Quantitative analysis and anti-inflammatory effects of Gleditsia sinensis thorns in RAW 264.7 macrophages and HaCaT keratinocytes

Abstract

Gleditsia sinensis thorns have traditionally been used to treat edema and carbuncles and drain abscesses. In the present study, a simultaneous analysis of four flavonoids [(+)-catechin, (-)-epicatechin, eriodictyol and quercetin] and two phenolic compounds (caffeic acid and ethyl gallate), obtained from a 70% ethanol extract of G. sinensis, was performed using high-performance liquid chromatography-photodiode array techniques. In addition, the inhibitory activities of the solvent fractions from a G. sinensis extract and its major constituents on the lipopolysaccharide-stimulated production of inflammatory mediators by macrophage R AW 264.7 cells and the tumor necrosis factor (TNF)-α and interferon (IFN)-γ (TI)-stimulated production of chemokines by HaCaT keratinocyte cells were investigated. The established analytical method showed high linearity, with a correlation coefficient of ≥0.9998. The limits of detection and quantification of the six compounds were 0.037-0.425 and 0.124-1.418 μg/ml, respectively. The ethyl acetate fraction inhibited nitric oxide and prostaglandin E2 production in RAW 264.7 cells and the production of thymus- and activation-regulated chemokine (TARC) in HaCaT cells more than did the other fractions. Furthermore, the six compounds reduced the production of TARC, macrophage-derived chemokine and regulated on activation normal T-cell expressed and secreted in TI-stimulated HaCaT cells; in particular, ethyl gallate and quercetin exhibited a significant dose-dependent inhibition. Further elucidation of the signaling pathways involved in the T-helper cell 2 chemokine inhibition by G. sinensis is necessary to facilitate the design of therapeutic agents for the in flammatory response.