Naveen Dubey

Nitric oxide ameliorates zinc oxide nanoparticles phytotoxicity in wheat seedlings: Implication of the ascorbate-glutathione cycle

The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate–glutatione cycle (AsA–GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA–GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA–GSH cycle.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC–MS/MS and its application in bioequivalence studies

A validated ultra-performance liquid chromatography mass spectrometric method (UPLC–MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC–MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid–liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d4 and HCT-13Cd2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Phenomenex, Gemini NX (100 mm×4.6 mm, 5 µm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.

Current Trends of Engineered Nanoparticles (ENPs) in Sustainable Agriculture: An Overview

Nanotechnology is an interesting area of multifaceted research in agricultural perspective. This technology incorporates the manufacturing of material at nano level. Nanoparticles (NPs) have now become an integral part of research because of their unique features like their size, shape and surface reactivity. In agriculture sector engineered nanoparticles (ENPs) i.e., metal NPs, metal oxide NPs and Carbon Nano Tubes (CNTs) etc has been used in the form of nanofertilizers and nanopesticide/ herbicides. Therefore, the appropriate use of nanoparticles could provide a proficient sustainable platform to achieve the food requirement of global massive population. As of the application of nanotechnology to agriculture and food industry is outturn in enhanced crop yield with better food quality as well as safety. Inspite of the significances of nano-material, negative outcomes should also be taken in consideration before applying it on a large scale.

Bioanalytical method development and validation of alimemazine in human plasma by LC-MS/MS and its application in bioequivalence studies

Background: The use of anti-histaminic agents has been increased significantly from last decades and till now no method is available for quantitation of ALZ in human plasma which can be applied in a bioequivalence study using LC-MS/MS. Objective: The present study is concerned with the development and validation of ALZ in human plasma by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Materials and Methods: Sample preparation involved the extraction with liquid-liquid extraction method by using ethyl acetate as an organic solvent. Chromatographic separation was performed on Atlantis® T3 5 μm 4.6 mm × 150 mm column with the mobile phase consisting of acetonitrile: (10 mm ammonium formate buffer: Formic acid: 99.9:00.1 v/v) 50:50 v/v. The interface used with the application programming interface 4000 LC-MS/MS was a turbo ion spray in which positive ions were measured in multiple reaction monitoring mode. The precursor to product ions transition of m/z 299.30 → 100.20 amu and 305.30 → 106.30 amu were used for ALZ and ALZ D6 respectively. Results: The method was validated over the concentration range of 20.013-10006.551 pg/mL. The mean percent recovery of ALZ was found 77.771% with a precision of 7.71% and the lower limit of quantification was 20.013 pg/mL. The intra- and inter-day precision of the method at three concentrations was 0.98-4.50% and 1.57-5.72% while the intra- and inter-day % accuracy was 99.02-93.82% and 101.78-106.96%. Stability of compounds was established in a series of stability studies. The application of this method was demonstrated in the bioequivalence study and was found suitable in a study of sample size as big as 30 enrolled volunteers. Conclusion: For the very first time, a sensitive, selective and robust Liquid Chromatography- Mass Spectrometry method for the determination of alimemazine (ALZ) in human plasma has been developed and validated using ALZ D6 as an internal standard.

Influence of High and Low Levels of Plant-Beneficial Heavy Metal Ions on Plant Growth and Development

Heavy metals (HMs) exists in the environment in both forms as essential and non-essential. These HM ions enter in soil biota from various sources like natural and anthropogenic. Essential HMs such as cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn) plays a beneficial role in plant growth and development. At optimum level these beneficial elements improves the plant’s nutritional level and also several mechanisms essential for the normal growth and better yield of plants. The range of their optimality for land plants is varied. Plant uptake heavy metals as a soluble component or solubilized them by root exudates. While their presence in excess become toxic for plants that switches the plant’s ability to uptake and accumulate other nonessential elements. The increased amount of HMs within the plant tissue displays direct and indirect toxic impacts. Such direct effects are the generation of oxidative stress which further aggravates inhibition of cytoplasmic enzymes and damage to cell structures. Although, indirect possession is the substitution of essential nutrients at plant’s cation exchange sites. These ions readily influence role of various enzymes and proteins, arrest metabolism, and reveal phytotoxicity. On account of recent advancements on beneficial HMs ions Co, Cu, Fe, Mn, Mo, Ni, and Zn in soil-plant system, the present paper: overview the sources of HMs in soils and their uptake and transportation mechanism, here we have discussed the role of metal transporters in transporting the essential metal ions from soil to plants. The role played by Co, Cu, Fe, Mn, Mo, Ni, and Zn at both low and high level on the plant growth and development and the mechanism to alleviate metal toxicity at high level have been also discussed. At the end, on concluding the article we have also discussed the future perspective in respect to beneficial HM ions interaction with plant at both levels.

Assessment of Antioxidant Potential of Plants in Response to Heavy Metals

Heavy metals (HMs) are consequential environmental contaminant, and their prodigious bioaccumulation in the surroundings has become an enigma for all living organisms including plants. Heavy metal has the potential to react with various indispensable cellular components like DNA, protein, and enzymes and in turn induce several stress responses in plants like oxidative stress which is the root cause for the progression of cell death in the plant. Stress responses inflicted by oxidative stress include severe morphological, metabolic, and physiological amendments in plants like DNA strand breakage, defragmentation of proteins, and damage of photosynthetic pigment, which may stimulate cell death. In reaction, plants have a range of mechanisms to minimize the heavy metal toxicity. Plants are endowed with antioxidant defense mechanism, which can be divided into two groups such as enzymatic antioxidants and nonenzymatic antioxidants, for instance, SOD, CAT, APX, GPX, GR and AsA, GSH, carotenoids, alkaloids, tocopherols, proline, and phenolic compounds, respectively, that together act as the scavengers for free radicals to mitigate the damaging impacts of heavy metal agglomeration in the cells. These antioxidant potentials could be assessed by different in vivo and in vitro methods such as hydrogen atom transfer and electron transfer through which we can evaluate the ROS detrimental action of antioxidant enzymes. Therefore, the present chapter attempts to provide the contemporary knowledge regarding the metal-influenced antioxidant status in plants and also provides the precise pathway that should follow for the future research in the area of antioxidant potentials.

Exogenous Mineral Regulation Under Heavy Metal Stress: Advances and Prospects

Heavy metals (HMs) contaminate the soil through various natural and anthropogenic resources and are transported to the plant systems. These heavy metals are translocated within the plant system by the apoplast and symplast through various transporters such as HMAs, ZIP, ABC. HMs disturb plant metabolism, cause oxidative stress and nutrient dearth. Many researchers have applied exogenous minerals to alleviate these negative impacts caused by HMs. Minerals mitigate the HMAs induced negative impacts by the enhancement of biochemical reactions and physiological processes in plants. In the present article the role of exogenous mineral regulation under heavy metal toxicity is being discussed.

Ultra-performance liquid chromatography electrospray ionization–tandem mass spectrometry method for the simultaneous determination of itraconazole and hydroxy itraconazole in human plasma

A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid–liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.

A liquid chromatography tandem mass spectrometry based regulatory compliant method for the determination of tenofovir in human serum.

A simple, rapid, and specific assay based on solid phase extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS-MS) for the quantitative analysis of Tenofovir in human serum using Tenofovir D6 as internal standard (IS) have been developed. The precursor to product ion transitions of m/z 288.2/176.2 and m/z 293.9/182.3 used to measure the analyte and internal standard (Tenofovir and Tenofovir D6). The method was validated over a concentration range of 5.06-603.72 ng mL(-1). The method was validated over the parameters like selectivity, matrix effect, sensitivity, linearity, precision, accuracy, various stabilities (bench top stability, standard stock solution stability in refrigerator and at room temperature, stock dilution stability, auto sampler stability, freeze thaw stability, long term stability - 65°C±10°C & long term stability - 22°C±5°C, reagent stability, dry extract stability, wet extract stability in refrigerator and at bench top, blood stability), effect of potentially interfering drugs, dilution integrity, recovery and reinjection reproducibility. The mean % recovery of Tenofovir was 98.22% with a precision of 2.42%, The mean % recovery of Tenofovir D6 was 100.96% with a precision of 2.88%. The RSD % of intra-day and inter-day assay was≤15%.