Catalyzes the NADPH-dependent reduction of a wide variety of carbonyl-containing compounds to their corresponding alcohols. Displays enzymatic activity towards endogenous metabolites such as aromatic and aliphatic aldehydes, ketones, monosacharides, bile acids and xenobiotics substrates. Key enzyme in the polyol pathway, catalyzes reduction of glucose to sorbitol during hyperglycemia (PubMed:1936586). Reduces steroids and their derivatives and prostaglandins. Displays low enzymatic activity toward all-trans-retinal, 9-cis-retinal, and 13-cis-retinal (PubMed:12732097, PubMed:19010934, PubMed:8343525). Catalyzes the reduction of diverse phospholipid aldehydes such as 1-palmitoyl-2-(5-oxovaleroyl)-sn -glycero-3-phosphoethanolamin (POVPC) and related phospholipid aldehydes that are generated from the oxydation of phosphotidylcholine and phosphatdyleethanolamides (PubMed:17381426). Plays a role in detoxifying dietary and lipid-derived unsaturated carbonyls, such as crotonaldehyde, 4-hydroxynonenal, trans-2-hexenal, trans-2,4-hexadienal and their glutathione-conjugates carbonyls (GS-carbonyls) (PubMed:21329684). an alditol + NADP(+) = an aldose + H(+) + NADPH all-trans-retinol + NADP(+) = all-trans-retinal + H(+) + NADPH 9-cis-retinol + NADP(+) = 9-cis-retinal + H(+) + NADPH 13-cis-retinol + NADP(+) = 13-cis-retinal + H(+) + NADPH glycerol + NADP(+) = D-glyceraldehyde + H(+) + NADPH glycerol + NADP(+) = H(+) + L-glyceraldehyde + NADPH NADP(+) + prenol = 3-methyl-2-butenal + H(+) + NADPH (E)-hex-2-en-1-ol + NADP(+) = (E)-hex-2-enal + H(+) + NADPH (E,E)-2,4-hexadien-1-ol + NADP(+) = (E,E)-2,4-hexadienal + H(+) + NADPH a 4-hydroxynonen-1-ol + NADP(+) = a 4-hydroxynonenal + H(+) + NADPH NADP(+) + prostaglandin F2alpha = H(+) + NADPH + prostaglandin H2 allyl alcohol + NADP(+) = acrolein + H(+) + NADPH NADP(+) + pyridine 3-methanol = H(+) + NADPH + pyridine-3-carbaldehyde 1-hexadecanoyl-2-(5-oxopentanoyl)-sn-glycero-3-phosphocholine + H(+) + NADPH = 1-hexadecanoyl-2-(5-hydroxypentanoyl)-sn-glycero-3-phosphocholine + NADP(+) 1-hexadecanoyl-2-(7-oxoheptanoyl)-sn-glycero-3-phosphocholine + H(+) + NADPH = 1-hexadecanoyl-2-(7-hydroxyheptanoyl)-sn-glycero-3-phosphocholine + NADP(+) 1-hexadecanoyl-2-(9-oxononanoyl)-sn-glycero-3-phosphocholine + H(+) + NADPH = 1-hexadecanoyl-2-(9-hydroxynonanoyl)-sn-glycero-3-phosphocholine + NADP(+) 1-hexadecanoyl-2-(5-oxopentanoyl)-sn-glycero-3-phosphoethanolamine + H(+) + NADPH = 1-hexadecanoyl-2-(5-hydroxypentanoyl)-sn-glycero-3-phosphoethanolamine + NADP(+) Cys-299 may regulate the kinetic and inhibition properties of the enzyme, but does not participate in catalysis (PubMed:8343525). Tolrestat inhibits retinal reduction (PubMed:12732097). kcat is 15 min(-1) for all-trans-retinal as substrate. kcat is 30 min(-1) for 9-cis-retinal as substrate. kcat is 94 min(-1) for 13-cis-retinal as substrate (PubMed:12732097). kcat is 11 min(-1) for acrolein as substrate. kcat is 31 min(-1) for 3-methyl-2-butenal as substrate. kcat is 41 min(-1) for (E)-2-hexenal as substrate. kcat is 43 min(-1) for (E,E)-2,4-hexadienal as substrate. kcat is 50 min(-1) for 4-hydroxynonenal as substrate. kcat is 16 min(-1) for GS-(E)-4-hexenal as substrate. kcat is 16 min(-1) for GS-hexenal as substrate. kcat is 13 min(-1) for GS-4-hydroxynonenal as substrate (PubMed:21329684). kcat is 31 min(-1) for D,L-glyceraldehyde (PubMed:21329680). Monomer. Highly expressed in embryonic epithelial cells (EUE) in response to osmotic stress. Belongs to the aldo/keto reductase family.