IN VITRO STUDIES ON CYANIDIN PROTECTION AGAINST DOXORUBICIN CARDIOMYOCYTE CYTOTOXICITY AND ANTICANCER ACTIVITY

Mitochondrial reactive oxygen species (ROS) are recognized for their role in several health related problems when produced at excessively high concentrations. Due to their potent antioxidant activity and potential mitochondriotropic behavior, the anthocyanidins may have the potential to lower mitochondrial ROS levels. Nevertheless, the effect of anthocyanidins remains overlooked due to their presumed low stability and bioavailability. In addition, this instability has lead to a general belief that the phenolic degradation products, protocatechuic acid (PCA) and phloroglucinaldehye (PGA), exert the bioactivity rather than the parent compound. In this work, doxorubicin-induced cytotoxicity in differentiated H9c2 cardiomyocytes was initially established as a model in which the mitochondrial antioxidant activity of the selected flavonoids would be examined. First, we delineated the mechanisms by which doxorubicin affected H9c2 cell survival and mitochondrial function. The results showed that the early effects of doxorubicin on mitochondrial superoxide generation led to a delayed effect on cell survival. Using this model, we then revealed the protective ability of cyanidin against doxorubicin-induced cytological damage, showing protection to mitochondria. While cyanidin co-incubation with doxorubicin did not show protection when cell survival was assessed after 24 h, it gave delayed protection after a further 24 h drug-free period. Using the delayed protection model, we also showed that cyanidin had greater bioactivity over other flavonoids tested (quercetin, catechin and cyanidin-3-glucoside (C3G)). The protection by cyanidin also exceeded that of its degradation products (PCA and PGA), suggesting that the parent compound has additional bioactivity. The cytoprotective ability of the flavonoids was related to their ability to lower mitochondrial superoxide at early time points, with cyanidin being the most effective. Experiments on doxorubicin cytotoxicity to HepG2 (liver cancer) and K562 (erythroleukemia) cells showed no protective effect with cyanidin. These results suggest cyanidin protects cardiomyocytes but does not interfere with the cytotoxic activity of doxorubicin in the cancer cell lines. Investigations on the degradation of cyanidin in physiological media, UV-vis, HPLC and MS analytical techniques provided evidence that cyanidin does not degrade immediately to PCA and PGA. Instead, intermediate compounds (hemiketal and chalcone) survived for sufficient periods to exert putative bioactivity. Studies on the influence of different media on the degradation of cyanidin showed that the stability in human serum was significantly higher (t½ 43.2 min at room temperature, 22 ¬± 1°C) compared to phosphate buffered saline and Dulbecco’s Modified Eagle’s Medium with and without 10% fetal bovine serum (t½ 10.2-32.6 min). In conclusion, using differentiated H9c2 cells, our results show an ability of cyanidin to survive long enough in cell culture media, and presumably intracellularly, to exert cytoprotection against doxorubicin which exceeded that of other flavonoids (quercetin, catechin, C3G) and its degradation products (PCA and PGA). The results present cyanidin as a possible antioxidant choice to use in clinical practice to protect the heart from the mitochondrial toxicity of doxorubicin and warrants investigation into this possible therapeutic application

Optimizing photo-mineralization of aqueous methyl orange by nano-ZnO catalyst under simulated natural conditions.

Photo-degradation of organic contaminants into non-hazardous mineral compounds is emerging as a strategy to purify water and environment. Tremendous research is being done using direct solar light for these purposes. In this paper we report on optimum conditions for complete mineralization of aqueous methyl orange using lab-prepared ZnO nanopowder catalyst under simulated solar light. Nano-scale ZnO powder was prepared in the lab by standard methods, and then characterized using electronic absorption spectra, photolumenscence emission (PL) spectra, XRD, and SEM. The powder involved a wurtzite structure with ~19 nm particles living in agglomerates. Photo-degradation progressed faster under neutral or slightly acidic conditions which resemble natural waters. Increasing catalyst concentration increased photodegradation rate to a certain limit. Values of catalyst turn over number and degradation percentage increased under higher light intensity, whereas the quantum yield values decreased. The photocatalytic efficiency of nano-ZnO powders in methyl orange photodegradation in water with solar light has been affected by changing the working conditions. More importantly, the process may be used under natural water conditions with pH normally less than 7, with no need to use high concentrations of catalyst or contaminant. The results also highlight the negative impact of possible high concentrations of CO2 on water purification processes. Effects of other added gaseous flows to the reaction mixture are also discussed. ZnO nano-particles are useful catalyst for complete mineralization of organic contaminants in water. Photo-degradation of organic contaminants with ZnO nano-particles, methyl orange being an example, should be considered for future large scale water purification processes under natural conditions

Anthocyanin-Sensitized TiO2 Nanoparticles for Phenazopyridine Photodegradation under Solar Simulated Light

Pharmaceutical wastes are emerging as water contaminants. Like other organic contaminants, it is necessary to find safe and economic methods to remove them from the water. In this work, anthocyanin was used as a natural dye sensitizer for the wide band gap nanosize rutile TiO2. The TiO2/Anthocyanin particles were supported on activated carbon particle surfaces. The resulting composite, which was prepared and characterized by different methods, was then used as a catalyst in the photodegradation of phenazopyridine (a model pharmaceutical contaminant) under a solar simulated light. Depending on experimental conditions, up to 90% of the contaminant was mineralized leaving no new organic products in the reaction mixture. The results show the feasibility of using the activated carbon-supported TiO2/Anthocyanin photocatalyst for pharmaceutical contaminant removal in water. The natural dye anthocyanin readily sensitized the TiO2 to visible light. The unsupported TiO2, with its nanosize particles, was not easy to recover by simple separation methods, while the activated carbon-supported catalyst was easily isolated by decantation after reaction cessation. Moreover, the recovered AC/TiO2 catalyst could also be regenerated by adding fresh anthocyanin sensitizer after recovery for further reuse. Keeping the contaminant molecules closer to the catalytic sites by adsorption, the support also enhanced the efficiency of photocatalyst

Diaminobenzene Schiff Base Induces Caspase 9-dependent Apoptosis In U937 Leukemia Cells Diaminobenzene Schiff Base Induces Caspase 9-dependent Apoptosis In U937 Leukemia Cells

Abstract Metal complex Schiff base compounds have been shown to be cytotoxic in vitro. However little is known concerning anticancer activity of Schiff bases that lack metal cations. The antineoplastic properties of two isomeric derivatives of diaminobenzene bis-Schiff base compounds, namely: N,N '-Bis(2-hydroxy-3-methoxybenzylidene)-1,2-diaminobe nzene (2MJ) and N,N '-Bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminobe nzene (2MH) towards U937 and K562 leukemia cell lines were investigated in this study. Both compounds were more cytotoxic towards U937 lymphoma cell with little effect on K562 cells when analysed using Sodium 3′-[1-(phenylamino-carbonyl)-3,4-Tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (XTT) cell proliferation assay technique . The IC 50 value for 2MJ was almost half of 2MH . Both compounds were also found to induce apoptosis in U937 leukemia cells as evidenced by the induction of caspase 3 and 7. The level of caspase 3/7 induction was more pronounced in cells treated with 2MJ compared to 2MH. Caspase-9 was identifiedas the regulatory upstream caspase activated in U937 cells treatedwith 2MH and 2MJ, implicating the mitochondrial apoptoticpathway in diaminobenzene Schiff base-induced leukemia cell death. Both agents caused negligible effect on caspase-8 indicating a non Fas ligand receptor involvement in the apoptosis cascade. Neither compounds showed significant mutagenic outcome in the AMES mutagenicity assay. The result of this study highlights the potential of diaminobenzene bis-Schiff base compounds as a prospective agent to target cancer cells via the mitochondria

Photocatalytic degradation of phenazopyridine contaminant in soil with direct solar light

<p>Photocatalytic degradation of waste pharmaceutics, with solar radiation, is described here as a feasible method to purify pre-contaminated soils. Phenazopyridine has been used as a model soil contaminant. Two different nano-size powders have been first examined as catalysts, namely commercial TiO₂ (anatase) and commercial ZnO. As the ZnO showed higher catalytic efficiency, the study was then focused on it. The commercial ZnO powder was then compared with lab-prepared ZnO powder, and the latter shows relatively higher efficiency. The ZnO was used in two different ways. In one way, dry ZnO catalyst powder was spread onto the soil, while in the other way the ZnO was sprayed onto the soil surface by a wet spray method. The spray technique shows slightly higher efficiency, in addition to being easier to apply at future large scale. Depending on conditions and type of photocatalyst used, up to 90% contaminant removal can be achieved in 30 min. In case of photocatalysis experiments, the reacted contaminant molecules undergo complete degradation with no detectable side reaction organic products. Possible evaporation or escape of organic contaminant, or other possibly resulting organics, is ruled out by a series of control experiments. Photodegradation process takes place only at the catalytic sites on the soil surface, where contaminant molecules that diffuse from the soil bulk are completely degraded. Other useful organisms inside the soil are not affected as they are kept away from catalyst sites. A plausible mechanism is proposed for the degradation process.</p

Alternative natural dyes in water purification: Anthocyanin as TiO2-sensitizer in methyl orange photo-degradation

Natural molecular dye, anthocyanin, is described here as safe sensitizer for TiO2 particles in photo-degradation of organic contaminants in water. The dye is a promising replacement for the more costly and hazardous heavy metal based systems, such as CdS particles and Ru-compounds. TiO2/anthocyanin effectively catalyzed the photo-degradation of methyl orange contaminant under solar simulator radiation. The new TiO2/anthocyanin catalyst showed comparable efficiency to earlier systems, while avoiding their hazardous nature. When supported onto activated carbon (AC) particles, the resulting AC/TiO2/anthocyanin system showed enhanced efficiency and ease of recovery from the catalytic reaction mixture. The natural dye molecules showed the tendency to degrade under photo-degradation conditions, just like earlier hazardous sensitizers. However, complete mineralization of anthocyanin occurred leaving no traces of organic species in solution. Sensitizer degradation caused deactivation of the supported catalyst on recovery. Such a shortcoming was overcome by re-treatment of the recovered catalysts with fresh dye. Effects of different reaction parameters on the catalyst efficiency were studied. A mechanism, similar to earlier CdS-sensitized catalyst systems, is proposed for the TiO2/anthocyanin catalyst

Perovskite Nano-Powder and Nano-Film Catalysts in Mineralization of Aqueous Organic Contaminants through Solar Simulated Radiation

Water contamination with various contaminants, including organic species, is a global concern. Reclamation through safe, economic and technically feasible methods is imperative. Two perovskites, zinc titanate (ZnTiO3) and manganese titanate (MnTiO3), mixed with TiO2 phases, were prepared as nano-powders and nano-films. The materials were characterized and used as catalysts in photodegradation of aqueous methylene blue, a hazardous model contaminant, using solar simulated radiation. The effects of various reaction conditions on the photodegradation were examined. The kinetics indicated the suitability of using the process at various contaminant concentrations and catalyst loadings. Both powder and film catalysts completely removed the contaminant in less than 6 h. Powder and film forms of the MnTiO3 mixture were more efficient than their ZnTiO3 counterparts. In both perovskite mixtures, the films exhibited higher catalytic efficiency than the powders. The film materials exhibited high catalytic efficiency in both the continuous flow and batch processes. Water contaminated with various methylene blue concentrations can be treated by the film catalysts that can be recovered and reused with no technical difficulties. The results open new horizons for larger-scale water purification processes

Natural dye-sensitized ZnO nano-particles as photo-catalysts in complete degradation of E. coli bacteria and their organic content

This communication describes for the first time how nano-size particles, sensitized with natural dye molecules of anthocyanin, can be used as catalysts in photo-degradation of gram negative Escherichia coli bacteria in water. The naked ZnO nano-particles degraded up to 83% of the bacteria under solar simulator light, while the dye-sensitized particles increased the bacterial loss by ∼10%. Solar simulator light includes about 5% of UV tail (shorter than 400 nm) which means that both UV and visible light (longer than 400 nm) radiations could be involved. When a cut-off filter was used, the naked ZnO caused only 40% bacterial loss, in accordance with earlier literature that described killing of bacteria with ZnO particles both in the dark and under light. With the cut-off filter, the sensitized ZnO particles caused higher than 90% bacterial loss, which confirms sensitization of the ZnO particles to visible light. Moreover, the results show that the catalyzed photo-degradation process causes mineralization of the bacteria and their organic internal components which leach out by killing. The catalyst can be recovered and reused losing ∼10% of its activity each time due to mineralization of the dye molecules. However, catalyst activity can be totally regained by re-sensitizing it with the anthocyanin dye. The effects of different experimental conditions, such as reaction temperature, pH, bacterial concentration and catalyst amount together with nutrient broth and saline media, will be discussed together with the role of the sensitizer