11,15-Dihydroxy-16-kauren-19-oic acid

11,12-Epoxyeicosatrienoic acid induces vasodilator response in the rat perfused mesenteric vasculature.[Pubmed:28332266]

Auton Autacoid Pharmacol. 2017 Jan;37(1):3-12.

Epoxyeicosatrienoic acids (EETs) are endogenous ligands that undergo hydrolysis by soluble epoxide hydrolase (sEH). The responses of 11, 12-EET in comparison with other vasodilator agonists including carbachol and sodium nitroprusside (SNP) were investigated. The effect of 1-cyclohexyl-3-dodecyl urea (CDU), a sEH, was tested on the vasodilator effect induced by 11, 12-EET in the perfused mesenteric beds isolated from normo-glycaemic and type-1 STZ-diabetic rats. In the perfused mesenteric beds of control and diabetic animals, 11, 12-EET produced vasodilation in a dose-dependent manner. The vasodilator response induced by 11, 12-EET was significantly decreased in tissues obtained from diabetic animals, but this was significantly corrected through inhibition of sEH. The effects of nitric oxide synthase inhibitor, cyclo-oxygenase inhibitor, specific potassium channel inhibitors, soluble guanylyl cyclase inhibitor and transient receptor potential channel V4 inhibitor, on vasodilator response to 11, 12-EET were investigated. In tissues isolated from control animals, vasodilator responses to 11, 12-EET were not inhibited by acute incubation with l-NAME, l-NAME with indomethacin, glibenclamide, iberiotoxin, charybdotoxin, apamin or ODQ. Incubation with the transient receptor potential channel V4 inhibitor ruthenium red caused significantly reduced vasodilator responses induced by 11, 12-EET. In conclusion, results from this study indicate that 11, 12-EET has a vasodilator effect in the perfused mesenteric bed, partly through activation of vanilloid receptor. A strategy to elevate the levels of EETs may have a significant impact in correcting microvascular abnormality associated with diabetes.

Coenzyme A thioester formation of 11- and 15-oxo-eicosatetraenoic acid.[Pubmed:28238887]

Prostaglandins Other Lipid Mediat. 2017 May;130:1-7.

Release of arachidonic acid (AA) by cytoplasmic phospholipase A2 (cPLA2), followed by metabolism through cyclooxygenase-2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH), results in the formation of the eicosanoids 11-oxo- and 15-oxo-eicosatetraenoic acid (oxo-ETE). Both 11-oxo- and 15-oxo-ETE have been identified in human biospecimens but their function and further metabolism is poorly described. The oxo-ETEs contain an alpha,beta-unsaturated ketone and a free carboxyclic acid, and thus may form Michael adducts with a nucleophile or a thioester with the free thiol of Coenzyme A (CoA). To examine the potential for eicosanoid-CoA formation, which has not previously been a metabolic route examined for this class of lipids, we applied a semi-targeted neutral loss scanning approach following arachidonic acid treatment in cell culture and detected inducible long-chain acyl-CoAs including a predominant AA-CoA peak. Interestingly, a series of AA-inducible acyl-CoAs at lower abundance but higher mass, likely corresponding to eicosanoid metabolites, was detected. Using a targeted LC-MS/MS approach we detected the formation of CoA thioesters of both 11-oxo- and 15-oxo-ETE and monitored the kinetics of their formation. Subsequently, we demonstrated that these acyl-CoA species undergo up to four double bond reductions. We confirmed the generation of 15-oxo-ETE-CoA in human platelets via LC-high resolution MS. Acyl-CoA thioesters of eicosanoids may provide a route to generate reducing equivalents, substrates for fatty acid oxidation, and substrates for acyl-transferases through cPLA2-dependent eicosanoid metabolism outside of the signaling contexts traditionally ascribed to eicosanoid metabolites.

Understanding the role of 3-O-Acetyl-11-keto-beta-boswellic acid in conditions of oxidative-stress mediated hepatic dysfunction during benzo(a)pyrene induced toxicity.[Pubmed:28363852]

Food Chem Toxicol. 2017 Nov;109(Pt 2):871-878.

The present study was planned to see whether 3-O-Acetyl-11- keto-beta-boswellic acid has any protective effects against benzo(a)pyrene (BaP) induced toxicity or not. In vitro studies show concentration dependent linear association of radical scavenging activity of AK which is comparable to ascorbic acid taken as reference compound. For in vivo studies, the animals were divided randomly into five groups which included a) normal control, b) vehicle treated (olive oil), c) BaP treated, d) AK treated and e) AK + BaP (combined treated). BaP was administered at a dose of 50mg/kg in olive oil twice a week orally for 4 weeks and AK (50mg/kg) was given in olive oil thrice a week for 4 weeks before and after BaP exposure. BaP treated animals showed a significant increase (p < 0.001) in lipid peroxidation (LPO) and protein carbonyl contents (PCC) in hepatic tissue. Further, a significant increase (p < 0.001) in the liver marker enzymes as well as citrulline and nitric oxide levels in the hepatic tissue was also observed. Interestingly, AK when supplemented to BaP treated animals ameliorated the above said biochemical indices appreciately. The histopathological observations also showed appreciable improvement when BaP treated animals were supplemented with AK, thus emphasing the protective potential of AK.

An open sandwich immunoassay for detection of 13(R,S)-hydroxy-9(E),11(E)-octadecadienoic acid.[Pubmed:28144646]

Analyst. 2017 Feb 27;142(5):787-793.

Lipid peroxidation is involved in many disorders and diseases such as cardiovascular disease, cancers, neurodegenerative diseases, and even aging. Lipid peroxidation products existing in blood or bodily fluids are very important biomarkers for the diagnosis of such diseases. In particular, 13(R,S)-hydroxy-9(E),11(E)-octadecadienoic acid (13-(E,E)-HODE) is an oxidiation product of linoleic acid, which is an important biomarker for many diseases such as diabetes and Alzheimer's disease. In this study, we successfully displayed the antigen-binding fragment of an antibody produced by hybridoma 1213-1 on the M13 phage and performed analysis of the antibody variable region genes. The blast results suggested that it is a novel antibody. We also developed a phage-antibody-based competitive ELISA and a novel Open Sandwich ELISA (OS ELISA) for the detection of 13-(E,E)-HODE. The OS ELISA showed a limit of detection (LOD) of 15.6 nM of 13-(E,E)-HODE and low cross-reactivity with other HODE such as 9-(E,E)-HODE. Another format of the open sandwich ELISA with purified maltose binding protein-fused VL and VH-phage showed a lower LOD of 2.2 nM of 13-(E,E)-HODE, which may be sensitive enough to detect the concentration of 13-(E,E)-HODE in patients' blood samples. This is the first OS ELISA for the detection of lipids, and we believe it also represents the first molecular cloning of anti-HODE antibody genes.