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Intrinsically cancer cells have higher basal levels of reactive oxygen species (ROS), which when augmented by pro-oxidants such as Malabaricone-A (MAL-A) triggers apoptotic cell death, secondary to 'turning on' of the apoptosis related cell signaling pathways. The effects of MAL-A upon key inflammation related signaling molecules were evaluated by western blotting in U937, a histiocytic lymphoma derived cell line. The impact of inhibitors of the pro-apoptotic MAPK and anti-apoptotic PI3K/AKT signaling pathways upon MAL-A induced cytotoxicity and generation of ROS was evaluated by a cell viability assay and flow cytometry respectively in two hematopoietic cell lines, U937 and MOLT3. MAL-A enhanced phosphorylation of the components of the pro-apoptotic pathway, namely ASK1, p38 and JNK. Alongside, MAL-A decreased the phosphorylation of AKT and mTOR. The cytotoxicity of MAL-A was attenuated by inhibitors of p38 and JNK, whereas its cytotoxic potential was enhanced in the presence of a PI3K/AKT inhibitor. Similarly, MAL-A mediated generation of ROS was decreased by inhibitors of p38MAPK and JNK, whereas the PI3K/AKT inhibitor potentiated its generation of ROS. Taken together, MAL-A mediated its cytotoxicity by enhanced generation of ROS via modulation of the apoptosis related cellular signaling pathways and tilting the balance towards a pro-apoptotic scenario. This was achieved via an up-regulation of MAPK (p38 and JNK) along with down-regulation of the PI3K/AKT/mTOR pathway indicating that manipulation of these pathways by compounds such as MAL-A are promising therapeutic targets, worthy of future pharmacological consideration., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Purpose: The 'two-faced' character of reactive oxygen species (ROS) plays an important role in cancer biology by acting as secondary messengers in intracellular signaling cascades, enhancing cell proliferation and survival, thereby sustaining the oncogenic phenotype. Conversely, enhanced generation of ROS can trigger an oxidative assault leading to a redox imbalance translating into an apoptotic cell death. Intrinsically, cancer cells have higher basal levels of ROS which if supplemented by additional oxidative insult by pro-oxidants can be cytotoxic, an example being Malabaricone-A (MAL-A). MAL-A is a plant derived diarylnonanoid, purified from fruit rind of the plant Myristica malabarica whose anti-cancer activity has been demonstrated in leukemic cell lines, the modality of cell death being apoptosis. This study aimed to compare the degree of effectiveness of MAL-A in leukemic vs. solid tumor cell lines., Methods: The cytotoxicity of MAL-A was evaluated by the MTS-PMS cell viability assay in leukemic cell lines (MOLT3, K562 and HL-60) and compared with solid tumor cell lines (MCF7, A549 and HepG2); further studies then proceeded with MOLT3 vs. MCF7 and A549. The contribution of redox imbalance in MAL-A induced cytotoxicity was confirmed by pre-incubating cells with an antioxidant, N-acetyl-L-cysteine (NAC) or a thiol depletor, buthionine sulfoximine (BSO). MAL-A induced redox imbalance was quantitated by flow cytometry, by measuring the generation of ROS and levels of non protein thiols using dichlorofluorescein diacetate (CM-H2DCFDA) and 5-chloromethylfluorescein diacetate (CMFDA) respectively. The activities of glutathione peroxidase (GPx), superoxide dismutase, catalase (CAT), NAD(P)H dehydrogenase (quinone 1) NQO1 and glutathione-S-transferase GST were measured spectrophotometrically. The mitochondrial involvement of MAL-A induced cell death was measured by evaluation of cardiolipin peroxidation using 10-N-nonyl acridine orange (NAO), transition pore activity with calcein-AM, while the mitochondrial transmembrane electrochemical gradient (∆ψ(m)) was measured by JC-1, fluorescence being acquired in a flow cytometer. The apoptotic mode of cell death was evaluated by double staining with annexin V-FITC and propidium iodide (PI), cell cycle analysis by flow cytometry and caspase-3 activity spectrophotometrically. The expression of Nrf2 and HO-1 was examined by western blotting., Results: MAL-A demonstrated a higher degree of cytotoxicity in three leukemic cell lines whose IC50 ranged from 12.70 ± 0.10 to 18.10 ± 0.95 µg/ml, whereas in three solid tumor cell lines, the IC50 ranged from 28.10 ± 0.58 to 55.26 ± 5.90 µg/ml. This higher degree of cytotoxicity in MOLT3, a leukemic cell line was due to a higher induction of redox imbalance, evident by both an increased generation of ROS and concomitant depletion of thiols. This was confirmed by pre-incubation with NAC and BSO, wherein NAC decreased MAL-A induced cytotoxicity by 2.04 fold while BSO enhanced MAL-A cytotoxicity and decreased the IC50 by 5.60 fold. However, in solid tumor cell lines (MCF7 and A549), NAC minimally decreased MAL-A induced cytotoxicity, and BSO increased the IC50 by 1.96 and 2.39 fold respectively. Furthermore, the generation of ROS by MAL-A increased maximally in MOLT3 as the fluorescence increased from 44.28 ± 7.85 to 273.99 ± 32.78, and to a lesser degree in solid tumor cell lines, MCF7 (44.28 ± 14.89 to 207.97 ± 70.64) and A549 (37.87 ± 3.24 to 147.12 ± 38.53). In all three cell lines there was a concomitant depletion of thiols as in MOLT3, the GMFC decreased from 340.65 ± 60.39 to 62.67 ± 11.32, in MCF7 (277.82 ± 50.32 to 100.39 ± 31.93) and in A549 (274.05 ± 59.13 to 83.15 ± 21.43). In MOLT3 as compared to MCF7 and A549, decrease in the activities of GPx, CAT, NQO1 and GST was substantially greater. In all cell lines, the MAL-A induced redox imbalance translated into triggering of initial mitochondrial apoptotic events. Here again, MAL-A induced a higher degree of cardiolipin peroxidation in MOLT3 (67.01%) than MCF7 and A549 (29.15% and 44.30%), as also down regulated the mitochondrial transition pore activity from baseline to a higher extent, GMFC being 48.05 ± 2.37 to 10.70 ± 3.97 (MOLT3), 43.55 ± 3.36 to 15.36 ± 0.60 (MCF7) and 39.58 ± 0.4 to 12.65 ± 1.56 (A549). Perturbation of mitochondrial membrane potential evident by a decrease in the ratio of red/green (J-aggregates/monomers) was 134 fold (14.73/0.11) in MOLT3, 45 fold in MCF7 (20.72/0.46) and 34 fold in A549 (22.01/0.64). The extent of apoptosis using a similar concentration of MAL-A was maximal in MOLT3, wherein a 105 fold increase in annexin V binding was evident (0.83 ± 0.51 to 87.08 ± 9.85%) whereas it increased by 43.11 fold in MCF7 (0.69 ± 0.30 to 29.75 ± 11.79%) and 47.52 fold in A549 (0.61 ± 0.31 to 28.99 ± 17.21%). MAL-A induced apoptosis was also associated with a higher degree of caspase-3 activity in MOLT3 vs. MCF7 or A549 which translated into halting of cell cycle progression, evident by an increment in the sub-G0/G1 population [19.26 fold in MOLT3 (0.95 ± 0.45 vs. 18.30 ± 1.90%), 11.01 fold in MCF7 (0.97 ± 0.37 vs. 10.68 ± 0.69%) and 8.58 fold in A549 (1.06 ± 0.45 vs. 9.10 ± 1.05%)]. MAL-A effectively inhibited Nrf2 and HO-1, more prominently in MOLT3. Furthermore, the decreased expression of Nrf2 in MOLT3 correlated with the decreased activities of NQO1 and GST, suggesting that targeting of the Nrf2 anti-oxidant pathway could be considered., Conclusion: Taken together, MAL-A a pro-oxidant compound is likely to be more effective in leukemias, meriting further pharmacological consideration., (Copyright © 2015. Published by Elsevier GmbH.)

Background: The 'two-faced' character of reactive oxygen species (ROS) plays an important role in cancer biology by acting both as secondary messengers in intracellular signaling cascades and sustaining the oncogenic phenotype of cancer cells, while on the other hand, it triggers an oxidative assault that causes a redox imbalance translating into an apoptotic cell death., Principal Findings: Using a tetrazolium [{3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl}-2H-tetrazolium] based cell viability assay, we evaluated the cytotoxicity of a plant derived diarylnonanoid, malabaricone-A on leukemic cell lines U937 and MOLT-3. This cytotoxicity hinged on its ability to cause a redox imbalance via its ability to increase ROS, measured by flow cytometry using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and by decreasing glutathione peroxidase activity. This redox imbalance mediated apoptosis was evident by an increase in cytosolic [Ca(2+)], externalization of phosphatidyl serine as also depolarization of the mitochondrial membrane potential as measured by flow cytometry. There was concomitant peroxidation of cardiolipin, release of free cytochrome c to cytosol along with activation of caspases 9, 8 and 3. This led to cleavage of the DNA repair enzyme, poly (ADP-ribose) polymerase that caused DNA damage as proved by labeling with 4',6-diamidino-2-phenylindole (DAPI); furthermore, terminal deoxy ribonucleotide transferase catalysed incorporation of deoxy uridine triphosphate confirmed DNA nicking and was accompanied by arrest of cell cycle progression., Conclusions: Taken together, compounds like MAL-A having pro-oxidant activity mediate their cytotoxicity in leukemic cells via induction of oxidative stress triggering a caspase dependent apoptosis.

Free radicals are involved in the pathogenesis of Rheumatoid arthritis, a systemic autoimmune disorder characterized by unchecked synovial inflammation. Allylpyrocatechol, a phytoconstituent of Piper betle leaves, has potent anti-inflammatory activity and this study evaluated its anti-oxidant effect on the synovial infiltrate of patients with Rheumatoid arthritis. The ex vivo effect of allylpyrocatechol upon generation of reactive oxygen species in neutrophils, macrophages and lymphocytes was measured by flow cytometry using dichlorodihydrofluorescein diacetate, wherein it significantly decreased basal levels as also scavenged phorbol myristate acetate generated reactive oxygen species. Furthermore, its effect on generation of superoxide and hydroxyl radicals produced within infiltrated neutrophils was measured by cytochrome c and deoxyribose assay, respectively. Allylpyrocatechol significantly scavenged superoxide and hydroxyl radicals in infiltrated neutrophils. The effect of allylpyrocatechol on nitric oxide was measured in macrophages using 4,5-diaminofluorescein diacetate by flow cytometry wherein it decreased production of nitric oxide in infiltrated macrophages, which correlated with its in vitro nitric oxide scavenging activity. Taken together, this ex vivo study has established that allylpyrocatechol has potent scavenging activity and could be considered as an add-on therapy in the treatment of inflammation-associated disorders like Rheumatoid Arthritis.

Despite being an essential element for normal functioning of cells and organisms, iron, in excess, can induce oxidative stress by generating reactive oxygen species. A water-soluble, non-toxic iron chelator can reduce the iron-induced oxidative stress in the body as well as help in extricating excess iron. Herein, we report an Ocimum sanctum-derived antioxidant polysaccharide (OSP) that inhibits the deleterious effect of iron. Ocimum sanctum is a widely acknowledged medicinal plant contributing toward several biological benefits. Besides showing good hydroxyl radical scavenging activity, OSP could bind to ferric and ferrous ions to prevent their participation in redox reactions as revealed from modified 2-deoxyribose assays, carried out under various conditions. It also acted as an iron modulator to prevent site-specific damage and was effective in protecting mouse fibroblast L929 cells against iron induced death. [ABSTRACT FROM AUTHOR]

Background: Breast cancer is considered as an increasing major life-threatening concern among the malignancies encountered globally in females. Traditional therapy is far from satisfactory due to drug resistance and various side effects, thus a search for complementary/alternative medicines from natural sources with lesser side effects is being emphasized. Andrographis paniculata, an oriental, traditional medicinal herb commonly available in Asian countries, has a long history of treating a variety of diseases, such as respiratory infection, fever, bacterial dysentery, diarrhea, inflammation etc. Extracts of this plant showed a wide spectrum of therapeutic effects, such as anti-bacterial, anti-malarial, anti-viral and anti-carcinogenic properties. Andrographolide, a diterpenoid lactone, is the major active component of this plant. This study reports on andrographolide induced apoptosis and its possible mechanism in highly proliferative, invasive breast cancer cells, MDA-MB-231 lacking a functional p53 and estrogen receptor (ER). Furthermore, the pharmacokinetic properties of andrographolide have also been studied in mice following intravenous and oral administration. Results: Andrographolide showed a time- and concentration- dependent inhibitory effect on MDA-MB-231 breast cancer cell proliferation, but the treatment did not affect normal breast epithelial cells, MCF-10A (>80 %). The number of cells in S as well as G2/M phase was increased after 36 h of treatment. Elevated reactive oxygen species (ROS) production with concomitant decrease in Mitochondrial Membrane Potential (MMP) and externalization of phosphatidyl serine were observed. Flow cytometry with Annexin V revealed that the population of apoptotic cells increased with prolonged exposure to andrographolide. Activation of caspase-3 and caspase-9 were also noted. Bax and Apaf-1 expression were notably increased with decreased Bcl-2 and Bcl-xL expression in andrographolide-treated cells. Pharmacokinetic study with andrographolide showed the bioavailability of 9.27 ± 1.69 % with a Cmax, of 0.73 ± 0.17 μmol/L and Tmax of 0.42 ± 0.14 h following oral administration. AG showed rapid clearance and moderate terminal half lives (T1/2) of 1.86 ± 0.21 and 3.30 ± 0.35 h following IV and oral administration respectively. Conclusion: This investigation indicates that andrographolide might be useful as a possible chemopreventive/ chemotherapeutic agent for human breast cancers. [ABSTRACT FROM AUTHOR]

Allylpyrocatechol (APC) is responsible for the antiinflammatory activity exhibited by the methanolic extract of leaves of Piper betle. As antiinflammatory compounds may display antioxidant properties and vice versa, we investigated the antioxidant effect of APC. APC effectively reduced phorbol-myristate-acetate-induced generation of reactive oxygen species and superoxide in murine peritoneal macrophages as well as inhibited Escherichia-coli-induced phagocytic activity of macrophages. Furthermore, pBluescript SK+ plasmid DNA damage induced by addition of sodium ascorbate was attenuated by APC as it inhibited transformation of the supercoiled form to a relaxed form. In addition, APC increased the enzymatic (catalase) and nonenzymatic (GSH) antioxidant components of murine macrophages. Taken together, APC exhibited an antioxidant activity which was mediated both via decreased generation of free radicals along with increase in cellular antioxidants. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis is an inflammatory, autoimmune disease where oxidative stress has been proposed to contribute to the joint tissue damage. To establish whether measurement of the redox status in blood mirrors the oxidant status at sites of inflammation in patients with rheumatoid arthritis, we concomitantly examined their oxidant status by spectrophotometry and/or flow cytometry. The basal levels of total reactive oxygen species (ROS), superoxide and hydroxyl radicals were significantly raised in neutrophils sourced from peripheral blood and synovial infiltrate, as also showed a strong positive correlation; however, there was no major increase in the reactive nitrogen species RNS generated in monocytes from both sources. Furthermore, raised levels of superoxide in neutrophils of synovial infiltrate showed a positive correlation with NADPH oxidase activity in synovial fluid. Additionally, as ROS generated in both peripheral blood and synovial infiltrate correlated positively with both DAS 28 and CRP/anti-CCP levels, its measurement can serve as an indirect measure of the degree of inflammation in patients with RA. [ABSTRACT FROM AUTHOR]

African sleeping sickness is a parasitic disease in humans and livestock caused by Trypanosoma brucei throughout sub-Saharan Africa. Absence of appropriate vaccines and prevalence of drug resistance proclaim that a new way of therapeutic interventions is essential against African trypanosomiasis. In the present study, we have looked into the effect of andrographolide (andro), a diterpenoid lactone from Andrographis paiculata on Trypanosoma brucei PRA 380. Although andro has been recognized as a promosing anti-cancer drug, its usefulness against Trypanosoma spp remained unexplored. Andro showed promising anti-trypanosomal activity with an IC 50 value of 8.3 μM assessed through SYBR Green cell viability assay and also showed no cytotoxicity towards normal murine macrophages. Cell cycle analysis revealed that andro could induce sub-G 0 /G 1 phase arrest. Flow cytometric analysis also revealed that incubation with andro caused exposure of phosphatidyl serine to the outer leaflet of plasma membrane in T. brucei PCF. This event was preceded by andro-induced depolarization of mitochondrial membrane potential (Δym) and elevation of cytosolic calcium. Andro also caused elevation of intracellular reactive oxygen species (ROS) as well as lipid peroxidation level, and depletion in reduced thiol levels. Taken together, these data indicate that andro has promising antitrypanosomal activity mediated by promoting oxidative stress and depolarizing the mitochondrial membrane potential and thereby triggering an apoptosis-like programmed cell death. Therefore, this study merits further investigation to the therapeutic possibility of using andro for the treatment of African trypanosomiasis. [ABSTRACT FROM AUTHOR]

Boradiazaindacene (BODIPY) class of laser dyes are highly efficient but degrade rapidly in alcohol solution during lasing action, progressively reducing output power. Photodegradation of these dyes is mainly due to reaction with the in situ generated singlet oxygen ( 1 O 2 ). With the aim to increase the lasing lifetimes of these dyes, we have designed and synthesized a new congener of the widely used BODIPY dye (PM567) by substitution at its B-centre. The new dye was highly fluorescent, and showed comparable lasing efficiency, but better photostability relative to PM567 in both polar (ethanol) and non-polar (1,4-dioxane) solvents, when excited by 2nd harmonic (532 nm) of a pulsed Nd-YAG laser. More interestingly, the lasing efficiency and photostability of both the dyes were much better in 1,4-dioxane than in ethanol. The relative photostabilities of the dyes were rationalized by absorption spectroscopic analyses of their triplet state properties in the respective solvents in the presence of a 1 O 2 generator or quencher as an additive, pulse radiolysis studies and quantum chemical calculations. [ABSTRACT FROM AUTHOR]

A convenient synthesis of six phenolic diarylpropanes has been formulated. A CuBr2-catalyzed regioselective reaction was the key step for bromination of the arylpropanes. All the compounds showed good cytotoxicity to the human lung cancer A549 cell line. However, only one of these compounds induced apoptosis and a G1 cell cycle arrest by augmenting cellular ROS status. Introduction of bromo-substitution at the aryl groups increased the cytotoxicity significantly, but that was mainly due to necrosis. [ABSTRACT FROM AUTHOR]

In an attempt to develop a photostable and efficient pyrromethene compound for use in liquid dye lasers, three congeners of the commercially available pyrromethene 567 (PM567) laser dye were synthesized and their photophysical properties, lasing efficiencies, and photochemical stabilities were studied. In general the presence of an aryl group at C-8 of the pyrromethene chromophore increased the photostability. One of the congeners possessing a C-8 trimethoxyphenyl moiety showed significantly improved lasing parameters than PM567. Compared to PM567, the photochemical stability of the new dye was 2-fold, while it showed an equivalent lasing efficiency to that of PM567 at a significantly lower concentration. The increased photostability of these new dye molecules could be explained by theoretical calculation on their capacity to generate singlet oxygen (1O2) and probability of reaction with 1O2. Our calculations were in agreement with the experimental results and indicated that a systematic design of new derivatives of pyrromethene chromophore might lead to improved laser dye molecules. [ABSTRACT FROM AUTHOR]