Comparison of the inducible effects of licorice products with or without heat-processing and pre-treatment with honey on granulocyte colony-stimulating factor secretion in cultured enterocytes

Abstract

Ethnopharmacological relevanceLicorice (the roots and rhizomes of Glycyrrhiza uralensis Fisch.) is occasionally used as crude drug following processing including roasting or honey-roasting (soaking with honey before roasting) in traditional Japanese Kampo medicine and traditional Chinese medicine (TCM). Aim of the studyWe investigated the differences in the inducible effect of processed licorice products on granulocyte colony-stimulating factor (G-CSF) secretion in cultured intestinal epithelial cells and elucidated the active ingredients in both unprocessed and processed licorice products. Materials and methodsWe prepared heat-processed licorice with or without pretreatment with honey, and fractionated the extracts by Sephadex G-100. Enterocyte-like differentiated MCE301 cells were incubated in media comprising a hot water extract of licorice products for 24h, and the concentrations of G-CSF in the media were measured using enzyme-linked immunosorbent assay (ELISA). ResultsLicorice extract induced G-CSF secretion in MCE301 cells, and the active ingredients of licorice were high molecular compounds. Although the roasted licorice extract exhibited the activity similar to that of the unprocessed licorice extract, honey-roasted licorice extracts exhibited a significantly higher inducible effect on G-CSF secretion in the cells than that of unprocessed or roasted licorice extracts without pretreatment with honey. This enhanced activity was dependent on the temperature and heating time. ConclusionsThe enhanced inducible effect of honey-roasted licorice on G-CSF secretion might be attributed to the combined effect of licorice-derived high molecular compounds and heated-honey-derived compounds. The results of this study can scientifically explain the objective of processing via honey-roasting in TCM theory.