Ayyavu Mahesh

Aminoquinoline based highly sensitive fluorescent sensor for lead(II) and aluminum(III) and its application in live cell imaging.

We have synthesized a new probe 5-((anthracen-9-ylmethylene) amino)quinolin-10-ol (ANQ) based on anthracene platform. The probe was tested for its sensing behavior toward heavy metal ions Hg(2+), Pb(2+), light metal Al(3+) ion, alkali, alkaline earth, and transition metal ions by UV-visible and fluorescent techniques in ACN/H2O mixture buffered with HEPES (pH 7.4). It shows high selectivity toward sensing Pb(2+)/Al(3+) metal ions. Importantly, 10-fold and 5- fold fluorescence enhancement at 429 nm was observed for probe upon complexation with Pb(2+) and Al(3+) ions, respectively. This fluorescence enhancement is attributable to the prevention of photoinduced electron transfer. The photonic studies indicate that the probe can be adopted as a sensitive fluorescent chemosensor for Pb(2+) and Al(3+) ions.

Synthesis and characterization of curcumin loaded polymer/lipid based nanoparticles and evaluation of their antitumor effects on MCF-7 cells

BACKGROUND Hybrid materials are synthesized using hydrophilic polymer and lipids which ensure their long term systemic circulation through intravenous administration and enhance loading of hydrophobic drugs. The purpose of this study is to prepare, characterize and evaluate the in vitro efficacy of curcumin loaded poly-hydroxyethyl methacrylate/stearic acid nanoparticles in MCF-7. METHODS C-PSA-NPs, prepared using the emulsification-solvent evaporation method were characterized by dynamic laser scattering, SEM, AFM, FT-IR, X-ray diffraction, and TGA. The in vitro release behavior was observed in PBS pH7.4, the anticancer potential was analyzed by MTT assay, cell cycle and apoptosis studies were performed through flow cytometry. C-PSA-NPs drug localization and cancer cell morphological changes were analyzed in MCF-7 cell line. RESULTS C-PSA-NPs exhibited the mean particle size in the range of 184nm with no aggregation. The surface charge of the material was around -29.3mV. Thermal studies (TGA) and surface chemistry studies (FT-IR, XRD) showed the existence of drug curcumin in C-PSA-NPs. The MTT assay indicated higher anticancer properties and flow cytometry studies revealed that there were better apoptotic activity and maximum localization of C-PSA-NPs than curcumin. CONCLUSIONS Polymer lipid based drug delivery appeared as one of the advancements in drug delivery systems. Through the present study, a novel polymer lipid based nanocarrier delivery system loaded with curcumin was demonstrated as an effective and potential alternative method for tumor treatment in MCF-7 cell line. GENERAL SIGNIFICANCE C-PSA-NPs exhibited potent anticancer activity in MCF-7 cell line and it indicates that C-PSA-NPs are a suitable carrier for curcumin.

Triazole based ratiometric fluorescent probe for Zn2+ and its application in bioimaging

An efficient fluorescent chemosensor 4-((2-hydroxynaphthalen-1-yl)methyleneamino)-3-phenyl-1H-1,2,4-triazole-5(4H)-thione, based on triazole has been designed by condensing 2-hydroxy-1-napthaldehyde with amine, appended to 1,2,4-triazole unit. The probe displays excellent selectivity and sensitivity in both absorbance and fluorescence detection of Zn2+ over other essential metal ions. The nature of fluorescence behavior of receptor upon addition of Zn2+ has been obtained from Density Functional Theory calculations. Imaging experiment indicates that probe works effectively for intracellular Zn2+ imaging with good cell permeability and biocompatibility.

Protective effect of Indian honey on acetaminophen induced oxidative stress and liver toxicity in rat

The present study was undertaken to investigate the protective effect of Indian honey on acetaminophen induced oxidative stress and liver damage in rat. Honey serves as a source of natural medicine, which is effective to reducing the risk of heart disease, liver toxicity and inflammatory processes. The hepatoprotective activity of the Indian honey was determined by assessing levels of Serum transaminases, ALP and total bilirubin. Finally, the effects of the test substances on the antioxidant enzymes of the liver were also studied by assessing changes in the level of reduced glutathione, glutathione peroxidase, catalase and superoxide dismutase. Serum transaminase, ALP and total bilirubin level were significantly elevated and the antioxidant status in liver such as activities of SOD, CAT, GPx and the levels of GSH were declined significantly in APAP alone treated animals. Pretreatment with honey and silymarin prior to the administration of APAP significantly prevented the increase in the serum levels of hepatic enzyme markers and reduced oxidative stress. The histopathological evaluation of the livers also revealed that honey reduced the incidence of liver lesions induced by APAP. Results suggest that the Indian honey protects liver against oxidative damage and it could be used as an effective hepatoprotector against APAP induced liver damage.

Mosquito larvicidal efficacy of phenolic acids of seaweed Chaetomorpha antennina (Bory) Kuetz. against Aedes aegypti

Mosquito larvicidal and repellent activities of phenolic acids of Chaetomorpha antennina (Bory) Kuetz. against the third instar larvae of Aedes aegypti were investigated. The larval mortality was observed after 24 h exposure. Results of mosquito larvicidal tests revealed that insoluble bound phenolic acids and soluble conjugated phenolic acid fractions of C. antennina had an excellent inhibitory effect against A. aegypti and its LC50 values were 23.4 and 44.6 μg ml−1, respectively. The repellency assay of insoluble bound phenolic acids and soluble conjugated phenolic acid fractions of C. antennina, at 10 μg cm−2 concentration gave 100% protection up to 120 min. The results indicate that phenolic acids of C. antennina have a wide spectrum of larvicidal and repellent activities against Aedes aegypti.

Hemocompatible glutaminase free L-asparaginase from marine Bacillus tequilensis PV9W with anticancer potential modulating p53 expression

Bacillus tequilensis PV9W, a marine bacterial isolate obtained from Gulf of Mannar, Rameswaram, India, produced glutaminase free L-asparaginase which was purified to homogeneity with a significant increase (13 fold) in specific activity. The apparent Km (0.045 ± 0.013 mM) and Vmax (7.465 ± 0.372 μmol ml−1 min−1) values of this purified L-asparaginase was identified and it was found that the maximum activity of the L-asparaginase was at a pH 8.5 and a temperature of 35 °C. The enzyme is a mixed α/β protein and the influence of different effectors were documented. The purified L-asparaginase had effective acrylamide degradation activity (6 IU per ml) and cytotoxic activity against HeLa cell lines with an IC50 of 0.036 ± 0.009 IU per ml. Furthermore, the purified enzyme showed p53 dependent G2 arrest in HeLa cells analyzed by FACS and was hemocompatible. Thus, this study highlights the marine isolate PV9W as a potential source for glutaminase free L-asparaginase with industrial as well as pharmaceutical applications. This study also paves a way for a possible therapeutic drug with the least amount of side effects.

Molecular analysis of oxalate-induced endoplasmic reticulum stress mediated apoptosis in the pathogenesis of kidney stone disease

Oxalate, a non-essential end product of metabolism, causes hyperoxaluria and eventually calcium oxalate (CaOx) stone disease. Kidney cells exposed to oxalate stress results in generation of reactive oxygen species (ROS) and progression of stone formation. Perturbations in endoplasmic reticulum (ER) result in accumulation of misfolded proteins and Ca2+ ions homeostasis imbalance and serve as a common pathway for various diseases, including kidney disorders. ER stress induces up-regulation of pro-survival protein glucose-regulated protein 78 (GRP78) and pro-apoptotic signaling protein C/EBP homologous protein (CHOP). Since the association of oxalate toxicity and ER stress on renal cell damage is uncertain, the present study is an attempt to elucidate the interaction of GRP78 with oxalate by computational analysis and study the role of ER stress in oxalate-mediated apoptosis in vitro and in vivo. Molecular docking results showed that GRP78-oxalate/CaOx interaction takes place. Oxalate stress significantly up-regulated expression of ER stress markers GRP78 and CHOP both in vitro and in vivo. Exposure of oxalate increased ROS generation and altered antioxidant enzyme activities. N-Acetyl cysteine treatment significantly ameliorated oxalate-mediated oxidative stress and moderately attenuated ER stress marker expression. The result indicates oxalate toxicity initiated oxidative stress-induced ER stress and also activating ER stress mediated apoptosis directly. In addition, the up-regulation of transforming growth factor β-1 revealed oxalate may induce kidney fibrosis through ER stress-mediated mechanisms. The present study provide insights into the pathogenic role of oxidative and ER stress by oxalate exposure in the formation of calcium oxalate stone.

Ultrafast synthesis of stabilized gold nanoparticles using aqueous fruit extract of Limonia acidissima L. and conjugated epirubicin: targeted drug delivery for treatment of breast cancer

In this study, a green chemistry approach was used for the quick synthesis (within 30 seconds) of gold nanoparticles (AuNPs) by using the fruit extract of Limonia acidissima L. The study focused on the formation of L. acidissima L. stabilized AuNPs without using any catalytic agent. The synthesis of the AuNPs was confirmed by observation of the surface plasmon resonance (SPR) band at 537 nm. On the surface of these capped AuNPs, epirubicin (EPI) was conjugated along with activated folic acid (FA) for targeted drug delivery. The EPI–FA–AuNPs complex was characterized using FTIR and a UV-visible spectrophotometer and the AuNPs were characterized by HR-TEM, particle size analyzer, and zeta potential measurements. In vitro stability experiments revealed that the AuNPs were stable in physiological conditions. The in vitro cytotoxicity of free EPI and EPI–FA–AuNPs was investigated against MCF-7 cells, and the results showed that 50% of EPI–FA–AuNPs was enough to achieve inhibition of growth (IC50) and that the amount was lower than that of free EPI. Flow cytometry analysis showed significant reduction in G2/M cells after treatment with EPI–FA–AuNPs, and molecular levels of apoptosis were studied using western blotting. Overall, the results revealed that the EPI–FA–AuNPs have better regression activity on tumor cells than free EPI.

Cellular imaging and folate receptor targeting delivery of gum kondagogu capped gold nanoparticles in cancer cells

In this study, the green synthesis of gum kondagogu capped gold nanoparticles (GK-GNPs) was prepared using a naturally available polysaccharide. The anionic gum capped GK-GNPs enabled the successful coupling of folic acid (FA) and fluorescein isothiocyanate (FITC) to produce a fluorescently labelled GNP (F2-GNP). F2-GNPs were further characterized using different physicochemical methods Cellular viability, cellular imaging, and targeted delivery of F2-GNPs were further evaluated in both folate receptor positive (MCF-7) and folate receptor negative (A549) cancer cells. Physicochemical characterization revealed a nanoparticle with a small size (37 nm), smooth surface (surface charge of -23.7 mV), crystallinity of gold nanoparticles and existence of gum kondagogu in the F2-GNPs. Cellular uptake of F2-GNPs indicated a greater affinity towards folate receptor positive cells. This study shows that the F2-GNPs is as an effective nanocarrier for targeted drug delivery and cellular imaging via folate receptors.

Rapid in vitro plant regeneration from leaf explants of Launaea sarmentosa (Willd.) Sch. Bip. ex Kuntze

An efficient protocol for organogenesis through leaves has been established for Launaea sarmentosa (Willd.) Sch. Bip. ex Kuntze, a highly valuable medicinal plant. The leaf explants produced microshoots on MS basal medium when fortified with cytokinins and auxins. A combination of 6-benzylaminopurine (BAP) at 0.5mg/l and naphthaleneacetic acid (NAA) at 0.2mg/l resulted in the induction of high frequency microshoots in 30 days. The microshoots were successfully subcultured for shoot elongation and eventually for rooting on MS medium supplemented with indole-3-butyric acid (IBA) at 0.5mg/l. The regenerated plantlets were hardened under greenhouse conditions and transferred to garden, resulting in a 90% survival rate.