Protective Effect of Tetrahydroquinolines from the Edible Insect on LPS-Induced Vascular Inflammatory Responses.

The larva of (family Scarabaeidae) is an edible insect that is registered in the Korean Food Standards Codex as a food resource. The chemical study on the larvae of resulted in the isolation of three new tetrahydroquinolines, allomyrinaines A-C (-), one new dopamine derivative, allomyrinamide A (), and four known compounds (-). The structures were elucidated on the basis of 1D and 2D nuclear magnetic resonance (NMR) and MS spectroscopic data analysis. Allomyrinaines A-C (-) possessed three stereogenic centers at C-2, C-3, and C-4, whose relative configurations were determined by analyses of the coupling constants and the nuclear Overhauser enhancement spectroscopy (NOESY) data, as well as DP4+ calculation. The anti-inflammatory effects of compounds - were evaluated in human endothelial cells. Allomyrinaines A-C (-) could stabilize vascular barrier integrity on lipopolysaccharide (LPS)-induced vascular inflammation via inhibition of the nuclear factor-κB (NF-κB) pathway. The physiologically relevant concentration was confirmed by Q-TOF-MS-based quantitative analysis on allomyrinaines A-C in crude extract. This study suggests that allomyrinaines A-C (-) are bioactive constituents of to treat vascular inflammatory disorder.