Removal of hexavalent chromium by biochar derived from Azadirachta indica leaves: Batch and column studies.

This report details the preparation, characterization, and applications of an inexpensive adsorbent obtained from Azadirachta indica leaves (Neem biochar (NBC)) and used to remove Cr(VI) from the synthetic waste water. The obtained NBC was characterized by XRD, FTIR, FESEM, EDX and Zeta potential measurements. Adsorption experiments conducted at various pH levels confirmed that 58.54 mg g-1 of Cr(VI) was removed by NBC at pH 2. Experiments conducted at various temperatures revealed that the Cr(VI) adsorption on NBC fits the Langmuir-type adsorption isotherm. A fixed-bed column study was conducted to obtain breakthrough curve for the adsorption process, which confirmed that the NBC usage rate was 4.63 g/L. Cr(VI)NBC was reactivated by NaOH treatment, and the reactivated NBC was used as a sorbent to remove fresh Cr(VI) from the synthetic waste water repeatedly. A cost analysis was also performed for the Cr(VI) removal confirmed that the process was less expensive.

Evaluation of antioxidant, DNA targeting, antimicrobial and cytotoxic studies of imine capped copper and nickel nanoparticles.

In this work, we have synthesized pyrimidine derivatives of Schiff base ligand 2-(4,6-dimethoxypyrimidin-2-ylimino)methyl)-6-methoxyphenol (DPMM) stabilized copper nanoparticles (DPMM-CuNPs) and nickel nanoparticles (DPMM-NiNPs) by modified Brust-Schiffrin technique as two step phase transfer assisted method and confirmed by UV-Visible, SEM and TEM analysis. The free radical scavenging activity of DPMM, DPMM-CuNPs &DPMM-NiNPs with 2, 2'-diphenylpicryl hydrazyl (DPPH), hydrogen peroxide (H2O2) super oxide dismutase (SOD) and nitric oxide (NO) shows that the antioxidant activity of DPMM-CuNPs is higher than DPMM &DPMM-NiNPs. Interaction study of DPMM-CuNPs &DPMM-NiNPs with CT-DNA has been investigated by absorption spectral titration, fluorescence studies, cyclic voltammetry and viscometric measurements. Dose dependent antibacterial and antifungal studies of DPMM-CuNPs & DPMM-NiNPs against five different bacteria Shigella sonnei, Staphylococcus aureus, Escherichia coli, Klepsiella pneumoniae, Pseudomonas fluoroscens and five different fungi Aspergillus niger, Candida albicans, Candida tropicalis, Mucor indicus and Rhizopus show that the compounds have significant antibacterial and antifungal activity. Cytotoxicity studies of DPMM-CuNPs &DPMM-NiNPs on human breast cancer cell line (MCF-7) were studied by 3-(4, 5-dimethylthiazol-2-yl-)-2, 5-diphenyltetrazolium bromide (MTT) assay. 50% cell viability was found at 25µg/mL for DPMM-CuNPs and 300µg/mL for DPMM-NiNPs. Collective biological results reveal that the synthesized DPMM-CuNPs is more biologically active than DPMM-NiNPs.

New pyrimidine based ligand capped gold and platinum nano particles: Synthesis, characterization, antimicrobial, antioxidant, DNA interaction and in vitro anticancer activities.

In this research work, we have synthesized new pyrimidine based Schiff base ligand, 2-((4,6-dimethoxypyrimidine-2-yl)methyleneenamino)-6-methoxyphenol (DPMM) capped gold (Au) and platinum (Pt) nanoparticles (NPs) by modified Brust-Schiffrin method. The characteristics of DPMM-Au NPs and DPMM-Pt NPs have been examined by UV-Visible, FTIR, SEM, TEM and powder XRD analysis. SEM analysis result shows that surface morphology of the DPMM-Au NPs and DPMM-Pt NPs are in granular and spherical shape, correspondingly. The size of the DPMM-Au NPs and DPMM-Pt NPs are approximately 38.14±4.5 and 58.64±3.0nm respectively, which confirmed by TEM analysis. The DPMM-Au NPs and DPMM-Pt NPs have potent antimicrobial against Escherichia coli, Klebsiella pneumonia, Pseudomonas fluorescens, Shigella sonnei, Staphylococcus aureus and Aspergillus niger, Candida albicans, Candida tropicalis, Mucor indicus, Rhizopus strains. The DPMM-Au NPs and DPMM-Pt NPs have good antioxidant activities than the free ligand (DPMM). The spectroscopic and viscometric measurement confirms the hydrophobic DNA binding abilities of the newly prepared DPMM capped metal NPs. Moreover, the in vitro anticancer activity of DPMM, DPMM-Au NPs and DPMM-Pt NPs against cancer (MCF-7, HeLa & HEp2) and normal (NHDF) cell lines have performed using MTT assay. These results reveals that, DPMM-Au NPs and DPMM-Pt NPs having significant cytotoxic activity against the cancer cell lines and least toxic effect on normal cell line as compared to standard drug cisplatin.

DNA interaction, antimicrobial, antioxidant and anticancer studies on Cu(II) complexes of Luotonin A.

Luotonin A (L), a novel natural cytotoxic and anti-inflammatory alkaloid, chelated with copper(II) to improve its cytotoxic effect against the cancer cells. The complexes [Cu(L)H2OCl]Cl (1) and [Cu(L)2]Cl2 (2) are prepared by using copper(II) chloride and L with ligand/metal molar ratio of 1:1 and 2:1 respectively. A solution of complexes 1 &2 are characterized by physical spectroscopic methods using Ultraviolet-visible (UV-Vis) spectrophotometer, Fourier Transform-Infra red (FT-IR) spectroscopy, Electron Para magnetic Resonance Spectroscopy (EPR) and by electrochemical methods. The interaction of these complexes 1 &2 with calf thymus (CT-DNA) have been investigated by physical methods to propose the modes of DNA binding with the complexes 1 &2. Absorption spectral titration studies of complex 1 with CT-DNA shows a red-shift of 5nm with the DNA binding affinity of Kb, 8.65×103M-1, but complex 2does not show any red-shift with binding constant Kb, 7.32×103M-1 reveals that the complex 1 binding with DNA strongly than complex 2 and the binding occurs in between the base pairs of DNA as intercalation. Strong interactions of the two complexes 1 & 2 with CT-DNA have also been confirmed by fluorescence spectral titration studies. The evaluated values of KSV and Kass shows that, the complexes 1 &2 interact with DNA through the intercalation, coincide with other partial intercalators strongly than the free ligand L. Complex 1 exhibits potent antioxidant activity with SC50 value of 23.9±0.69µM is evaluated by DPPH radical scavenging assay and which has potent antimicrobial activity against pathogens than 2 and L. The anticancer activity of L, complexes 1 &2 against human breast cancer cell line (MCF-7) and cervical cancer cell line (HeLa) has also been studied by using fluorescence staining method. The IC50 values of L, complexes 1&2 against MCF-7 and HeLa cell lines with the incubation time intervals of 24hrs are 1 (5.0±0.25, 12.0±0.30µM)<2 (6.5±0.27, 15.0±0.30µM)