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Background and aim: The leaves of AnnonareticulataLinn (牛心果niú x ınguǒ; Bullock’s heart), a member of Annonaceae family, have been used extensively in folk medicine; however, its wound healing potential is yet to be explored. Our aim was to investigate the wound healing ability of A. reticulataleaf extract in vitro and in streptozotocin induced diabetic mice model. Material and methods: We observed the plant extract induced proliferation and migration of primary human dermal fibroblast (HDF), human skin fibroblast cell line (GM00637) and human keratinocyte cell line (HACAT). The expression of transforming growth factor beta (TGF-β), connective tissue growth factor (CTGF), vascular endothelial growth factor (VEGF), alpha smooth muscle actin (α-SMA), matrix metalloproteinases (MMP-2, MMP-9), collagen-1, collagen-3, focal adhesion kinase (FAK) were evaluated by Western blot and gelatin zymography. Excisional diabetic wound model was used for in vivo wound healing assay. Furthermore, we processed wound tissue for histological and immunohistochemical study. Result: A. reticulata L. leaf extract stimulates proliferation and migration of HDF, skin fibroblast and keratinocyte significantly in a dose dependent manner; expression of TGF-β, CTGF, VEGF, α-SMA, MMP-2, MMP-9, collagen-1, collagen-3, FAK increased. Additionally, an enhanced expression of phospho-SMAD2, phospho-SMAD3 in the treated cells indicated the activation of TGF-β signal transduction pathway, similarly increased expression of phospho-AkT suggested activation of PI3/AkT pathway. Expression of CTGF and α-SMA was also increased significantly in wound tissue. Mass spectrometric analysis revealed that mainly two compounds to be present in the extract: quercetin and β-sitosterol. Conclusion: Collective data suggest that A.reticulata leaf extract may have a stimulatory effect in diabetic wound healing.

Cytotoxicity by anthracycline antibiotics is attributed to several pathways. Important among them are formation of free-radical intermediates. However, their generation makes anthracyclines cardiotoxic which is a concern on their use as anticancer agents. Hence, any change in redox behavior that address cardiotoxicity is welcome. Modulation of redox behavior raises the fear that cytotoxicity could be compromised. Regarding the generation of free radical intermediates on anthracyclines, a lot depends on the surrounding environment (oxic or anoxic), polarity and pH of the medium. In case of anthracyclines, one-electron reduction to semiquinone or two-electron reduction to quinone-dianion are crucial both for cytotoxicity and for cardiotoxic side effects. The disproportion-comproportionation equilibria at play between quinone-dianion, free quinone and semiquinone control biological activity. Whatever is the form of reduction, semiquinones are generated as a consequence of the presence of anthracyclines and these interact with a biological target. Alizarin, a simpler anthracycline analogue and its MnII complex were subjected to electrochemical reduction to realize what happens when anthracyclines are reduced by compounds present in cells as members of the electron transport chain. Glassy carbon electrode maintained at the pre-determined reduction potential of a compound was used for reduction of the compounds. Nucleobases and calf thymus DNA that were maintained in immediate vicinity of such radical generation were used as biological targets. Changes due to the generated species under aerated/de-aerated conditions on nucleobases and on DNA helps one to realize the process by which alizarin and its MnII complex might affect DNA. The study reveals alizarin was more effective on nucleobases than the complex in the free radical pathway. Difference in damage caused by alizarin and the MnII complex on DNA is comparatively less than that observed on nucleobases; the complex makes up for any inefficacy in the free radical pathway by its other attributes.

The pressing need for accurate and reliable precipitation measurements and forecasting poses theoretical and technological problems. Remote-sensing instruments with increased coverage and sensitivity (such as space-borne and ground-based radar) are available; however, their full exploitation requires physical calibration and validation based on a deep knowledge of precipitation microphysics. This study reports a detailed analysis of the evidence of non-terminal velocities in a mid-latitude (Bologna, Italy) and a tropical location (Kolkata, India). The data from two identical disdrometers OTT-Parsivel2 were analyzed to shed light on the nature of the raindrops that fall at a velocity that is significantly higher (i.e., super-terminal drops) or lower (sub-terminal drops) than the terminal velocity expected for the raindrop sizes. The results show a significant fraction of super- and sub-terminal drops in both locations. The percentages of both super- and sub-terminal drops were higher in Kolkata. However, the difference was more notable for convective rain. The percentages of both super- and sub-terminal drops were found to be high within a drop diameter of 1 mm. The number of sub-terminal drops seemed to increase with an increase in diameter for drops larger than ~2.5 mm. The natural rain in Bologna showed stronger evidence of drop break-up in correspondence with the evolution of non-terminal velocities. Moreover, this study once again pointed toward the fact that the process of break-up cannot be neglected in natural rain of tropical or mid-latitude locations. We found that 7% and 10% of rain samples in Bologna and Kolkata seemed to be subjected to drop break-up. The results indicate that radar measurements of rain in the tropics or mid-latitude regions, relying on the Gunn–Kinzer relationship between velocity and diameter, should be verified by observations of disdrometers for a high precision QPE.

Purpose: To explain the observed radio-protection properties of an azo compound, 2-(2-hydroxyphenylazo)-indole-3∕-acetic acid (HPIA). Materials and methods: Mechanism of radioprotection by HPIA was attempted using the stable free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH) using UV-Vis and electron paramagnetic resonance (EPR) spectroscopy. The radical destroying ability of HPIA was studied by depletion of reactive oxygen species (ROS) in WI 38 lung fibroblast cells. Results & Discussion: Studies indicate HPIA interacts with radical intermediates formed in solution following irradiation by 60Co γ-rays. As a result, reactive radical intermediates do not cause any damage on chosen substrates like thymine or calf thymus DNA when irradiated in presence of HPIA. The study showed that reactive intermediates not only react with HPIA but that the kinetics of their reaction is definitely faster than their interaction either with thymine or with DNA. Had this not been the case, much more damage would have been observed on chosen substrates following irradiation with 60Co γ-rays, in the presence of HPIA than actually observed in experiments, particularly those that were performed in a relatively high dose. Experiments reveal radiation induced-damage caused to thymine in presence of HPIA was ~ 136 to ~ 132times that caused in its absence under different conditions indicating the radio-protection properties of HPIA. In case of calf thymus DNA, damage in presence of HPIA was much lower than in its absence. A fluorometric microplate assay for depletion of ROS by detecting the oxidation of 2′,7′-dichlorofluorescin-diacetate (DCF-DA) into the highly fluorescent compound 2′,7′ dichlorofluorescein (DCF) indicated HPIA brought about a considerable check on ROS-mediated damage to cells by scavenging them right away. Conclusion: The study indicates HPIA may be an antioxidant supplement during radiotherapy.

Electrochemical behavior of the anticancer drug doxorubicin hydrochloride was studied using cyclic voltammetry in aqueous medium using Hepes buffer (pH~7.4). At this pH, doxorubicin hydrochloride undergoes a reversible two-electron reduction with E1/2 value −665±5 mV (versus Ag/AgCl, saturated KCl). Depending on scan rates, processes were either quasireversible (at low scan rates) or near perfect reversible (at high scan rates). This difference in behavior of doxorubicin hydrochloride with scan rate studied over the same potential range speaks of differences in electron transfer processes in doxorubicin hydrochloride. Attempt was made to identify and understand the species involved using simulation. The information obtained was used to study the interaction of doxorubicin hydrochloride with calf thymus DNA. Cathodic peak current gradually decreased as more calf thymus DNA was added. The decrease in cathodic peak current was used to estimate the interaction of the drug with calf thymus DNA. Nonlinear curve fit analysis was applied to evaluate the intrinsic binding constant and site size of interaction that was compared with previous results on doxorubicin hydrochloride-DNA interaction monitored by cyclic voltammetry or spectroscopic techniques.

Hydroxy-9,10-anthraquinones are cheaper alternatives to anthracycline drugs. They closely resemble anthracycline drugs both from a structural and functional viewpoint. Electrochemical behavior of the Ni(II) complex (Na2[Ni(NaLH)2Cl2]⋅2H2O) of sodium 1,4-dihydroxy-9,10-anthraquinone-2-sulphonate (NaLH2), analogue of the core unit of anthracycline anticancer drugs, was studied at physiological pH using cyclic voltammetry. The Ni(II) complex of sodium 1,4-dihydroxy-9,10-anthraquinone-2-sulphonate undergoes diffusion-controlled one-electron reduction that enables performing an electrochemical study on the interaction of the complex with calf thymus DNA. The complex was titrated with increasing concentrations of DNA, and the reduction peak for the unbound complex helped in evaluating binding parameters. Analysis of binding data using nonlinear curve fit in a cyclic voltammetry experiment is the first such attempt. The paper evaluates site size of interaction that also serves as a means to determine stoichiometry of complex formation, between a metal ion and ligand from a DNA interaction study, probably a first of its kind.

The electron transfer reactions involving quinones, hydroquinones, and catechols are very important in many areas of chemistry, especially in biological systems. The therapeutic efficiency as well as toxicity of anthracycline anticancer drugs, a class of anthraquinones, is governed by their electrochemical properties. Other quinones serve as important functional moiety in various biological systems like electron-proton carriers in the respiratory chain and their involvement in photosynthetic electron flow systems. The present paper summarizes literatures on the reduction of quinones in different solvents under various conditions using different electrochemical methods. The influence of different reaction conditions including pH of the media, nature of supporting electrolytes, nature of other additives, intramolecular or intermolecular hydrogen bonding, ion pair formation, polarity of the solvents, stabilization of the semiquinone and quinone dianion, catalytic property, and adsorption at the electrode surface, are discussed and relationships between reaction conditions and products formed have been presented.

Syntheses and crystal structures of four new hydrazone-based Cu(ii) complexes, [{Cu(L1)(H2O)}2(μ-pyraz)](ClO4)2(1), [{Cu(L1)(OClO3)}2(μ-4,4′-bipy)] (2), [{Cu(L2H)}(μ-pyraz){Cu(L2H)(OClO3)}].(ClO4) (3) and [{Cu(L2)}2(μ-bpe)] (4) [L1H = condensation product of benzhydrazide and pyridine-2-carbaldehyde and L2H2= condensation product of benzoyl acetone and benzhydrazide], bridged by various organic spacers [pyrazine (pyraz), 4,4′-bipyridine (4,4′-bipy) and 1,2-di(4-pyridyl)ethane (bpe)] are reported in this paper. The single-crystal X-ray crystallographic studies reveal that all are dinuclear units where 1and 3form strong intermolecular H-bonding to form sheets of interconnected ions, whereas 2forms sheets of dinuclear chains through π–π interactions; in 4, molecules are linked only through van der Waals interactions. The variable-temperature magnetic moment studies reveal that 1and 3show antiferromagnetic coupling between the Cu(ii) centers at lower temperatures. The binding ability of 1with calf thymus DNA [CT-DNA] is reported using various spectroscopic studies (UV-Vis titration, circular dichroism and fluorescence). The binding constants of 1with CT-DNA, as calculated by different methodologies, are of the order of 105M−1. The mode of interaction between 1and CT-DNA has been predicted using circular dichroic (CD) spectroscopy, where it has been shown that 1most probably interacts with DNA viaintercalation between the base pairs leading to a change in B-DNA conformation. 1is also able to cleave supercoiled (SC) plasmid DNA pUC19 in a time and dose dependent manner as demonstrated by agarose gel electrophoresis, and also demonstrates its potential to cleave the SC plasmid DNA viaboth oxidative and hydrolytic mechanisms. Approximately 50% of leukemic cells are found to be dead when two representative leukemic cell lines are exposed to 1(∼80 μM) even for 24 h as determined by different cell cytotoxicity assays. Preliminary results also showed that, at 20 μM, 1could selectively induce apoptosis in leukemic cells without affecting normal lymphocytes. [ABSTRACT FROM AUTHOR]