A. Subastri

Spectroscopic and molecular docking studies on the interaction of troxerutin with DNA.

Troxerutin (TXER) is a derivative of naturally occurring bioflavonoid rutin. It possesses different biological activities in rising clinical world. The biological activity possessed by most of the drugs mainly targets on macromolecules. Hence, in the current study we have examined the interaction mechanism of TXER with calf thymus DNA (CT-DNA) by using various spectroscopic methods, isothermal titration calorimetry (ITC) and molecular docking studies. Further, DNA cleavage study was carried out to find the DNA protection activity of TXER. UV-absorption and emission spectroscopy showed low binding constant values via groove binding. Circular dichroism study indicates that TXER does not modify native B-form of DNA, and it retains the native B-conformation. Furthermore, no effective positive potential peak shift was observed in TXER-DNA complex during electrochemical analysis by which it represents an interaction of TXER with DNA through groove binding. Molecular docking study showed thymine guanine based interaction with docking score -7.09 kcal/mol. This result was compared to experimental ITC value. The DNA cleavage study illustrates that TXER does not cause any DNA damage as well as TXER showed DNA protection against hydroxyl radical induced DNA damage. From this study, we conclude that TXER interacts with DNA by fashion of groove binding.

Extracellularly synthesized ZnO nanoparticles interact with DNA and augment gamma radiation induced DNA damage through reactive oxygen species

The present study proposes a green synthesis of highly stable and biocompatible ZnO nanoparticles (ZnONPs) using ferulic acid as the reductant. The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, photoluminescence spectroscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, atomic mass spectroscopy, energy dispersive X-ray spectroscopy and elemental mapping. The characterization results elucidate the formation of crystalline wurtzite structured acicular shaped ZnONPs. Furthermore, the intricate mechanism of ZnONPs–DNA interaction was studied. The binding affinity and mechanism of ZnONPs with calf thymus-DNA interactions were scrutinized and the conformational changes were analyzed. The results reveal the interaction of ZnONPs with DNA in intercalation mode and the values of the binding constant (K) and Stern–Volmer quenching constant (Ksv) were found to be 5.8 × 105 M−1 and 4.1 × 105 M−1, respectively. Furthermore, gamma radiation induced reactive oxygen species (ROS) generation and DNA damage by ZnONPs were analyzed by various spectrophotometric methods, which unveiled the radiosensitizer role of ZnONPs through the significantly increased generation of ROS. Our current experimental evidence explores the ZnONPs’ dual role capacity as DNA binders as well as radiosensitizers. Based on the present research findings we conclude that ZnONPs can be excellent anticancer agents, warranting in vivo studies.

Selenium nanoparticles synthesized in aqueous extract of Allium sativum perturbs the structural integrity of Calf thymus DNA through intercalation and groove binding

Biomedical application of selenium nanoparticles (SeNPs) demands the eco-friendly composite for synthesis of SeNPs. The present study reports an aqueous extract of Allium sativum (AqEAS) plug-up the current need. Modern spectroscopic, microscopic and gravimetric techniques were employed to characterize the synthesized nanoparticles. Characterization studies revealed the formation of crystalline spherical shaped SeNPs. FTIR spectrum brings out the presence of different functional groups in AqEAS, which influence the SeNPs formation and stabilization. Furthermore the different aspects of the interaction between SeNPs and CT-DNA were scrutinized by various spectroscopic and cyclic voltametric studies. The results reveals the intercalation and groove binding mode of interaction of SeNPs with stacked base pair of CT-DNA. The Stern-Volmer quenching constant (KSV) were found to be 7.02×106M-1 (ethidium bromide), 4.22×106 M-1 (acridine orange) and 7.6×106M-1 (Hoechst) indicating strong binding of SeNPs with CT-DNA. The SeNPs - CT-DNA interactions were directly visualized by atomic force microscopy. The present study unveils the cost effective, innocuous, highly stable SeNPs intricate mechanism of DNA interaction, which will be a milestone in DNA targeted chemotherapy.

Probing the interaction of troxerutin with transfer RNA by spectroscopic and molecular modeling

The studies on the interaction between tRNA (transfer RNA) and small molecules are an area of remarkable recent attention. For this notion a fundamental knowledge of the molecular features involving the interaction of small molecules with tRNA is crucial. Hence, in the present study we have investigated the interaction of TXER (troxerutin), natural bioflavonoid rutin derivative with yeast tRNA by using various spectroscopic techniques and molecular docking studies. The UV absorption and fluorescence emission studies demonstrated external binding of TXER on tRNA with low binding constant values as compared to strong binders. Circular dichroism (CD) spectroscopy study revealed that TXER did not show any significant modification on native conformation of tRNA. Furthermore in electrochemical study, the complex of TXER-tRNA did not expose any noticeable positive potential peak shift which indicated an interaction of TXER with tRNA by electrostatic or external binding mode. The docking study showed that the hydrogen and hydrophobic interactions were involved in binding of TXER-tRNA with docking score -7.0 kcal/mol. These findings led us to confirm the interaction of TXER on tRNA through external binding with low binding affinity, indicating its potential bioapplication in the future.

Size Dependent Uptake and Hemolytic Effect of Zinc Oxide Nanoparticles on Erythrocytes and Biomedical Potential of ZnO-Ferulic acid Conjugates

Despite zinc oxide nanoparticles (ZnONPs) being increasingly used as carriers in biomedical fields due to their multifaceted properties and therapeutic importance, better understanding of the mechanisms and cellular consequences resulting from their interaction with cells and cellular components has been warranted. In the present study, we investigate the size-dependent interaction of ZnONPs on RBCs, and its impact on cell viability, DNA damage, ROS generation and morphological changes, employing cellular and analytical methods. Size, charge, stability and solubility were confirmed by DLS, zeta potential, ICP-AES and TEM analysis. Further ICP-AES, TEM, spectroscopic observations and cell based assays showed that ZnONPs exhibited a size dependent impact on RBCs and haemoglobin (Hb), particularly size <50 nm. Conversely, ferulic acid (FA) conjugates and serum albumin significantly reduced the adverse effects exhibited by ZnONPs. The extent of DNA damage and ROS generation is comparatively low in ZnONPs-FA than in ZnONPs alone treated cells. Thus our study documents a novel conceptualization delineating the influence of size on the material properties and therapeutic potential of nanoparticle.

Effect of troxerutin on 2-aminoanthracene and DNA interaction and its anti-mutagenic property

One of the pivotal mechanisms projected for bioflavonoids in cancer chemoprevention is through their intervention against mutagen-DNA interaction. Recent literatures emphasize the role of troxerutin (TXER) as an emerging anticancer agent. However, there are no reports on its intervention in any carcinogen-DNA interaction. The present study investigates the possibility of TXER, in prevention of 2-aminoanthracene (2-AA) contact with DNA. Steady state and time resolved fluorescence spectroscopy results, highlight the direct contact of 2-AA with DNA, while presence of TXER prevented this interaction. Gel-electrophoresis study clearly revealed that, TXER inhibits 2-AA+UVA radiation induced DNA damage. Fluorescence microscopic studies elucidated that, TXER treatment obstructs the 2-AA interaction with cellular DNA, while molecular docking showed the energetically favourable structure of TXER/2-AA/TXER complex. Further anti-mutagenicity experiment revealed that, TXER prevents the mutation induced colony formation in mutant strain of S. typhymurium. Our in vitro and ex vivo experimental findings provide imperative evidence about the protective role of TXER against environmental carcinogens through the inhibition of carcinogen-DNA interaction, implicating its potential for therapeutic applications in cancer.

Nutrient profile of porridge made from Eleusine coracana (L.) grains: effect of germination and fermentation.

Porridge (koozh) is one of the traditional foods made from Eleusine coracana L. grains (Finger millet). It is a soft food prepared from processed (germinated & fermented) finger millet flour (FMF). However, in the modern world of fast food, koozh is usually prepared from non-processed (non-germinated & non-fermented) FMF. Hence, present study was undertaken to evaluate the macro and micro nutrient contents in koozh prepared from germinated (fermented & non-fermented) and non-germinated (fermented & non-fermented) FMF. Highest protein, carbohydrate and glycoprotein contents were found in koozh prepared from germinated & non-fermented FMF. The free amino acid contents are higher in germinated & fermented condition when compare to other preparations. No significant change was observed in the calorific value of all preparations. There is no statistical difference in macro-nutrients & micro-nutrients minerals such as calcium, iron, magnesium, manganese, phosphorous and zinc among all the preparations. However, copper content is higher in non-germinated condition, whereas selenium, silicon and sulphur are higher in germinated FMF when compared to others. Significant level of total phenol, total flavonoid and free radical scavenging activity was observed in all preparations, which increased further during fermentation. The present observations, lead us to conclude that koozh prepared from germinated & non-fermented FMF contains higher level of carbohydrate, protein and glycoprotein, however germinated & fermented koozh has increased aminoacids, phytochemicals and free radical scavenging activity. Hence it is suggested that the consumption of koozh made from germinated & fermented FMF may provide easily digestible and energetic nutrients for healthier life.

Synthesis and characterisation of arsenic nanoparticles and its interaction with DNA and cytotoxic potential on breast cancer cells

Therapeutic applications of arsenic trioxide (ATO) are limited due to their severe adverse effects. However, nanoparticles of ATO might possess inimitable biologic effects based on their structure and size which differ from their parent molecules. Based on this conception, AsNPs were synthesized from ATO and comparatively analysed for their interaction mechanism with DNA using spectroscopic & electrochemical techniques. Finally, anti-proliferative activity was assessed against different breast cancer cells (MDA-MB-231 & MCF-7) and normal non-cancerous cells (HEK-293). The DNA interaction study revealed that AsNPs and ATO exhibit binding constant values in the order of 106 which indicates strong binding interaction. Binding of AsNPs did not disturb the structural integrity of DNA, on the other hand an opposing effect was observed with ATO through biophysical techniques. Further, in vitro study, confirms cytotoxicity of ATO and AsNPs against different cells, however at particular concentration ATO exhibits more cytotoxicity than that of AsNPs. Furthermore, cytotoxicity was confirmed through acridine orange and comet assay. In conclusion, AsNPs are safer than ATO with comparable efficacy and might be a suitable candidate for the development of novel therapeutic agent against breast cancer and other solid tumours.

Anticancer potential of ZnO nanoparticle-ferulic acid conjugate on Huh-7 and HepG2 cells and diethyl nitrosamine induced hepatocellular cancer on Wistar albino rat

Drawbacks and limitations of recently available therapies to hepatocellular cancer (HCC) devoted the scientist to focus on emerging new strategies. ZnO nanoparticles (ZnONPs) based chemotherapeutics has been emanating as a promising approach to maximize therapeutic synergy facilitating the discovery of novel multitargeted combinations. In the present study we conjugated ZnONPs with ferulic acid (ZnONPs-FAC) characterized by computational, spectroscopic and microscopic techniques. In vitro anticancer potential has been evaluated by assessing cell viability, morphology, ROS generation, mitochondrial membrane permeability, comet assay, immunofluorescent staining of 8-OHdG, Ki67 and γ-H2AX, cell cycle analysis and western blot analysis and in vivo anticancer potential against DEN induced HCC was analyzed by histopathological and immunohistochemical methods. The results revealed that ZnONPs-FAC induces cell death through apoptosis and can suppress the DEN-induced HCC. Our study documents therapeutic potential of nanoparticle conjugated with phytochemicals, suggesting a new platform for combinatorial chemotherapy.

Troxerutin with copper generates oxidative stress in cancer cells: its possible chemotherapeutic mechanism against hepatocellular carcinoma†

Troxerutin (TXER) a rutin derivative is known for its anticancer effect against hepatocellular carcinoma (HCC). As part of large study, recently we have shown TXER interact with genetic material and its anti‐mutagenic property. In the present study we have explored its possible mode of action in HCC. Since TXER alone did not show significant anticancer effect on Huh‐7 cells, in vitro biochemical assays were performed for determining anticancer efficacy of TXER + metal complex using transition metals such as Cu, Zn, and Fe. The anticancer efficacy of TXER + Cu on Huh‐7 cells were evaluated using MTT assay, DCFDA, JC‐1 staining, comet assay, cell cycle analysis, immunocytochemistry, and Western blotting. Non‐toxic nature of TXER was analyzed on primary rat hepatocytes. The in vivo efficacy of TXER was tested in N‐nitrosodiethylamine initiated and γ‐benzene hexachloride and partial hepatectomy promoted rat liver cancer. Liver markers, transition metal levels, histopathological examination, and expression levels of GST‐P, 8‐OHdG and Ki‐67 were studied to assess the in vivo anticancer effect of TXER. We observed that TXER + Cu induced extensive cellular death on Huh‐7 cells through generating free radicals and did not possess any toxic effect on normal hepatocytes. The in vivo studies revealed that TXER possess significant anti‐cancer effect as assessed through improved liver markers and suppressed GST‐P, 8‐OHdG, and Ki‐67 expression. TXER treatment reduced the hepatic Cu level in cancer bearing animals. Current study brings the putative mechanism involved in anti‐cancer effect of TXER, further it will help to formulate phytoconstituents coupled anti‐cancer drug for effective treatment of HCC.