Facile green synthesis of ZnO-RGO nanocomposites with enhanced anticancer efficacy.

Drug resistance and inability to distinguish between cancerous and non-cancerous cells are important obstacles in the treatment of cancer. Zinc oxide nanoparticles (ZnO NPs) is now emerging as a crucial material to challenge this global issue due to its tunable properties. Developing an effective, inexpensive, and eco-friendly method in order to tailor the properties of ZnO NPs with enhanced anticancer efficacy is still challenging. For the first time, we reported a facile, inexpensive, and eco-friendly approach for green synthesis of ZnO-reduced graphene oxide nanocomposites (ZnO-RGO NCs) using garlic clove extract. Garlic has been playing one of the most important dietary and medicinal roles for humans since centuries. We aimed to minimize the use of toxic chemicals and enhance the anticancer potential of ZnO-RGO NCs with minimum side effects to normal cells. Aqueous extract of garlic clove was used as reducing and stabilizing agent for green synthesis of ZnO-RGO NCs from the zinc nitrate and graphene oxide (GO) precursors. A potential mechanism of ZnO-RGO NCs synthesis with garlic clove extract was also proposed. Preparation of pure ZnO NPs and ZnO-RGO NCs was confirmed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS). The in vitro study showed that ZnO-RGO NCs induce two-fold higher cytotoxicity in human breast cancer (MCF7) and human colorectal cancer (HCT116) cells as compared to pure ZnO NPs. Besides, biocompatibility of ZnO-RGO NCs in non-cancerous human normal breast (MCF10A) and normal colon epithelial (NCM460) cells was higher than those of pure ZnO NPs. This work highlighted a facile and inexpensive green approach for the preparation of ZnO-RGO NCs with enhanced anticancer activity and improved biocompatibility.

Evaluating heavy metals contamination in soil and vegetables in the region of North India: Levels, transfer and potential human health risk analysis.

This study determined the heavy metals (HMs) accumulation in different vegetables in different seasons and attributed a serious health hazard to human adults due to the consumption of such vegetables in Jhansi. The total amounts of zinc (Zn), lead (Pb), nickel (Ni), manganese (Mn), copper (Cu), cobalt (Co), and cadmium (Cd) were analysed in 28 composite samples of soil and vegetables (Fenugreek, spinach, eggplant, and chilli) collected from seven agricultural fields. The transfer factor (TF) of HMs from soil to analysed vegetables was calculated, and significant non-carcinogenic health risks due to exposure to analysed heavy metals via consumption of these vegetables were computed. The statistical analysis involving Principal Component Analysis (PCA) and Pearson's correlation matrix suggested that anthropogenic activities were a major source of HMs in the study areas. The target hazard quotient of Cd, Mn, and Pb for fenugreek (2.156, 2.143, and 2.228, respectively) and spinach (3.697, 3.509, 5.539, respectively) exceeded the unity, indicating the high possibilities of non-carcinogenic health risks if regularly consumed by human beings. This study strongly suggests the continuous monitoring of soil, irrigation water, and vegetables to prohibit excessive accumulation in the food chain.

Oxidative stress mediated cytotoxicity of tin (IV) oxide (SnO2) nanoparticles in human breast cancer (MCF-7) cells.

Due to unique optical and electronic properties tin oxide nanoparticles (SnO2 NPs) have shown potential for various applications including solar cell, catalyst, and biomedicine. However, there is limited information concerning the interaction of SnO2 NPs with human cells. In this study, we explored the potential mechanisms of cytotoxicity of SnO2 NPs in human breast cancer (MCF-7) cells. Results demonstrated that SnO2 NPs induce cell viability reduction, lactate dehydrogenase leakage, rounded cell morphology, cell cycle arrest and low mitochondrial membrane potential in dose- and time-dependent manner. SnO2 NPs were also found to provoke oxidative stress evident by generation of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and lipid peroxidation, while depletion of glutathione (GSH) level and lower activity of several antioxidant enzymes. Remarkably, we observed that ROS generation, GSH depletion, and cytotoxicity induced by SnO2 NPs were effectively abrogated by antioxidant N-acetylcycteine. Our data have shown that SnO2 NPs induce toxicity in MCF-7 cells via oxidative stress. This study warrants further research to explore the genotoxicity of SnO2 NPs in different types of cancer cells.

Modes of tetra(4-pyridyl)porphyrinatomanganese(III) ion intercalation inside natural clays.

BACKGROUND: Metalloporphyrin ions, with planar shape, have been known to intercalate horizontally and diagonally between montmorillonite layers. Perpendicular intercalation inside montmorillonite has not been reported earlier. This work aims at achieving perpendicular intercalation inside montmorillonite in natural clays. Possible intercalation inside other forms of natural clay will also be investigated. METHODS: Natural clays were purified and characterized. The naked clay powder was then refluxed with tetra(4-pyridyl)porphyrinatomanganese(III) ion (MnTPyP(+)) solution in methanol with continuous stirring for different times. Electronic absorption spectra, atomic absorption spectra, Fourier Transform infrared spectra, scanning electron microscopy and X-ray diffraction were all used in clay characterization and in intercalation study. RESULTS: The natural clay involved different phases, namely montmorillonite, biotite, kaolinite, illite and traces of quartz. Montmorillonite clay allowed horizontal, diagonal and perpendicular intercalation of the metalloporphyrin ions. Biotite allowed only horizontal intercalation. The mode of intercalation was deduced by monitoring the clay inter-planar distance value change. Intercalation occurred inside both micro- and nano-size clay powders to different extents. The nano-powder (average size ~50 nm) showed uptake values up to 3.8 mg MnTPyP/g solid, whereas the micro-size powder (average size ~316 nm) exhibited lower uptake (2.4 mg MnTPyP/g solid). Non-expandable clay phases did not allow any intercalation. The intercalated MnTPyP(+) ions showed promising future supported catalyst applications. CONCLUSIONS: Depending on their phase, natural clays hosted metalloporphyrin ions. Montmorillonite can allow all three possible intercalation geometries, horizontal, diagonal and for the first time perpendicular. Biotite allows horizontal intercalation only. Non-expandable clays allow no intercalation. Graphical abstractMetalloporphyrin complexes can be intercalated into montmorillonite in horizontal, perpendicular and diagonal geometries.

Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells.

We investigated whether Aluminum (Al) doping tunes band gap energy level as well as selective cytotoxicity of ZnO nanoparticles in human breast cancer cells (MCF-7). Pure and Al-doped ZnO nanoparticles were prepared by a simple sol-gel method. Characterization study confirmed the formation of single phase of Al(x)Zn(1-x)O nanocrystals with the size range of 33-55 nm. Al-doping increased the band gap energy of ZnO nanoparticles (from 3.51 eV for pure to 3.87 eV for Al-doped ZnO). Al-doping also enhanced the cytotoxicity and oxidative stress response of ZnO nanoparticles in MCF-7 cells. The IC50 for undoped ZnO nanoparticles was 44 µg/ml while for the Al-doped ZnO counterparts was 31 µg/ml. Up-regulation of apoptotic genes (e.g. p53, bax/bcl2 ratio, caspase-3 &caspase-9) along with loss of mitochondrial membrane potential suggested that Al-doped ZnO nanoparticles induced apoptosis in MCF-7 cells through mitochondrial pathway. Importantly, Al-doping did not change the benign nature of ZnO nanoparticles towards normal cells suggesting that Al-doping improves the selective cytotoxicity of ZnO nanoparticles toward MCF-7 cells without affecting the normal cells. Our results indicated a novel approach through which the inherent selective cytotoxicity of ZnO nanoparticles against cancer cells can be further improved.

Nickel oxide nanoparticles induce cytotoxicity, oxidative stress and apoptosis in cultured human cells that is abrogated by the dietary antioxidant curcumin.

Nickel oxide nanoparticles (NiO NPs) are increasingly utilized in a number of applications. However, little is known about the toxicity of NiO NPs following exposure to human cells. This study was designed to investigate NiO NPs induced cytotoxicity, oxidative stress and apoptosis in cultured human airway epithelial (HEp-2) and human breast cancer (MCF-7) cells. The results show that cell viability was reduced by NiO NPs and degree of reduction was dose-dependent. NiO NPs were also found to induce oxidative stress in dose-dependent manner indicated by depletion of glutathione and induction of reactive oxygen species and lipid peroxidation. Induction of caspase-3 enzyme activity and DNA fragmentation, biomarkers of apoptosis were also observed in NiO NPs exposed cells. Preventive potential of a dietary antioxidant curcumin against NiO NPs induced toxicity in HEp-2 MCF-7 cells was further examined. We found that co-exposure of curcumin significantly attenuated the cytotoxicity and oxidative stress induced by NiO NPs in both types of cells. This is the first report showing that NiO NPs induced ROS mediated cytotoxicity and apoptosis that is abrogated by curcumin. The pharmacological potential of curcumin against NiO NPs induced toxicity warrants further investigation.