Increased anti-inflammatory activity and enhanced phytochemical concentrations in superfine powders obtained by controlled differential sieving process from four medicinal plants

Anti-inflammatory effect of Rosa canina, Salix alba, Scrophularia nodosa and Hedera helix were studied in LPS-stimulated primary peripheral blood mononuclear cells (PBMCs) from mice (n=18) by comparing homogeneous powders of small microparticles (50-100 μm, 100-180 μm and 180-315 μm) obtained from plants via a controlled differential sieving process (CDSp) versus total plant materials obtained via hydroethanolic (HE) extraction. Further, phytochemical composition of the fine powders and HE extracts was determined by LC-PDA-ESI/MS analyses. Results showed that a one-hour pretreatment of PBMCs with fine powders, particularly those with superfine particle sizes (i.e. 50-100 μm and 100-180 μm), significantly inhibited TNFα, IL-1β, IL-6 and NO production in LPS-stimulated PBMCs, by at least ca. 20% more than HE extracts (all, p<0.05). For each of the plants studied, their superfine powdered fractions were more concentrated in phenolic contents than their HE extracts. Overall, our results further confirm CDSp, as an environmentally friendly method, for improving the concentration of bioactive compounds as well as their biological activities.