Sodium tanshinone IIA sulfonate promotes endothelial integrity via regulating VE-cadherin dynamics and RhoA/ROCK-mediated cellular contractility and prevents atorvastatin-induced intracerebral hemorrhage in zebrafish.

Impaired vascular integrity leads to serious cerebral vascular diseases such as intracerebral hemorrhage (ICH). In addition, high-dose statin therapy is suggested to cause increased ICH risk due to unclear effects of general inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) on the vascular system. Here we evaluated the protective effects of sodium tanshinone IIA sulfonate (STS), which has high efficacy and safety in clinical studies of ischemic stroke, by using atorvastatin (Ator) induced ICH zebrafish embryos and human umbilical vein endothelial cells (HUVECs). By using double transgenic Tg(fli1a:EGFP)y1 & Tg(gata1a:dsRed)sd2 zebrafish, we demonstrated that STS effectively reduced the occurrence and area of hemorrhage induced by Ator in zebrafish and restored impairment in motor function. We further demonstrated that Ator-induced disruption in VE-cadherin (VEC)-containing cell-cell adherens junctions (AJs) in HUVECs by enhancing Src-induced VEC internalization and RhoA/ROCK-mediated cellular contraction. STS inhibited Ator-induced Src activation and subsequent VEC internalization and actin depolymerization near cell borders, reducing lesions between neighboring cells and increasing barrier functions. STS also inhibited the Ator-induced RhoA/ROCK-mediated cellular contraction by regulating downstream LIMK/cofilin and MYPT1/MLC phosphatase signaling. These results showed that STS significantly promoted the stability of cell junctions and vascular integrity. Moreover, we observed that regulations of both Src and RhoA/ROCK are required for the maintenance of vascular integrity, and Src inhibitor (PP2) or ROCK inhibitors (fasudil and H1152) alone could not reduce the occurrence Ator-induced ICH. Taken together, we investigated the underlying mechanisms of Ator-induced endothelial instability, and provided scientific evidences of STS as potential ICH therapeutics by promoting vascular integrity.

Recent advances in structure-based drug design and virtual screening of VEGFR tyrosine kinase inhibitors.

During the past decade, developments in computational processing and X-ray crystallography have allowed virtual screening become integrated into drug discovery campaigns. This review focuses on the recent advancements in the drug discovery of VEGFR2 tyrosine kinase inhibitors (VEGFR2 TKIs) by using in silico methodologies. An introduction for the methodology framework of pharmacophore modeling, molecular docking and structure-based design are provided. We discuss the recent studies on the structures of VEGFR2 protein kinase in different binding modes, and the insights on molecular interactions gained from knowledge of the co-crystal structures complex with structurally diverse VEGFR2 inhibitors. We provide some aspects of model construction and molecular docking techniques. Several representative examples of successful applications on VEGFR2 virtual screening for hit discovery, lead optimization and structure-based design are also presented.

[Use of zebrafish models for the research of traditional Chinese medicine].

Traditional Chinese medicine (TCM) exhibits a broad range of effects on biological activity that is probably due to interactions of complex chemical constituents with multiple targets in the body. Understanding the active chemical constituents in TCM is very important in providing rationales for the clinical usage of TCM. The zebrafish (Danio rerio) has recently become a popular model in the field of drug screening, specifically emerging as an important vertebrate model for in vivo high-content drug screening of multiple efficacy parameters and whole-organism toxicity. The authors also discussed the advantages of the zebrafish model for evaluating drug metabolism. Zebrafish usage in TCM screening should be a viable approach that helps identify active chemical markers, biological pathways and mechanistic actions of TCM.

Protective, antioxidative and antiapoptotic effects of 2-methoxy-6-acetyl-7-methyljuglone from Polygonum cuspidatum in PC12 cells.

Much correlative evidence indicates that the oxidative modification of protein by reactive oxygen species (ROS) is involved in normal aging as well as the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. In this study, we explored the antioxidative and neuroprotective effects of a naphthoquinone, 2-methoxy-6-acetyl-7-methyljuglone (MAM), purified from the dried rhizome of POLYGONUM CUSPIDATUM (Chinese name Hu-Zhang). Pretreatments with MAM (24 h) were investigated for their protective effects against apoptosis induced by the oxidizing agent TERT-butyl hydroperoxide ( T-BHP) in PC12 cells. The results indicated that MAM pretreatments could effectively protect PC12 cells against cytotoxicity induced by T-BHP in a dose-dependent manner. Cell viability was determined by both MTT and LDH assays. Increasing concentrations of MAM enhanced cell viability significantly and completely prevented cell death induced by T-BHP at 2.5 µM. The corresponding extracellular lactate dehydrogenase (LDH) levels were also attenuated significantly by various concentrations of MAM. In addition, it was found that the antioxidative effect of MAM was stronger than those of resveratrol and lipoic acid. The antiapoptotic property of MAM was further investigated with Hoechst 33342 nuclear staining and TUNEL assay. Pretreatments of MAM were able to prevent the T-BHP-induced nucleus fragmentation and accumulation of apoptotic bodies (commonly accepted as markers of apoptosis) inside the cells in a dose-dependent manner. T-BHP induced the phosphorylation of ERK 1/2, JNK and p38 MAPK, which were all impeded by pretreatments with MAM, indicating that MAM may act as a potent antioxidant which significantly interferes with the MAPK apoptotic cascades, probably rescuing cells by inhibiting the death pathways.

Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor.

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2+/-0.2 microM, Rmax=99.1+/-3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3+/-1.6 microM, Rmax=59.2+/-7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1+/-0.2 microM, Rmax=58.4+/-1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 microM for 30 min) shifted the oleamide concentration-response curve approximately 30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml-1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2+/-0.4 microM, Rmax=66.8+/-4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 microM) significantly inhibited relaxation induced by oleamide (EC50=3.5+/-0.3 microM, Rmax=75.1+/-1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 microM), nor the CB2 antagonist, SR144528 (1 microM), had significant effects. O-1918 (10 microM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KC)) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KC) and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site.

Amelioration of acute myocardial infarction by saponins from flower buds of Panax notoginseng via pro-angiogenesis and anti-apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Panax notoginseng is traditionally used as an anti-hemorrhagic agent to promote blood circulation without causing "congealed" blood. Furthermore, the flower of P. notoginseng is a popular, traditional medicine taken daily for the preventing of hypertension and for reducing blood cholesterol profiles. Besides, the flower of P. notoginseng contains a higher level of saponins, particularly protopanaxadiol-type ginsenosides, as compared to the root. However, detailed pharmacological studies on this flower have rarely been conducted. MATERIAL AND METHODS: In this study, the saponins extracted from the flower of P. notoginseng (FS) were examined on the endothelial cell migration assay, chemically induced vascular insufficiency model in zebrafish larvae and myocardial infraction (MI) model in rats, for determination of their pro-angiogenic and therapeutic effects on MI treatment. RESULTS: Our results demonstrate that FS significantly promoted VEGF-induced migration of human umbilical vein endothelial cells (HUVECs) and partially restored defective intersegmental vessels (ISV) in a chemically induced vascular insufficiency model of zebrafish larvae. When compared to MI group, two weeks post-treatment of FS (25-50mg/kg/day) induced approximately 3-fold upregulation of VEGF mRNA expression and a concomitant increase in blood vessel density in the peri-infarct area of the heart. Moreover, TUNEL analysis indicates a reduction in the mean apoptotic nuclei per field in peri-infarct myocardium upon FS treatment. CONCLUSIONS: The pro-angiogenic effects of FS demonstrated in in vitro and in vivo experimental models suggest that the purified saponin preparation from flowers of P. notoginseng may potentially provide preventive and therapeutic agent for cardiovascular diseases.

Chemical and pharmacological evaluations on the extract of Scutellaria baicalensis Georgi (Huang-Qin) prepared by various extraction methods.

BACKGROUND: This study reported a comprehensive approach (comparing the extraction yields, chemical profiles, antioxidant properties and CYP450-inhibitory effects) to evaluated the effectiveness of various extraction methods [microwave-assisted extraction using water (MAE-W), heat reflux extraction using water (HRE-W), ultrasonic extraction using 70 % ethanol and ultrasonic extraction using ethanol (UE-E)] for Huang-Qin (HQ), the dried root of Scutellaria baicalensis Georgi. RESULTS: The HQ extraction efficiency by MAE-W was the best. The chemical profiles of extracts obtained using HRE-W and MAE-W were similar; whereas more flavones but less flavone glycosides were detected in the UE-E extract. There was no difference in the antioxidant properties among different extracts. In vitro human liver microsome assays illustrated that all extracts possessed herb-drug interaction potentials but the UE-E extract are shown with a potent interaction with CYP3A4-metabolized drugs. CONCLUSION: MAE-W is a favorable method for the preparation of HQ extracts based on extraction yield, pharmacological properties and safety.

Membrane receptor probes: solid-phase synthesis of biotin-Asp-PEG-arvanil derivatives.

[structure: see text] A modular, flexible solid-phase synthetic route for the preparation of biotinylated cross-linking probes of membrane receptors is described. The route utilizes an orthogonal protection strategy employing a Pd[0] cleavable allyl linker attached to the probe via an aspartate residue. The versatility of the method is illustrated through the synthesis of a number of arvanil-derived cannabinoid receptor ligands displaying either a photoaffinity or a chemical cross-linking group.

Discovery of novel anti-parkinsonian effect of schisantherin A in in vitro and in vivo.

Dibenzocyclooctadiene lignans represent a unique group of natural chemical structures, are considered as protectants against neuronal cell death and cognitive impairment in neurological disorders. Among the family of dibenzocyclooctadiene lignan analogs from the fruit of Schisandra chinensis (Turcz.) Baill, neuroprotective potential of schisantherin A (StA) has not yet been characterized. In this study, 1-methyl-4-phenylpyridinium ion (MPP(+))-incubated SH-SY5Y cells and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice were used to study the neuroprotection of StA. Pretreatment with StA significantly inhibited MPP(+)-induced cytotoxicity in SH-SY5Y cells. Moreover, StA conferred significant protection against MPTP-induced loss of TH-positive dopaminergic neurons in a Parkinson's disease (PD) mice model. Structure activity relationship analysis suggested that methylenedioxy, benzoyloxy and methoxyl groups, in the dibenzocyclooctadiene lignan of StA, were probably functionally important to its neuroprotective activity. In addition, Western blotting analysis demonstrated that StA exhibited neuroprotection against MPP(+) through the regulation of two distinct pathways including increasing CREB-mediated Bcl-2 expression and activating PI3K/Akt survival signaling suggesting that StA might be a promising neuroprotective agent for the prevention of PD.

L-tetrahydropalamatine inhibits tumor necrosis factor-α-induced monocyte-endothelial cell adhesion through downregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 involving suppression of nuclear factor-κ B signaling pathway.

OBJECTIVE: To investigate whether I-tetrahydropalmatine (I-THP), an alkaloid mainly present in Corydalis family, could ameliorate early vascular inflammatory responses in atherosclerotic processes. METHODS: Fluorescently labeled monocytes were co-incubated with human umbilical vein endothelial cells (HUVECs), which were pretreated with I-THP and then simulated with tumor necrosis factor (TNF)-α in absence of I-THP to determine if I-THP could reduce thecytokine-induced adhesion of monocytes to HUVECs. Then I-THP were further studied the underlying mechanisms through observing the transcriptional and translational level of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and the nuclear translocation of nuclear factor (NF)-κ B in HUVECs. RESULTS: L-THP could block TNF-α-induced adhesion of monocytes to HUVECs and could significantly inhibited the expression of ICAM-1 and VCAM-1 on cell surface by 31% and 36% at 30 µ mol/L. L-THP pretreatment could also markedly reduce transcriptional and translational level of VCAM-1 as well as mildly reduce the total protein and mRNA expression levels of ICAM-1. Furthermore, I-THP attenuated TNF-α-stimulated NF-κ B nuclear translocation. CONCLUSION: These results provide evidences supporting that I-THP could be a promising compound in the prevention and treatment of the early vascular inflammatory reaction in atherosclerosis by inhibiting monocyte adhesion to vascular endothelial cell through downregulating ICAM-1 and VCAM-1 in vascular endothelial cell based on suppressing NF-κ B.

Schisantherin A protects against 6-OHDA-induced dopaminergic neuron damage in zebrafish and cytotoxicity in SH-SY5Y cells through the ROS/NO and AKT/GSK3ß pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: The fruit of Schisandra chinensis (Turcz.) Baill, has been traditionally used in management of liver diseases and ageing associated neurodegeneration. The bioactive compound from this medicinal plant would be valuable for its potential use in prevention and treatment of Parkinson׳s disease. AIM OF THE STUDY: The overall objective of the present study was to understand the neuroprotective effect of schisantherin A, a dibenzocyclooctadiene lignan from the fruit of S. chinensis (Turcz.) Baill, and to elucidate its underlying mechanism of action. MATERIAL AND METHODS: This study investigated the protective effect of schisantherin A against selective dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA)-induced neural damage in human neuroblastoma SH-SY5Y cells and zebrafish models. Oxidative stress and related signaling pathways underlying the neuroprotective effect were determined by multiple biochemical assays and Western blot. RESULTS: Pretreatment with schisantherin A offered neuroprotection against 6-OHDA-induced SH-SY5Y cytotoxicity. Moreover, schisantherin A could prevent 6-OHDA-stimulated dopaminergic neuron loss in zebrafish. Our mechanistic study showed that schisantherin A can regulate intracellular ROS accumulation, and inhibit NO overproduction by down-regulating the over-expression of iNOS in 6-OHDA treated SH-SY5Y cells. Schisantherin A also protects against 6-OHDA-mediated activation of MAPKs, PI3K/Akt and GSK3ß. CONCLUSION: These findings demonstrate that schisantherin A may have potential therapeutic value for neurodegenerative diseases associated with abnormal oxidative stress such as Parkinson׳s disease.

New perspective on the dual functions of indirubins in cancer therapy and neuroprotection.

Indirubin is an active ingredient mainly used to treat leukemia in China and is reported to be a leading inhibitor of cyclindependent kinases (CDKs) and glycogen synthase kinase-3 (GSK-3) by competing with ATP binding sites. New findings have indicated that its comprehensive structure may contribute to its polypharmacological activities particularly in cancer and neurodegenerative disease therapy, as both of these diseases are usually accompanied by a common molecular link related to abnormal phosphorylation of CDKs and GSK-3. In the elderly, cancer and neurodegenerative disease are tightly associated common diseases and sometimes unavoidably coexist. In this review, the underlying mechanisms of the dual actions of indirubin and its structurally-related compounds in cancer and neurodegenerative disease therapy are presented.

The novel tetramethylpyrazine bis-nitrone (TN-2) protects against MPTP/MPP+-induced neurotoxicity via inhibition of mitochondrial-dependent apoptosis.

Mitochondrial-dependent apoptosis plays an important role in the degeneration of dopaminergic neurons in Parkinson's disease (PD). Methyl-4-phenyl-1,2,3,6-tetra- hydropyridine (MPTP), the most widely used neurotoxin to simulate PD, is converted to 1-methyl-4-phenylpyridinium (MPP(+)) in vivo. MPP(+) induces excessive intracellular reactive oxygen species (ROS), leading to mitochondrial-dependent apoptosis via sequentially opening mitochondria permeability transition pore (mPTP) to release cytochrome c from mitochondria into cytoplasm and activate pro-apoptotic caspase proteins. We have previously synthesized 2,5-[[(1,1-dimethylethyl)oxidoimino]methyl]-3,6-trimethylpyrazine (TN-2), a novel derivative of the Chinese herb medicine tetramethylpyrazine (TMP). TN-2 is armed with two powerful free radical-scavenging nitrone moieties. TN-2 significantly reversed the loss of dopaminergic neurons in the substantia nigra and the decrease in dopamine level in the striatum induced by MPTP in mice. TN-2 ameliorated the MPTP-induced decrease of brain superoxide dismutase activity and glutathione concentration and increase of brain malondialdehyde. In addition, TN-2 inhibited MPP(+)-induced neuronal damage/apoptosis in primary cerebellum granular neurons (CGNs) and SH-SY5Y cells. TN-2 decreased excessive intracellular ROS, prevented the loss of mitochondrial membrane potential, blocked the release of mitochondrial cytochrome c and inhibited the activation of caspase-3 and caspase-9. Moreover, TN-2 treatment increased the mRNA expression of mitochondrial biogenesis factors peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 (PGC- 1α and ß) and mitochondrial transcription factor A (Tfam) in SH-SY5Y cells and CGNs. These results suggest that TN-2 protects dopaminergic neurons against MPTP/MPP(+)-induced neurotoxicity via the inhibition of mitochondrial-dependent apoptosis and possibly via the activation of mitochondrial biogenesis, indicating that TN-2 is a potential new treatment for PD.

A rhodium(III) complex inhibits LPS-induced nitric oxide production and angiogenic activity in cellulo.

Metal-containing complexes have arisen as viable alternatives to organic molecules as therapeutic agents. Metal complexes possess a number of advantages compared to conventional carbon-based compounds, such as distinct geometries, interesting electronic properties, variable oxidation states and the ability to arrange different ligands around the metal centre in a precise fashion. Meanwhile, nitric oxide (NO) plays key roles in the regulation of angiogenesis, vascular permeability and inflammation. We herein report a novel cyclometalated rhodium(III) complex as an inhibitor of lipopolysaccharides (LPS)-induced NO production in RAW264.7 macrophages. Experiments suggested that the inhibition of NO production in cells by complex 1 was mediated through the down-regulation of nuclear factor-κB (NF-κB) activity. Furthermore, complex 1 inhibited angiogenesis in human umbilical vein endothelial cells (HUVECs) as revealed by an endothelial tube formation assay. This study demonstrates that kinetically inert rhodium(III) complexes may be potentially developed as effective anti-angiogenic agents.

A novel tetramethylpyrazine bis-nitrone (TN-2) protects against 6-hydroxyldopamine-induced neurotoxicity via modulation of the NF-κB and the PKCα/PI3-K/Akt pathways.

INTRODUCTION: The natural product tetramethylpyrazine (TMP) has a variety of biologic activities, including neuroprotection. Nitrones are powerful free radical scavengers. We have designed and synthesized a TMP derivative, TN-2, which is armed with two nitrone moieties. AIMS: In this study, we investigated the neuroprotective effect of TN-2 against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro and in zebrafish. METHODS: PC12 cells, zebrafish and rats were exposed to 6-OHDA challenge. MTT assay, LDH release, Hoechst staining, DAF-FM staining, luciferase reporter construct transfection, and western blotting were applied to detect cell viability, apoptosis, intracellular nitric oxide (NO), NF-κB transcriptional activity and proteins expression. In zebrafish, whole-mount staining and real-time PCR were performed to quantify dopaminergic neurons and mRNA expression. Hematoxylin and eosin staining and immunohistochemistry for glial fibrillary acidic protein were used to detect the astrocyte activation in the unilateral 6-OHDA rat model. RESULTS: TN-2 but not TMP exhibited potent neuroprotective effect against 6-OHDA-induced apoptosis in PC12 cells. Moreover, TN-2 prevented dopaminergic neuron loss and suppressed mRNA expression of pro-inflammatory genes, including IL-1ß, TNF-α and COX-2, in 6-OHDA-treated zebrafish. TN-2 remarkably attenuated microglial/astrocyte activation in the unilateral 6-OHDA rat model. The mechanistic study demonstrated that TN-2 inhibited over-production of intracellular NO and protein expression of inducible nitric oxide synthase through down-regulating NF-κB activity. Additionally, the PKCα/PI3-K/Akt pathway was also involved in the neuroprotection of TN-2. CONCLUSION: These results suggest that TN-2 protected against 6-OHDA-induced neurotoxicity via modulating the NF-κB-medicated neuroinflammation and PKCα/PI3-K/Akt pathways.

In vivo angiogenesis screening and mechanism of action of novel tanshinone derivatives produced by one-pot combinatorial modification of natural tanshinone mixture from Salvia miltiorrhiza.

BACKGROUND: Natural products present in low quantity in herb medicines constitute an important source of chemical diversity. However, the isolation of sufficient amounts of these low abundant constituents for structural modification has been a challenge for several decades and subsequently halts research on the utilization of this important source of chemical entities for drug discovery and development. And, pro-angiogenic therapies are being explored as options to treat cardio-cerebral vascular diseases and wound healing recently. The present study investigates the pro-angiogenic potential of tanshinone derivatives produced by one-pot synthesis using zebrafish model. METHODOLOGY/PRINCIPAL FINDINGS: In order to address the difficulty of chemical modification of low abundant constituents in herb medicines, a novel one-pot combinatorial modification was used to diversify a partially purified tanshinone mixture from Salvia miltiorrhiza. This led to the isolation of ten new imidazole-tanshinones (Compounds 1-10) and one oxazole-tanshinone (Compound 11), the structures of which were characterized by spectroscopic methods in combination with single-crystal X-ray crystallographic analysis. The angiogenesis activities of the new tanshinone derivatives were determined in an experimental model of chemical-induced blood vessels damage in zebrafish. Of all the tested new derivatives, compound 10 exhibited the most potent vascular protective and restorative activity with an EC50 value of 0.026 µM. Moreover, the mechanism underlying the pro-angiogenesis effect of 10 probably involved the VEGF/FGF-Src-MAPK and PI3K-P38 signalling pathways by gene expression analysis and a blocking assay with pathways-specific kinase inhibitors. CONCLUSIONS/SIGNIFICANCE: Taken together, our study demonstrated the more distinctive pro-angiogenic properties of 10 than other tanshinones and revealed 10 has potential for development as a pro-angiogenic agent for diseases associated with insufficient angiogenesis. Our results highlighted the great potential of adopting a newly modified one-pot approach to enhance the chemical diversity and biological activities of constituents from natural products regardless of their abundances.

Discovery of a benzofuran derivative (MBPTA) as a novel ROCK inhibitor that protects against MPP⁺-induced oxidative stress and cell death in SH-SY5Y cells.

Parkinson disease (PD) is a neurodegenerative disease with multifactorial etiopathogenesis. The discovery of drug candidates that act on new targets of PD is required to address the varied pathological aspects and modify the disease process. In this study, a small compound, 2-(5-methyl-1-benzofuran-3-yl)-N-(5-propylsulfanyl-1,3,4-thiadiazol-2-yl) acetamide (MBPTA) was identified as a novel Rho-associated protein kinase inhibitor with significant protective effects against 1-methyl-4-phenylpyridinium ion (MPP(+))-induced damage in SH-SY5Y neuroblastoma cells. Further investigation showed that pretreatment of SH-SY5Y cells with MBPTA significantly suppressed MPP(+)-induced cell death by restoring abnormal changes in nuclear morphology, mitochondrial membrane potential, and numerous apoptotic regulators. MBPTA was able to inhibit MPP(+)-induced reactive oxygen species (ROS)/NO generation, overexpression of inducible NO synthase, and activation of NF-κB, indicating the critical role of MBPTA in regulating ROS/NO-mediated cell death. Furthermore, MBPTA was shown to activate PI3K/Akt survival signaling, and its cytoprotective effect was abolished by PI3K and Akt inhibitors. The structural comparison of a series of MBPTA analogs revealed that the benzofuran moiety probably plays a crucial role in the anti-oxidative stress action. Taken together, these results suggest that MBPTA protects against MPP(+)-induced apoptosis in a neuronal cell line through inhibition of ROS/NO generation and activation of PI3K/Akt signaling.

Bisdemethoxycurcumin suppresses MCF-7 cells proliferation by inducing ROS accumulation and modulating senescence-related pathways.

BACKGROUND: Bisdemethoxycurcumin (BDMC) is a natural derivative of curcumin present in the phenolic components extracted from the dried rhizome of Curcuma longa L. BDMC demonstrated potential chemotherapeutic activities but the underlying mechanisms have not been fully clarified. In the present study, the role of reactive oxidative species (ROS) in the anti-cancer effects of BDMC was investigated. METHODS: MCF-7 cells were exposed to BDMC, and then the cell proliferation, colony formation ability and cell cycle profile were analyzed. Cellular ROS level was determined by flow cytometry and fluorescent microscope observation using specific fluorescent probes. Mitochondrial membrane potential (ψm) was assessed using JC-1. In addition, effects of BDMC on senescence-related molecules were analyzed by western blot assay. RESULTS: BDMC significantly inhibited MCF-7 breast cancer cell proliferation, while a rapid rise of the intracellular ROS level accompanied with a reduction of Dym were observed. In addition, BDMC activated the pro-apoptotic protein p53 and its downstream effector p21 as well as the cell cycle regulatory proteins p16 and its downstream effector retinoblastoma protein (Rb). All of these BDMC-induced effects were counteracted with the pre-incubation of the antioxidant N-acetylcysteine (NAC). CONCLUSIONS: These results suggested that BDMC-induced ROS accumulation may contribute to its inhibitory effect on MCF-7 cell viability through regulation of p53/p21 and p16/Rb pathways.

Enzyme kinetic and molecular docking studies for the inhibitions of miltirone on major human cytochrome P450 isozymes.

Previous studies have shown that major tanshinones isolated from Danshen (Salvia miltiorrhiza) inhibited human and rat CYP450 enzymes-mediated metabolism of model probe substrates, with potential in causing herb-drug interactions. Miltirone, another abietane type-diterpene quinone isolated from Danshen, has been reported for its anti-oxidative, anxiolytic and anti-cancer effects. The aim of this study was to study the effect of miltirone on the metabolism of model probe substrates of CYP1A2, 2C9, 2D6 and 3A4 in pooled human liver microsomes. Miltirone showed moderate inhibition on CYP1A2 (IC(50)=1.73 µM) and CYP2C9 (IC(50)=8.61 µM), and weak inhibition on CYP2D6 (IC(50)=30.20 µM) and CYP3A4 (IC(50)=33.88 µM). Enzyme kinetic studies showed that miltirone competitively inhibited CYP2C9 (K(i)=1.48 µM), and displayed mixed type inhibitions on CYP1A2, CYP2D6 and CYP3A4 with K(i) values of 3.17 µM, 24.25 µM and 35.09 µM, respectively. Molecular docking study further confirmed the ligand-binding conformations of miltirone in the active sites of these human CYP450 isoforms, and provided some information on structure-activity relationships for the CYPs inhibition by tanshinones. Taken together, CYPs inhibitions of miltirone were weaker than dihydrotanshinone, but stronger than cryptotanshinone, tanshinone I and tanshinone IIA.

Danshensu protects against 6-hydroxydopamine-induced damage of PC12 cells in vitro and dopaminergic neurons in zebrafish.

The overproduction of reactive oxygen species (ROS) has been implicated in the development of neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD). Previous studies have indicated that danshensu (beta-3,4-dihydroxyphenyl-lactic acid), a main hydrophilic component of the Chinese materia medica Radix Salviae Miltiorrhizae (Danshen, Pharmacopoeia of PR China), has ROS scavenging and antioxidant activities, however its mechanism of action was not clear. In this study, we investigated whether the protective effects of danshensu against neurotoxin 6-hydroxydopamine (6-OHDA)-induced oxidative stress involved the Nrf2/HO-1 pathways. Pretreatment with danshensu in PC12 cells significantly attenuated 6-OHDA-induced cytotoxicity and the production of ROS. Danshensu activated the nuclear translocation of Nrf2 to increase heme oxygenase-1 (HO-1), conferring protection against ROS. Danshensu induced the phosphorylation of Akt, and its cytoprotective effect was abolished by PI3K, Akt and HO-1 inhibitors. These results confirmed the crucial role of PI3K/Akt and HO-1 signaling pathways as the underlying mechanistic action of danshensu. Taken together, the results suggest that danshensu enhances HO-1 expression to suppress 6-OHDA-induced oxidative damage via PI3K/Akt/Nrf2 signaling pathways. Moreover, 6-OHDA-induced dopaminergic neuronal loss in zebrafish could be reduced by danshensu, further supporting the neuroprotective potential of danshensu.