Seema Zargar

Protective effects of quercetin on cadmium fluoride induced oxidative stress at different intervals of time in mouse liver

Quercetin, a member of the flavonoid family is a major antioxidant acquired in humans by food consumption, while Cadmium fluoride (CdF2) is one of the naturally occurring chemicals having adverse effects. The protective effect of quercetin on time dependent oxidative damage induced in mice liver by CdF2 was studied in the following groups of mice consisting of six mice each: (i) control group; (ii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 24 h; (iii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 48 h; (iv) mice treated with single i.p injection of quercetin (100 mg/kg bw); (v) mice treated with i.p injection of 100 mg/kg bw of quercetin followed by i.p injection of CdF2 (2 mg/kg bw) for 24 h; and (vi) mice treated with i.p injection of 100mg/kg bw of quercetin followed by CdF2 (2 mg/kg bw) for 48 h. Administration of quercetin two hours before CdF2 significantly reduced the biochemical alterations in reduced glutathione, ascorbic acid, lipid peroxidation, super oxide dismutase, catalase and total protein (p<0.05). Histopathology also showed the protective effect of quercetin. The livers treated with CdF2 were atrophic, markedly nodular, inflamed and necrotic. However, this effect was reduced to a minimum in the mice pre-treated for two hours with quercetin.

Morphological changes in vero cells postinfection with dengue virus type-2.

Although no specific antiviral tablets or injections that can kill the dengue virus are currently available, adequate care and treatment could control its morbidity. Interaction of dengue virus to target cells could be an important feature for virus propagation. Ultrastructural analysis of this interaction was studied with vero cells. Vero cells were treated with Dengue virus type‐2 at different time intervals at multiplicity of infection (m.o.i) < 10, m.o.i > 10, and m.o.i = 100. It was found that m.o.i < 10 is best to study morphological changes. At an m.o.i > 10 apoptosis occurs and at m.o.i. = 100, cell necrosis occurs. While studying morphological changes, it was found that at 30 min postinfection cells have morphology very similar to that of the control cells although some have irregular outline and show cytoplasmic projections and intense cytoplasmic vacuolization. After 1–12 hours postinfection (h.p.i), the nuclei ran from normal looking to diffuse. Nuclear membrane begins to disintegrate. Some nucleoli are difficult to be seen. The cytoplasm appears as a mottled, lumps diffuse mass distributed throughout the cytosol, with dense lysosomes and myelin figures, also in the mitochondria. In later hours (24 h.p.i), the intranuclear euchromatin is dispersed and heterochromatin forms peripheral clumps. The cytoplasmic processes are short and few in numbers. A proportion of damaged mitochondria with disrupted cristae appear, suggesting that dengue virus may induce mitochondrial dysfunction and nucleus and mitochondria may be the primary organelles helping in dissemination of virus. Microsc. Res. Tech. 2011.

New analytical application of antibody-based biosensor in estimation of thyroid-stimulating hormone in serum

BACKGROUND Conventionally, ELISA is used to measure thyroid-stimulating hormone (TSH) for diagnosis of thyroid disease. In this study, an immunosensor-based, kinetic-exclusion analysis (KinExA) was used for TSH estimation. METHODOLOGY A PMMA microbead column coated with TSH antigen is formed inside the flow cell. Samples consisting of mouse anti-TSH monoclonal antibody and TSH antigen complex in solution are passed over the beads and the unbound anti-TSH antibody is captured by the TSH-coated beads, followed by passing fluorescent-labeled antibody over the beads to generate signals for analysis. The limit of detection for the assay was 0.4 mIU l(-1) and the precision was acceptable. CONCLUSION The developed sensor was advantageous due to the automated nature and its convenience, without compromising the sensitivity for estimation of TSH.

Effect of quercetin on cadmium fluoride-induced alterations in hydroxyproline/collagen content in mice liver

Abstract Purpose/aim of the study: To study the effect of quercetin, a flavanoid on cadmium fluoride-induced alterations in hydroxyproline and collagen content in mice liver. Materials and methods: Following experimental groups were studied: Group 1, normal mice; Group 2, CdF2-treated mice administered single intraperitoneal (i.p.) injections of CdF2 1 mg/kg bw (body weight); Group 3, CdF2-treated mice administered single i.p. injections of CdF2 2 mg/kg bw; Group 4, mice-injected i.p. with 100 mg quercetin/kg bw; and Group 5, mice-injected i.p. with 100 mg quercetin/kg bw followed by 2 mg CdF2/kg bw after 2 h. Mice were sacrificed 24 h after CdF injection by asphyxiation with carbon dioxide. Results: 1 mg/kg and 2 mg/kg body weight (bw) of CdF2 caused a significant increase in hepatic total Hyp and collagen when compared with the liver of control mice. This was associated with significant changes in free, peptide bound, and protein bound Hyp fraction in the livers of treated mice. Quercetin treatment alone and with CdF2 also caused a significant increase in total Hyp and total collagen in mice liver. Conclusion: We conclude that quercetin has a synergestic effect with CdF2 on the total Hyp and collagen content in mice liver.

Amelioration of thioacetamide-induced liver toxicity in Wistar rats by rutin

This study was designed to evaluate the effect of rutin on hepatotoxicity induced by thioacetamide (TAA) in rats. Four groups of male Wistar rats consisting of six rats each were used: Group I: control group; Group II: rats receiving single injection of 300 mg kg−1 body weight of TAA intraperitoneally; Group III: rats administered rutin (10 mg kg−1 body weight) dissolved in saline orally for 2 weeks; and Group IV: rats administered rutin (10 mg kg−1 body weight) dissolved in saline orally for 2 weeks followed by TAA injection last day of second week. All groups were sacrificed after 24 h of treatment and hepatic toxicity was analyzed with respect to liver toxicity markers, liver DNA fragmentation, and histology of liver tissue. Administration of TAA in Wistar rats resulted in significant increase of hepatic markers, DNA fragmentation in the hepatocytes, and changes in histology. Pretreatment of rats with rutin before 2 weeks of TAA assault resulted in the complete reversal of TAA-mediated hepatic toxicity (P < 0.0001 to P < 0.01) with concomitant restoration of DNA fragmentation. This study suggests rutin as a protective agent for restoration of toxicity caused by TAA.

Therapeutic role of quercetin on oxidative damage induced by acrylamide in rat brain

Abstract Context Quercetin (QE), a bioflavonoid present abundantly in fruits and vegetables, has been reported to possess antioxidant properties. Acrylamide (ACR) is formed in foods during cooking and is known to be neurotoxic. Objective The present study was designed to evaluate the protective effect of QE against neurotoxicity induced by ACR. Materials and methods Four groups of Wistar rats consisting of six rats each: (i) control group; (ii) acrylamide treated group (50 mg/kg body weight as single dose); (iii) quercetin group: rats were treated intraperitoneally (i.p.) with QE (10 mg/kg body weight alone every day for 5 d); (iv) quercetin + acrylamide group: quercetin (10 mg/kg bw) was given i.p. every day for 5 d followed by acrylamide i.p. injection (50 mg/kg bw) on fifth day (single dose). Rats were killed after 48 h. Results Administration of ACR (50 mg/kg bw) in Wistar rats resulted in significant increase of dopamine, interferon-γ and 8-hydroxyguanosine with concomitant decrease of serotonin (p < 0.001) in the rat brain. Treatment of rats with QE intraperitonealy (10 mg/kg body weight) before ACR assault resulted in the diminution of ACR-mediated neurotoxicity as evident from decreased levels of dopamine, interferon-γ (p < 0.001) and 8-hydroxyguanosine with concomitant restoration of serotonin levels (p < 0.001). Discussion and conclusion On the basis of the above results, the present study suggests that quercetin may be a potential therapeutic agent for restoration of oxidative damage to neurons.

Spectrophotometric and molecular modelling studies on in vitro interaction of tyrosine kinase inhibitor linifanib with bovine serum albumin

Linifanib (LNF) possess antitumor activity and acts by inhibiting receptor tyrosine kinase VEGF and PDGF. The interaction of BSA with the drug can provide valuable information regarding the pharmacokinetic and pharmacodynamics behavior of drug. In our study the spectrophotometric methods and molecular docking studies were executed to understand the interaction behavior of BSA and LNF. BSA has an intrinsic fluorescence and that fluorescence was quenched by LNF. This quenching process was studied at three different temperatures of 288, 300and 308 K. The interaction between LNF and BSA was due to static quenching because the Ksv (Stern-Volmer constant) at 288 K was higher than at 300 and 308 K. Kq (quenching rate constant) behaved in a similar fashion as the Ksv. Several other parameters like binding constants, number of binding sites and binding energy in addition to molecular docking studies were also used to evaluate the interaction process. A decrease in the binding constants was observed with increasing temperatures and the binding site number approximated unity. The decreasing binding constant indicates LNF–BSA complex stability. The site mark competition experiment confirmed the binding site for LNF was located on site II of BSA. UV–visible studies along with synchronous fluorescence confirm a small change in the conformation of BSA upon interaction with LNF. The thermodynamic analysis provided the values for free energy ΔG0, ΔH0 and ΔS0. The ΔG0 at the 288, 300 and 308 K ranged in between -21.5 to -23.3 kJ mol-1, whereas the calculated values of ΔH (-55.91 kJ mol-1) and ΔS0 (-111.74 J mol-1·K-1). The experimental and molecular docking results suggest that the interaction between LNF and BSA was spontaneous and they exhibited hydrogen bonding and van der Waals force between them.

Study of the Interactions of Bovine Serum Albumin with the New Anti-Inflammatory Agent 4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)-N′-[(4-ethoxy-phenyl)methylidene]benzohydrazide Using a Multi-Spectroscopic Approach and Molecular Docking

The lipophilic derivative of thalidomide (4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-N′-[(4-ethoxyphenyl)methylidene]benzohydrazide, 6P) was synthesized to enhance its characteristics and efficacy. Earlier studies have proved the immunomodulatory and anti-inflammatory effects of 6P. In this study the interaction between bovine serum albumin (BSA) and 6P was studied using a multi-spectroscopic approach which included UV spectrophotometry, spectrofluorimetry and three dimensional spectrofluorometric and molecular docking studies. Static quenching was involved in quenching the fluorescence of BSA by 6P, because a complex formation occurred between the 6P and BSA. The binding constant decreased with higher temperature and was in the range of 2.5 × 105–4.8 × 103 L mol−1 suggesting an unstable complex at higher temperatures. A single binding site was observed and the the site probe experiments showed site II (sub-domain IIIA) of BSA as the binding site for 6P. The negative values of ∆G0, ∆H0 and ∆S0 at (298/303/308 K) indicated spontaneous binding between 6P and BSA as well as the interaction was enthalpy driven and van der Waals forces and hydrogen bonding were involved in the interaction. The docking results and the results from the experimental studies are complimentary to each other and confirm that 6P binds at site II (sub-domain IIIA) of BSA.

Study of Interactions of an Anticancer Drug Neratinib With Bovine Serum Albumin: Spectroscopic and Molecular Docking Approach

Binding of therapeutic agents to plasma proteins, particularly to serum albumin, provides valuable information in the drug development. This study was designed to evaluate the binding interaction of neratinib with bovine serum albumin (BSA). Neratinib blocks HER2 signaling and is effective in trastuzumab-resistant breast cancer treatment. Spectrofluorometric, UV spectrophotometric, and fourier transform infrared (FT-IR) and molecular docking experiments were performed to study this interaction. The fluorescence of BSA is attributed to the presence of tryptophan (Trp) residues. The fluorescence of BSA in presence of neratinib was studied using the excitation wavelength of 280 nm and the emission was measured at 300-500 nm at three different temperatures. Neratinib quenched the BSA intrinsic fluorescence by static mechanism. A complex formation occurred due to the interaction leading to BSA absorption shift. The fluorescence, UV- absorption, three dimensional fluorescence and FT-IR data showed conformational changes occurred in BSA after interaction with neratinib. The binding constant values decreased as the temperature increased suggesting an instable complex formation at high temperature. Site I (sub-domain IIA) was observed as the principal binding site for neratinib. Hydrogen bonding and Van der Waals forces were suggested to be involved in the BSA-neratinib interaction due to the negative values of entropy and enthalpy changes.

Simultaneous quantification of two bioactive flavonoids, homoeriodictyol and persicogenin, in the methanol extract of the aerial parts of two different species of genus Rhus by a validated high-performance thin-layer chromatographic-densitometric method

A simple and sensitive high-performance thin-layer chromatographic (HPTLC)—densitometric method was developed for the simultaneous quantification of two flavonoid compounds, persicogenin and homoeriodictyol, in the methanol extracts of the aerial parts of two species (Rhus retinorrhoea and Rhus tripartita) of the genus Rhus grown in the Kingdom of Saudi Arabia. Chromatography was performed on glass-backed silica gel 60 F254 HPTLC plates using toluene-ethyl acetate-methanol (8:2:0.5, v/v) as the mobile phase. Scanning and quantification were done at 293 nm. The system was found to give compact spot for homoeriodictyol and persicogenin at, RF = 0.30 ± 0.01 and 0.48 ± 0.01, respectively. The linearity ranges for homoeriodictyol and persicogenin were found to be the same (100–800 ng spot−1) with correlation coefficients (r2 values) of 0.9989 and 0.9983, respectively. The limit of detection (LOD) for homoeriodictyol and persicogenin was found to be 26 and 31 ng band−1, respectively, while the limit of quantification (LOQ) was found to be 77 and 92 ng band−1, respectively. Homoeriodictyol (7.06%) and persicogenin (2.33%) were only found in R. retinorrhoea. The developed method was found to be accurate and precise; hence, it can be used as an important tool to assure the therapeutic dose of homoeriodictyol and persicogenin in herbal formulations as well as for the standardization and quality control of bulk drugs.