A Compound from Vietnamese <i>Acacia pennata</i> (L.) Willd Inhibits LPS-Induced Inflammatory Signals on Macrophage

Abstract

Background: Acacia pennata (L.) Willd is used as an herbal medicine worldwide. However, the compounds isolated from this plant that have anti-inflammatory properties require further study. Objectives: This study isolated compounds with anti-inflammatory and reactive oxygen species (ROS) inhibitory properties from A. pennata (L.) Willd. Methods: The compounds from the stem of Vietnamese A. pennata (L.) Willd were extracted with ethanol. High-performance liquid chromatography (HPLC) was used to analyze the purity of the obtained substances. The substances were analyzed by 1H, 13C- nuclear magnetic resonance (NMR) spectroscopy, distortionless enhancement by polarization transfer (DEPT), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) spectra. The anti-inflammatory ability of compound 3 (ARg1) was assessed through the inhibition of pro-inflammatory cytokines using ELISA. The effectiveness of inhibiting ROS was measured by a specific fluorescent immunostaining technique. The activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme was determined using a luminometer, and the expression of phosphorylated p47phox was detected by protein gel electrophoresis in Raw 264.7 cells (mouse macrophage cell line). Results: The obtained results indicated that ARg1 was identified as ginsenoside Rg1. In this study, ARg1 (40 μg/mL, P < 0.001) inhibited lipopolysaccharide (LPS)-mediated secretion of tumor necrosis factor (TNF)-α, as well as interleukin (IL)-6 in macrophages. The phosphorylation of p47phox and NADPH oxidase was inhibited by ARg1 (40 μg/mL, P < 0.01) in LPS-stimulated cells. More importantly, ROS generated in LPS-stimulated cells was also destroyed by ARg1 (40 μg/mL). Conclusions: Collectively, the data showed that ARg1 found in the chemical composition of A. pennata (L.) Willd was similar to ginsenoside Rg1. This is the first result found in a species of the genus Acacia. In addition, these data showed that inflammatory cytokines and ROS generated by LPS in cells were inhibited by ARg1.