Effect of gamma-ray irradiated reduced graphene oxide (rGO) on environmental health: An in-vitro and in-vivo studies.

The unique properties of reduced graphene oxide (rGO) have drawn the attention of scientists worldwide since the last decade and it is explored for a wide range of applications. However, the rapid expansion of rGO use in various products will eventually lead to environenal exposure and rises a safety concern on the environment and humal health risk. Moreover, the utilization of toxic chemicals for the reduction of graphene oxide (GO) into rGO is not environmentally friendly, warranting the exploration of non-toxic approaches. In the present work, rGO was synthesized using a different dose of gamma-ray irradiation and characterized. The in-vitro and in-vivo analysis indicated that the gamma-irradiated rGO induced toxicity depending on its degree of reduction and dosage. In the L929 cells, rGO-30 KGy significantly induced cytotoxicity even at low concentration (1 mg L-1) by inducing reactive oxygen species (ROS), lactate dehydrogenase (LDH) enzyme production, nuclear fragmentation and apoptosis. The change in morphology of the cells like membrane blebbing and cell rounding was also observed via FESEM. In the in-vivo model Caenorhabditis elegans, rGO-30 KGy significantly affected the functioning of primary and secondary targeted organs and also negatively influenced the nuclear accumulation of transcription factors (DAF-16/FOXO and SKN-1/Nrf2), neuronal health, and antioxidant defense mechanism of the nematodes. The real-time PCR analysis showed significant up-regulation (ced-3, ced-4, cep-1, egl-1, and hus-1) and down-regulation (ced-9) of the gene involved in germ-line and DNA damage-induced apoptosis. The detailed toxicity mechanism of gamma irradiated rGO has been elucidated. This work highlights the toxicity of rGO prepared by gamma-ray radiation and paves way for understating the toxicity mechanism.

Elucidating the role of microstructural modification on stress corrosion cracking of biodegradable Mg4Zn alloy in simulated body fluid.

This paper investigates the effect of microstructure modification by heat treatment on stress corrosion cracking (SCC) behavior of Mg4Zn alloy in simulated body fluid (SBF). Mg4Zn alloy in as cast, solution heat treated and peak aged conditions was susceptible to SCC in SBF when strained at 3.6 × 10-6 s-1. SCC index based on fracture energy is least for solutionized alloy (0.84), while 0.88 for as cast and peak aged alloys. Fractographic analysis indicates predominantly intergranular SCC for solution treated alloy initiated by anodic dissolution near grain boundaries. As cast and peak aged alloy shows mainly transgranular failure due to hydrogen embrittlement adjacent to secondary phase particles.

Intensification of enzymatic hydrolysis of waste newspaper using ultrasound for fermentable sugar production.

An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioethanol in an eco-friendly and cost effective manner. In this study, the effect of ultrasound on enzymatic hydrolysis of newspaper, a potential feedstock for bioethanol production due to its high cellulosic content, was investigated. The effect of substrate loading, enzyme loading, temperature, ultrasonic power and duty cycle on the hydrolysis has been studied. Optimum conditions for conventional enzymatic hydrolysis were substrate loading of 5% (w/v), enzyme loading of 0.14% (w/v), temperature of 323K, and under these conditions and 72h of hydrolysis, reducing sugar yield of 11.569g/L was obtained. In case of ultrasound-assisted enzymatic hydrolysis approach, optimum conditions obtained were substrate loading of 3% (w/v), enzyme loading of 0.8% (w/v), sonication power of 60W, duty cycle of 70%, hydrolysis time of 6.5h and the reducing sugar yield obtained under these conditions was 27.6g/L. Approximately 2.4 times increase in the release of reducing sugar concentration was obtained by the ultrasound-assisted enzymatic hydrolysis approach. Results indicate that there is a synergistic effect obtained from the combination of ultrasound and enzymes which lowers the diffusion-limiting barrier to enzyme/substrate binding and results in an increase in reaction rate. The experimental data were also fitted in a simple three parameter kinetic model.

Chemopreventive effect and HPTLC fingerprinting analysis of Jasminum sambac (L.) Ait. Extract against DLA-induced lymphoma in experimental animals.

The anticancer activity of the ethanolic extract of Jasminum sambac against Dalton's lymphoma ascites-induced lymphatic cancer in Swiss albino mice was investigated. The anticancer activity of J. sambac was studied against lymphoma using lipid profiles, biochemical parameters, and membrane-bound marker enzymes by standard procedures. A high-performance thin-layer chromatography fingerprinting analysis showed the presence of terpenoids and flavonoids. The levels of cholesterol, triglyceride, VLDL cholesterol, and LDL cholesterol were significantly decreased in tumor-induced mice, while HDL cholesterol showed increased levels compared with those profiles. On treatment with J. sambac, the levels were brought back to near normal. The albumin, creatinine, total protein, urea, and uric acid contents were also approaching normal values. There was s significant increase in the levels of ATPase in group II. These levels were brought back to normal upon plant extract treatment of mice. DNA fragmentation occurred in the tumor-induced group of tissue, and treatment with ethanolic extract reduced the DNA damage caused by lymphoma. Expression of lactate dehydrogenase (LDH) isoenzymes shows an increase in the levels of LDH-4 and LDH-5 in cancer-bearing animals which is brought back to near normal. Histopathological investigation showed normal sections of liver tissues in the treatment group. The results found in mice treated with ethanolic extract 100 mg kg(-1) body weight quite promising and were comparable with the standard drug 5-fluorouracil. The statistically processed results support the conclusion that the ethanolic extract of J. sambac flower (100 mg kg(-1)) possesses a dose-dependent significant anticancer activity against lymphoma.

Glucose lowering effect of aqueous extract of Bauhinia tomentosa L. on alloxan induced type 2 diabetes mellitus in wistar albino rats.

The study was designed to evaluate the anti-diabetic effect of aqueous extract of Bauhinia tomentosa L. leaf on alloxan induced Wistar albino rats. Diabetes was induced in albino rat models with alloxan monohydrate (150mg/kg body weight). Aqueous leaf extract of Bauhinia tomentosa at the dose of 300 mg/kg was orally administered once a day for 30 days to the diabetic animals. In this study, glycemic parameters, lipid parameters and serum enzymes were reduced whereas the level of high-density lipoprotein-cholesterol was elevated. The extract significantly increased the total protein and glycogen level in the liver of diabetic rats. Furthermore, the liver carbohydrate metabolizing enzymes were normalized by the administration of the extracts. Histopatholgical examination results of liver, pancreas and kidney were normal in general. The above results indicated the anti-diabetic efficacy of the B.tomentosa leaf extract.

Larvicidal activity of Saraca indica, Nyctanthes arbor-tristis, and Clitoria ternatea extracts against three mosquito vector species.

Screening of natural products for mosquito larvicidal activity against three major mosquito vectors Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi resulted in the identification of three potential plant extracts viz., Saraca indica/asoca, Nyctanthes arbor-tristis, and Clitoria ternatea for mosquito larval control. In the case of S. indica/asoca, the petroleum ether extract of the leaves and the chloroform extract of the bark were effective against the larvae of C. quinquefasciatus with respective LC(50) values 228.9 and 291.5 ppm. The LC(50) values of chloroform extract of N. arbor-tristis leaves were 303.2, 518.2, and 420.2 ppm against A. aegypti, A. stephensi, and C. quinquefasciatus, respectively. The methanol and chloroform extracts of flowers of N. arbor-tristis showed larvicidal activity against larvae of A. stephensi with the respective LC(50) values of 244.4 and 747.7 ppm. Among the methanol extracts of C. ternatea leaves, roots, flowers, and seeds, the seed extract was effective against the larvae of all the three species with LC(50) values 65.2, 154.5, and 54.4 ppm, respectively, for A. stephensi, A. aegypti, and C. quinquefasciatus. Among the three plant species studied for mosquito larvicidal activity, C. ternatea was showing the most promising mosquito larvicidal activity. The phytochemical analysis of the promising methanolic extract of the seed extract was positive for carbohydrates, saponins, terpenoids, tannins, and proteins. In conclusion, bioassay-guided fractionation of effective extracts may result in identification of a useful molecule for the control of mosquito vectors.