An analysis on the suppression of NO and PGE2 by diphenylheptane A and its effect on glycerophospholipids of lipopolysaccharide-induced RAW264.7 cells with UPLC/ESI-QTOF-MS.

ABSTRACT

Diarylheptanoid A, 5-hydroxy-7-(4'-hydroxy-3'-methoxyphenyl)-1-phenyl-3-heptanone, is a naturally occurring phytochemical ingredient isolated from the rhizome of Alpinia officinarum. In order to confirm the anti-inflammatory activity of diphenylheptane A, we investigated its effects on lipopolysaccharide (LPS)-induced pro-inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-1ß (IL-1ß), and tumor necrosis factor α (TNF-α), as well as upstream genes, including the inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor κB (NF-κB) p65, p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase 1/2 (ERK1/2). Our results have proved the anti-inflammatory property of diphenylheptane A. Based on this finding, an LPS-induced RAW264.7 cell inflammatory model was introduced to evaluate the anti-inflammatory activity associated with glycerophospholipid (GPL) metabolism regulated by diphenylheptane A. We applied ultra-performance liquid chromatography/electrospray ionization-quadruple time of flight-mass spectrometry (UPLC/ESI-QTOF-MS) to the metabolic profiling of GPL synthesis in LPS-stimulated macrophages with the aim of identifying differentially synthesized GPL metabolites. Sixteen GPL metabolites, whose changes were restored to normal level after diphenylheptane A treatment, were further screened to be considered as useful biomarkers of inflammation. Overall, our study revealed for the first time that diphenylheptane A reestablished the production of 16 plasma membrane GPLs to basal level in LPS-activated RAW264.7 cells, suggesting the potential therapeutic property of phytochemical compounds against inflammatory diseases.