Octadecanal

Erythromycin was purchased from Tokyo Chemical Industry (Tokyo, Japan). NF-κB inhibitor, 5HPP-33, was purchased from Merck KGaA (Darmstadt, Germany). Acrolein, crotonaldehyde, dansyl hydrazine (DH), glyoxal, 2,4-decadienal (DDE), heptadecanal, hexadecanal, 2,4-nonadienal (NDE), octadecanal, 2-octenal, pentadecanal, tetradecanal and 2-undecenal were also purchased from Tokyo Chemical Industry (Tokyo, Japan). Acetaldehyde, p-Toluenesulfonic acid (p-TsOH) and the reactive carbonyl species (RCs), including propanal, pentanal, butanal, 2-hexenal, hexanal, 2-heptenal, heptanal, octanal, 2-nonenal, nonanal, decanal, undecanal, dodecanal and tridecanal, were obtained from Sigma-Aldrich (St. Louis, MO). 4-Hydroxy-2-hexenal (HHE), 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) were purchased from Cayman Chemical Company (Ann Arbor, MI). p-Benzyloxybenzaldehyde (p-BOBA) was purchased from Wako Pure Chemical Industries (Osaka, Japan). 8-Heptadecenal (8-HpDE), 8,11-heptadecadienal (8,11-HpDDE) and 8,11,14-heptadecatrienal (8,11,14-HpDTE) were synthesized using a previously described method.^{(10 (link),11 (link))} Secosterol-A and B were synthesized according to a procedure reported by Wentworth et al.^{(12 (link))} Stock solutions of the RCs and an internal standard (IS) (p-BOBA, 10 µM) were prepared separately in acetonitrile and stored at −20°C prior to use.

All chemicals purchased were of analytical grade (ACS grade) and were used as received without any additional purification. Crotonaldehyde, dansyl hydrazine (DH), 2,4-decadienal, glyoxal, heptadecanal, hexadecanal, 2,4-nonadienal, octadecanal, pentadecanal, and tetradecanal were purchased from Tokyo Chemical Industry (Tokyo, Japan). p-Toluenesulfonic acid (p-TsOH), butanal, decanal, dodecanal, 2-hexenal, hexanal, 2-heptenal, heptanal, octanal, 2-nonenal, nonanal, pentanal, propanal, tridecanal, and undecanal were obtained from Sigma-Aldrich (St. Louis, MO, USA). 4,5-Epoxy-2-decenal, 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal, and 4-oxo-2-nonenal were purchased from the Cayman Chemical Company (Ann Arbor, MI, USA). All other chemicals were obtained from Wako Pure Chemical Industries (Osaka, Japan). 8-Heptadecenal, 8,11-heptadecadienal, and 8,11,14-heptadecatrienal were synthesized following the published method [31 (link)].

Dansyl hydrazine (DH), glyoxal, crotonaldehyde, 2,4-nonadienal (NDE), 2,4-decadienal (DDE), heptadecanal, hexadecanal, irsogladine maleate, octadecanal, pentadecanal, rebamipide, teprenone, tetradecanal and troxipide were purchased from Tokyo Chemical Industry (Tokyo, Japan). The NF-κB inhibitor SM-7368 was obtained from Merck KGaA (Darmstadt, Germany). p-Toluenesulfonic acid (p-TsOH) and the RCs including propanal, pentanal, butanal, 2-hexenal, hexanal, 2-heptenal, heptanal, octanal, 2-nonenal, nonanal, decanal, undecanal, dodecanal and tridecanal were obtained from Sigma-Aldrich (St. Louis, MO, USA). 4-Hydroxy-2-hexenal (HHE), 4-hydroxy-2-nonenal (HNE), 4-oxo-2-nonenal (ONE) and 4,5-epoxy-2-decenal (EDE) were purchased from the Cayman Chemical Company (Ann Arbor, MI, USA). Ecabet sodium hydrate, p-benzyloxybenzaldehyde (p-BOBA), sofalcone and other chemicals used in the current study were purchased from Wako Pure Chemical Industries (Osaka, Japan). 8-Heptadecenal (8-HpDE), 8,11-heptadecadienal (8,11-HpDDE) and 8,11,14-heptadecatrienal (8,11,14-HpDTE) were synthesized by a method previously described [26 (link), 27 (link)]. Secosterol-A and -B were synthesized according to the procedure reported by Wentworth et al. [28 (link)]. Stock solutions of the RCs and an internal standard (IS) (p-BOBA, 10 mM) were prepared separately in acetonitrile and stored at −20°C prior to use.