclear localization, and the expression of NF-κB target gene cyclooxygenase (COX2) and inducible nitric oxide synthase (iNOS). Furthermore, both NADPH and apocynin suppressed the expression of inflammasome proteins including NLRP3 ASC, caspase-1, interleukin (IL)-1β and IL-18 in the ischemic cortex as revealed by Western blot analysis and immunofluorescence. Moreover, all these effects were greatly amplified by combination of NADPH and apocynin. Both NADPH and apocynin significantly reduced infarct volume, improved post-stroke survival, and recovery of neurological functions in mouse model of stroke. Consistently, the combination of NADPH and apocynin produced greater beneficial effects in against ischemic brain damage. These studies suggest that, beyond anti-oxidative effects, NADPH may also have anti-inflammatory effects and combination of NADPH and NOX inhibitors could produce a greater neuroprotective effect in ischemic stroke.

One-Compound-Multi-Target: Combination Prospect of Natural Compounds with Thrombolytic Therapy in Acute Ischemic Stroke

Tissue plasminogen activator (t-PA) is the only FDA-approved drug for acute ischemic stroke treatment, but its clinical use is limited due to the narrow therapeutic time window and severe adverse effects, including hemorrhagic transformation (HT) and neurotoxicity. One of the potential resolutions is to use adjunct therapies to reduce the side effects and extend t-PA's therapeutic time window. However, therapies modulating single target seem not to be satisfied, and a multitarget strategy is warranted to resolve such complex disease. Recently, large amount of efforts have been made to explore the active compounds from herbal supplements to treat ischemic stroke. Some natural compounds revealed both neuro- and bloodbrain- barrier (BBB)-protective effects by concurrently targeting multiple cellular signaling pathways in cerebral ischemia-reperfusion injury. Thus, those compounds are potential to be one-drug-multi-target agents as combined therapy with t-PA for ischemic stroke. In this review article, we summarize current progress about molecular targets involving in t-PA-mediated HT and neurotoxicity in ischemic brain injury. Based on these targets, we select 23 promising compounds from currently available literature with the bioactivities simultaneously targeting several important molecular targets. We propose that those compounds merit further investigation as combined therapy with t-PA. Finally, we discuss the potential drawbacks of the natural compounds' studies and raise several important issues to be addressed in the future for the development of natural compound as an adjunct therapy.

Non-toxic dose of liposomal honokiol suppresses metastasis of hepatocellular carcinoma through destabilizing EGFR and inhibiting the downstream pathways

At present, there is no specific anti-metastasis drug in HCC treatment. Drugs used for primary HCC tumors and tumor metastasis are very similar, among which cytotoxic drugs are prevalent, such as cisplatin, doxorubicin and 5-FU. The EGFR pathway plays an important role in promoting hepatocellular carcinoma (HCC) metastasis. Hence, development of non-toxic anti-metastasis drugs, such as EGFR or downstream pathways inhibitors, is of great importance. In our present study, we found non-toxic dose of liposomal honokiol (LH) could inhibit the HCC metastasis by destabilizing EGFR and inhibiting the downstream pathways. Non-toxic dose of LH significantly inhibited the motility, migration and lamellipodia formation of HepG2 cells in vitro and decreased extravasation of HepG2 cells in a novel metastasis model of transgenic zebrafish. In two lung metastasis models (HepG2 and B16F10) and a spontaneous metastasis model of HepG2 cells, LH remarkably inhibited pulmonary metastasis and regional lymph nodes metastasis without obvious toxicity. Further study showed that destabilizing EGFR and inhibiting the downstream pathways were the main mechanisms of non-toxic dose of LH on metastasis inhibition. Our results provide the preclinical rationale and the underlying mechanisms of LH to suppress HCC metastasis, implicating LH as a potential therapeutic agent to block HCC metastasis without severe side effects.

Honokiol suppresses TNF-α-induced neutrophil adhesion on cerebral endothelial cells by disrupting polyubiquitination and degradation of IκBα

Adhesion molecules expressed on cerebral endothelial cells (ECs) mediate leukocyte recruitment and play a significant role in cerebral inflammation. Increased levels of adhesion molecules on the EC surface induce leukocyte infiltration into inflammatory areas and are thus hallmarkers of inflammation. Honokiol, isolated from the Chinese medicinal herb Magnolia officinalis, has various pharmacological activities, including anti-inflammatory effects, yet the nature of honokiol targeting molecules remains to be revealed. Here, we investigated the inhibitory effect of honokiol on neutrophil adhesion and vascular cell adhesion molecule-1 (VCAM-1) expression, which underlie its molecular target, and mechanisms for inactivating nuclear factor κ enhancer binding protein (NF-κB) in mouse cerebral ECs. Honokiol inhibited tumour necrosis factor-α (TNF-α)-induced neutrophil adhesion and VCAM-1 gene expression in cerebral ECs. The inflammatory transcription factor NF-κB was downregulated by honokiol. Honokiol significantly blocked TNF-α-induced NF-κB p65 nuclear translocation and degradation of the proteasome-dependent inhibitor of NF-κB α (IκBα). From docking model prediction, honokiol directly targeted the ubiquitin-ubiquitin interface of Lys48-linked polychains. Moreover, honokiol prevented the TNF-α-induced Lys48-linked polyubiquitination, including IκBα-polyubiquitin interaction. Honokiol has protective anti-inflammatory effects on TNF-α-induced neutrophil adhesion and VCAM-1 gene expression in cerebral ECs, at least in part by directly inhibiting ubiquitination-mediated IκBα degradation and then preventing NF-κB nuclear translocation.

Protective effects of honokiol on ischemia/reperfusion injury of rat ovary: an experimental study

Aim

The purpose of this study was to investigate the protective effect of honokiol on experimental ischemia/reperfusion injury of rat ovary.

Materials and methods

A total of 40 female Wistar albino rats were used in this study. The rats were divided into five groups as follows: sham (Group I), torsion (Group II), torsion + detorsion (Group III), torsion + detorsion + saline (Group IV), and torsion + detorsion + honokiol (Group V). Bilateral adnexa in all the rats except for those in the sham group were exposed to torsion for 3 hours. The rats in Group IV were administered saline, whereas the rats in Group V were administered honokiol by intraperitoneal route 30 minutes before detorsion. Tissue and plasma concentrations of malondialdehyde and nitric oxide were determined. Ovarian tissue was histologically evaluated. Data analyses were performed by means of Kruskal–Wallis test and Mann–Whitney U-test (Bonferroni correction) in SPSS 15.0 (Statistical Package for Social Sciences; SPSS Inc., Chicago, IL, USA).

Results

The torsion and detorsion groups had higher scores in vascular congestion, hemorrhage, and inflammatory cell infiltration compared with the sham group (P<0.005). In addition, total histopathological scores were significantly higher in the torsion and detorsion groups compared with the sham group (P<0.005). A significant reduction was observed in hemorrhage, inflammatory cell infiltration, and cellular degeneration scores, of all histopathological scores, in the honokiol group (P<0.005). Ovarian tissue concentrations of malondialdehyde were significantly higher in the torsion and detorsion groups compared with the sham and honokiol groups (P<0.005). Ovarian tissue concentrations of nitric oxide, on the other hand, were significantly higher in the torsion group compared with the sham, saline, and honokiol groups (P<0.005).

Conclusion

Honokiol has a beneficial effect on ovarian torsion-related ischemia/reperfusion injury.

NADPH Oxidase: A Potential Target for Treatment of Stroke

Stroke is the third leading cause of death in industrialized nations. Oxidative stress is involved in the pathogenesis of stroke, and excessive generation of reactive oxygen species (ROS) by mitochondria is thought to be the main cause of oxidative stress. NADPH oxidase (NOX) enzymes have recently been identified and studied as important producers of ROS in brain tissues after stroke. Several reports have shown that knockout or deletion of NOX exerts a neuroprotective effect in three major experimental stroke models. Recent studies also confirmed that NOX inhibitors ameliorate brain injury and improve neurological outcome after stroke. However, the physiological and pathophysiological roles of NOX enzymes in the central nervous system (CNS) are not known well. In this review, we provide a comprehensive summary of our current understanding about expression and physiological function of NOX enzymes in the CNS and its pathophysiological roles in the three major types of stroke: ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.

NADPH oxidase 2 does not contribute to early reperfusion-associated reactive oxygen species generation following transient focal cerebral ischemia

Excess production of reactive oxygen species (ROS) critically contributes to occurrence of reperfusion injury, the paradoxical response of ischemic brain tissue to restoration of cerebral blood flow. However, the enzymatic sources of ROS generation remain to be unclear. This study examined Nox2-containing NADPH oxidase (Nox2) expression and its activity in ischemic brain tissue following post-ischemic reperfusion to clarify the mechanism of enzymatic reaction of ROS. Male Sprague-Dawley rats were subjected to 90-minute middle cerebral artery occlusion, followed by 3 or 22.5 hours of reperfusion. Quantitative reverse transcriptase PCR and western blot assay were performed to measure mRNA and protein expression of Nox2. Lucigenin fluorescence assays were performed to assess Nox activity. Our data showed that Nox2 mRNA and protein expression levels were significantly increased (3.7-fold for mRNA and 3.6-fold for protein) in ischemic brain tissue at 22.5 hours but not at 3 hours following post-ischemic reperfusion. Similar results were obtained for the changes of NADPH oxidase activity in ischemic cerebral tissue at the two reperfusion time points. Our results suggest that Nox2 may not contribute to the early burst of reperfusion-related ROS generation, but is rather an important source of ROS generation during prolonged reperfusion.

Embryo-fetal development toxicity of honokiol microemulsion intravenously administered to pregnant rats

The aim of this study was to evaluate the embryo-fetal development toxicity of honokiol microemulsion. The drug was intravenously injected to pregnant SD rats at dose levels of 0, 200, 600 and 2000 μg/kg/day from day 6-15 of gestation. All the pregnant animals were observed for body weights and any abnormal changes and subjected to caesarean-section on gestation day (GD) 20; all fetuses obtained from caesarean-section were assessed by external inspection, visceral and skeletal examinations. No treatment-related external alterations as well as visceral and skeletal malformations were observed in honokiol microemulsion groups. There was no significant difference in the body weight gain of the pregnant rats, average number of corpora lutea, and the gravid uterus weight in the honokiol microemulsion groups compared with the vehicle control group. However, at a dose level of 2000 μg/kg/day, there was embryo-fetal developmental toxicity observed, including a decrease in the body length and tail length of fetuses. In conclusion, the no-observed-adverse-effect level (NOAEL) of honokiol microemulsion is 600 μg/kg/day, 75 times above the therapeutic dosage and it has embryo-fetal toxicity at a dose level of 2000 μg/kg/day, which is approximately 250 times above the therapeutic dosage.

Antagonism of human formyl peptide receptor 1 with natural compounds and their synthetic derivatives

Formyl peptide receptor 1 (FPR1) regulates a wide variety of neutrophil functional responses and plays an important role in inflammation and the pathogenesis of various diseases. To date, a variety of natural and synthetic molecules have been identified as FPR1 ligands. Here, we review current knowledge on natural products and natural product-inspired small molecules reported to antagonize and/or inhibit the FPR1-mediated responses. Based on this literature, additional screening of selected commercially available natural compounds for their ability to inhibit fMLF-induced Ca(2+) mobilization in human neutrophils and FPR1 transfected HL-60 cells, and pharmacophore modeling, natural products with potential as FPR1 antagonists are considered and discussed in this review. The identification and characterization of natural products that antagonize FPR1 activity may have potential for the development of novel therapeutics to limit or alter the outcome of inflammatory processes.

Honokiol, a Lignan Biphenol Derived from the Magnolia Tree, Inhibits Dengue Virus Type 2 Infection

Dengue is the most widespread arbovirus infection and poses a serious health and economic issue in tropical and subtropical countries. Currently no licensed vaccine or compounds can be used to prevent or manage the severity of dengue virus (DENV) infection. Honokiol, a lignan biphenol derived from the Magnolia tree, is commonly used in Eastern medicine. Here we report that honokiol has profound antiviral activity against serotype 2 DENV (DENV-2). In addition to inhibiting the intracellular DENV-2 replicon, honokiol was shown to suppress the replication of DENV-2 in baby hamster kidney (BHK) and human hepatocarcinoma Huh7 cells. At the maximum non-toxic dose of honokiol treatment, the production of infectious DENV particles was reduced >90% in BHK and Huh7 cells. The underlying mechanisms revealed that the expression of DENV-2 nonstructural protein NS1/NS3 and its replicating intermediate, double-strand RNA, was dramatically reduced by honokiol treatment. Honokiol has no effect on the expression of DENV putative receptors, but may interfere with the endocytosis of DENV-2 by abrogating the co-localization of DENV envelope glycoprotein and the early endosomes. These results indicate that honokiol inhibits the replication, viral gene expression, and endocytotic process of DENV-2, making it a promising agent for chemotherapy of DENV infection.