G. Madhumitha

Efficient phyto-synthesis and structural characterization of rutile TiO2 nanoparticles using Annona squamosa peel extract.

In the present study, the biosynthesis of rutile TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using fruit peel Annona squamosa aqueous extract. This is the first report on the new, simple, rapid, eco-friendly and cheaper methods for the synthesis of rutile TiO(2) NPs at lower temperature using agricultural waste. Rutile TiO(2) NPs were characterized by UV, XRD, SEM, TEM and EDS studies. The UV-Vis spectrophotometer results were promising and showed a rapid production of TiO(2) NPs with a surface plasmon resonance occurring at 284 nm. The formation of the TiO(2) NPs as observed from the XRD spectrum is confirmed to be TiO(2) particles in the rutile form as evidenced by the peaks at 2θ=27.42°, 36.10°, 41.30° and 54.33° when compared with the literature. The TEM images showed polydisperse nanoparticles with spherical shapes and size 23±2 nm ranges.

Synthesis and characterization of palladium nanoparticles using Catharanthus roseus leaf extract and its application in the photo-catalytic degradation

The potential effect of Catharanthus roseus leaf extract for the formation of palladium nanoparticles and its application on dye degradation was discussed. The efficiency of C.roseus leaves are used as a bio-material for the first time as reducing agent. Synthesized palladium nanoparticles were supported by UV-vis spectrometry, XRD, FT-IR and TEM analysis. The secondary metabolites which are responsible for the formation of nanoparticles were identified by GC-MS. The results showed that effect of time was directly related to synthesized nanoparticles and functional groups has a critical role in reducing the metal ions and stabilizing the palladium nanoparticles in an eco-friendly process.

Preliminary phytochemical analysis, antibacterial, antifungal and anticandidal activities of successive extracts of Crossandra infundibuliformis.

OBJECTIVE To investigate the phytochemical, antibacterial, antifungal and anticandidal activity of successive extracts of Crossandra infundibuliformis (Acanthaceae) leaves. METHODS Preliminary screening on the presence of alkaloids, saponins, phytosterols, phenolic compounds, flavanoids, tannins, carbohydrates, terpenoids, oils and fats were carried out by phytochemical analysis. The antibacterial, antifungal and anticandidal activities were done by agar well diffusion technique. RESULTS The successive extracts have an array of chemical constituents and the MIC values of antibacterial activity ranges from 0.007 8 to 0.015 0 μg/mL. In case of antifungal and anticandidal activities the MIC values were between 0.125 and 0.250 μg/mL. CONCLUSIONS These findings demonstrate that the leaf extracts of C. infundibuliformis presents excellent antimicrobial activities and thus have great potential as a source for natural health care products.

Biotechnological aspects of ZnO nanoparticles: overview on synthesis and its applications

The physicochemical methods of the synthesis of zinc nanoparticles (ZnO NPs) and some detailed studies on ZnO toxicity mechanism and biokinetics have been reported. However, some of these physical and chemical methods of synthesis are expensive and can also have toxic substances absorbed onto them. Hence, eco-friendly synthesis of nanoparticles due to their easier process, cheaper availability, and high stability is dominating new research. In particular, ZnO NPs which are now being synthesized through major biological systems involved in this are bacteria, fungi, and plant extracts; this has increased studies in various applications in the biological field. In this review, we have elaborated on various natural source-mediated syntheses of ZnO NPs and their role in various biological activities like antimicrobial, anticandidal, larvicidal, cytotoxic, and photocatalytic activities. Apart from these applications, ZnO NPs are also reported to help to prevent dust formation, for several years, on oil paintings.

Function of nanocatalyst in chemistry of organic compounds revolution: an overview

Heterocyclic motif is an important scaffoldwhich has both industrial and pharmaceutical applications. Thesemotifs can be prepared using wide variety of reaction conditions such as the use of expensive catalyst, toxic solvent, harsh reaction condition like the use of base, high temperature, and multistep reaction. Although variousmethods are involved, the chemistry arena is now shifted towards the greener way of synthesis. Nanocatalyst constitutes an important role in the green synthesis. This is because the activity of the catalyst resides in the exposed portion of the particles. By decreasing the size of the catalyst, advantages such as more surface area would be exposed to the reactant, only negligible amount would be required to give the significant result and selectivity could be achieved, thereby, eliminating the undesired products. The current review enlists the various types of nanocatalyst involved in the heterocyclic ring formation and also some other important functionalization over the ring.

Bio-functionalized doped silver nanoparticles and its antimicrobial studies

In recent era researchers are mainly focused on silver (Ag) and silver doped nanoparticles due to its vast area of applications which are effectively acts against the microbial activity. Silver nanoparticles (AgNP’s) were one of the metal nanoparticles which have high activity against various diseases causing pathogens to safeguard the environment. However, there is increasing concern related to biological impacts by the use of silver doped nanoparticles on a large scale. The synthesized silver nanoparticles were doped with other chemical reagents by using various physio-chemical methods. The stability of silver nanoparticles was governed by morphological features, capping agents and organic molecules. This review article briefs about the synthesis of silver doped nanoparticles using different methods and their antimicrobial activity.

2,3-Dihydroquinazolin-4(1H)-ones: Visible light mediated synthesis, solvatochromism and biological activity

The photochemical synthesis of a series of 2,3-dihydroquinazolin-4(1H)-ones were evaluated under the irradiation of visible light (>390nm). The effect of the visible light mediated synthesis was carried out in the presence/absence of solvent. The effect of solvent plays a key role in the synthesis was evidenced through the formation of product in short duration. The solvatochromic effects of the fluorescent compounds (3a-k) were studied with respect to the solvents of increasing polarity (DCM<methanol<DMF<DMSO). The determination of in vitro anti-inflammatory activity of the compounds (3a-k) by the inhibition of bovine serum albumin (BSA) denaturation and 2,2-di(4-t-octylphenyl)-1-picrylhydrazyl (DOPPH) radical scavenging consequence of the compounds (3a-k) were determined by spectroscopic technique. The compound 3j in DMSO exhibited extreme high quantum yield. The compound 3i was found to be superior both in the efficiency of the anti-inflammatory activity and radical scavenging ability.

Photocatalytic degradation of Congo red using Carissa edulis extract capped zinc oxide nanoparticles

The use of plant extract to synthesize nanoparticle has been considered as one of the eco-friendly method. Additionally, it is a strong alternate for conventional methods which includes chemical and physical approach. In this study, microwave assisted extraction of Carissa edulis (C. edulis) at 70°C and 400W was used to extract the secondary metabolites. Further, the metabolites were used as capping agent and Zn (NO3)2 as the metal precursor to synthesize ZnO nanoparticles (ZnO NPs). UV-Vis spectroscopy, FT-IR, XRD, SEM and HR-TEM were used for the characterization of nanoparticles. The Surface Plasmon Resonance around 358nm from the UV-Vis spectroscopy result represents the ZnO NPs formation. The FT-IR confirms the presence of functional groups that acts as the capping agent for the synthesis of ZnO NPs. The crystalline structure of nanoparticles is revealed in the XRD result, morphology showed by SEM results and the size of the ZnO NPs were predicted by HR-TEM. We have carried out the photocatalytic degradation of Congo red at 365nm in photo reactor using ZnO NPs. The result from the photocatalytic degradation Congo red showed rate constant is (-k) 0.4947 with 97% of degradation. This is our first attempt on the C. edulis extract on ZnO NPs preparation and Congo red dye degradation revels that ZnO NPs exhibit good photocatalytic property.

Free radical scavenging and reducing power of Lawsonia inermis L.seeds

OBJECTIVE To determine the antioxidant activity, total phenolic and flavonoid content of Petroleum ether extract (PE), Dichloromethane extract (DCM), Ethanol extract (ET) and aqueous extract (AQ) of henna seeds. METHODS Total antioxidant assay (phosphomolybenum method), DPPH radical scavenging assay, reducing power assay and lipid peroxidation inhibition assay were used to ascertain the potential of seeds as an antioxidant. RESULTS In all the assays carried out ET showed a greater potential to scavenge DPPH radical, reduce MO (VI) to MO (V) complex and Fe (III) to Fe (II) and to inhibit lipid peroxidation. The IC(50) of ET was far greater than that of the standard, ascorbic acid (AS) in the lipid peroxidation assay. The activity of AQ was lesser when compared with that of ET but greater than PE and DCM. The amount of phenolics and flavonoids were present in higher amounts in ET followed by AQ. Trace amounts of phenolics were detected in PE and DCM, but the amount of flavonoids were below the detection level. The study showed that the antioxidant activity and the concentrations of phenolics and flavonoids are proportionate to each other. CONCLUSIONS Ethanolic extract of henna seeds are efficient antioxidants, which can be utilized for further isolation of active compounds and pharmaceutical applications.

Hepatoprotective potential of petroleum ether leaf extract of Crossandra infundibuliformis on CCl4 induced liver toxicity in albino mice.

Abstract Objective To analyze the hepatoprotective effect of the Crossandra infundibuliformis . Methods Hepatotoxicity was induced by carbon tetrachloride. Petroleum ether extract of dried leaves was administrated to mice for 7 days. The hepatoprotective effect of petroleum ether extract was evaluated by the assay of liver function biochemical parameters. Results The result clearly indicates that petroleum ether extract showed significant hepatoprotection when compared with standard Silumarin. Conclusions The petroleum ether extract of the leaves of Crossandra infundibuliformis possess significant acute hepatoprotective activity. Thus further investigation on this species would bring a promising drug for liver disorders.