Durai Prabhu

Green synthesis of silver nanoparticles using Delphinium denudatum root extract exhibits antibacterial and mosquito larvicidal activities

Green synthesis of silver nanoparticles (AgNPs) using aqueous root extract of Delphinium denudatum (Dd) by reduction of Ag(+) ions from silver nitrate solution has been investigated. The synthesized DdAgNPs were characterized by using UV-Vis spectroscopy, X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FTIR). The prepared DdAgNPs showed maximum absorbance at 416nm and particles were polydispersed in nature, spherical in shape and the size of the particle obtained was⩽85nm. The DdAgNPs exhibited antibacterial activity against Staphylococcus aureus ATCC 6538, Bacillus cereus NCIM 2106, Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027. The DdAgNPs showed potent larvicidal activity against second instar larvae of dengue vector Aedes aegypti with a LC50 value of 9.6ppm.

Synergistic anticancer activity of curcumin and catechin: An in vitro study using human cancer cell lines

The most practical approach to reduce morbidity and mortality of cancer is to delay the process of carcinogenesis by usage of anticancer agents. This necessitates that safer compounds are to be critically examined for anticancer activity especially, those derived from natural sources. A spice commonly found in India and the surrounding regions, is turmeric, derived from the rhizome of Curcuma longa and the major active component is a phytochemical termed curcumin. Green tea is one of the most popular beverages used worldwide, produced from the leaves of evergreen plant Camellia sinensis and the major active ingredients are polyphenolic compounds known as catechins. In this study, synergistic anticancer activity of curcumin and catechin was evaluated in human colon adenocarcinoma HCT 15, HCT 116, and human larynx carcinoma Hep G‐2 cell lines. Although, both curcumin or catechin inhibited the growth of above cell lines, interestingly, in combination of both these compounds highest level of growth control was observed. The anticancer activity shown is due to cytotoxicity, nuclear fragmentation as well as condensation, and DNA fragmentation associated with the appearance of apoptosis. These results suggest that curcumin and catechin in combination can inhibit the proliferation of HCT 15, HCT 116, as well as Hep G‐2 cells efficiently through induction of apoptosis. Microsc. Res. Tech., 2011.

Toxicity Effect of Silver Nanoparticles in Brine Shrimp Artemia

The present study revealed the toxic effect of silver nanoparticles (AgNPs) in Artemia nauplii and evaluated the mortality rate, hatching percentage, and genotoxic effect in Artemia nauplii/cysts. The AgNPs were commercially purchased and characterized using field emission scanning electron microscope with energy dispersive X-ray spectroscopy. Nanoparticles were spherical in nature and with size range of 30–40 nm. Artemia cysts were collected from salt pan, processed, and hatched in sea water. Artemia nauplii (II instar) were treated using silver nanoparticles of various nanomolar concentrations and LC50 value (10 nM) and mortality rate (24 and 48 hours) was evaluated. Hatching percentage of decapsulated cysts treated with AgNPs was examined. Aggregation of AgNPs in the gut region of nauplii was studied using phase contrast microscope and apoptotic cells in nauplii stained with acridine orange were observed using fluorescence microscope. DNA damage of single cell of nauplii was determined by comet assay. This study showed that as the concentration of AgNPs increased, the mortality rate, aggregation in gut region, apoptotic cells, and DNA damage increased in nauplii, whereas the percentage of hatching in Artemia cysts decreased. Thus this study revealed that the nanomolar concentrations of AgNPs have toxic effect on both Artemia nauplii and cysts.

Apoptosis in liver cancer (HepG2) cells induced by functionalized gold nanoparticles.

An ethnopharmacological approach for biosynthesis of gold nanoparticles is being demonstrated using seed coat of Cajanus cajan. Medicinal value of capping molecule investigated for anticancer activity and results disclose its greater potential. The active principle of the seed coat [3-butoxy-2-hydroxypropyl 2-(2,4-dihydroxyphenyl) acetate] is elucidated. Rapid one-step synthesis yields highly stable, monodisperse (spherical) gold nanoparticles in the size ranging from 9 to 41 nm. Anticancer activity has been studied using liver cancer cells and cytotoxic mechanism has been evaluated using MTT, Annexin-V/PI Double-Staining Assay, Cell cycle, Comet assay and Flow cytometric analysis for apoptosis. The present investigation will open up a new possibility of functionalizing gold nanoparticles for apoptosis studies in liver cancer cells.

Magneto-structural correlation, antioxidant, DNA interaction and growth inhibition activities of new chloro-bridged phenolate complexes

A new class of chloro-bridged dinuclear nickel(II) and copper(II) phenolate complexes (1–8) were synthesized from 4-substituted-2-((2-(piperazin-1-yl)ethylimino)methyl)phenols (L1−4) and characterized. The XRD analysis of complexes 4 and 8 shows two mononuclear units connected through a bridged chlorine atom that gives dinuclear complexes. The stability of the complexes has been determined using a spectrophotometric method. Complexes 5–8 possess significant antioxidant activity against the DPPH radical. The binding studies of complexes with CT-DNA suggest partial intercalative/electrostatic interaction and the cleavage ability for pBR322 DNA shows the involvement of the hydroxyl radical as an intermediate in the cleavage reaction. The IC50 value of complexes 2, 6 and 8 against the HepG2 cell line is comparable with that of cisplatin. To find the extent of nuclear chromatin cleavage, propidium iodide staining and comet assays were employed. Among the newly synthesized complexes, copper(II) complexes exhibited superior biological activity when compared to their nickel(II) analogues.

In vitro trans-differentiation of human umbilical cord derived hematopoietic stem cells into hepatocyte like cells using combination of growth factors for cell based therapy

The aim of the study was to develop a new strategy for the differentiation of hematopoietic stem cell (HSC) derived from UCB into hepatocyte like cells and also to estimate the effects of combination of fibroblast growth factor 4 (FGF 4) and hepatocyte growth factor (HGF) on hematopoietic stem cell differentiation. HSCs were isolated and purified by magnetic activated cell sorting. HSCs were induced to hepatocyte like cells under a 2-step protocol with combination of growth factors. Reverse transcription polymerase chain reaction was performed to detect multiple genes related to hepatocyte like cells development and function. Hepatocyte like morphology was illustrated by inverted repeat microscope and the secretion of albumin and α- fetoprotein by these cells was confirmed by enzyme linked immunosorbent assay. Hepatocyte like cells was observed at the end of the protocol (days 14). These differentiated cells were observed to show high expression of genes related to hepatocytes (tryptophan 2, 3-dioxygenase [TO], glucose 6-phosphate [G6P], cytokeratin 18 [CK 18], albumin and α- fetoprotein [AFP]). The quantities of albumin and AFP at day 0 were low and upon differentiation the cells were able to produce albumin and AFP at high levels. Our results show a new strategy for differentiation in a short duration, using a combination of growth factors for the differentiation of umbilical cord blood derived HSC into hepatocyte like cells under certain in vitro conditions. After further studies this approach has the potency, for widespread cell replacement therapy for liver diseases.

Induction of apoptosis by the aqueous and ethanolic leaf extract of Vitex negundo L. in MCF-7 human breast cancer cells.

The aim of this investigation was to evaluate the anti-proliferative potential of aqueous and ethanolic extract from Vitex negundo against human breast cancer cell (MCF-7). The aqueous and ethanol extract from V. negundo potently inhibited growth of MCF-7 in a concentration-dependent manner. V. negundo pretreatment resulted in deferential cell viability and IC50 value were observed in MCF-7 cell line but not in control cell line. The above result suggested that V. negundo has a potential benefits in breast cancer cells. Keywords - Anti-cancer, anti-proliferative, breast cancer, cytotoxicity, V. negundo , MCF-7

Anti-proliferative effect of a compound isolated from Cassia auriculata against human colon cancer cell line HCT 15

The compound was isolated from leaves of Cassia auriculata and its structure was characterized using high-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC-MS), UV-vis spectroscopy (UV-vis), fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, cytotoxicity, nuclear morphology and lactate dehydrogenase assay of isolated compound was tested against human colon cancer cell line HCT 15. The isolated compound, 4-(4-chlorobenzyl)-2,3,4,5,6,7-hexahydro-7-(2-ethoxyphenyl)benzo[h][1,4,7]triazecin-8(1H)-one at 25μg/ml concentration and by 48h showed 50% inhibition of human colon cancer cells (HCT 15). The results suggest that isolated compound from C. auriculata has potential to prevent colon cancer cell line.

Dinuclear manganese(II) complexes of hexaazamacrocycles bearing N-benzoylated pendant separated by aromatic spacers: Antibacterial, DNA interaction, cytotoxic and molecular docking studies.

Three new homodinuclear manganese(II) complexes of the type [Mn2L(1-3)(ClO4)(H2O)](ClO4)3 (1-3) have been synthesized via cyclocondensation of terephthalaldehyde with three different benzoylated pendants in the presence of manganese(II) perchlorate and characterized by spectroscopic methods. Cyclic voltammetric investigation of complexes (1-3) depict two quasi-reversible one electron reduction processes in the cathodic potential region (E(1)pc=-0.73 to-0.83 V, E(2)pc=-1.31 to -1.40 V) and two quasi-reversible one electron oxidation processes in the anodic potential region (E(1)pa=1.03 to 1.10 V, E(2)pa=1.69 to 1.77 V). Electronic absorption spectra of the complexes suggested tetrahedral geometry around the central metal ion. The observed low magnetic moment values (μeff, 5.60-5.68 B.M.) of the complexes indicate the presence of an antiferromagnetic spin-exchange interaction between two metal centers, which was also supported by the broad EPR signal. All the compounds were tested for antibacterial activity against Gram (-ve) and Gram (+ve) bacterial strains. The binding studies of complexes with CT-DNA suggested minor-groove mode of interaction. Molecular docking studies were carried out in order to find the binding affinity of complexes with DNA and protein EGFR Kinase. The complexes are stabilized by additional electrostatic and van der Waals interaction with the DNA, and support minor groove mode of binding. The cleavage activity of complexes on pBR322 plasmid DNA displays efficient activity through a mechanistic pathway involving hydroxyl radicals. The cytotoxicity of complexes 2 and 3 have been tested against human liver adenocarcinoma (HepG2) cell line. Nuclear-chromatin cleavage has also been observed with propidium iodide (PI) staining and alkaline single-cell gel electrophoresis (comet assay) techniques.

Apoptosis mediated anti-proliferative effect of compound isolated from Cassia auriculata leaves against human colon cancer cell line

A compound was isolated from Cassia auriculata leaves and characterized by high-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC-MS), UV-vis spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The in vitro anticancer effect of the compound isolated from C. auriculata was evaluated in human colon cancer cells HCT 15 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cytotoxicity, nuclear morphology analysis and measurement of lactate dehydrogenase. The isolated compound 4-(2,5 dichlorobenzyl)-2,3,4,5,6,7 hexahydro7(4 methoxyphenyl)benzo[h][1,4,7] triazecin8(1H)-one showed 50% inhibition of HCT 15 cells when tested at 20μg/ml after 24h incubation. Cytotoxicity, nuclear morphology and lactate dehydrogenase assays clearly show potent anticancer activity of the isolated compound against colon cancer. Thus, the in vitro findings suggest that the compound isolated from C. auriculata leaves have potent anti-cancer properties with possible clinical applications.