Chemical profiling of Egregia menziesii and anti-inflammatory potential in LPS-activated RAW 264.7 macrophages

Abstract

Egregia menziesii (E. menziesii) is recognized for its anticancer and hypoglycemic properties. Chemically, it contains compounds with potential anti-inflammatory activity. Within the immune system, macrophages play an essential role in containing and eradicating pathogens through phenotypic polarization. The ethanol and water (1:1 v/v) (EtOH: H2O), extract of E. menziesii was obtained and fractionated. The chemical profiles of the extracts featured signals linked to sulfated polysaccharides and mannitol. Cell viability was evaluated at various concentrations with MTT assay and confirmed the safety (≥ 90% of cell viability) of the extract and fractions for cellular experimentation. The scratching assay demonstrates the impact of the EtOH: H2O and aqueous fraction (FR_Aq) treatments, evidenced by a reduction of up to 40% and 10% in the free scratched area at 24 and 48 h, respectively. The phagocytosis assay, determined by the neutral red assay, shows that EtOH: H2O treatment decreases the process to levels below those of the LPS- control group (< 120%). Proton signals of the extract and fractions were correlated with the scratched area value via Multivariate Data Analysis (MVDA) of the 1H-NMR data of the extract and fractions and the results from scratching assay showed the signals at δ 0.6–3 ppm as the main contributors to the activity. Additionally, interleukin-1β (IL-1β) and interleukin-6 (IL-6) expression levels were determined by RT-qPCR and ELISA, showing that the EtOH: H2O extract could influence their mRNA expression (Fold change < 0.5 and < 3, respectively) and protein levels. E. menziesii safely regulates macrophage behavior, IL-1β and IL-6 release and promotes scratch area reduction. The immunomodulatory effect could be linked to the presence of sulfate polysaccharides and mannitol.