Cardiotoxicity of sanguinarine via regulating apoptosis and MAPK pathways in zebrafish and HL1 cardiomyocytes.

Sanguinarine, a plant phytoalexin, possesses extensive biological activities including antimicrobial, insecticidal, antitumor, anti-inflammatory and anti-angiogenesis effect. But its cardiotoxicity has rarely been studied. Here, we assess the cardiotoxicity of sanguinarine in vivo using larval zebrafish from 48 hpf to 96 hpf. The results show that sanguinarine caused severe malformation and the dysfunction of the heart including reductions of heart rate, red blood cell number, blood flow dynamics, stroke volume and increase of SV-BA distance, subintestinal venous congestion. Further studies showed that apoptosis in the zebrafish heart region was observed after sanguinarine exposure using TUNEL assay and AO staining method. In addition, the genes, such as sox9b, myl7, nkx2.5 and bmp10, which play crucial parts in the development and the function of the heart, were changed after sanguinarine treatment. caspase3, caspase9, bax and bcl2, apoptosis-related genes, were also altered by sanguinarine. Further studies were performed to study the cardiotoxicity in vitro using cardiomyocytes HL1 cell line. The results showed that remarkable increase of apoptosis and ROS level in HL1 cells were induced by sanguinarine. Moreover, the MAPK pathway (JNK and P38) were notably enhanced and involved in the cardiotoxicity induced by sanguinarine. Our findings will provide better understanding of sanguinarine in the toxic effect on heart.

Roxadustat Does Not Affect Platelet Production, Activation, and Thrombosis Formation.

Objective: Roxadustat is a new medication for the treatment of renal anemia. EPO (erythropoietin)-the current treatment standard-has been reported to enhance platelet activation and production. However, to date, the effect of roxadustat on platelets is unclear. To address this deficiency, herein, we have evaluated the effect of roxadustat on platelet production and function. Approach and Results: We performed several mouse platelet functional assays in the presence/absence of in vitro and in vivo roxadustat treatment. Both healthy and 5/6 nephrectomized mice were utilized. The effect of roxadustat on platelet function of healthy volunteers and chronic kidney disease patients was also evaluated. For platelet production, megakaryocyte maturation and proplatelet formation were assayed in vitro. Peripheral platelet and bone marrow megakaryocyte counts were also determined. We found that roxadustat could not stimulate washed platelets directly, and platelet aggregation, spreading, clot retraction, and P-selectin/JON/A exposure were similar with or without in vitro or in vivo roxadustat treatment among both healthy and 5/6 nephrectomized mice. In vivo mouse thrombosis models were additionally performed, and no differences were detected between the vehicle and roxadustat treatment groups. EPO, which was considered a positive control in the present study, promoted platelet function and production as reported previously. Megakaryocyte maturation and proplatelet formation were also not significantly different between control mice and those treated with roxadustat. After receiving roxadustat for 14 days, no difference in the peripheral platelet count was observed in the mice. Conclusions: Administration of roxadustat has no significant impact on platelet production and function.

Developmental toxicity caused by sanguinarine in zebrafish embryos via regulating oxidative stress, apoptosis and wnt pathways.

Sanguinarine, derived from the root of Sanguinaria canadensis, have multiple biological activities, such as antimicrobial, insecticidal, antitumor, anti-inflammatory and anti-angiogenesis effect, but little is known about its toxicity on normal embryonic development. Here, we study the developmental toxicity using zebrafish model. Notably, sanguinarine caused a significant increase of the malformation rate and decrease of hatching rates and body length of zebrafish embryos. Sanguinarine also impaired the normal development of heart, liver and nerve system of zebrafish embryos. Further, the ROS level and MDA concentrations were remarkably increased, while the activity of T-SOD was decreased. In addition, obvious increase of apoptosis were observed by AO staining or TUNEL assay. Further studies showed that the oxidative stress-, apoptosis-related genes were changed, while genes of nrf2 and wnt pathways were inhibited by sangunarine. To sum up, our study will be helpful to understand the adverse effect of sanguinarine on embryonic development and the underlying molecular mechanism.

Molecular Initiating Events Associated with Drug-Induced Liver Malignant Tumors: An Integrated Study of the FDA Adverse Event Reporting System and Toxicity Predictions.

Liver malignant tumors (LMTs) represent a serious adverse drug event associated with drug-induced liver injury. Increases in endocrine-disrupting chemicals (EDCs) have attracted attention in recent years, due to their liver function-inhibiting abilities. Exposure to EDCs can induce nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, which are major etiologies of LMTs, through interaction with nuclear receptors (NR) and stress response pathways (SRs). Therefore, exposure to potential EDC drugs could be associated with drug-induced LMTs. However, the drug classes associated with LMTs and the molecular initiating events (MIEs) that are specific to these drugs are not well understood. In this study, using the Food and Drug Administration Adverse Event Reporting System, we detected LMT-inducing drug signals based on adjusted odds ratios. Furthermore, based on the hypothesis that drug-induced LMTs are triggered by NR and SR modulation of potential EDCs, we used the quantitative structure-activity relationship platform for toxicity prediction to identify potential MIEs that are specific to LMT-inducing drug classes. Events related to cell proliferation and apoptosis, DNA damage, and lipid accumulation were identified as potential MIEs, and their relevance to LMTs was supported by the literature. The findings of this study may contribute to drug development and research, as well as regulatory decision making.

Managing toxicities of phosphatidylinositol-3-kinase (PI3K) inhibitors.

Despite the proven effective approach to targeting the phosphatidylinositol-3-kinase (PI3K) pathway in B-cell malignancies, the approved PI3K inhibitors idelalisib and duvelisib have been less commonly selected for patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), given the availability of other more tolerable agents. However, patients with CLL/SLL can experience a disease course that is multiply relapsed, refractory, or intolerant to treatment, and PI3K inhibitors can achieve meaningful responses. This article reviews the common early- and late-onset (considered immune-mediated) toxicities with PI3K inhibitors, including infections, hepatotoxicity, diarrhea and/or colitis, and pneumonitis. Data on pretreatment considerations, toxicity management, and drug rechallenge are presented. In addition, next-generation PI3K inhibitors and novel treatment approaches with PI3K inhibitors, including combinations, time-limited treatments, and intermittent dosing, are highlighted.

Synergistic Neuroprotective Effect of Endogenously-Produced Hydroxytyrosol and Synaptic Vesicle Proteins on Pheochromocytoma Cell Line Against Salsolinol.

Oxidative stress triggers a lethal cascade, leading to Parkinson's disease by causing degeneration of dopaminergic neurons. In this study, eight antioxidants were screened for their neuroprotective effect on PC12 cells (pheochromocytoma cell line) under oxidative stress induced by salsolinol (OSibS). Hydroxytyrosol was found to be the strongest neuroprotective agent; it improved viability of PC12 cells by up to 81.69% under OSibS. Afterward, two synaptic vesicle proteins, synapsin-1 and septin-5, were screened for their neuroprotective role; the overexpression of synapsin-1 and the downregulation of septin-5 separately improved the viability of PC12 cells by up to 71.17% and 67.00%, respectively, compared to PC12 cells only treated with salsolinol (PoTwS) under OSibS. Subsequently, the PC12+syn++sep- cell line was constructed and pretreated with 100 µM hydroxytyrosol, which improved its cell viability by up to 99.03% and led to 14.71- and 6.37-fold reductions in the levels of MDA and H2O2, respectively, and 6.8-, 12.97-, 10.57-, and 7.57-fold increases in the activity of catalase, glutathione reductase, superoxide dismutase, and glutathione peroxidase, respectively, compared to PoTwS under OSibS. Finally, alcohol dehydrogenase-6 from Saccharomyces cerevisiae was expressed in PC12+syn++sep- cells to convert 3,4-dihydroxyphenylacetaldehyde (an endogenous neurotoxin) into hydroxytyrosol. The PC12+syn++sep-+ADH6+ cell line also led to 22.38- and 12.33-fold decreases in the production of MDA and H2O2, respectively, and 7.15-, 13.93-, 12.08-, and 8.11-fold improvements in the activity of catalase, glutathione reductase, superoxide dismutase, and glutathione peroxidase, respectively, compared to PoTwS under OSibS. Herein, we report the endogenous production of a powerful antioxidant, hydroxytyrosol, from 3,4-dihydroxyphenylacetaldehyde, and evaluate its synergistic neuroprotective effect, along with synapsin-1 and septin-5, on PC12 cells under OSibS.

Salsolinol-neurotoxic or Neuroprotective?

Salsolinol (6,7-dihydroxy-1-methyl-1,2,3,4-tetrahydroisoquinoline), widely available in many edibles, is considered to alter the function of dopaminergic neurons in the central nervous system and thus, multiple hypotheses on its either physiological and/or pathophysiological role have emerged. The aim of our work was to revisit its potentially neurotoxic and/or neuroprotective role through a series of both in vitro and in vivo experiments. Salsolinol in the concentration range 10-250 µM did not show any significant release of lactate dehydrogenase from necrotic SH-SY5Y cells and was able in the concentration of 50 and 100 µM to rescue SH-SY5Y cells from death induced by H2O2. Its neuroprotective effect against neurotoxin 6-hydroxydopamine was also determined. Salsolinol was found to decrease significantly the reactive oxygen species level in SH-SY5Y cells treated by 500 µM H2O2 and the caspase activity induced by 300 µM of H2O2 or 100 µM of 6-hydroxydopamine. Serum levels of TNFα and CRP of salsolinol-treated rats were not significantly different from control animals. Both TNFα and CRP served as indirect markers of neurotoxicity and/or neuroprotection. Although the neurotoxic properties of salsolinol have numerously been emphasized, its neuroprotective properties should not be neglected and need greater consideration.

Determination of Selected Isoquinoline Alkaloids from Mahonia Aquifolia; Meconopsis Cambrica; Corydalis Lutea; Dicentra Spectabilis; Fumaria Officinalis; Macleaya Cordata Extracts by HPLC-DAD and Comparison of Their Cytotoxic Activity.

Alkaloids have protective functions for plants and can play an important role in living organisms. Alkaloids may have a wide range of pharmacological activities. Many of them have cytotoxic activity. Nowadays, cancer has become a serious public health problem. Searching for effective drugs with anticancer activity is one of the most significant challenges of modern scientific research. The aim of this study was the investigation of cytotoxic activity of extracts obtained from Corydalis lutea root and herb, Dicentra spectabilis root and herb, Fumaria officinalis, Macleaya cordata leaves and herb, Mahonia aquifolia leaves and cortex, Meconopsis cambrica root and herb on FaDu, SCC-25, MCF-7, and MDA-MB-231 cancer cell lines. The cytotoxic activity of these extracts has not been previously tested for these cell lines. The aim was also to quantify selected alkaloids in the investigated extracts by High Performance Liquid Chromatography (HPLC). The analyses of alkaloid content were performed using HPLC in reversed phase (RP) mode using Polar RP column and mobile phase containing acetonitrile, water and ionic liquid (IL). Cytotoxic effect of the tested plant extracts and respective alkaloid standards were examined using human pharyngeal squamous carcinoma cells (FaDu), human tongue squamous carcinoma cells (SCC-25), human breast adenocarcinoma cell line (MCF-7), human triple-negative breast adenocarcinoma cell line (MDA-MB-231). All investigated plant extracts possess cytotoxic activity against tested cancer cell lines: FaDu, SCC-25, MCF-7, and MDA-MB-231. The highest cytotoxic activity against FaDu, SCC-25, and MCF-7 cell lines was estimated for Macleaya cordata leaf extract, while the highest cytotoxic activity against MDA-MB-231 cell line was obtained for Macleaya cordata herb extract. Differences in cytotoxic activity were observed for extracts obtained from various parts of investigated plants. In almost all cases the cytotoxic activity of investigated plant extracts, especially at the highest concentration against tested cell lines was significantly higher than the activity of anticancer drug etoposide. Our investigations exhibit that these plant extracts can be recommended for further in vivo experiments to confirm their anticancer activity.

Sanguinarine caused larval lethality and growth inhibition by suppressing energy metabolism in silkworms, Bombyx mori.

Sanguinarine (Sang) is a natural alkaloid and distributed in several plants of Papaveraceae. The antitumor, antioxidant, antimicrobial and anti-inflammatory effects of Sang were extensively reported, but its speciality and mechanism against Lepidoptera insects were still unknown. In this study, detailed toxicological parameters of Sang against silkworms, Bombyx mori (B. mori), were determined by a toxicological test. Then, a nuclear magnetic resonance-based (NMR) metabolomics method was adopted to analyze the changes in hemolymph metabolites of silkworms after feeding Sang. The growth of fourth-instar larvae was significantly ceased by the oral administration of 0.05-0.3% Sang and vast deaths appeared in 0.3% Sang group on Day 4 and Day 5. The quantitative analysis of metabolites indicated that trehalose and citrate levels in hemolymph were increased after 24 h of feeding 0.3% Sang, whereas the concentrations of pyruvate, succinate, malate and fumarate were decreased. In addition, the enzymatic determination and reverse transcription quantitative PCR (RT-qPCR) showed that the trehalase (THL) activity and the transcriptional level of one gene coding THL were uniformly weakened by 0.3% Sang. One of the important mechanisms of Sang against silkworms might be interpreted as follows. Sang impaired trehalose hydrolysis, reduced THL activity and transcription, and led to the inhibition of energy metabolism, consequent antigrowth and high lethality in larvae of B. mori. Our findings offered new insights into the insecticidal effect of Sang from the perspective of energy metabolism and provided the basis for the application of Sang in the control of Lepidoptera pests.

Characterization of the cytotoxicity of selected Chelidonium alkaloids in rat hepatocytes.

Phytomedicinal preparations containing extracts of the plant Chelidonium majus (Greater Celandine) have been used in the therapy of upper abdominal disorders. C. majus alkaloids (CAL) were suspected to be responsible for reported cases of liver symptoms including cases of acute liver failure in patients upon treatment with certain C. majus preparations. Based on these reports, a safe oral daily dose limit of not more than 2.5 mg CAL was established in the EU. However, C. majus extracts and individual CAL were not able to elicit similar adverse effects when given orally to pigs or rats. We found that CAL differ considerably in their cytotoxicity in rat hepatocytes in culture. The cationic congeners chelerythrine, coptisine and sanguinarine were the most toxic ones (EC20 values ≤2 µM) while the neutral congeners chelidonine, dihydrosanguinarine and protopine were less toxic, with a rank order of toxicity of coptisine > chelerythrine > sanguinarine > chelidonine > protopine > dihydrosanguinarine. Calculation of octanol-water partition coefficients revealed that the most cytotoxic CAL in hepatocytes were the cationic polar ones. At cytotoxic concentrations sanguinarine led to a marked decrease in reduced and oxidized intracellular glutathione while the much less cytotoxic dihydrosanguinarine did not. After glutathione depletion with menadione, CAL toxicity was only slightly enhanced. Comparison of the cytotoxic concentrations to reported liver levels in experimental animals suggests that the latter were too low to cause hepatotoxicity, probably due to an extremely low oral availability of certain CAL.

A dual functional turn-on non-toxic chemosensor for highly selective and sensitive visual detection of Mg2+ and Zn2+: the solvent-controlled recognition effect and bio-imaging application.

A new dual functional turn-on chemosensor, 2,6-diformyl-4-methylphenol-di(isoquinolinyl-1-hydrazone) (HL), has been developed, which could highly selectively discriminate Mg2+ and Zn2+ in different solvent systems. The chemosensor HL exhibits rapid visual turn-on fluorescence enhancing recognition toward Mg2+/Zn2+, which is not interfered by other cations, especially for respective congeners Ca2+/Cd2+. The remarkable fluorescence enhancement (71-fold or 11-fold) was observed after adding Mg2+ in acetonitrile or Zn2+ in DMF-H2O solvent systems. Additionally such a solvent medium-controlled platform could achieve the quantitative determination of Mg2+ and Zn2+ quantitation with low detection limits of 2.97 × 10-8 M and 3.07 × 10-7 M, respectively. Furthermore, the turn-on fluorescence sensing mechanism is also investigated by 1H NMR, FT-IR and ESI-MS spectroscopy. Density functional theory (DFT) calculations derive optimized geometries of HL and its complexes. Notably, non-toxic HL also can be successfully applied as a visual probe for the practical determination of Mg2+/Zn2+ in MCF-7 cells, Zebrafish larvae, syrup and water samples, which might provide extensive application in biology and medicine fields.

Duvelisib, an oral dual PI3K-δ, γ inhibitor, shows clinical activity in indolent non-Hodgkin lymphoma in a phase 1 study.

Duvelisib (IPI-145) is an oral dual inhibitor of phosphoinositide-3-kinase (PI3K)-δ and -γ in clinical development for the treatment of hematologic malignancies, including indolent non-Hodgkin lymphoma (iNHL). In a Phase 1, open-label study to determine the maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, clinical activity, and safety of duvelisib monotherapy in patients with advanced hematologic malignancies, duvelisib was administered at eight dose levels (8-100 mg BID) in a dose-escalation phase (n = 31 evaluable patients). Two dose-limiting toxicities (DLTs), Grade 3 transaminase elevations and Grade 3 rash, occurred at 100 mg BID, and the MTD was determined to be 75 mg BID. Across all doses, 58.1% of iNHL patients had a response (19.4% complete, 35.5% partial, and 3.2% minor); median time to response was 1.84 months and duration of response was 16.9 months. Median progression-free survival was 14.7 months, and the probability of overall survival at 24 months was 71.7%. Severe (Grade ≥ 3) adverse events included elevated liver enzymes (38.7%), diarrhea (25.8%), and neutropenia (29.0%). Three patients, all in the 75 mg BID cohort, experienced fatal AEs: E. coli sepsis, acute respiratory failure, and fungal pneumonia. No iNHL patients experienced Pneumocystis pneumonia. Duvelisib demonstrated favorable clinical activity and an acceptable safety profile in these high-risk, heavily pretreated, relapsed/refractory iNHL patients, with 25 mg BID selected for further clinical development.

Influence of PARP-1 inhibition in the cardiotoxicity of the topoisomerase 2 inhibitors doxorubicin and mitoxantrone.

Doxorubicin (DOX) and Mitoxantrone (MTX) are very effective drugs for a range of tumors despite being highly cardiotoxic. DNA topoisomerase 2 beta (Top2ß) was revealed as key mediator of DOX-induced cardiotoxicity, although ROS generation is also an important mechanism. Oxidative stress is also an important issue in MTX-induced cardiotoxicity that is manifested by mitochondrial dysfunction. Studies have demonstrated the relationship between PARP-1 overactivation and cell viability in DOX-treated cardiomyocytes. In reference of MTX, data regarding PARP-1 overactivation as the mechanism responsible for cardiotoxicity is difficult to find. The aim of this study was to evaluate the influence of PARP-1 inhibitor DPQ on DOX- and MTX-mediated cardiotoxicity. Cells were exposed for 24 h to DOX or MTX in the presence or absence of DPQ. Viability, apoptosis, and genotoxicity assays were carried out. Immunofluorescence of phosphorylated histone H2AX was analyzed in H9c2 cells and cardiomyocytes from neonatal rats. Results demonstrated that DPQ co-treatment increases DOX-induced apoptosis in H9c2 cells. DPQ also prevents DOX and MTX-ROS generation in part by increasing SOD and CAT activities. Furthermore, DPQ co-treatment increased the generation of DNA strand breaks by DOX and MTX whilst also inducing phosphorylation of H2AX, MRE11, and ATM in H9c2 cells. Our results demonstrated that as well as increasing DNA damage and inducing apoptotic cell death, DPQ enhances DOX- and MTX-mediated cytotoxicity in H9c2.

Design, synthesis and biological evaluation of novel tetrahydroisoquinoline derivatives as P-glycoprotein-mediated multidrug resistance inhibitors.

Multidrug resistance (MDR) is one of the main obstacles of clinical chemotherapy. A great deal of research shows that the occurrence of drug resistance in various malignant tumors is closely related to the expression of P-glycoprotein (P-gp) on the surface of the cell membrane. In this paper, based on the structure-activity relationship of phenylethyl tetrahydroisoquinoline, we choose tariquidar as the lead compound for the design and synthesis of 17 novel tetrahydroisoquinoline P-gp inhibitors. Additionally, in vitro and in vivo cytotoxicity assays and reversed MDR activity assays were evaluated. Among them, compound 3 had a good reversal of MDR activity and the reversal mechanism study of it was carried out. All of these results demonstrated that compound 3 was considered to be a promising P-gp-mediated MDR reversal candidate.

Assessing the risk of epidemic dropsy from black salve use.

Epidemic dropsy is a potentially life-threatening condition resulting from the ingestion of argemone oil derived from the seeds of Argemone mexicana Linn. Exposure to argemone oil is usually inadvertent, arising from mustard cooking oil adulteration. Sanguinarine, an alkaloid present in argemone oil, has been postulated as a causative agent with the severity of epidemic dropsy correlating with plasma sanguinarine levels. Cases of epidemic dropsy have also been reported following the topical application of argemone containing massage oil. Black salve, a topical skin cancer therapy also contains sanguinarine, but at significantly higher concentrations than that reported for contaminated massage oil. Although not reported to date, a theoretical risk therefore exists of black salve inducing epidemic dropsy. This literature review explores the presentation and pathophysiology of epidemic dropsy and assesses the risk of it being induced by black salve.

Evaluation of the Carcinogenic Potential of Roxadustat (FG-4592), a Small Molecule Inhibitor of Hypoxia-Inducible Factor Prolyl Hydroxylase in CD-1 Mice and Sprague Dawley Rats.

The carcinogenic potential of roxadustat (FG-4592), a novel orally active, heterocyclic small molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase (HIF-PH) enzymes in clinical development for treatment of anemia, was evaluated in CD-1 mice and Sprague Dawley rats. Inhibition of HIF-PH by roxadustat leads to a rapid increase in cytoplasmic HIF-α concentrations, followed by translocation of HIF-α to the nucleus and upregulation of HIF-responsive genes, including erythropoietin. Roxadustat was dosed by oral gavage 3 times weekly (TIW) for up to 104 weeks in mice at 0, 15, 30, and 60 mg/kg and in rats at 0, 2.5, 5, and 10 mg/kg. Treatment-associated changes in hematology parameters were consistent with the pharmacologic activity of roxadustat and included elevations in hematocrit in mice at 30 and 60 mg/kg TIW and elevations in erythrocyte count, hemoglobin, hematocrit, and red cell distribution width in rats at 10 mg/kg TIW. No increase in mortality or neoplastic effects compared with vehicle controls was observed after roxadustat treatment in either species. No treatment-related nonneoplastic findings were observed in mice, whereas nonneoplastic microscopic findings in rats were limited to atrial/aortic thromboses at 10 mg/kg TIW males and bone marrow hypercellularity in all treated male and female groups, consistent with the pharmacology of roxadustat. In conclusion, roxadustat administered by oral gavage to mice and rats TIW for up to 104 weeks resulted in dose-dependent exposure and hematologic effects with no effect on survival or development of neoplastic lesions at up to 60 mg/kg in mice and up to 10 mg/kg in rats.

Phytochemicals prevent mitochondrial membrane permeabilization and protect SH-SY5Y cells against apoptosis induced by PK11195, a ligand for outer membrane translocator protein.

Epidemiological studies present the beneficial effects of dietary habits on prevention of aging-associated decline of brain function. Phytochemicals, the second metabolites of food, protect neuronal cells from cell death in cellular models of neurodegenerative disorders, and the neuroprotective activity has been ascribed to the anti-oxidant and anti-inflammatory functions. In this paper, the cellular mechanism of neuroprotection by phytochemicals was investigated, using the cellular model of mitochondrial apoptosis induced by PK11195, a ligand of outer membrane translocator protein, in SH-SY5Y cells. PK11195 induced mitochondrial membrane permeabilization with rapid transit production of superoxide (superoxide flashes) and calcium release from mitochondria, and activated apoptosis signal pathway. Study on the structure-activity relationship of astaxanthin, ferulic acid derivatives, and sesame lignans revealed that these phytochemicals inhibited mitochondrial membrane permeabilization and protected cells from apoptosis. Ferulic acid derivatives and sesame lignans inhibited or enhanced the mitochondrial pore formation and cell death by PK11195 according to their amphiphilic properties, not directly depending on the antioxidant activity. Regulation of pore formation at mitochondrial membrane is discussed as a novel mechanism behind neuroprotective activity of phytochemicals in aging and age-associated neurodegenerative disorders, and also behind dual functions of phytochemicals in neuronal and cancer cells.

Sulfhydryl-Based Inhibition of δ-ALA-D and Na+ , K+ -ATPase Activities Depends on the Organoselenium Group Bonded to the Isoquinoline.

Organoselenium compounds and isoquinoline derivatives have their toxicity linked to induction of pro-oxidant situations. δ-Aminolevulinate dehydratase (δ-ALA-D) and Na+ , K+ -ATPase have sulfhydryl groups susceptible to oxidation. Thus, we investigated toxicological effects of 4-organoseleno-isoquinoline derivatives, cerebral monoamine oxidase B inhibitors, on rat cerebral δ-ALA-D and Na+ , K+ -ATPase activities and the involvement of sulfhydryl groups in vitro. Compounds substituted with fluoro (4-(4-fluorophenylseleno)-3-phenylisoquinoline), chloro (4-(4-chlorophenylseleno)-3-phenylisoquinoline) and trifluoro (4-(3-trifluoromethylphenylseleno)-3-phenylisoquinoline) at the selenium-bonded aromatic ring inhibited δ-ALA-D (IC50 values: 78.42, 92.27, 44.98 µM) and Na+ , K+ -ATPase (IC50 values: 41.36, 89.43, 50.66 µM) activities, possibly due to electronic effects induced by these groups. 3-Phenyl-4-(phenylseleno) isoquinoline (without substitution at the selenium-bonded aromatic ring) and 4-(4-methylphenylseleno)-3-phenylisoquinoline (with a methyl group substituted at the selenium-bonded aromatic ring) did not alter the activity of these enzymes. Dithiothreitol, a reducing agent, restored the enzymatic activities inhibited by 4-(4-fluorophenylseleno)-3-phenylisoquinoline, 4-(4-chlorophenylseleno)-3-phenylisoquinoline and 4-(3-trifluoromethylphenylseleno)-3-phenylisoquinoline, suggesting the involvement of sulfhydryl residues in this effect. However, the release of essential zinc seems not to be related to the δ-ALA-D inhibition by these compounds. According to these data, the effect of oral administration (300 mg/kg, intragastric) of 3-phenyl-4-(phenylseleno) isoquinoline on markers of systemic toxicity in Wistar rats was evaluated. None signs of toxicity was observed during or after treatment. This study suggests that the insertion of electron-withdrawing groups in the aromatic ring bonded to the selenium atom of isoquinolines tested increased its inhibitory effect on sulfhydryl enzymes in vitro. 3-Phenyl-4-(phenylseleno) isoquinoline, which has documented pharmacological properties, had no toxicological effects on the parameters evaluated in this study. J. Cell. Biochem. 118: 1144-1150, 2017. © 2016 Wiley Periodicals, Inc.

Cytotoxicity of Naturally Occurring Isoquinoline Alkaloids of Different Structural Types.

Forty-six isoquinoline alkaloids, of eleven structural types isolated in our laboratory, have been evaluated for their cytotoxicity against two cancer cell lines (Caco-2 and Hep-G2 cancer cells), as well as against normal human lung fibroblast cells. Only scoulerine, aromoline, berbamine and parfumidine showed significant cytotoxic effects, but only scoulerine was active against both Caco-2 and Hep-G2 cells (IC50 values 6.44 ± 0.87 and 4.57 ± 0.42, respectively). Unfortunately, except for parfumidine, the other active alkaloids were also cytotoxic to the normal human lung fibroblast cells.

Rasagiline and selegiline suppress calcium efflux from mitochondria by PK11195-induced opening of mitochondrial permeability transition pore: a novel anti-apoptotic function for neuroprotection.

Rasagiline and selegiline, inhibitors of type B monoamine oxidase (MAO-B), protect neurons from cell death in cellular and animal models. Suppression of mitochondrial membrane permeabilization and subsequent activation of apoptosis cascade, and induction of anti-apoptotic, pro-survival genes are proposed to contribute the anti-apoptotic function. Rasagiline suppresses neurotoxin- and oxidative stress-induced membrane permeabilization in isolated mitochondria, but the mechanism has been not fully clarified. In this paper, regulation of the mitochondrial permeability transition pore by rasagiline and selegiline was examined in apoptosis induced by PK11195, a ligand of the outer membrane translocator protein 18 kDa (TSPO) in SH-SY5Y cells. The pore opening was quantitatively measured using a simultaneous monitoring system for calcium (Ca(2+)) and superoxide (O2(-)) (Ishibashi et al. in Biochem Biophys Res Commun 344:571-580, 2006). The association of the pore opening with Ca(2+) efflux and ROS increase was proved by the inhibition of Bcl-2 overexpression and cyclosporine A treatment. Potency to release Ca(2+) was correlated with the cytotoxicity of TSPO antagonists, PK11195, FGIN-1-27 and protoporphyrin IX, whereas a TSPO agonist, 4-chloro-diazepamine, did not significantly increase Ca(2+) or cause cell death. Rasagiline and selegiline inhibited mitochondrial Ca(2+) efflux through the mitochondrial permeability transition pore dose dependently. Ca(2+) efflux was confirmed as the initial signal in mitochondrial apoptotic cascade, and the suppression of Ca(2+) efflux may account for the neuroprotective function of rasagiline and selegiline. The quantitative measurement of Ca(2+) efflux can be applied to determine anti-apoptotic activity of neuroprotective compounds. The role of mitochondrial Ca(2+) release in neuronal death and also in neuroprotection by MAO-B inhibitors is discussed.