Defining the window of opportunity of prenylated phenolics as natural antimicrobials – extraction, antimicrobial activity, and impact on the intestinal epithelium

Summary

Prenylated phenolics, found in Fabaceae plants such as licorice roots, are promising natural antimicrobials. This thesis aimed to valorize these compounds from licorice root waste-streams and explore their antimicrobial activity. This research showed that extracts from economically-relevant licorice species have strong antibacterial activity against spoilage and pathogenic bacteria. In-depth structure-activity relationship analysis showed that active compounds have two prenyl groups attached to the molecular backbone and an elongated shape. Additionally, the study examined the safety of these compounds by evaluating their impact on intestinal cells using advanced in vitro models. Using the most physiologically relevant in vitro model (namely apical-out small intestinal organoids), this thesis found that intestinal cells were generally resilient to these compounds. These findings suggest that prenylated phenolics, such as those from licorice root waste-streams, could potentially be valorized as natural antimicrobials in food preservation, in personal care products, or as lead structures for antibiotic development.