Deciphering the Anti-Listerial Activity and Phytochemical Composition of Licorice Root Extract Using LC-MS/MS in Combination with In Vitro and Computational Evaluations

Licorice roots are a rich source of bioactive compounds with multiple biological activities. The objective of this study was to evaluate the inhibitory effects of licorice root extract against a range of Listeria strains. In addition, the correlation of its phytochemical composition with antimicrobial properties was also investigated. Thus, the bacteriostatic and bactericidal effects of licorice root extract on seven Listeria monocytogenes strains, L. grayi, L. seeligeri, and L. ivanovii were determined. The minimum inhibitory and bactericidal concentrations ranged from 31.3 to 62.5 µg mL−1 and from 62.5 to 250 µg mL−1, respectively. The phytochemical composition of the extract was also analyzed using advanced LC-DAD- qTOF-MS; it is composed of fifty-one compounds belonging to different subgroups of flavonoids and triterpenoids. Subsequently, the anti-Listeria potency of the most abundant phytochemicals was determined using the AntiBac-Pred web tool. In silico calculation showed that liquiritin-apioside and licorice glycoside C1/C2 were strong growth inhibitors of L. monocytogenes, as their potency was comparable to well-known antibiotic substances. Overall, the present study demonstrates the potent antimicrobial effect of licorice root extract and reveals its active phytochemicals.