Honey: a novel antioxidant

The global prevalence of chronic diseases such as diabetes mellitus, hypertension, atherosclerosis, cancer and Alzheimer's disease is on the rise. These diseases, which constitute the major causes of death globally, are associated with oxidative stress. Oxidative stress is defined as an "imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage". Individuals with chronic diseases are more susceptible to oxidative stress and damage because they have elevated levels of oxidants and/or reduced antioxidants. This, therefore, necessitates supplementation with antioxidants so as to delay, prevent or remove oxidative damage. Honey is a natural substance with many medicinal effects such as antibacterial, hepatoprotective, hypoglycemic, reproductive, antihypertensive and antioxidant effects. This review presents findings that indicate honey may ameliorate oxidative stress in the gastrointestinal tract (GIT), liver, pancreas, kidney, reproductive organs and plasma/serum. Besides, the review highlights data that demonstrate the synergistic antioxidant effect of honey and antidiabetic drugs in the pancreas, kidney and serum of diabetic rats. These data suggest that honey, administered alone or in combination with conventional therapy, might be a novel antioxidant in the management of chronic diseases commonly associated with oxidative stress. In view of the fact that the majority of these data emanate from animal studies, there is an urgent need to investigate this antioxidant effect of honey in human subjects with chronic or degenerative diseases.     

Fructose might contribute to the hypoglycemic effect of honey

Honey is a natural substance with many medicinal properties, including antibacterial, hepatoprotective, hypoglycemic, antioxidant and antihypertensive effects. It reduces hyperglycemia in diabetic rats and humans. However, the mechanism(s) of its hypoglycemic effect remain(s) unknown. Honey comprises many constituents, making it difficult to ascertain which component(s) contribute(s) to its hypoglycemic effect. Nevertheless, available evidence indicates that honey consists of predominantly fructose and glucose. The objective of this review is to summarize findings which indicate that fructose exerts a hypoglycemic effect. The data show that glucose and fructose exert a synergistic effect in the gastrointestinal tract and pancreas. This synergistic effect might enhance intestinal fructose absorption and/or stimulate insulin secretion. The results indicate that fructose enhances hepatic glucose uptake and glycogen synthesis and storage via activation of hepatic glucokinase and glycogen synthase, respectively. The data also demonstrate the beneficial effects of fructose on glycemic control, glucose- and appetite-regulating hormones, body weight, food intake, oxidation of carbohydrate and energy expenditure. In view of the similarities of these effects of fructose with those of honey, the evidence may support the role of fructose in honey in mediating the hypoglycemic effect of honey.     

Measured and calculated oxidation potentials of 1-X-12-Y-CB11Me10- anions

Cyclic voltammetry of 31 icosahedral carborane anions 1-X-12-Y-CB(11)Me(10)(-) at a Pt electrode in liquid SO(2) revealed a completely reversible one-electron oxidation even at low scan rates, except for the anions with Y = I, which are oxidized irreversibly up to a scan rate of 5.0 V/s, and the anion with X = COOH and Y = H, whose oxidation is irreversible at scan rates below 1.0 V/s. Relative reversible oxidation potentials agree well with RI-B3LYP/TZVPP,COSMO and significantly less well with RI-BP86/TZVPP,COSMO or RI-HF/TZVPP,COSMO calculated adiabatic electron detachment energies. Correlations with HOMO energies of the anions are nearly as good, even though the oxidized forms are subject to considerable Jahn-Teller distortion. Except for the anion with X = F and Y = Me, the oxidation potentials vary linearly with substituent σ(p) Hammett constants. The slopes (reaction constants) are ~0.31 and ~0.55 V for positions 1 and 12, respectively.     

Two (Z)‐N‐aryl‐3‐benzylideneisoindolin‐1‐ones

Two isoindolin‐1‐one derivatives, (Z)‐3‐benzyl­idene‐N‐phenyl­isoindolin‐1‐one, C₂₁H₁₅NO, (II), and (Z)‐3‐benzyl­idene‐N‐(4‐methoxy­phenyl)­isoindolin‐1‐one, C₂₂H₁₇NO₂, (III), were synthesized by the palladium‐catalysed heteroannulation. The mol­ecules of both compounds have a Z configuration. The interplanar angles between the five‐ and six‐membered rings of the isoindolinone moiety in (II) and (III) are 1.66 (11) and 2.26 (7)°, respectively. The phenyl rings at the N‐position in (II) and (III) are twisted out of the C₄N ring plane by 62.77 (11) and 67.10 (7)°, respectively. The substitutions at the N and C‐3 positions of the isoindolinone system have little influence on the molecular dimensions of the resulting compounds.     

Design problem solved by optimal control theory

In this paper we present an application to airfoil design of an optimum design method based on optimal control theory. The method used here transforms the design problem by way of a change of variable into an optimal control problem for a distributed system with Neumann boundary control. This results in a set of variational inequalities which is solved by adding a penalty term to the differential equation. This is in turn solved by a finite element method.     

Chemical reactivity as a tool to study carcinogenicity: reaction between estradiol and estrone 3,4-quinones ultimate carcinogens and guanine

In this article we study the chemical reactions between guanine and two ultimate carcinogens, the 3,4-quinone forms of the estrogens estrone (E1) and estradiol (E2). DNA was truncated to guanine, i.e. no deoxyribose moiety was included. Due to a complex reaction that involves proton transfer via water molecules we applied linear free energy relationships rather than computation of the transition state and activation energies. The minima corresponding to reactants and products were obtained on the B3LYP/6-31G(d) level. The effects of hydration were considered using the solvent reaction field of Tomasi and co-workers and the Langevin dipoles model of Florian and Warshel. No significant difference in reaction free energy for the reaction involving estrone and estradiol metabolites was found, despite the fact that for the two substances different carcinogenic activities were reported. Differences in carcinogenicity may be therefore attributed to other types of interactions or reactions such as (i) specific interactions of the carbonyl or hydroxyl group with DNA giving rise to different activation free energies for the reactions, (ii) the reaction of depurination and subsequent effects on the DNA, (iii) enzymatic or nonenzymatic oxidation steps (P450, aromatase, peroxidases, O2) and detoxification reactions (catechol-O-methyl transferase, S-transferase), or (iv) binding of the hormone to its nuclear receptors.     

Structure and swelling-release behaviour of poly(vinyl pyrrolidone) (PVP) and acrylic acid (AAc) copolymer hydrogels prepared by gamma irradiation

Copolymer network hydrogels were prepared by gamma irradiation of aqueous solutions of poly(vinyl pyrrolidone) (PVP) and acrylic acid monomer (AAc). The composition of the final hydrogels compared to the composition of the initial preparation solutions of hydrogels was determined. The chemical structure and nature of bonding was characterized by IR spectroscopy analysis, while the thermal durability of the prepared hydrogels was assessed by thermogravimetric analysis (TGA). The kinetic swelling in water and the pH-sensitivity of PVP/AAc copolymer hydrogels was studied. The drug release properties of PVP/AAc hydrogels taking methyl orange indicator as a drug model was investigated. The IR spectra indicate the formation of copolymer networks, whereas the TGA study showed that the PVP/AAc hydrogels possess higher thermal stability than pure PAAc and lower than PVP hydrogels. The kinetic swelling in water showed that all the hydrogels reached equilibrium after 24 h and that the degree of swelling increases with increasing the ratio of AAc in the initial feeding solutions. It was found that the degree of swelling of PVP/AAc hydrogels increases greatly within the pH range 4-7 depending on composition.     

A radioactive method for the localization and estimation of sitosterol on paper chromatograms

Summary A new method is described for the localization and estimation of sitosterols on a radiochromatogram. The method depends upon the addition of rado-iodine at the double bond of sitosterol on the developed paper chromatogram. It denotes the presence of - and -sitosterol in the two materials investigated with new R_f values in a new developing system.

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Zusammenfassung Eine radiochemische Methode wird beschrieben zur Lokalisierung und Bestimmung von Sitosterinen auf Papierchromatogrammen. Das Verfahren beruht auf der Addition von radioaktivem Jod an die Doppelbindung des Sitosterols auf dem entwickelten Chromatogramm. In zwei untersuchten Substanzen konnten mit einem neuen Lösungsmittelsystem - und -Sitosterin nachgewiesen werden.