Specifically cleaves olefinic bonds in alpha,beta-unsaturated carbonyls and may be involved in detoxification or modification of these reactive compounds (Probable). May be involved in the biosynthesis or metabolism of oxylipin signaling molecules (PubMed:10872231) (Probable). In vitro, reduces 9R,13R-12-oxophytodienoic acid (9R,13R-OPDA) to 9R,13R-OPC-8:0, but only poorly 9S,13S-OPDA, the natural precursor of jasmonic acid (JA) (PubMed:10872231). Can detoxify the explosive 2,4,6-trinitrotoluene (TNT) in vitro and in vivo by catalyzing its nitroreduction to form hydroxylamino-dinitrotoluene (HADNT) (PubMed:19605548). Functions in an alternative and OPR3-independent pathway for JA biosynthesis (PubMed:29291349). Catalyzes the NADPH-dependent reduction of 4,5-didehydrojasmonates to jasmonates (PubMed:29291349). NADP(+) + OPC-8 = (10Z,15Z)-12-oxophytodienoate + H(+) + NADPH a 4,5-didehydrojasmonate + H(+) + NADPH = a jasmonate + NADP(+) kcat is 0.819 sec(-1) with 4,5-didehydrojasmonate as substrate. Lipid metabolism; oxylipin biosynthesis. Expressed at highest levels in roots and cotyledons, and at lower levels in leaves, shoots and flowers (sepals, petals, maturing siliques and developing pollen). Expressed during late steps of pollen development. By wounding, locally and systemically, by cold and heat stresses, and by UV-C. Seems to not be influenced by UV-A and UV-B. Induced by the chloroacetanilide herbicides acetochlor and metolachlor, and the explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Belongs to the NADH:flavin oxidoreductase/NADH oxidase family.