8-Iso-prostaglandin E2 (8-iso-PGE2) is one of the several isoprostanes produced from arachidonic acid during lipid peroxidation. Isoprostanes are a group of stable prostaglandin-like compounds produced by free radical-catalyzed, non-enzymatic peroxidation of arachidonic acid, which are used as markers of oxidative stress in several human diseases, including diabetes. In addition, 8-iso-prostaglandin E2 is biologically active compound involved in contraction of vascular smooth muscle and activation of platelets. 8-iso-PGE2 has been demonstrated to be the most potent vasoconstrictor isoprostane on the human umbilical artery and vein, activating the TPα isoform, which is present in the human umbilical vein and platelets. 8-iso-prostaglandin E2 stimulates human umbilical vein endothelial cells to specifically bind monocytes and this effect is mediated by cyclic AMP/protein kinase A- and p38 MAP kinase-dependent pathways and is independent of the classical inflammatory NFkappaB pathway.

15-Epi-prostaglandin E2 (15R-Prostaglandin E2) is the C-15 epimer of the naturally occurring 15S-Prostaglandin E2 (15S-PGE2) isomer. 15-Epi-prostaglandin E2 is the most physiologically abundant eicosanoid, which is produced predominantly from arachidonic acid by COX and PGES, and exists at some level in nearly all cell types. Prostaglandin E2 acts on four different receptors termed EP1 through EP4 yielding an astounding array of biological effects, but this compound shows much lower potency in most biological assays; however acid catalyzed epimerization can convert this compound to the active form - 15S-Prostaglandin E2. In the in vivo assay, 15R-PGE2 showed anti-inflammatory activity, as well as in vitro inhibition of elastase release from polymorphonuclear cells. In the from polymorphonuclear cells degranulation assay, 15R-PGE2, was the most active compound in the inhibition of myeloperoxidase release.