Computational modeling studies with β-glucogallin and AKR1B1.

<p>Modeling comparison between sorbinil (A) and β-glucogallin (B) showing ligands bound to AKR1B1. The solvent accessible surface depicts the active site anionic and specificity binding pockets, with expansion images to emphasize the detail of each pocket. The calculated binding energies for sorbinil and β-glucogallin are –32 kcal/mol and –44 kcal/mol, respectively. The active site interactions are summarized for sorbinil (C) and β-glucogallin (D) and were identified using Discovery Studio software v2.5.5 (Accelrys) and Ligand Scout v2.3. Based on the calculated binding energies and number of active site interactions β-glucogallin appears to bind AKR1B1 as effectively as the known active inhibitor sorbinil.</p

The elucidation of β-glucogallin as an active component and inhibitor of AKR1B1 from <i>E. officinalis.</i>

<p>(A) HPLC trace of pooled Sephadex® LH-20 fractions displaying activity against AKR1B1. The arrow indicates the fraction where activity against AKR1B1 appears to be localized. (B) The ¹H NMR spectrum of the abundant active fraction from HPLC purification. The ¹³C spectrum and accurate mass data are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031399#pone.0031399.s001" target="_blank">Figure S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031399#pone.0031399.s002" target="_blank">S2</a> respectively. All of these data identify the active component as β-glucogallin. C) LC/MS/MS data indicate a peak at 687 <i>m/z</i> as a [2M aggregate + Na]. Therefore, the only compound present in this active fraction is β-glucogallin.</p

Inhibition of AKR1B1 substrate oxidation by β-glucogallin.

<p>A) Data were nonlinearly fit to the Michaelis-Menten model in the absence and presence of 0, 10, 20, and 40 µM β-glucogallin. B) Lineweaver-Burk plot of the same data, depicting increasing slope and y-intercept characteristic of noncompetitive inhibition. C) No significant changes were observed in the apparent K_m values. D) A decreasing trend was observed in the apparent V_max values, and the differences were found to be statistically significant as follows: *indicates <i>P</i> = 0.01, and ***indicates <i>P</i> = 0.0002. All assays were repeated in triplicate and error bars represent standard deviation from the mean. GraphPad Prism software was used to fit data to the Michaelis-Menten model using nonlinear regression (method of least squares) and to determine significance by column analysis of triplicates using the unpaired, two-tailed student’s t-test.</p

β-glucogallin prevents sorbitol accumulation in transgenic (TG) human AKR1B1 expressing lenses <i>ex-vivo</i>.

<p>Lenses extracted from TG-animals were cultured under hyperglycemic conditions in the presence or absence β-glucogallin (30 µM) or sorbinil (10 µM) over 72 hours. β-glucogallin showed potent activity preventing sorbitol accumulation by 73% as compared to untreated lenses. Comparably, the positive control sorbinil inhibited sorbitol accumulation by 97%. The amount of sorbitol in the non-transgenic controls was below the limit of detection. GraphPad Prism software was used to compare sorbitol accumulation in treated lenses to untreated controls by column analysis of duplicates using the unpaired, one-tailed student’s t-test. The * symbol denotes a statistically significant difference (<i>P</i><0.05) from untreated TG lenses.</p

The effect of curcumin and nanocurcumin on blood glucose (Panel A) and insulin levels (Panel B) in STZ-treated rats.

<p>Data are average of all the animals in a given group. Different superscripts in Panel B indicate data are significantly different from other groups.</p

The effect of curcumin and nanocurcumin on crystallin distribution in the soluble protein fraction of rat lens.

<p>Soluble protein was loaded on TSK-G3000 SWXL gel filtration HPLC column and protein peaks were detected at 280 nm. Peaks representing α-, β- and γ- crystallins are indicated at their respective positions.</p

Immunodetection of advanced glycation endproducts, CML (Panel A) and AGE-BSA (Panel B), in the soluble protein fraction of rat lens.

<p>The data in bar diagram are mean ± SD (n=3) and the blot is a representative of three independent analyses. <i>Lane 1</i>: control; lane <i>2</i>: diabetic (D); lane <i>3</i>: D + curcumin; lane <i>4</i>: D + nanocurcumin and lane <i>5</i>: D + blank particles. Different superscripts indicate data are significantly different from other groups.</p

The effect of curcumin and nanocurcumin on STZ-induced cataract in rats.

<p><i>Top </i><i>panel</i>: Representative photographs of lens from each group at the end of 10 weeks. <i>Bottom </i><i>panel</i>: Quantitative representation of cataract progression in each group with time. Stage of cataract in each group was averaged at a given time and the average stage of cataract along with standard error was plotted as a function of time.</p

Particle characteristics measured by Malvern zeta sizer fresh (A) after centrifugation (B) and after freeze drying (C).

<p>The numbers in parenthesis are average particle size in nm.</p

Correlations of vitamin-B12 and homocysteine with demographic and other biochemical parameters.

<p>Correlations (r-value) were assessed by Spearman rank correlation. While positive r-value indicates direct correlation, negative r-value indicates inverse relationship between the variables.</p