Steric analysis of epoxyalcohol and trihydroxy derivatives of 9-hydroperoxy-linoleic acid from hematin and enzymatic synthesis.

We characterize the allylic epoxyalcohols and their trihydroxy hydrolysis products generated from 9R- and 9S-hydroperoxy-octadecenoic acid (HPODE) under non-enzymatic conditions, reaction with hematin and subsequent acid hydrolysis, and enzymatic conditions, incubation with Beta vulgaris containing a hydroperoxide isomerase and epoxide hydrolase. The products were resolved by HPLC and the regio and stereo-chemistry of the transformations were determined through a combination of (1)H NMR and GC-MS analysis of dimethoxypropane derivatives. Four trihydroxy isomers were identified upon mild acid hydrolysis of 9S,10S-trans-epoxy-11E-13S-hydroxyoctadecenoate: 9S,10R,13S, 9S,12R,13S, 9S,10S,13S and 9S,12S,13S-trihydroxy-octadecenoic acids, in the ratio 40:26:22:12. We also identified a prominent δ-ketol rearrangement product from the hydrolysis as mainly the 9-hydroxy-10E-13-oxo isomer. Short incubation (5 min) of 9R- and 9S-HPODE with B. vulgaris extract yielded the 9R- and 9S-hydroxy-10E-12R,13S-cis-epoxy products respectively. Longer incubation (60 min) gave one specific hydrolysis product via epoxide hydrolase, the 9R/S,12S,13S-trihydroxyoctadecenoate. These studies provide a practical approach for the isolation and characterization of allylic epoxy alcohol and trihydroxy products using a combination of HPLC, GC-MS and (1)H NMR.

Therapeutic potential of pegylated hemin for reactive oxygen species-related diseases via induction of heme oxygenase-1: results from a rat hepatic ischemia/reperfusion injury model.

Many diseases and pathological conditions, including ischemia/reperfusion (I/R) injury, are the consequence of the actions of reactive oxygen species (ROS). Controlling ROS generation or its level may thus hold promise as a standard therapeutic modality for ROS-related diseases. Here, we assessed heme oxygenase-1 (HO-1), which is a crucial antioxidative, antiapoptotic molecule against intracellular stresses, for its therapeutic potential via its inducer, hemin. To improve the solubility and in vivo pharmacokinetics of hemin for clinical applications, we developed a micellar hemin by conjugating it with poly(ethylene glycol) (PEG) (PEG-hemin). PEG-hemin showed higher solubility in water and significantly prolonged plasma half-life than free hemin, which resulted from its micellar nature with molecular mass of 126 kDa in aqueous media. In a rat I/R model, administration of PEG-hemin significantly elevated HO-1 expression and enzymatic activity. This induction of HO-1 led to significantly improved liver function, reduced apoptosis and thiobarbituric acid reactive substances of the liver, and decreased inflammatory cytokine production. PEG-hemin administration also markedly improved hepatic blood flow. These results suggest that PEG-hemin exerted a significant cytoprotective effect against I/R injury in rat liver by inducing HO-1 and thus seems to be a potential therapeutic for ROS-related diseases, including I/R injury.

A deuterohemin peptide extends lifespan and increases stress resistance in Caenorhabditis elegans.

This group has invented a novel deuterohemin containing peptide deuterohemin-AlaHisThrValGluLys (DhHP-6), which has various biological activities including protection of murine ischemia reperfusion injury, improving cell survival and preventing apoptosis. It was hypothesized that DhHP-6 is beneficial on the lifespan of Caenorhabditis elegans (C. elegans) and increases their resistance to heat and oxidative stress. C. elegans were treated with different concentrations of DhHP-6. Survival time and sensitivity to heat and paraquat were investigated. The data demonstrated that the mean survival time of C. elegans was significantly increased (p < 0.05) in the DhHP-6 treated group compared with the control group. The maximum lifespan was not affected by DhHP-6 treatment. DhHP-6 improved the survival rate of C. elegans in the acute heat stress (35 degrees C) and rescued the C. elegans' sensitivity to paraquat in acute oxidative stress. Superoxide dismutase 3 (SOD-3) protein was up-regulated by DhHP-6 treatment. It was further demonstrated that stress resistance genes such as hsp-16.1, hsp-16.49 and sir-2.1 were regulated by DhHP-6. DAF-16 and SIR-2.1 genes are essential for the beneficial effect of DhHP-6. Therefore, the investigation into the beneficial effect of DhHP-6 on C. elegans' lifespan has the potential to develop novel drugs to prevent ageing.