NEUROTOXIC EFFECT OF TITANIUM DIOXIDE NANOPARTICLES: BIOCHEMICAL AND PATHOLOGICAL APPROACH IN MALE WISTAR RATS

Objective: Titanium dioxide nanoparticles (TiO2 NPs) are widely used in pharmaceutical, cosmeceutical, biomedical and industrial applications. The adverse effects of TiO2 NPs are also increasing alarmingly. The purpose of this study is to investigate the toxicity of TiO2 NPs on biochemical and histological changes in different regions of brain in adult male Wistar rats.Methods: Two different doses of TiO2 NPs (50 mg/kg b. w and 100 mg/kg b. w) administered orally for 14 d along with one control group, each group consisting of six animals. Standard biochemical methods were adopted for the estimation of enzymes alkaline phosphatase, 5' nucleotidase, ATPases and gamma-glutamyl transpeptidase. Trace elements calcium, sodium, potassium and magnesium as well as metals like iron, zinc and copper were also estimated.Results: When compared with the control group, the enzymes ATPases, ALP, 5'-NT and GGT activities were significantly decreased in both the TiO2 NPs treated groups. Ca, Na, Fe, Cu and TiO2 contents were significantly increased in both the experimental groups, while the K, Mg and Zn contents decreased. However, the changes in the parameters studied were more in 100 mg treated group (p<0.001) when compared to the 50 mg treated group (p<0.05and p<0.01). Moreover, it is also evident that different regions responded differently due to TiO2 NPs exposure. The changes were maximum in the cerebral hemisphere (p<0.001) followed by medulla oblongata (p<0.001) and cerebrum (p<0.05).Conclusion: The results clearly imply that TiO2 NPs could impair the electrochemical gradient, ionic homeostasis and membrane stability in different regions of the rat brain

Extraction and correlation of total phenolic and flavonoid contents in seaweeds collected from Rameshwaram during pre- and post- monsoon period using different solvent systems with their antioxidant activity

The present study was carried out to compare and correlate the phenolic and flavonoid contents of Turbinaria sp., Sargassum sp. and Gracilaria sp. extracted using different solvents including methanol, isopropyl alcohol, acetone, acetonitrile, ethyl acetate and hexane, and elucidated for their anti-oxidant activity. The total phenolic and flavonoid contents of the solvent extracts were determined using the Folin-Ciocalteau assay and aluminium chloride colorimetric assay with gallic acid and quercetin as standards, respectively. The anti-oxidant activity in phenolic and flavonoid content was also estimated by phosphomolybdenum method and was compared with gallic acid and quercetin standard. The quantitative analysis of flavonoid content reveals that methanolic extract of Sargassum sp. (9.56±0.38 mg QE/g during pre-monsoon and 9.44±0.48 mg QE/g during post-monsoon season); acetone extract of Gracilaria sp. (2.16±0.11 mg QE/g during pre-monsoon and 2.12±0.07 mg QE/g during post-monsoon season) and methanolic extract of Turbinaria sp. (4.11±0.12 mg QE/g during pre-monsoon and 4.22±0.15 mg QE/g during post-monsoon season) had higher concentration of flavonoid content. However, the quantitative analysis of phenolic content was found to be lower in all the seaweed extracts as compared to flavonoids. The anti-oxidant activity of a phenolic content and flavonoid content were also found to be correlated. The findings of the current study conclusively demonstrate the content of phenolic and flavonoid compounds significantly correlate with anti-oxidant activity

A comparative study on chitosan nanoparticle synthesis methodologies for application in aquaculture through toxicity studies

Abstract Chitosan nanoparticles (CSNPs) have been recently used for various applications in aquaculture, especially as drug carriers. The aim of this study was to synthesise and investigate a superlative method of CSNP synthesis for application in aquaculture through aquaculture‐based toxicology screening methods. Two different methods were analysed: the first a direct ionic gelation method (A) and the other involving a low‐molecular‐weight chitosan microparticle intermediate method (B). Dynamic light scattering characterisation revealed that the CSNP particle sizes were 192.7 ± 11.8 and 22.9 nm from methods A and B, respectively. The LC50 values for brine shrimp toxicity were found to be 1.51 and 0.02 ppt in 24 h for methods A and B, respectively. Acute toxicity studies in Litopenaeus vannamei rendered LC50 values of 3235.94 and 2884.03 ppt in 24 h for methods A and B, respectively. Zebrafish toxicity studies revealed mortality rates of 21.67% and 55% at 20 mg/L concentration for methods A and B, respectively, with an increased expression of intracellular reactive oxygen species in method B. From these findings, it can be concluded that a comparatively reduced toxicity of CSNPs derived from ionic gelation method makes it more appropriate for application in aquaculture

Anti-Microbial Activity and Spectro-Chemical Investigation of Ink Extracts of <i> Sepiella inermis</i> (Van Hasselt 1835)

The crude petroleum ether and methanol ink extracts of Sepiella inermis were tested for their antimicrobial activity against human pathogenic fungi and bacteria by disc diffusion method. Spectral analysis was carried out by UV-VIS spectrophotometer, FT-IR, Raman IR and GC-MS. Of the two solvent extracts, only methanol extract was active and no activity was detected in petroleum ether extract. The human pathogenic fungus Candida albicans and bacterium Proteus vulgaris were found to be highly sensitive, with an inhibition zone of 20 and 19 mm respectively. GC-MS of methanol ink extract revealed sixteen compounds belonging to the derivatives of dihydroxy indole-2-carboxylic acid and dihydroxyindole. These investigations proved that methanol ink extract of Sepiella inermis possess significant antimicrobial property against both fungus and gram –ve bacteria. Since ink of sepia is available abundantly as a waste material, studies focused on isolation and characterization of bioactive substances pave the way for new antimicrobial compounds

Oral toxic exposure of titanium dioxide nanoparticles on serum biochemical changes in adult male Wistar rats

Objective(s): Titanium dioxide (TiO2) nanoparticles (NPs) are widely used in commercial food additives and cosmetics worldwide. Uptake of these nanoparticulate into humans by different routes and may exhibit potential side effects, lags behind the rapid development of nanotechnology. Thus, the present study designed to evaluate the toxic effect of mixed rutile and anatase TiO2 NPs on serum biochemical changes in rats. Materials and Methods: In this study, adult male Wistar rats were randomly allotted into the experimental and control groups (n=6), which were orally administered with 50 and 100 mg/kg body weight of TiO2 NPs. Toxic effects were assessed by the changes of serum biochemical parameters such as glucose, total protein, albumin, globulin, cholesterol, triglyceride, high density lipoprotein, alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, blood urea nitrogen, uric acid and creatinine. All the serum biochemical markers were experimented in rats, after 14-days of post exposure. Results: Changes of the serum specific parameters indicated that liver and kidney were significantly affected in both experimental groups. The changes between the levels of total protein, glucose, aspartate transaminase, alanine transaminase and alkaline phosphatase indicate that TiO2 NPs induces liver damage. Significant increase in the blood urea nitrogen and uric acid indicates the renal damage in the TiO2 NPs treated rats. Conclusion: The data shows that the oral administration of TiO2 NPs

Numerical simulation and experimental validation of arc welding of DMR-249A steel

The thermo-mechanical attributes of DMR-249A steel weld joints manufactured by shielded metal arc welding (SMAW) and activated gas tungsten arc welding (A-GTAW) processes were studied using Finite Element Model (FEM) simulation. The thermal gradients and residual stresses were analyzed with SYSWELD software using double ellipsoidal heat source distribution model. The numerically estimated temperature distribution was validated with online temperature measurements using thermocouples. The predicted residual stresses profile across the weld joints was compared with the values experimentally measured using non-destructive techniques. The measured and predicted thermal cycles and residual stress profile was observed to be comparable. The residual stress developed in double sided A-GTAW joint were marginally higher in comparison to five pass SMAW joint due to phase transformation associated with high heat input per weld pass for A-GTAW process. The present investigations suggest the applicability of numerical modeling as an effective approach for predicting the thermo-mechanical properties influenced by welding techniques for DMR-249A steel weld joints. The tensile, impact and micro-hardness tests were carried to compare the welds. Considering benefits of high productivity and savings of labor and cost associated with A-GTAW compared to SMAW process, the minor variation in residual stress build up of A-GTAW joint can be neglected to develop A-GTAW as qualified alternative welding technique for DMR-249A steel

Attenuation of oxidative stress induced mitochondrial dysfunction and cytotoxicity in fibroblast cells by sulfated polysaccharide from Padina gymnospora

In this present study, isolation, characterization and protective effect of sulfated polysaccharide (SP) isolated from the brown algae Padina gymnospora was investigated. SP was isolated and characterized through FT-IR, 1H NMR, TGA, GC–MS and CHN analysis. The molecular weight of SP was found to be 16 kDa. The isolated SP contains 29.4 ± 0.35% of sulfate, 27 ± 0.11% of fucose, 0.05 ± 0.12% of protein, respectively. Furthermore, SP exhibits its excellent radical scavenging effects were evaluated by DPPH, ABTS radical scavenging and reducing power assays. Moreover, pretreatment with SP significantly mitigates H2O2 induced cytotoxicity in L-929 cells in a dose dependent manner. Furthermore, SP pretreatment ameliorates oxidative stress induced apoptosis and DNA damage, alleviates the generation of intracellular reactive oxygen species (ROS) and restores mitochondrial membrane potential (MMP) in L-929 cells through its antioxidant potential. Together, these results suggest that SP can be exploited as a natural antioxidant in the food and pharmaceutical industries