D. Suresh

Artocarpus gomezianus aided green synthesis of ZnO nanoparticles: luminescence, photocatalytic and antioxidant properties.

We report green synthesis of multifunctional ZnO nanoparticles (NPs) using Artocarpus gomezianus (AG) extract as fuel by solution combustion synthesis. The formation of NPs was confirmed by powder XRD, SEM, TEM and UV-Visible studies. The NPs were subjected for photoluminescence, photodegradative and antioxidant studies. XRD data reveals that the ZnO NPs possess wurtzite structure. UV-Visible spectrum shows absorbance maximum at 370 nm which corresponds to the energy band gap of 3.3 eV. Morphology studies indicate the highly porous nature of the NPs. PL spectra of NPs found to display very interesting blue, green and red emissions upon excitation at 325 nm. The NPs exhibit potential photocatalytic activity towards the degradation of methylene blue (MB) dye upon exposure to sun light and UV light. ZnO NPs found to have considerable antioxidant activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals. The study successfully demonstrates a simple and eco-friendly method for the synthesis of efficient multifunctional ZnO nanoparticles using green synthetic approach.

Facile green fabrication of nanostructure ZnO plates, bullets, flower, prismatic tip, closed pine cone: Their antibacterial, antioxidant, photoluminescent and photocatalytic properties

Green synthesis of multifunctional Zinc oxide nanoparticles (NPs) with a variety of morphologies were achieved by low temperature solution combustion route employing neem (Azadirachta indica) extract as fuel. The nanoparticles were characterized by PXRD, FTIR, XPS, Raman and UV-Visible spectroscopic studies. The Morphologies were studied by SEM and TEM analysis. The NPs were subjected for photoluminescence, photocatalytic, antibacterial and antioxidant activity studies. PXRD pattern confirmed the hexagonal wurtzite structure of the product. SEM images indicated the transformation of mushroom like hexagonal disks to bullets, buds, cones, bundles and closed pine cone structured NPs with increase in the concentration of neem extract in reaction mixture. The NPs exhibited prominent green emission due to the presence of intrinsic defect centers. The as-formed bullet shaped ZnO with 4ml of neem extract was found to decolorize Methylene blue (MB) under Sunlight and UV light irradiation. The antibacterial studies indicated that ZnO NPs of concentration 500, 750 and 1000μg resulted in significant antibacterial activity on Klebsiella aerogenes and Staphylococcus aureus but not against Escherichia coli and Pseudomonas aeruginosa in agar well diffusion method. Further, ZnO NPs exhibited significant antioxidant activity against scavenging DPPH free radicals. The current investigation demonstrated green engineering method for the synthesis of multifunctional ZnO NPs with interesting morphologies using neem extract.

EGCG assisted green synthesis of ZnO nanopowders: Photodegradative, antimicrobial and antioxidant activities

Zinc oxide nanopowders were synthesized by solution combustion method using Epigallocatechin gallate (EGCG) a tea catechin as fuel. The structure and morphology of the product was characterized by Powder X-ray Diffraction, Scanning Electron Microscopy, photoluminescence and UV-Visible spectroscopy. The nanopowders (Nps) were subjected to photocatalytic and biological activities such as antimicrobial and antioxidant studies. PXRD patterns demonstrate that the formed product belongs to hexagonal wurtzite system. SEM images show that the particles are agglomerated to form sponge like structure and the average crystallite sizes were found to be ∼10-20nm. PL spectra exhibit broad and strong peak at 590nm due to the Zn-vacancies, and O-vacancies. The prepared ZnO Nps exhibit excellent photocatalytic activity for the photodegradation of malachite green (MG) and methylene blue (MB) indicating that the ZnO NPs are potential photocatalytic semiconductor materials. ZnO NPs exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus using the agar well diffusion method. Furthermore, the ZnO nano powders show good antioxidant activity by potentially scavenging DPPH radicals. The study successfully demonstrates synthesis of ZnO NPs by simple ecofriendly route employing EGCG as fuel that exhibit superior photodegradative, antibacterial and antioxidant activities.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm−1 indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV –Vis spectrum was found to be in the range 5.40–5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emission at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation.

In vitro anticancer and hepatoprotective activity studies of Garcinia xanthochymus

Natural products are very well known to exhibit anticancer activities. The present study aimed at assessing the potency of various extracts of Garcinia xanthochymus against cancer using in vitro cell lines. MCF 7, HepG2, HeLa, PC3, A549 and Vero cell lines were employed for the assessment. The ability of extracts to exert toxic insult on cancer cells has been the basis of anticancer activity. GxF was fond to be very potentially toxic (80 mg/ml) to HEP G2 cell lines among all the tested extracts. Also, it was found to be the most toxic compared to GxA and GxF whose average CTC 50 was found to be 180 and 118 mg/ml, respectively. Among all the tested extracts, GxF was found to be potentially toxic to the MCF 7 cell lines whose CTC 50 was found to be73 mg/ml. GxA possesses the CTC 50 of 810 mg/ml. GxR was found to be toxic with average CTC 50 of 303 mg/ml. This was followed by GxF and GxA with average CTC 50 values of 303 and 456 mg/ml. In vitro hepatoprotective activity of the plant extracts was studied by employing primary rat hepatocytes. The drug silymarin was found to exhibit 85.28 per cent protection against paracetamol induced toxicity in primary rat hepatocytes at the tested concentration of 250 mg/ml. It was found that GxF and GxR were found to have comparatively similar protective power like silymarin. These extract exhibited 83.63 per cent and 79.58 per cent protection against paracetamol induced toxicity in primary rat hepatocytes at the concentration of 200 mg/ml, respectively. GxA did not exhibit considerable activity with 55.61 per cent protection.