Polypodium glycyrrhiza Polypodium glycyrrhiza Polypodium glycyrrhiza, commonly known as licorice fern, many-footed fern, and sweet root, is a summer deciduous fern native to western North America, primarily in a narrow strip in southern Alaska, southwestern Yukon Territory, western British Columbia, Washington, Oregon, and California, though two highly disjunct populations are known from Idaho and Arizona. It thrives in a humid climate, prevailing in areas with cool and moist summers and warm and wet winters. "P. glycyrrhiza" can often be found growing on the trunks and branches of winter deciduous trees, particularly bigleaf maple, but is also often found on rocks, logs, and
Glycyrrhizin glycyrrhizin is first hydrolysed to 18β-glycyrrhetinic acid (enoxolone) by intestinal bacteria. After complete absorption from the gut, 18β-glycyrrhetinic acid is metabolised to 3β-monoglucuronyl-18β-glycyrrhetinic acid in the liver. This metabolite then circulates in the bloodstream. Consequently, its oral bioavailability is poor. The main part is eliminated by bile and only a minor part (0.31–0.67%) by urine. After oral ingestion of 600 mg of glycyrrhizin the metabolite appeared in urine after 1.5 to 14 hours. Maximal concentrations (0.49 to 2.69 mg/l) were achieved after 1.5 to 39 hours and metabolite can be detected in the urine after 2 to 4 days. Glycyrrhizin