Although licorice is sometimes categorized as an adaptogen, it does not strictly meet the criteria of one: Its actions are specific rather than nonspecific, and its use in certain patients in high doses or over a prolonged period is not always benign, and in fact can pose serious consequences. However, because of licorice’s action on the adrenal glands, as well as on several conditions associated with hypothalamic-pituitary-adrenal dysfunction, it raises questions about the potential role of licorice in the prevention and treatment of hypothalamic-pituitary-adrenal dysfunction, and merits mention in this section. Peptic ulcer was one of the first conditions ever to be associated with an overactive stress response. Interestingly, licorice extract has demonstrated efficacy against Helicobacter pylori, including against clarithromy-cin-resistant strains.
Licorice studies have demonstrated its positive effects in treating viral infection, particularly those caused by herpes simplex virus, an active infection associated with increased stress. A recent study demonstrated that licorice root extract might even interfere with the latency of the herpes virus. Licorice components also have demonstrated the ability to modulate bone disorders in menopausal women because of affinity to estradiol-17 beta. This potential exists with or without the presence of vitamin D. (Licorice has also demonstrated estrogen-inhibitory effects.) Licorice hydrophobic flavo-noids have evidenced abdominal fat-lowering and hypoglycemic effects, possibly mediated via activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma).
Researchers examined the effects of licorice on memory and learning in a mouse model and found promise as a memory enhancer in both exteroceptive and interoceptive behavioral models of memory. The anti-inflammatory and antioxidant properties of licorice may be contributing favorably to the memory enhancement effect. Because scopolamine-induced amnesia was reversed by licorice, it is possible that the beneficial effect on learning and memory may result from facilitation of cholinergic transmission in the brain. In the treatment of postpartum anterior pituitary insufficiency, 10 patients demonstrated complete recovery with a decoction of licorice and ginseng.
Licorice inhibits corticoid dehydrogenases, prolonging the half-life of cortisol in the body. The British Herbal Compendium cites licorice as having adrenocorticotropic activity, indicating it for adrenocorticoid insufficiency. Thus, it is sometimes described by herbalists as an adrenal tonic, and cortisol sparing.
Licorice is contraindicated by the German Commission E in patients with cholestatic liver disorders, liver cirrhosis, hypertension, hypokalemia, severe kidney insufficiency, and pregnancy. It is also contraindicated in congestive heart failure and edema. Licorice safety issues are discussed further in Plant Profiles and discussions of pregnancy and herb safety.