Kantha D. Arunachalam

Memecylon edule leaf extract mediated green synthesis of silver and gold nanoparticles

We used an aqueous leaf extract of Memecylon edule (Melastomataceae) to synthesize silver and gold nanoparticles. To our knowledge, this is the first report where M. edule leaf broth was found to be a suitable plant source for the green synthesis of silver and gold nanoparticles. On treatment of aqueous solutions of silver nitrate and chloroauric acid with M. edule leaf extract, stable silver and gold nanoparticles were rapidly formed. The gold nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infra-red spectroscopy (FTIR). The kinetics of reduction of aqueous silver and gold ions during reaction with the M. edule leaf broth were easily analyzed by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to M. edule leaf broth, were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. TEM analysis of gold nanoparticles showed formation of triangular, circular, and hexagonal shapes in the size range 10–45 nm. The resulting silver nanoparticles were predominantly square with uniform size range 50–90 nm. EDAX results confirmed the presence of triangular nanoparticles in the adsorption peak of 2.30 keV. Further FTIR analysis was also done to identify the functional groups in silver and gold nanoparticles. The characterized nanoparticles of M. edule have potential for various medical and industrial applications. Saponin presence in aqueous extract of M. edule is responsible for the mass production of silver and gold nanoparticles.

Tissue engineered plant extracts as nanofibrous wound dressing

Use of plant extracts for treatment of burns and wound is a common practice followed over the decades and it is an important aspect of health management. Many medicinal plants have a long history of curative properties in wound healing. Electrospun nanofibers provide high porosity with large surface area-to-volume ratio and are more appropriate for cell accommodation, nutrition infiltration, gas exchange and waste excretion. Electrospinning makes it possible to combine the advantages of utilizing these plant extracts in the form of nanofibrous mats to serve as skin graft substitutes. In this study, we investigated the potential of electrospinning four different plant extracts, namely Indigofera aspalathoides, Azadirachta indica, Memecylon edule (ME) and Myristica andamanica along with a biodegradable polymer, polycaprolactone (PCL) for skin tissue engineering. The ability of human dermal fibroblasts (HDF) to proliferate on the electrospun nanofibrous scaffolds was evaluated via cell proliferation assay. HDF proliferation on PCL/ME nanofibers was found the highest among all the other electrospun nanofibrous scaffolds and it was 31% higher than the proliferation on PCL nanofibers after 9 days of cell culture. The interaction of HDF with the electrospun scaffold was studied by F-actin and collagen staining studies. The results confirmed that PCL/ME had the least cytotoxicity among the different plant extract containing scaffolds studied here. Therefore we performed the epidermal differentiation of adipose derived stem cells on PCL/ME scaffolds and obtained early and intermediate stages of epidermal differentiation. Our studies demonstrate the potential of electrospun PCL/ME nanofibers as substrates for skin tissue engineering.

Evaluation of in vitro antibacterial property of seaweeds of southeast coast of India

Cowpea viruses are difficult to identify using morphological criteria which can be time consuming, challenging, and require extensive knowledge in taxonomy. In order to improve the quality and quantity of the germplasms and to significantly reduce the infection and transmission of virus to different cultivars of cowpea, proper diagnosis and control is essential. The immuno-diagnostic and moleculardiagnostic methods have shown great potential as far as specificity and sensitivity are concerned and can generate accurate results rapidly. The aim of this overview is to discuss the various immunodiagnostic and molecular diagnostic methods such as enzymes linked immunosorbent assay (ELISA), immunosorbent electron microscopy (ISEM), polymerase chain reaction (PCR), nucleic acid hybridization, dot immunoblotting assay (DTBIA) found suitable for diagnosis of Cowpea aphid-borne mosaic virus (CABMV), Cucumber mosaic virus (CMV) and Cowpea mottle virus (CMeV) infecting cowpea. These techniques do not only provide information for epidemiological purposes, but also help to develop disease free stock of cowpeas. Therefore, these various techniques with symptoms and history are of immense value to diagnose cowpea viruses and are the cornerstone of the management of cowpea cultivars.The in vitro antibacterial activities of seaweeds belong to Chlorophyceae (Caulerpa racemosa and Ulva lactuca), Rhodophyceae (Gracillaria folifera and Hypneme muciformis) and Phaeophyceae (Sargassum myricocystum, Sargassum tenneerimum and Padina tetrastomatica) were studied against both Gramnegative and Gram-positive pathogenic bacteria. Methanolic extracts of all seaweed extracts tested in the present study exhibited broad spectrum of antibacterial activity. Chlorophyceae members showed high antibacterial activity than other members of the algae tested in the present investigation. Escherchia coli alone resistant to all the seaweed extracts except S. teneerimum. Results of the present study confirmed the potential use of seaweed extracts as a source of antibacterial compounds.

One-step green synthesis and characterization of leaf extract-mediated biocompatible silver and gold nanoparticles from Memecylon umbellatum

In this experiment, green-synthesized silver and gold nanoparticles were produced rapidly by treating silver and gold ions with an extract of Memecylon umbellatum leaf. The reaction process was simple and easy to handle, and was monitored using ultraviolet-visible spectroscopy. The effect of the phytochemicals present in M. umbellatum, including saponins, phenolic compounds, phytosterols, and quinones, on formation of stable silver and gold nanoparticles was investigated by Fourier-transform infrared spectroscopy. The morphology and crystalline phase of the nanoparticles were determined by transmission electron microscopy and energy-dispersive x-ray spectroscopy. The results indicate that the saponins, phytosterols, and phenolic compounds present in the plant extract play a major role in formation of silver and gold nanoparticles in their respective ions in solution. The characteristics of the nanoparticles formed suggest application of silver and gold nanoparticles as chemical sensors in the future. Given the simple and eco-friendly approach for synthesis, these nanoparticles could easily be commercialized for large-scale production.

Role of Bifidobacteria in nutrition, medicine and technology

The purpose of this review is to discuss the relatively recent revival of interest in bacterial interference, particularly the use of Bifidobucferium spp. in nutrition, for treatment and prevention of disease in medicine and commercial food products by using recently developed technology. In 1910, Metchnikoff (1) first put forward the idea that the regular consumption of fermented milks might offer health benefits, the possible prophylactic and/or therapeutic properties of yogurt and related products have been the subject of much speculation. New fermented dairy products containing Lactobacillus species and Bifidobacten’um spp. have been developed and marketed in Europe, North America and the Far East. The potential “health-promoting” properties of Lactobacillus acidophilus is well documented, but possible roles of ingested bifidobacteria have not been reviewed much. Bijidobucteria are normal inhabitants of the human and animal gut, and newborns are colonized within days after birth. The population seems to be relatively stable until advanced age when it has been reported to decline. Although the population of bifidobacteria in the intestine is stable, it is influenced by diet, antibiotics, stress etc. Bifidobacteria were first described by Tissier in 1899 (2) as predominant flora in breast-fed infants. This review will consider the characteristics, ecology and role in human systems, the therapeutic and prophylactic activities of BQidobacteria, and the potential pharmaceutical and fermented products manufactured using bifidobacteria and advanced technology. The facts and the results of the some of the experiments done by different authors and the current areas of research interest and future development have also been reviewed. 0 1999 Elscvla Science Inc.

Ultrafine dispersed CuO nanoparticles and their antibacterial activity

Copper oxide nanoparticles with a particle size ranging from 80 to 160 nm were prepared by a wet chemical procedure. Copper carbonate hydroxide and sodium hydroxide were used as raw materials. Copper hydroxide was generated as a precursor which was thermally decomposed to CuO nanoparticles. The nanoparticles were characterised using atomic force microscopy, X-ray diffraction and UV-visible spectrometry. The nanoparticles were tested for antibacterial activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella paratyphi and Shigella strains.

Chrysopogon zizanioides aqueous extract mediated synthesis, characterization of crystalline silver and gold nanoparticles for biomedical applications

The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The aim of this study was to develop a simple biological method for the synthesis of silver and gold nanoparticles using Chrysopogon zizanioides. To exploit various plant materials for the biosynthesis of nanoparticles was considered a green technology. An aqueous leaf extract of C. zizanioides was used to synthesize silver and gold nanoparticles by the bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) respectively. Water-soluble organics present in the plant materials were mainly responsible for reducing silver or gold ions to nanosized Ag or Au particles. The synthesized silver and gold nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The kinetics decline reactions of aqueous silver/gold ion with the C. zizanioides crude extract were determined by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to the extract were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. This eco-friendly approach for the synthesis of nanoparticles is simple, can be scaled up for large-scale production with powerful bioactivity as demonstrated by the synthesized silver nanoparticles. The synthesized nanoparticles can have clinical use as antibacterial, antioxidant, as well as cytotoxic agents and can be used for biomedical applications.

Potential anticancer properties of bioactive compounds of Gymnema sylvestre and its biofunctionalized silver nanoparticles.

Background Gymnema sylvestre is an ethno-pharmacologically important medicinal plant used in many polyherbal formulations for its potential health benefits. Silver nanoparticles (SNPs) were biofunctionalized using aqueous leaf extracts of G. sylvestre. The anticancer properties of the bioactive compounds and the biofunctionalized SNPs were compared using the HT29 human adenoma colon cancer cell line. Methods The preliminary phytochemical screening for bioactive compounds from aqueous extracts revealed the presence of alkaloids, triterpenes, flavonoids, steroids, and saponins. Biofunctionalized SNPs were synthesized using silver nitrate and characterized by ultraviolet–visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and X-ray diffraction for size and shape. The characterized biofunctionalized G. sylvestre were tested for its in vitro anticancer activity against HT29 human colon adenocarcinoma cells. Results The biofunctionlized G. sylvestre SNPs showed the surface plasmon resonance band at 430 nm. The scanning electron microscopy images showed the presence of spherical nanoparticles of various sizes, which were further determined using the Scherrer equation. In vitro cytotoxic activity of the biofunctionalized green-synthesized SNPs (GSNPs) indicated that the sensitivity of HT29 human colon adenocarcinoma cells for cytotoxic drugs is higher than that of Vero cell line for the same cytotoxic agents and also higher than the bioactive compound of the aqueous extract. Conclusion Our results show that the anticancer properties of the bioactive compounds of G. sylvestre can be enhanced through biofunctionalizing the SNPs using the bioactive compounds present in the plant extract without compromising their medicinal properties.

Uranium (238U)-induced ROS and cell cycle perturbations, antioxidant responses and erythrocyte nuclear abnormalities in the freshwater iridescent shark fish Pangasius sutchi

The strategic plan of this study is to analyze any possible radiological impact on aquatic organisms from forthcoming uranium mining facilities around the Nagarjuna Sagar Dam in the future. The predominantly consumed and dominant fish species Pangasius sutchi, which is available year-round at Nagarjuna Sagar Dam, was selected for the study. To comprehend the outcome and to understand the mode of action of 238U, the fish species Pangasius sutchi was exposed to ¼ and ½ of the LC50 doses of waterborne 238U in a static system in duplicate for 21 days. Blood and organs, including the gills, liver, brain and muscles, were collected at different time periods-0h, 24h, 48h, 72h, 96h, 7, days 14days and 21 days-using ICP-MS to determine the toxic effects of uranium and the accumulation of 238U concentrations. The bioaccumulation of 238U in P. sutchi tissues was dependent on exposure time and concentration. The accumulation of uranium was, in order of magnitude, measured as gills>liver>brain>tissue, with the highest accumulation in the gills. It was observed that exposure to 238U significantly reduced antioxidant enzymes such as superoxide dismutase, catalase, and lipid peroxidase. The analysis of DNA fragmentation by comet assay and cell viability by flow cytometry was performed at different time intervals. DNA histograms by flow cytometry analysis revealed an increase in the G2/M phase and the S phase. The long-term 238U exposure studies in fish showed increasing micronucleus frequencies in erythrocytes with greater exposure time. The higher the concentration of 238U is, the greater is the effect observed, suggesting a close relationship between accumulation and toxicity. A possible ROS-mediated 238U toxicity mechanism and antioxidant responses have been proposed.

Ingestion of Polonium ( 210 Po) via dietary sources in high background radiation areas of south India

Abstract Purpose: To study the distribution of Polonium (210Po) activity in dietary sources in the high background radiation zone of Puttetti in southern Tamil Nadu. Materials and methods: 210Po was analyzed in the food materials consumed by the male and female individual representatives living in the high background areas by 24-h Duplicate Diet Study (DDS) and Market Basket Study (MBS). The MBS was performed by collecting the food samples such as, cereals, fruits, leafy vegetables, roots and tubers, other vegetables, fish, meat and milk grown in the high background radiation zone of southern Tamil Nadu as a part of baseline study in this region. The DDS was done by collecting the food materials consumed including the beverages in 24 h from different age groups of male and female individuals living in the village of Puttetti. The intake and ingestion dose of the radionuclide 210Po was estimated. Results: The average concentration of 210Po in DDS (n = 33) was found to be 74 mBq.kg− 1 of fresh weight. The MBS was collected based on food consumption representing more than 85–95% of annual supply, and were divided into eight food groups. The average concentration of 210Po in the eight food groups namely leafy vegetables was 2176 mBq.kg− 1 (n = 3), vegetables 55 mBq.kg− 1 (n = 10), roots and tubers 251 mBq.kg− 1 (n = 4), fruits 65 mBq.kg− 1 (n = 5), fish 345 mBq.kg− 1 (n = 2), meat food 117 mBq.kg− 1 (n = 3), milk 20 mBq.kg− 1 (n = 1) and cereal 290 (n = 1) mBq.kg− 1 of fresh weight, respectively. The annual intake and ingestion dose due to 210Po was estimated by DDS and MBS in adults, adolescents and children. The overall results showed that the MBS was moderately higher than the DDS in all age groups. Moreover, a DDS approach may even be more realistic, as cooked foodstuffs are used for dietary exposure assessment. Conclusion: The study confirms that the current levels of 210Po do not pose a significant radiological risk to the local inhabitants.