Arnab Kumar De

Poly (lactide-co-glycolide) acid nanoencapsulation of a synthetic coumarin: cytotoxicity and bio-distribution in mice, in cancer cell line and interaction with calf thymus DNA as target.

Several naturally occurring coumarin compounds, including scopoletin (7 hydroxy-6 methoxycoumarin), of plant origin have been reported to have anti-cancer potentials. A related but chemically synthesized coumarin, 4-methyl-7-hydroxy coumarin (SC), was also shown to have similar anti-cancer potentials. In the present study, to test if nano-encapsulated SC could be a more potent anti-cancer agent, we encapsulated SC with poly lactide-co-glycolide acid (PLGA) nanoparticles (Nano Coumarin; NC) and tested its potentials with a variety of protocols. NC demonstrated greater efficiency of drug uptake and showed anti-cancer potentials in melanoma cell line A375, as revealed from scanning electronic and atomic force microscopies. To test its possible interaction with target DNA, the combined data of circular dichroism spectra (CD) and melting temperature profile (T(m)) of calf thymus DNA treated with NC were analyzed. Results indicated a concentration dependent interaction of NC with calf thymus DNA, bringing in effective change in structure and conformation, and forming a new complex that increased its stability. Particle size and morphology of NC determined through polydispersity index and zeta potential using dynamic light scattering qualified NC to be a more potent anti-cancer agent than SC. Further, SC and NC showed negligible cytotoxic effects on normal skin cells and peripheral blood mononuclear cells of mice. Distribution assay of PLGA nanoparticles in different tissues like brain, heart, kidneys, liver, lungs, and spleen in mice revealed the presence of nanoparticles in different tissues including brain, indicating that the particles could cross the blood brain barrier, significant information for drug design.

Poly(lactic-co-glycolic) acid loaded nano-insulin has greater potentials of combating arsenic induced hyperglycemia in mice: Some novel findings

Diabetes is a menacing problem, particularly to inhabitants of groundwater arsenic contaminated areas needing new medical approaches. This study examines if PLGA loaded nano-insulin (NIn), administered either intraperitoneally (i.p.) or through oral route, has a greater cost-effective anti-hyperglycemic potential than that of insulin in chronically arsenite-fed hyperglycemic mice. The particle size, morphology and zeta potential of nano-insulin were determined using dynamic light scattering method, scanning electronic and atomic force microscopies. The ability of the nano-insulin (NIn) to cross the blood-brain barrier (BBB) was also checked. Circular dichroic spectroscopic (CD) data of insulin and nano-insulin in presence or absence of arsenic were compared. Several diabetic markers in different groups of experimental and control mice were assessed. The mitochondrial functioning through indices like cytochrome c, pyruvate-kinase, glucokinase, ATP/ADP ratio, mitochondrial membrane potential, cell membrane potential and calcium-ion level was also evaluated. Expressions of the relevant marker proteins and mRNAs like insulin, GLUT2, GLUT4, IRS1, IRS2, UCP2, PI3, PPARγ, CYP1A1, Bcl2, caspase3 and p38 for tracking-down the signaling cascade were also analyzed. Results revealed that i.p.-injected nano-encapsulated-insulin showed better results; NIn, due to its smaller size, faster mobility, site-specific release, could cross BBB and showed positive modulation in mitochondrial signaling cascades and other downstream signaling molecules in reducing arsenic-induced-hyperglycemia. CD data indicated that nano-insulin had less distorted secondary structure as compared with that of insulin in presence of arsenic. Thus, overall analyses revealed that PLGA nano-insulin showed better efficacy in combating arsenite-induced-hyperglycemia than that of insulin and therefore, has greater potentials for use in nano-encapsulated form.

Bio indices for 2,4-D sensitivity between two plant species: Azolla pinnata R.Br. and Vernonia cinerea L. with their cellular responses.

In the present experiment a pteridophytic species Azolla and an angiospermic species Vernonia were evaluated on the basis of cellular reactivity for herbicidal action through ongoing concentrations. Initially, both the species recorded a significant activity of IAA-oxidase as mark of IAA metabolism with herbicidal sensitivity. Still, Vernonia species were more affected on 2,4-D mediated auxin catabolism. The loss of auxin concentrations on the tissues by 2,4-D reaction was also reflected on growth parameters including relative growth rate and chlorophyll biosynthesis. In a dose dependent manner Vernonia plants were more affected with loss of chlorophyll content and decline in relative growth rate. On the other hand, both those parameters were adjusted significantly with 2,4-D accumulation in Azolla. The stability of cellular metabolism was documented by significant down regulation of protein and lipid peroxidation with concomitant moderation to superoxide and hydrogen peroxide accumulation. The later two were more vulnerable to damage in the Vernonia plant with profuse accumulation of protein and lipid peroxidation products. Similarly, tissue specific reaction to superoxide and hydrogen peroxide accumulation were distinctly demarcated in two species significantly. As a whole, the cellular responses and metabolite distribution to 2,4-D sensitization are the features to describe bio-indices for aquatic fern species Azolla with comparison to angiospermic species Vernonia.

Modulation of physiological responses with TiO 2 nano-particle in Azolla pinnata R.Br. under 2,4-D toxicity

The present work is emphasised with the herbicidal tolerance of Azolla pinnata R.Br. and its modulation with TiO2 nano-particle. Both carbohydrate and nitrogen metabolism were effected with 2,4-D as herbicide and in few cases TiO2-NP had recovered few detrimental effects. From the nutrient status in Azolla it recorded the recovery of nitrogen as well as potassium by TiO2-NP but not in case of phosphorus. However, a conversion of nitrate to ammonium was more induced by TiO2-NP under herbicidal toxicity. Similar results were obtained for inter-conversion of amino acid–nitrate pool, but no changes with glutamine synthase activity with TiO2-NP. Initially, the effects of 2,4-D was monitored with changes of chlorophyll content but had not been recovered with nanoparticle. Photosynthetic reserves expressed as both total and reducing sugar were insensitive to TiO2-NP interference but activity of soluble and wall bound invertase was in reverse trend as compared to control. The 2,4-D mediated changes of redox and its oxidative stress was ameliorated in plants with over expressed ADH activity. As a whole the Azolla bio system with TiO2 supplementation may be useful in sustenance against 2,4-D toxicity through recovery of nitrogen metabolism. Thus, Azolla-TiO2-NP bio system would be realised to monitor the herbicidal toxicity in soil and its possible bioremediation.

Moderation of physiological responses in rice plants with Azolla under 2,4-Dichlorophenoxy acetic acid stress

The present work highlights some preliminary observations on metabolism in rice (Oryza sativa Linn.) when an aquatic fern Azolla pinnata R.Br. was co-cultured under 2,4-Dichlorophenoxy acetic acid toxicity. We have observed the effects of Azolla in both fresh and dried forms. This work signifies the possible physiological changes of a crop plant by using Azolla as a bioremediator. In brief the herbicide 2,4-D is considered as stressor to rice plants and by applying the fresh and dried Azolla we investigate the changes occurred. The activities of different nitrogen metabolizing enzymes and reactive oxygen species were observed. On the other hand chlorophyll and carotenoids synthesis were retrieved by addition of fresh and dried Azolla mass over 2,4-D toxicity. Thus, the efficiency of fresh and dried Azolla mass was evaluated under herbicidal toxicity in rice. We evaluate the bio remediating role of Azolla plants against 2,4-D stress and conclude this species would also be supporting in supplementation of major nutrients to rice plants.

Some Physiological Insights of 2,4-D Sensitivity in an Aquatic Fern: Azolla pinnata R.Br

In an experiment with Azolla pinnata R.Br. under varying concentrations of herbicide (2,4-D), it reveals that the fern species has an wider ranges of physiological activities in moderation. Initially, the effects of the herbicide were reflected with minimum changes in dry matter accumulation in a dose dependent manner. The changes of membrane permeability had the maximum effects on 1000 μM of 2,4-D following the concentration gradient. However, the intermediate concentration of herbicide had not brought any significant changes in electrolytic conductivity. At initial concentration of herbicide treatments the electrolyte conductivity remains more stable. In support to osmotic stability plants recorded a significant change in water deficits that was experienced by proline accumulation in tissues. Thus, a steady increase in proline concentration was the feature of this species when interacts with 2,4-D. In another way the fern species had tolerated the loss of turgidity with significant accumulation of glycine-betaine with their maximum value at 1000 μM of 2,4-D. In further progress of effects of 2,4-D the plants were significantly characterised with an increase in ROS activities. Thus, ROS induced tissue lysis was detected by in vivo Evans Blue staining of the root tissues with maximum intensity at 1000 μM of 2,4-D. The initial defence barrier of this species against ROS at cellular spaces was studied with in-gel analysis of enzyme like wallbound peroxidase. Plants registered a maximum peroxidase activities at influence of 2,4-D with 1000 μM. In addition to gene expression in Azolla a distinct polymorphism was observed as a function of 2,4-D treatments and that may be set as a bio indicator to herbicide interaction.