Biological Activities of Licorice F1 Lines and Content Analysis of Phytochemical Constituents

The biological activities of licorice F1 (Glycyrrhiza glabra ${\times}$ G. uralensis) lines (G) were investigated, revealing strong radical scavenging activity targeting 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (${\cdot}OH$) radicals. At a concentration of $100{\mu}g/mL$, most of the licorice F1 lines scavenged DPPH and ${\cdot}OH$ by more than 80%. Gs-1, -2, and -6 can be considered good scavengers of DPPH radical and G-7 have higher antioxidant activity against ${\cdot}OH$ radical. In addition, licorice F1 lines exerted effective anti-microbial activities against Escherichia coli (Gs-12, -17, and -18) and Staphylococcus aureus (Gs-3, -4, -5, -21, and -26). Moreover, Gs-2, - 20, -31, and -32 effectively inhibited the growth of Helicobacter pylori. Among licorice F1 lines, Gs-25 exhibited high anti-inflammatory effects on nitric oxide produced by lipopolysaccharide- and interferon-${\gamma}$-activated RAW 264.7 cells. Furthermore, Gs-1, -12, and -20 inhibited the growth of AGS human gastric adenocarcinoma cells by more than 60% at a concentration of $100{\mu}g/mL$ and Gs-5, -11, -19, and -32 showed inhibitory effects against rat lens aldose reductase ($IC_{50}$ values, 1.69, 6.07, 6.12, and $4.54{\mu}g/mL$, respectively). The total content of glycyrrhizin (1), glycyrrhetinic acid (2), glabridin (3), and isoliquiritigenin (4) in licorice F1 lines was high in Gs-11, -15, and -30. The present study therefore indicated that Gs-2, -26, -31, and -32 of licorice F1 possessing strong anti-oxidative, anti-microbial, anti-inflammatory, anti-cancer, and aldose reductase inhibitory effects may be used as a possible source material for natural health supplements in the future.