Characterization of Cellular Phenotypic Changes in Dendritic Cells as a Response to Medicinal Herb Extracts

Abstract

A broad range of stimuli including pathogen-derived products, adjuvants, inflammatory mediators and phytocompounds can influence the function of dendritic cells (DCs) and then impact upon the subsequent T cell responses. According an approach of pharmacognosy, we tested the fractionated plant extracts from Anoectochilus formosanus, Bidens pilosa, Crassocephalum rabens, Dioscorea batatas and Echinacea purpurea, which had some legend and claims on immuno-modulatory effects. Therefore, we try to understand the possible effect of herbal extracts on modulating the cellular function of human monocyte-derived DCs (MDDCs). The functional activities and their modification of MDDCs were investigated by evaluating the morphology, endocytosis activity and expression levels of CD markers in primary cultures of MDDCs. Anoectochilus formosanus and Crassocephalum rabens which can block or inhibit the differentiation process without exhibiting a significant effect on DC maturation; Bidens pilosa and Echinacea purpurea, which can confer a weak activating effect on differentiation and maturation of DC; and Dioscorea batatas which may confer a weak activating effect on differentiation of DC, but have no significant effect on maturation of DCs. Our results suggest that mixtures of specific medicinal herb extracts may contain certain immune modulators, and they can work synergistically towards multiple targets of the DC immune cell system. Based on these results, we suggest that the current DC-based functional assay system may have application for systematic evaluation and screening of key immuno-regulatory bioactivities of candidate medicinal phytocompounds or plant extracts.